Bone marrow transplantation for CML

10

Bone marrow transplantation for C M L STEPHEN MACKINNON J O H N M. G O L D M A N

Chemotherapy is effective in controlling symptoms and reversing leukocytosis in patients with Philadelphia (Ph) positive chronic myeloid leukaemia (CML) in chronic phase but does not usually lead to re-establishment in the marrow of Ph negative or normal haemopoiesis which would be tantamount to .complete remission. Furthermore, conventional chemotherapy is not associated with a significant increase in survival, the median period from diagnosis to death being 31 months. Other approaches such as aggressive chemotherapy or splenectomy have not altered the course of the disease. The onset of the blastic phase, sometimes preceded by a recognizable accelerated phase, marks the terminal stage of the disease which is usually refractory to chemotherapy. This failure to achieve remission by conventional treatment has in the last 10 years encouraged study of the curative potential of high dose chemoradiotherapy followed by bone marrow transplantation (BMT). SYNGENEIC BONE MARROW TRANSPLANTATION The treatment of CML with cytotoxic agents is limited in part by their toxicity to host marrow. The availability of normal marrow for transplantation permits the administration of far higher and potentially curative antitumour doses of chemotherapy or chemoradiotherapy with salvage of the host haemopoietic and immunological functions by the donor cells. In theory, therefore, ablation of the host marrow and transfusion of marrow from an identical twin could provide an opportunity for cure. Syngeneic BMT was initially performed with a variety of chemoradiotherapy regimens on eight patients who had entered blast crisis in the late 1970s (Fefer et al, 1982). The results of BMT in this late phase of the disease were generally poor; three patients died of leukaemia and four died of treatment complications. The eighth patient relapsed 10 months after BMT but was still in remission 4.5 years after a second syngeneic transplant (Fefer et al, 1984). Because the transformed cells are extremely resistant to vigorous treatment, various investigators speculated that the best chance of cure was to offer patients with identical twins BMT while they were still in chronic phase. This led to studies of the value of syngeneic BMT in chronic phase (Fefer et al, Baillibre's Clinical Haematolog)~Vol. 1, No. 4, December 1987

1055

1056

S. MACKINNON AND J. M. GOLDMAN Table 1. Estimated probability of relapse after transplantation for CML in chronic phase in different clinical situations. Type of transplant

Estimated actuarial relapse at 3 years (%)

Syngeneic

25

Allogeneic, without T-cell depletion: (i) all (ii) without GVHD (iii) with GVHD

10 15 5

Allogeneic, with T-cell depletion

50

1979; 1982; 1986; Goldman et al, 1981; Jones et al, 1987). In the absence of graft-versus-host disease (GVHD) the morbidity and mortality associated with the procedure were low but occasional patients died of idiopathic or cytomegalovirus-associated pneumonitis post-transplant. The probability of relapse after syngeneic transplantation seems rather variable. Based on experience obtained in Seattle (Fefer et al, 1979; 1982; 1986) and the Hammersmith Hospital in London (Jones et al, 1987) the risk of relapse is no greater than that following HLA-identical sibling transplants for comparable patients. Others have found that the risk is higher (Table 1) (International Bone Marrow Transplant Registry, personal communication 1987). It could be relevant that most patients in Seattle and at the Hammersmith Hospital received high dose busulphan in addition to the cyclophosphamide and total body irradiation (TBI) as conditioning pre-transplant. These results suggest that patients with CML in chronic phase who have identical twin donors should be offered BMT at the earliest opportunity. TIMING OF TRANSPLANTATION The results of transplantation in CML show that BMT performed in chronic phase offers the best chance of long-term survival and cure (Speck et al, 1984; Thomas et al, 1986). However the optimal timing of BMT in chronic phase remains controversial. Patients receiving conventional treatment in stable chronic phase have a 5-10% chance of death within the first 12 months of diagnosis, but this increases to an annual rate of 20-25% in the third and subsequent years (Sokal et al, 1985). It is clear that BMT within the first 2 years ofdiagnosis carries a higher risk ofmortality than the disease itselfand it might be reasonable to propose a 2-year delay before undertaking BMT. However, as entry into blast transformation is unpredictable, a proportion of patients will still die within the 2 years. Recently, several groups have attempted to identify 'good risk' populations (Cervantes et al, 1982; Tura et al, 1981; M R C Working Party, 1983; Sokal et

BONE MARROX,V T R A N S P L A N T A T I O N

1057

al, 1985). Sokal and colleagues (1985) published the results of a cooperative study in which they evaluated the prognostic significance of various factors prior to treatment and attempted to divide the whole population of Ph positive 'non-blastic' patients under the age of 45 into subgroups with different survival patterns. The most important prognostic indicators in patients aged less than 45 years were patient sex, spleen size, percentage blasts in blood a6d marrow, platelet count and serum lactate dehydrogenase. Another approach to predicting the duration of the chronic phase is to examine the course of the disease after initial treatment. The rate of doubling of the leukocyte count after the first course of treatment and the amount of chemotherapy administered in the first year both carry predictive value (Wareham et al, 1982). For patients transplanted in the chronic phase of CML the transplantrelated mortality within the first 2 years after the procedure is approximately 30%. This means that if one could accurately define a cohort of patients likely to live 4 or 5 years without transplantation, it might be reasonable for these patients to delay transplantation for 2 or 3 years. Segel et al (1986) have constructed a computer program that attempts to balance in individual patients the risk of transformation against the risk of transplant-related "mortality and to predict the optimal time after diagnosis for the transplant to be performed. Such a program necessarily makes use of a number of assumptions whose validity cannot be tested. Recent data reported from Seattle cast doubt on the value of the approach described above (Thomas et al, 1986). The Seattle team found an inverse correlation between the interval from diagnosis to transplant and the probability of survival after BMT in chronic phase. This observation could not be explained on the basis of an increased probability of relapse posttransplant in patients with more 'evolved' chronic phase disease since relapse was not a major cause of death in these patients. It is possible that prolonged treatment with cytotoxic drugs, especially busulphan, might for some reason reduce the probability of survival post-transplant. However a recent analysis performed by the International Bone Marrow Transplant Registry (IBMTR) has failed to confirm this relationship between disease duration and survival (Goldman et al, 1988). In practice the decision to undergo transplantation and its precise timing is frequently made by the patient, sometimes in conflict with advice given by the clinician. CONDITIONING REGIMENS It has been conventional until recently to believe that for a patient with CML fortunate enough to have an identical twin donor the sole objective of administering chemoradiotherapy before transplant is to eradicate all leukaemic cells, while for patients receiving allogeneic marrow from an HLA identical sibling the chemoradiotherapy has two objectives: firstly, to eradicate the leukaemia, and secondly, to induce a degree of immune suppression that will permit the donor haemopoietic stem cells to engraft. New evidence challenges these beliefs. CML may still be cured even when

1058

S. MACKINNON AND J. M. GOLDMAN

occasional Ph positive cells are identified after transplant. Moreover the presence o f T lymphocytes in the donor marrow inoculum may be important both to facilitate engraftment and to effect cure. A host-versus-graft (HVG) reaction normally prevents engraftment of allogeneic bone marrow unless the recipient is subjected to immunosuppressive treatment before transplantation. With standard conditioning protocols and unmanipulated donor marrow rejection of HLA identical grafts is rare. If however the donor marrow is depleted ofT lymphocytes graft failure occurs in approximately 15% of transplants (Hale et al, 1988). The risk of graft failure can be reduced by increasing the total dose of TBI before BMT (Patterson et al, 1986; Burnett et al, 1988). A similar approach used successfully by our own group when using matched unrelated donors has been to increase the pretransplant immunosuppression by administering in vivo monoclonal antibodies to the recipient in conjunction with additional total lymphoid irradiation (TLI) (Arthur et al, 1987). The general strategy in attempting curative treatment of CML is to increase the doses of the appropriate chemoradiotherapy to the limits of normal tissue tolerance. Since in many instances the critical tissue is the bone marrow the treatment can in theory eliminate the leukaemia and rescue the patient with donor marrow. The initial attempts to treat patients with CML by allogeneic BMT were directed mainly at patients whose disease had already progressed beyond chronic phase (Doney et al, 1978; 1981). The standard conditioning involved the use ofcyclophosphamide (usually 60 mg/kg for 2 days) followed by TBI, usually 10 Gy. The results were mostly unsatisfactory with deaths from both recurrent leukaemia and transplant-related complications. When attention was turned to transplantation for patients still in chronic phase, similar protocols were adopted (Curtis & Messner, 1982; Clift et al, 1982; Goldman et al, 1982; Champlin et al, 1982; Speck et al, 1982). Thus for example the Seattle group has in general used cyclophosphamide and TBI, either single dose or fractionated (Clift et al, 1982; Thomas et al, 1986), and we at the Hammersmith Hospital have used cyclophosphamide followed by fractionated TBI (2 Gy fractions twice daily for 5 or 6 doses) (Goldman et al, 1982; 1986). At the Sloan Kettering Cancer Center in New York the standard protocol comprises cyclophosphamide with hyperfractionated TBI (120 qGy three times daily to a total dose of 1320 or 1440 cGy) (Cunningham et al, 1987). There is no clear evidence that radiotherapy forms an essential component of conditioning for patients undergoing allogeneic transplantation for CML. The Baltimore group has accumulated extensive experience with the use of busulphan (4 mg/kg daily for 4 days) followed by cyclophosphamide (50 mg/ kg daily for 4 days) (Santos et al, 1985; Tutschka et al, 1987). Although this combination may be unduly toxic for patients who have already received substantial doses of busulphan before transplantation, it is certainly an effective conditioning schedule for patients with acute ieukaemia and success with its use in CML casts doubt on the necessity for including TBI in the conditioning regimen. When donor marrow is depleted of T cells in vitro

BONE MARROW TRANSPLANTATION

1059

recurrence of leukaemia is a major risk for patients transplanted for CML (Apperley et al, 1986a; Goldman et al, 1988). A more effective antileukaemic protocol without increased systemic toxicity might reduce the risk of relapse. RESULTS O F BMT IN ACCELERATION AND BLAST CRISIS For some years the substantial morbidity and mortality associated with allogeneic BMT deterred its use in patients with CML in chronic phase. Thus the initial reports included mainly patients transplanted in the accelerated or blastic phase ofCM L (Doney et al, 1978; 1981). The most recent analysis from Seattle (Thomas et al, 1986) included 45 patients transplanted in accelerated phase and 42 in blast crisis. The actuarial probability of survival at 4 years in these patients was 15% and 14% respectively with the major causes of death being leukaemic relapse followed by pneumonitis, infection and GVHD. In results reported by the IBMTR (Speck et al, 1984) the probability of survival for patients in acceleration and blast crisis were 35% and 12% respectively. The difference in survival figures between the two study groups for patients transplanted in accelerated phase may reflect differences in definition. Thus a transplant undertaken for a patient in blast transformation is highly likely to fail but is not entirely hopeless and is very logical from the patient's point of view. RESULTS OF BMT IN CHRONIC PHASE One approach to the problems associated with transplantation in accelerated or blastic phase is to transplant during the stable chronic phase when the disease may be more sensitive to chemoradiotherapy and the patients may be in better clinical condition. This approach was encouraged by two principal observations: firstly, patients with acute myeloid leukaemia in remission who received an allogeneic transplant while in good clinical condition had fewer transplant-related deaths and a far lower incidence of post-transplant leukaemic relapse than did patients transplanted in relapse (Thomas et al, 1979); and secondly, BMT was known to eradicate Ph positive cells since the majority of patients with chronic phase disease receiving syngeneic transplants had sustained remissions (Fefer et al, 1979; 1982). A number of individual centres have now reported the results of transplant performed for CML in chronic phase using HLA identical sibling donors (Armitage et al, 91984; Goldman et al, 1986; Thomas et al, 1986; Lehn et al, 1986; Bacigalupo et al, 1986; McGlave et al, 1987a). The results of transplant in a relatively large series of patients have been reported at intervals by the IBMTR (Speck et al, 1984; Goldman et al, 1985; 1988); many of the patients in the individual reports are included in the IBMTR analyses9 In summary the probability of survival and relapse at 4 years are 55% and 19% respectively (Goldman et al, 1988)9 It should be noted however that this recent IBMTR analysis included some patients who had received T-cell depleted bone marrow grafts. If these

1060

S. MACKINNON AND J. M. GOLDMAN

are excluded from the analysis, the probability of relapse is 9% and the probability of leukaemia-free survival is 47%. These results agree relatively well with those of the large series reported independently from Seattle, in which the actuarial probabilities of survival and of relapse were 49% and 20% respectively (Thomas et al, 1986). It should be noted that the term 'relapse' for the purposes of these figures includes haematological or clinical relapses but e~cludes 'cytogenetie only' relapse (see below). DONOR AVAILABILITY To minimize the risk of serious GVHD, donors for BMT have hitherto been mainly syngeneic or genotypically HLA identical siblings. In Western Europe and North America, however, the average size of families means that only about one third of patients who would otherwise be eligible for BMT have HLA identical siblings (Black, 1982). For transplantation to make a greater impact on the management of CML the donor pool must be extended by using partially matched family donors or matched unrelated donors. Partially matched family donors Although the role of histocompatibility in transplantation is well defined in laboratory animals (Simonsen, 1962; Storb et al, 1977), there were until recently few clinical data available to assess the extent of HLA incompatibility permissible in human marrow transplantation. This made it difficult to predict the risks of graft failure or GVHD. Transplants performed using related donors mismatched for two or more HLA A, B or DR loci are associated with poorer results (Powles et al, 1983; Beatty et al, 1985). If the degee of mismatch involves only a single HLA A, B or DR antigen, partially mismatched family donor transplants can apparently be as successful as those using fully matched siblings in 'good risk' patients (Beatty et al, !985). There has recently been some success with T-cell depleted bone marrow transplants from partially matched family donors for patients with leukaemia resulting in good engraftment and a reduced incidence of GVHD, though it is too early to assess the potential problem ofleukaemic relapse (Ash et al, 1987). Despite extending the donor pool in this way the majority of patients otherwise eligible for BMT still lack a suitable family member donor. For this reason the possibility ofextending the donor pool further using HLA matched unrelated volunteer donors has been investigated. Matched unrelated donors A number of registers holding data on individuals who have volunteered to donate bone marrow have now been established in various countries. In the United Kingdom the Anthony Nolan Research Centre has data on 130 000 volunteer donors typed for HLA A and B, of whom about 10 000 have also been DR typed. Other registries in Europe and North America have a total of approximately 100 000 HLA A and B typed donors. The relationship between the size of the donor panel and the chance of finding a donor for an individual

BONE MARROXV T R A N S P L A N T A T I O N

1061

patient has been examined by Bradley et al (1987). They took into account the known linkage disequilibrium between A, B and DR genes in the donor population and assumed that only 1 in 8 of A, B and DR matched donors would be unreactive in mixed lymphocyte reaction (MLR) with the prospective recipient. They calculated that with a donor pool size of 250000, approximately the size of all current registries combined, one or more donors matched fo? A, B and DR antigens and negative in M L R should be found for 59% ofpatients. However, ira transplant centre was prepared to make use of a donor mismatched for one class I antigen, then donors could be found for 82% of patients. The complexity ofthe HLA region makes it difficult to identify an unrelated donor for a given patient. In contrast to HLA identical sibling donor/recipient pairs, initial serological screening of unrelated donor/recipient pairs only ensures limited phenotypie identity rather than genotypic identity for the whole HLA region. Additional matching procedures using the MLR, complotyping (Awdeh et al, 1986) and DNA restriction fragment length polymorphisms (Bidwell and Jarrold, 1986) may be of value in predicting the outcome of transplantation although these have not yet been systematically studied. Only a small number of transplants have been performed for patients with CML using unrelated donors (Goldman et al, 1987; McGlave et al, 1987b). It is too early to draw firm conclusions but the use of such donors may yield results similar to those using HLA identical siblings. MANAGEMENT OF THE SPLEEN AT TRANSPLANTATION For the patient in chronic phase the spleen should be relatively small or the classification of chronic phase is suspect. Nonetheless there was at one time some suspicion that relapse might be more likely in patients who retained even normal-sized spleens than in those subjected to splenectomy before transplant (Gluckman et al, 1982). This led investigators at some centres to recommend routine splenectomy or additional splenic irradiation before transplant (Speck et al, 1982; Goldman et al, 1986; Lehn et al, 1986). No clearcut benefit from splenectomy or splenic irradiation has yet been demonstrated (Baughan et al, 1984; Gratwohl et al, 1985). The European Bone Marrow Transplant Group (EBMTG) is currently assessing the value ofadditional splenic irradiation in a randomized multi-centre study. Longer term follow-up is necessary to adequately define the role of splenectomy or splenic irradiation prior to 9transplant. PREVENTION OF GVHD

Drug therapy to prevent GVHD Most attempts to prevent GVHD have involved the use of immunosuppressive therapy. Methotrexate was initially used by the Seattle group starting within 24 hours of marrow transplantation and continuing for approximately

1062

S. MACKINNON AND J. M. GOLDMAN

3 months (Storb et al, 1970) but GVHD remained a serious problem in 2560% of patients. More recently cyclosporin has been used for prophylaxis of GVHD. Although initial uncontrolled studies suggested that it was more effective than methotrexate (Powles et al, 1980), a controlled study in CML patients found no difference in the incidence of GVHD between patients given methotrexate and those given cyclosporin (Storb et al, 1983). Because of the g~nerally disappointing results, various combinations of active agents have been tested. No significant benefit was observed by combining methotrexate with antithymocyte globulin when compared to methotrexate alone (Doney et al, 1981). The Minneapolis group, however, reported a significant reduction in the incidence of GVHD, albeit without significant improvement in survival, in patients given methotrexate combined with corticosteroids and antithymocyte globulin as compared to patients given methotrexate alone (Ramsay et al, 1982). More recently cyclosporin combined with 'short methotrexate' has resulted in a significantly lower incidence of GVHD than can be achieved with either agent alone (Storb et al, 1986). Nevertheless even with the best of the above regimens a significant number of patients die from GVHD or its sequelae in the post-transplant period. In an attempt to reduce the incidence of GVHD and its associated mortality the focus has recently switched to immunological techniques of prophylaxis and in particular the use of monoclonal antibodies for T-cell depletion. T-cell depletion of donor marrow

Various methods of depleting donor marrow of T cells have been used. The most common and convenient technique is to incubate donor marrow in vitro with anti-T lymphocyte monoclonal antibodies and complement to induce Tcell lysis. The Royal Free Hospital group in London used monoclonals with CD6 and CD8 specificities (Prentice et al, 1984). The monoclonal used by the UCLA group has CD2 activity (Mitsuyasu et al, 1986). Much experience worldwide has been accumulated with the use of Campath-1, an IgM monoclonal antibody active against incompletely defined antigens on T and B lymphocytes and on some monocytes which fixes human complement in vitro (Apperley et al, 1986a; 1988; HeR et al, 1986; Papa et al, 1986; Hale et al, 1988). Other techniques for the elimination of T cells include soybean lectin agglutination in conjunction with E-rosette formation and counterflow elutriation (Cunningham et al, 1987; de Witte et al, 1986). In general these different methods reduce the number of residual T cells in the marrow to less than 1% of the pre-treatment levels. The use of T-cell depleted donor marrow is associated with a lower incidence and severity of GVHD, but the risk of graft failure is increased (Hale et al, 1988). The graft failure may be due to survival in the host of chemoradioresistant immunologicallycompetent cells which in the absence of T cells of donor origin are capable ofmediating graft rejection (Butturini et al, 1986). In patients with CML the major problem associated with the use ofT-cell depleted bone marrow is the substantially increased risk of relapse which is independent of the method of T-cell depletion. It applies both to patients

1063

BONE MARROW TRANSPLANTATION Table 2. Probability of survival and of relapse after BMT for CML in chronic phase using T-depleted donor marrow9 Probability of Patient Depletion numbers technique

Relapse (%) P*

Survival (%) Reference 25 NQ

7 19 5 20t 33 24t

8 McAbs Controls McAb CT-2 Controls 3 McAbs Controls

13 NQ 80 I0 15 NQ

--

102 106 87 318

Campath-Iw Controls Various Controls

33 <0.001 3 48_.+1882<0.0001 9 4-5

<0.007t <0.05

Martin et al (1985) Mitsuyasu et al (1986)

NQ NQ

Maraninchi et al (1987)

50 II 56 II NQ NQ

Apperley et al (1988) Goldmanetal(1988)

NQ=Data not quoted in the original paper; McAbs=monoclonal antibodies. * P value for difference in relapse rates between recipients T-depleted donor marrow and control patients; t The P value is based on comparison of relapse rates between total patient numbers in each group; :~Control group included patients with acute leukaemia as well as those with CM L; wIn 12 cases donor marrow was T-depleted with McAb CT-2 (CD2); II Values quoted refer to leukaemia-free survival at 3 years; 82Data are quoted_+.95% confidence intervals. The analysis performed by the IBMTR (Goldman et al, 1988) includes some but not all patients reported by Mitsuyasu et al (1986), Maraninchi et al 0987) and Apperley et al, 1988. t r a n s p l a n t e d in c h r o n i c phase (Table 2) a n d to those t r a n s p l a n t e d in l a t e r phases o f the disease. In a recent r e p o r t f r o m Seattle, 100% o f p a t i e n t s t r a n s p l a n t e d in a c c e l e r a t e d p h a s e with T - d e p l e t e d m a r r o w w h o survived l o n g e n o u g h h a d evidence o f recurrent l e u k a e m i a (Clift et al, 1987); this c o n t r a s t s with an a c t u a r i a l risk o f relapse o f 55% for p a t i e n t s in acceleration t r a n s p l a n t e d with u n m a n i p u l a t e d d o n o r m a r r o w (Speck et al, 1984). O n e m a y c o n c l u d e that d e p l e t i n g the d o n o r m a r r o w o f T cells n o t o n l y prevents G V H D b u t also a b r o g a t e s a p o o r l y defined g r a f t - v e r s u s - l e u k a e m i a ( G V L ) effect. In a n i m a l m o d e l systems G V H D m a y exert an a n t i l e u k a e m i c 9effect ( T r u i t t et al, 1986). In the clinical setting there is evidence that p a t i e n t s with acute l e u k a e m i a w h o u n d e r g o allogeneic t r a n s p l a n t a t i o n a n d sustain acute o r acute a n d c h r o n i c G V H D have a lower p r o b a b i l i t y o f relapse t h a n c o m p a r a b l e p a t i e n t s w i t h o u t G V H D ( W e i d e n et al, 1979; 1981; Butturini et al, 1987). T h u s it is a s s u m e d that T l y m p h o c y t e s in the d o n o r m a r r o w are c a p a b l e o f m e d i a t i n g G V H D on one h a n d a n d a G V L effect o n the o t h e r ( G a l e & Reisner, 1986). In a n i m a l s at least s o m e o f the ceils responsible for G V L reactions are clearly distinct f r o m those causing G V H D (Bortin et al, 1979; T r u i t t et al, 1986) b u t w h e t h e r similar s u b p o p u l a t i o n s a r e distinguishable in

1064 t-oO _

S. MACKINNON AND J. M. GOLDMAN 1 ~

~

Not T-cell depleted Mild - severe CGVHD (n=108)

-

O3 (,O ~

E

\

0.8-

T-cell depleted Mild - severe CGVHD (n=15)

o~

~

E~ E:

Not T-cell depleted No CGVHD (n=174)

0.6

r" oN

E

(l)

~ - . . - T-cell depleted No CGVHD (n=62)

0.4

O ~

d::}

0.2

O 13_

0

I

I

I

I

I

12

24

36

48

60

Time (months)

(23)

(6)

Patients at risk

(359) (183) (124) (64)

Figure I. Life table analysesshowingactuarial probability of remainingin remissionfor patients transplanted in chronic phase of CML according to whether donor marrow was or was not depleted of T cells and whether chronic GVHD developed in patients at risk. The number of patients living and available for analysis at each time interval is indicated in parentheses. Data collected by the International Bone Marrow Transplant Registry (Goldman et al, 1988) and reproduced with permission. humans is currently unknown. A similar trend is seen in patients ailografted for C M L in chronic phase but the overall relapse rateis low and the beneficial antileukaemie effect of G V H D is not statistically significant. This concept that a GVL effect in C M L is important in eradicating the leukaemia gains further support from the analysis of results ofT-cell depleted transplants. Transplants not depleted o f T cells had an actuarial relapse rate of 9% which was significantly lower than 48% in those depleted o f T cells (Goldman et al, 1988) (Figure 1). These clinical data are inconsistent with the notion that the only component of the transplant procedure critical for cure is the chemoradiotherapy and that the graft functions only as haemopoietic rescue. Instead it seems likely that T cells in the donor marrow contribute to cure by more than one mechanism (Butturini & Gale, 1987). There are various possible approaches to reversing the increased risk of relapse in patients receiving T-cell depleted transplants (Table 3). Efforts have been made to increase the intensity o f the antileukaemic treatment and to add back graded numbers of T lymphocytes post-transplant. The administration of or-interferon post-BMT might be valuable. Perhaps the best hope for the future is the possibility o f separating the lymphocyte subpopulations that mediate G V H D from those that mediate GVL. It would then be possible to select for an antileukaemie effect without the risk of GVHD.

BONE MARROW TRANSPLANTATION

1065

Table 3. Possible approaches to minimizing the risk of relapse after transplantation with T-depleted marrow cells. 1. Increased antileukaemic therapy pre-transplant 2. Partial T-cell depletion, e.g. 90% removal 3. Selective T-cell depletion, e.g. CD8 + cells

4. 5. 6. 7. 8. 9. 10. 1I.

Transfusion of graded numbers of donor T cells post-BMT Transfusion of irradiated donor T cells post-BMT Administration of donor LAK cells post-BMT Administration of ~-interferon post-BMT Administration of IL-2 post-BMT Administration of GM-CSF or IL-3 post-BMT Administration ofother lymphokines,e.g. TNF, TGF~ or p. Combinations of the above.

A D D I T I O N A L F A C T O R S A F F E C T I N G T H E O U T C O M E OF TRANSPLANTATION In view of the relatively long list of factors that could theoretically influence the probability o f relapse or o f survival post-transplant (Table 4), it is somewhat surprising that relatively few are generally agreed. These include the degree of histocompatibility between patient and donor, the disease status at the time of transplant, the use of T-cell depleted d o n o r marrow (discussed above), the age of the patient and the incidence and severity of G V H D posttransplant (discussed below).

Age at transplant It is a general observation that the incidence o f morbidity and mortality following transplantation for leukaemia is related to the age of the patient, and C M L in this regard is no exception. Data reported by the I B M T R and from Seattle show that mortality post-transplant is lower in patients under the age o f 20 than in older patients (Thomas et al, 1986; Goldman et al, 1988) (Figure 2). It is not clear however whether this age-related risk is a continuous or a dichotomized variable. In some reports patients in the age ranges 20-30, 30-40 and 40-50 fare equally well. In the Seattle study, age was related to a greater frequency and severity of G V H D and to an increasing interval from diagnosis to transplant, but age was found to have no additional effect on mortality after adjusting for these two factors (Thomas et al, 1986). Graft-versus-host disease Acute or chronic G V H D is one of the principal causes o f death in patients who receive transplants in chronic phase (Thomas et al, 1986). It may lead directly to death or may contribute indirectly to death from other causes such as infection or interstitial pneumonitis. A recent analysis reported by the I B M T R showed that survival o f patients allografted in chronic phase who develop grades I I - I V acute G V H D was significantly worse than that of

1066

S. MACKINNON AND J. M. GOLDMAN Table 4. List of factors that could be of prognostic significance after BMT for CM L in chronic phase. (This list is not intended to be comprehensive but simply to specify the more important factors likely to influence the outcome of BMT). Factors intrinsic to the patient Age Sex Ethnic origin HLA type CMV antibody status Factors characteristic of the disease Ph chromosome status Spleen size at presentation Leukocyte count at presentation Platelet count at presentation Factors that may be relerant bet ween diagnosis and B M T Interval between diagnosis and transplant Amount of treatment with cytotoxic drugs Splenectomy if performed Factors related to the transplant procedure HLA compatibility of donor Sex of donor Age of donor CMV status of donor Spleen size before transplant Leukocyte count before transplant Platelet count before transplant Details of chemoradiotherapy Use of T-cell depletion Total number of marrow cells transfused Factors that may apply after the transplant procedure Choice of drugs for prevention of GVHD Use of intestinal decontamination Use of CMV-negative blood products Occurrence and severity of acute GVHD Occurrence and severity of chronic GVHD

patients who do not (Figure 2). Conversely the probability of relapse was higher in those who did not develop chronic GVHD than in those who did, 24% vs. 12%, P<0.004 (Goldman et al, 1988).

R E L A P S E OF L E U K A E M I A

The recognition of relapse after transplant for C M L is not always straightforward. In some cases the clinical, haematological and cytogenetic features of the relapse are obvious. Such cases we have designated 'haematological relapse'. In other cases the only evidence for relapse is the finding of Ph positive metaphases in a minority of marrow cells after transplant. These we have called 'cytogenetic relapses' (Arthur et al, 1988). Most intriguing are the

BONE

MARROW

1067

TRANSPLANTATION

1.0 Age <20 No or mild AGVHD (n=34)

m

0.8

Age >_20No or mild AGVHD (n=187)

63

._>

\

>

r t,r

0.6

Age <20 Mod or severe AGVHD (n=31)

o 0.4

Age >_20Mod or severe AGVHD (n=143)

63

J3 o 13_

0.2

0

0

I

I

I

I

I

12

24

36

48

60

Time (months)

(8)

Patients at risk

(359) (194) (134) (64) (24)

Figure2. Lifetable analysesshowingactuarial probabilityof survival for patients transplanted in first chronic phase of CML accordingto grade of acute GVHD in patients at risk and age. Data collected by the International Bone Marrow Transplant Registry (Goldman et al, 1988) and reproduced with permission. cases reported in which relapse has occurred in cells o f apparently donor origin.

Haematological relapse Patients transplanted in accelerated or blastic phases o f disease may if they relapse show the same morphological and cytogenetic features as they did pretransplant. Thus the relapse is presumably due to failure to eradicate the transformed clone and not to the development o f a new clone of transformed cells. Relapse may be more likely to occur in those with cytogenetic abnormalities in addition to the standard Ph chromosome, especially + 8 , + P h or variant Ph, than in those without evidence ofcytogenetic evolution .before transplant (Przepiorka and Thomas, 1988). If the patient was in chronic phase of C M L at the time of the transplant and received unmanipulated donor cells relapse is uncommon but can still occur. If however the patient received a transplant with a donor marrow depleted o f T cells, relapse is much more common. In either case relapse is usually recognized within 2 years o f transplant but may occasionally occur at intervals up to 4 years posttransplant (Goldman et al, 1988). Very occasional patients transplanted in chronic phase relapse directly to blastic transformation without an identifiable intermediate period of Ph positive chronic phase haemopoiesis. More commonly the first indication of relapse is the finding o f abnormalities in the

1068

S. MACKINNON AND J. hi. GOLDMAN

peripheral blood suggestive of CML in the absence of leukocytosis, such as basophilia or the presence of myelocytes. Examination of the marrow trephine at this stage may show a degree of cellularity in excess of what would normally be expected within I or 2 years of transplantation (Lampert et al, 1987). Cytogenetic analysis will then reveal the Ph chromosome in the majority of metaphases (Zaccaria et al, 1987; 1988; Arthur et al, 1988). The pattern of rearrangement in the B C R gene at relapse is identical to that seen before transplantation (Ganesan et al, 1987; Gao et al, 1988), a finding that further supports the conclusion that relapse is due to failure to eliminate the original leukaemic clone.

Cytogenetic relapse In all large series in which cytogenetic analysis of the marrow was carried out at regular intervals a small number of cases have been seen in which a low proportion of the Ph positive metaphases was identified within 1 or 2 years of transplant without progression to haematological relapse (Thomas et al, 1986; Apperley et al, 1986b; Sessarego et al, 1987; Zaccaria et al, 1987; 1988; Arthur et al, 1988). Indeed in some of these cases the proportion of Ph positive metaphases rose to a peak value and then declined (Apperley et al, 1986). The interpretation of these transient cytogenetic relapses is unclear. It may be that the cytogenetic analysis has revealed evidence of a myeloid leukaemic clone that is small and doomed to extinction. Alternatively the Ph positive metaphases may be derived from lymphoid cells which have no capacity to maintain haemopoiesis. If however the T-cell component of the graft is important in suppressing leukaemia post-transplant it is possible that these transient cytogenetic relapses are a manifestation of the temporary failure of this putative GVL effect. It is likely that the significance and natural history of these transient cytogenetic relapses will be clarified by wider application of the polymerase chain reaction, a technique which allows detection of very small numbers o f B C R positive cells post-transplant. In other cases the finding of Ph positive marrow metaphases persists for months or years or proceeds to overt haematological relapse (Arthur et al, 1988).

Relapse in cells of donor origin Two cases have been reported in which relapse after transplant occurred in cells that appeared to be of donor origin (Marmont et al, 1984; Smith et al, 1986). Both patients were transplanted with marrow from HLA identical siblings of the opposite sex and in both cases blast cells at relapse had a sex chromosome pattern of the donor. It may be of significance that both patients were transplanted in second chronic phase after treatment for lymphoid transformation and both relapsed directly to a second blastic phase without an obvious preceding chronic phase. There are in theory many mechanisms by which relapse after BMT could occur in cells of donor origin (Fialkow et al, 1971; Editorial, 1984). For example there could exist a powerful microenvironmental influence that caused the original leukaemia in the host and later induced leukaemia in the donor cells. Alternatively the appearance of relapse in donor cells might be artefactual if exchange of sex chromosomes had taken

BONE MARROW TRANSPLANTATION

1069

place between the host's leukaemic cells and normal cells of donor origin. Perhaps the most likely interpretation is the transfer or transfection of a 'transforming' sequence of DNA from residual leukaemic cells of host origin to the donor cells.

Management of relapse after transplant The management of patients who relapse after transplantation is difficult. A patient who relapses directly into transformation, be it after transplant in accelerated/transformed phase or in chronic phase, may be treated with cytotoxic drugs in the hope ofrestoring Ph negative donor type haemopoiesis, though the likelihood of success is small. A second transplant using the original donor or another is even less likely to succeed. For the patient who relapses into chronic phase there are various possibilities. We have treated such patients with recombinant human or-interferon in the hope that the relapsed leukaemia would be relatively sensitive and that haemopoiesis of donor origin could be re-established. This has not proved to be the case. However conventional treatment with cytotoxic drugs is as effective after transplant than before. Patients who relapse into second chronic phase following transplant with T-cell depleted donor marrow can be offered second transplants using unmanipulated marrow from the same donor. There is some evidence that the probability of a successful second transplant is increased if the interval between the two transplants is 2 years or more (Atkinson et al, 1987).

LATE COMPLICATIONS OF TRANSPLANTATION Late complications have been arbitrarily defined as those occurring more than 100 days from transplant (Sullivan et al, 1984). These may be due to the late effects of chemoradiotherapy, chronic GVHD, immunosuppression or a combination of these factors.

Pulmonary complications Interstitial pneumonitis is a common cause of morbidity and mortality following transplantation. It may be idiopathic, possibly secondary to the chemoradiotherapy or more commonly associated with CMV infection, and once established the outcome is generally poor. Even in the absence of interstitial pneumonitis transplants can be shown to have subclinical abnormalities on pulmonary function testing with both a reduction in lung volumes and gas transfer (Depledge et al, 1983). Both restrictive and obstructive pulmonary abnormalities can be demonstrated late after transplant especially in the context of chronic GVHD (Ralph ct al, 1984; Wyatt et al, 1984). Deterioration in respiratory function post-transplant may be multifactorial with chemoradiotherapy, chronic GVHD and infection all being important in this regard.

1070

S. MACKINNON AND J. 51. GOLDMAN

Cataracts Cataracts are a recognized complication of radiation exposure. They are thought to be more common in patients who receive single fraction TBI with an incidence of 75% as opposed to 25% in patients who received fractionated TBI (Deeg et al, 1984). They may also be more common in patients who develop chronic GVHD affecting the eyes and are treated with topical steroids (Sullivan et al, 1981). Endocrine function, growth and development Among recipients of bone marrow transplants the doses of irradiation used in the conditioning regimen are known to affect thyroid function; many patients have elevated TSH levels and a minority of patients require replacement therapy (Sklar et al, 1982; Sanders et al, 1986). Gonadal function is usually severely affected by chemoradiotherapy and in post-pubertal males this is usually associated with elevated FSH levels and azoospermia (Sanders et al, 1983). Sperm storage should be considered before TBI therapy. Similarly most post-pubertal females develop ovarian failure with elevated gonadotrophin levels and many have symptoms related to the menopause (Sanders et al, 1983). Prior to transplant such women should ideally be offered embryo storage and following transplant the use of cyclical hormone therapy may prevent the complications of an early menopause. In pre-pubertal children the situation is complicated by the fact that they are still growing. Chemoradiotherapy can reduce growth hormone levels and growth velocity and this effect may be exacerbated by giving TBI as a single fraction, by previous cranial irradiation, by the development of chronic GVHD and by the use of steroids for its treatment (Sanders et al, 1986). An additional factor affecting the growth ofpre-pubertal transplant recipients is a delay in the onset of secondary sexual characteristics due to hypergonadotrophie hypogonadism. Their low levels of sex hormones may be a major factor in the lack of increase of growth velocity during adolescence since normally the increasing sex hormone levels during puberty contribute to growth by increasing growth hormone production (Martin et al, 1968). The observation that following chemoradiotherapy a few girls can achieve menarche and that some boys have normal levels of LH, FSH and testosterone suggests that irradiation to the pre-pubertal ovary and testis may not always result in irreversible damage (Sanders et al, 1986). Sex hormone therapy may be appropriate in children with delayed puberty.

FUTURE PROSPECTS The major obstacles to improving survival after transplantation remain GVHD and interstitial pneumonitis. Improved post-transplant immunosuppression therapy with regimens such as cyclosporin plus methotrexate may reduce the morbidity and mortality of acute GVHD (Storb et al, 1986), but it is still a major and not infrequently lethal complication. Attempts to prevent it

BONE MARROW TRANSPLANTATION

1071

with T-cell depletion have been associated with a significantly increased risk o f relapse. It remains to be seen whether any o f the modifications to the technique of T-cell depletion now under study will reduce the risk o f relapse while retaining its benefits. The incidence of CMV pneumonitis has been reduced in CMV-seronegative recipients with the use o f CMV-negative blood products (Bowden et al, 1986) and there is preliminary evidence that seropositive'recipients may benefit from prophylactic acyclovir infusion (Meyers et al, 1988). The possibility o f curing C M L by autografting deserves mention though it still seems remote. The majority of patients treated by high-dose chemotherapy and autografting for C M L in transformation recover partial and transient Ph negative haemopoiesis (Haines et al, 1984). There are anecdotal reports of patients rendered Ph negative by high-dose busulphan or by autografting in chronic phase (Brito-Babapulle et al, 1987). Similarly a small minority o f patients treated with e-interferon become Ph negative (Talpaz et al, 1986). In each case one could contemplate the use of Ph negative autologous marrow in an autograft procedure designed to cure the patient. Perhaps the most promising approach to autografting involves the use o f peripheral blood or marrow cells collected from the patient at diagnosis and "'purged' in vitro to permit selective regeneration o f Ph negative, putatively normal, haemopoietic stem cells. How exactly this purging is best achieved, whether by immunological, pharmacological or cytokinetic means, is at present speculative.

CONCLUSIONS Little progress has been made in recent years in prolonging the life ofpatients with C M L with the use ofcytotoxic drugs. Allogeneic B M T is still associated with substantial morbidity and risk of mortality but may if successful cure the disease. Although the optimal timing o f transplantation for patients in chronic phase is controversial, results of transplanting patients in accelerated or blastic phases are generally poor. Efforts to increase the proportion of patients who may be offered transplantation are now warranted.

REFERENCES ApperleyJ F, Jones L, Hale Get al (1986a)Bonemarrowtransplantation for patientswithchronic myeloid leukaemia: T-celldepletion with Campath-I reducesthe incidenceof graft-versushost diseasebut may increasethe risk ofleukaemierelapse. Bone Marrow Transplantation 1: 53-68. ApperleyJF, Rassool F, Parreira Aet al (1986b)Philadelphiapositivemetaphasesin the marrow after bone marrow transplantation for chronic granulocyticleukemia. American Journal of Hematology 22: 199-204. Apperley JF, Mauro F, Goldman JM et al (1988) Bone marrow transplantation for chronic myeloid leukaemia in chronic phase: importanceof a graft-versus-leukaemiaeffect.British Journal of Haematology 69: 239-245. Armitage JO, KlassenLW, Patil SR et al (1984)Marrow transplantation for stable phase chronic granulocyticleukemia. Experhnental ltematology 12:717-719.

1072

S. MACKINNON AND J. M. GOLDMAN

Arthur CK, Hows J, Jones L e t al (1987) Marrow transplantation in the absence of an HLA identical donor: the use of in vivo and ex vivo monoclonal antibodies. Bone Marrow Transplantation 2 supplement 1: 137. Arthur CK, Apperley JF, Guo A-P, Rassool F & Goldman JM (1988) Cytogenetic events after bone marrow transplantation for chronic myeloid leukemia. Blood 71:1179-1186. Atkinson K, Biggs J, Concannon A e t al (1986) Second marrow transplants for recurrence of haematological malignancy. Bone Marrow Transplantation 1: 159-166. Ash RC, Casper J, Serwint MS et al (1987) Extending the application of allogeneic marrow transplantation for leukemic patients who lack matched sibling donors, utilizing partially matched donors in concert with T-cell depletion for GVHD prophylaxis. In Gale RP & Champlin R (eds). Progress hi Bone Marrow Transplantation, pp 365-379. New York: Alan Liss Inc. Awdeh ZL, Alper CA, Eynon E, Alosio SM, Stein R & Yunis EJ (1986) Unrelated individuals matched for MHC extended haplotypes and HLA-identical siblings show comparable responses in mixed lymphocyte culture. Lancet it: 853-856. Bacigalupo A, Frassoni F, van Lint MT et al (1986) Bone marrow transplantation for chronic granulocytic leukemia. Cancer 58:2307-2311. Baughan AS J, Worsley AM, McCarthy DM et al (1984) Haematological reconstitution and severity of graft-versus-host disease after bone marrow transplantation for chronic granulocytic leukaemia: the influence of previous splenectomy. British Journal o f Haematolog)' 56: 445-545. Beatty PG, Clift RA, Michelson EM et al (1985) Marrow transplantation from related donors other than HLA-identical siblings. New England Journal o f Medicine 313: 765-771. Bidwell JL & Jarrold EA (1986) HLA-DR allogenotyping using exon specific cDNA probes and application of rapid minigel methods. Molecular Immunology 23:1111-1116. Black D (1982) Report o f the working group on bone marrow transplantation. London: HM Stationery Office. Bortin MM, Truitt RL, Rimm A A & Bach FH (1979) Graft-versus-leukaemia reactivity induced by alloimmunisation without augmentation of graft-versus-host reactivity. Nature 281: 490491. Bowden RA, Sayers M, Flournoy N e t al (1986) Cytomegalovirus immune globulin and seronegative blood products to prevent primary cytomegalovirus infection after bone marrow transplantation. New England Journal o f ~Iedichze 314: 1006-1010. Bradley BA, Gilks WR, Gore SM & Klouda PT (1987) How many HLA typed volunteer donors for marrow transplantation are needed to provide an effective service? Bone Marrow Transplantation 2 supplement 1: 79. Brito-Babapulle F, Apperley JF, Rassool F et al (1987) Complete remission after autografting for chronic myeloid leukemia. Leukemia Research 11:1115-1117. Burnett AK, Hann IM, Robertson AG et al (1988) Prevention of graft-versus-host disease by ex vivo T-cell depletion: reduction in graft failure with augmented total body irradiation. Leukemia 2: 300-303. Butturini A, Seeger RC & Gale RP (1986) Recipient immune competent T lymphocytes ~an survive intensive conditioning for bone marrow transplantation. Blood 68: 954-956. Butturini A, Bortin MM & Gale RP (1987) Graft-versus-leukemia following bone marrow transplantation. Bone Marrow Transplantation 2: 233-242. Butturini A & Gale RP (1987) The role o f T cells in preventing relapse in chronic myelogenous leukemia. Bone Marrow Transplantation 2: 351-354. Cervantes F, Rozman C, Ballesta F & Mila M (1982) Prognostic significance of cytogenetical studies in chronic granulocytic leukaemia. Scandinavian Journal o f Haematology 28:77-8 I. Champlin R, Ho W, Arenson E & Gale RP (1982) Allogeneic bone marrow transplantation for chronic myelogenous leukemia. Blood 60:1038-104 !. Clift RA, Thomas ED, Buckner CD et al (1982) Treatment of chronic granul0cytic leukaemia in chronic phase by bone marrow transplantation. Lancet it: 621-623. Clift RA, Martin PJ, Fisher L, Buckner CD & Thomas ED (1987) Allogeneie marrow transplantation for CML in accelerated phase--risk factors for survival and relapse. Blood 70 supplement 1: 291. Cunningham I, Castro-Malaspina H, Flomenberg N e t al (1987) Improved results of bone

BONE MARROW TRANSPLANTATION

1073

marrow transplantation (BMT) for chronic myelogenous leukemia using marrow depleted o f T cells by soybean lectin agglutination and E-rosette depletion. In Gale RP & Champlin RE (eds) Progress in Bone 3farrow Transplantation, pp 359-363. New York: Alan Liss Inc. Curtis JE & Messner HA (1982) Bone marrow transplantation for leukemia and aplastic anemia: management of ABO incompatibility. Canadian Medical Association Journal 126: 649-655. Deeg HJ, Flournoy N, Sullivan KM et al (1984) Cataracts after total body irradiation and marrow transplantation: a sparing effect of dose fractionation. International Journal of Radiation Oncology, Biology and Physics I0: 957-964. Depledge MH, Barrett A & Powles RL (1983) Lung function after bone marrow grafting. International Journal of Radiation Oncology, Biology and Physics 9: 145-151. de Witte T, Hoogenhout J, de Pauw B et al (1986) Depletion of donor lymphocytes by counterflow centrifugation successfully prevents graft-versus-host disease in matched aUogeneic marrow transplantation. Blood 67:1302-1308. Doney K, Buckner CD, Sale GE et al (1978) Allogeneic bone marrow transplantation for chronic granulocytic leukemia. Experimental ttematology 6: 738-747. Doney K, Buckner CD, Thomas ED et al (1981) Allogeneic bone marrow transplantation for chronic granulocytic leukemia. Experimental Hematology 9:966-97 !. Editorial. (1984) Leukaemic transfection in vitro'?. Lancet i: ! 001-1002. Fefer A, Cheever M, Thomas ED et al (1979) Disappearance ofPh ~positive cells in four patients with chronic granulocytic leukemia after chemotherapy, irradiation and bone marrow transplantation from an identical twin. New England Journal of 31edichze 300: 333-337. Fefer A, Cheever MD, Greenberg PD et al (1982) Treatment of chronic granulocytic leukemia with chemoradiotherapy and transplantation of marrow from identical twins. New England Journal of Medicine 306: 63-68. Fefer A, Clift RA, Doney K et al (1984) Syngeneic and allogeneic bone marrow transplantation for chronic granulocytic leukemia. Proceedingsof the American Societyfor ClinicalOncology 3: 205. Fefer A, Cheever MA, Greenberg PD et al (1986) Identical twin (syngeneic) marrow transplantation for hematologic cancers. Journal of the National Cancer Institute 76: 12691273. Fialkow P J, Thomas ED, Bryant JI & Neiman P. (1971) Leukaemic transformation of engrafted human marrow cells in vivo. Lancet i: 251-255. Ganesan T, Gao L-M, Goldman JM & Young BD (1987) Molecular analysis of relapse in chronic myeloid leukemia after allogeneic bone marrow transplantation. BloodTO: 873-876. Ga0 L-M, Hibbin J, Arthur CK et al (1988) Use ofminisatellite DNA probes for recognition and characterization of relapse after allogeneic bone marrow transplantation. British Journal of Haematology 68: 195-201. Gluckman E, Devergie A, Bernheim A & Berger R (1982) Splenectomy and bone marrow transplantation in chronic granulocytic leukaemia. Lancet ii: 1392-1393 (letter). Goldman JM, Johnson SA, Catovsky D et al (1981) Identical twin bone marrow transplantation for patients with leukemia and lymphoma. Transplantation 31: 140-141. Goldman JM, Baughan AS J, McCarthy DM et al (1982) Marrow transplantation for patients in chronic phase of chronic granulocytic leukaemia. Lancet ii: 623-625. Goldman JM, Bortin MM, Champlin RE et al (1985) Bone marrow transplantation for chronic myelogenous leukaemia. Lancet ii: 1925 (letter). Goldman JM, Apperley JF, Jones L c t al (1986) Bone marrow transplantation in patients with chronic myeloid leukemia. New England Journal of Medicine 314: 202-207. Goldman JM, Apperley JF, Mackinnon Set al (1987) Bone marrow transplantation (BMT) for chronic myeloid leukemia (CML) using matched unrelated donors. BloodTO supplement 1: 294. Goldman JM, Gale RP, ttorowitz MM et al (1988) Bone marrow transplantation for chronic myelogenous leukemia in chronic phase: increased risk of relapse associated with T cell depletion. Annals of htternal 3Iedichze 108:806-814. Gratwohl A, Goldman JM, Gluckman E & Zwaan F (1985) Effect of splenectomy before bone marrow transplantation on survival in chronic granulocytic leukaemia. Lancetii: 1290-1291. Haines ME, Goldman JM, Worsley AM et al (1984) Chemotherapy and autografting for patients with chronic granulocytic leukaemia in transformation: probable prolongation of life for some patients. British Journal of Haematology 58:711-722.

1074

S. MACKINNON AND J. M. GOLDMAN

Hale G, Cobbold S, Waldmann tt for Campath- i users (I 988) T-cell depletion with Campath- 1 in allogeneic bone marrow transplantation. Transplantation 45: 753-758. Heit W, Bunjes D, Wiesneth Met al (I 986) Ex vivo T-cell depletion with the monoclonal antibody Campath-I plus human complement effectively prevents acute graft-versus-host disease in allogeneic bone marrow transplantation. British Journal of Haematology 64: 479-486. Jones L, Thein SL, Jeffreys AJ et al (1987) Identical twin marrow transplantation for 5 patients with chronic myeloid leukaemia: role of DNA fingerprinting to confirm homozygosity. European Journal of Haematology 39: 144-147. Lampert IA, Piaza-Biza P, Thompson I et al (1987) Reduced marrow cellularity at varying intervals after allogeneic bone marrow transplantation for chronic myeloid leukaemia. Bone Marrow Transplantation 2 supplement I: 111. Lehn P, Devergie A, Benbunan M et al (1986) Bone marrow transplantation for chronic granulocytic leukemia. Journal of the National Cancer htstitute 314: 202-207. McGlave PB, Arthur DC, Haake R et al (1987a) Therapy ofchronic myelogenous leukemia with allogeneic bone marrow transplantation. Journal of Clinical Oncology 5: 1033-1040. McGlave PB, Scott E, Ramsay N et al (1987b) Unrelated donor bone marrow transplantation therapy for chronic myelogenous leukemia. Blood 70: 877-881. Maraninchi D, Gluckman E, Blaise D et al (1987) Impact of T-cell depletion on outcome of allogeneic bone marrow transplantation for standard-risk leukaemias. Lancet ii: 175-178. Marmont A, Frassoni F, Bacigalupo A e t al (1984) Recurrence of Ph I positive leukemia after marrow transplantation for chronic granulocytic leukemia. New England Journal of Medichle 310: 903-906. Martin LG, Clark JW & Connor TB (1968) Growth hormone secretion enhanced by androgens. Journal of Clinical Endocrinology 28: 425-428. Martin PJ, Hansen JA, Buckner CD et al (1985) Effects of in vitro depletion o f T cells in HLA identical marrow grafts. Blood 66: 664-672. Meyers JD, Reed EC, Shepp DH et al (1988) Acyclovir for the prevention of cytomegalovirus infection and disease after allogeneic marrow transplantation. New England Journal of Medicflle 318: 70-75. Mitsuyasu RT, Champlin RE, Gale RP et al (1986) Treatment of donor bone marrow with monoelonal anti-T-cell antibody and complement for the prevention of graft-versus-host disease: a prospective randomized double blind trial. Annals oflnternalMedicine 105: 20-26. MRC Working Party for Therapeutic Trials in Leukaemia (1983) Randomized trial of splenectomy in Ph positive chronic granulocytic leukaemia, including an analysis of prognostic features. British Journal of Haematology 54: 415-430. Papa G, Arcese W, Mauro F R e t al (1986) Standard conditioning regimen and T-cell depleted donor marrow for transplantation in chronic myeloid leukemia. Leukemia Research 10: 1469-1475. Patterson HG, Blacklock HA, Brenner MK et al (1986) Graft rejection following ttLA matched T-lymphocyte depleted bone marrow transplantation. British Journal of Haematology 63221-230. Powles RL, Clink HM, Spence D et al (1980) Cyclosporin A to prevent graft-versus-host disease in man after allogeneic bone marrow transplantation. Lancet i: 327-329. Powles RL, Morgenstern GR, Kay HEM et al (1983) Mismatched family donors for bone marrow transplantation as treatment for acute leukaemia. Lancet i: 612-615. Prentice HG, Blacklock HA, Janossy G e t al (1984) Depletion ofT lymphocytes in donor marrow prevents significant graft-versus-host disease in matched allogeneic leukaemic marrow transplant recipients. Lancet i: 472-475. Przepiorka D & Thomas ED (1988) Prognostic significance of cytogenetic abnormalities in patients with chronic myelogenous leukemia. Bone Marrow Transplantation 3:113-119. Ralph DD, Springmeyer SC, Sullivan KM et al (1984) Rapidly progressive air-flow obstruction in marrow transplant recipients. Possible association between obliterative bronchiolitis and chronic graft-versus-host disease. American Review of Respiratory Diseases 129: 641-644. Ramsay NK, Kersey JH, Robison LL et al (1982) A randomized study of the prevention of acute graft-versus-host disease. New England Journal of Medicine 306: 392-397. Sanders JE, Buckner CD, Leonard JM et al (1983) Late effects on gonadal function of cyclophosphamide, total body irradiation and marrow transplantation. Transplantation 36: 252-255.

BONE MARROW TRANSPLANTATION

1075

Sanders JE, Pritchard S, Mahoney P e t al (1986) Growth and development following marrow transplantation for leukemia. Blood 68:1129-1135. Santos GW, Tutschka PJ, Brookmeyer R et al (1985) Marrow transplantation for acute nonlymphocytic leukemia after treatment with busulfan and cyclophosphamide. New England Journal of Medicine 309:1347-1353. Segel GB, Simon W & Lichtman MA (1986) Variables influencing the timing of marrow transplantation in patients with chronic myelogenous leukemia. Blood 68: 1055-1064. Sessarego M, Frassoni F, van Lint MT et al (1987) Competition between Ph positive and Ph negative cell populations after bone marrow transplantation for chronic granulocytic leukemia. Fourth International Symposium on Therapy of Acute Leukemias. Rome, 1987, p243. Simonsen M (1962) Graft versus host reactions: their natural history and applicability as tools of research. Progress hz Allergy 6: 349-467. Sklar CA, Kim TH & Ramsay NK (1982) Thyroid dysfunction among long-term survivors of bone marrow transplantation. American Journal of Medicble 73: 688-694. Smith JL, Heerema NA & Provisor AJ (1985) Leukaemic transformation of engrafted bone marrow cells. British Journal of Haematology 60: 415-422. Sokal JE, Baccarani M, Tufa S e t al (1985) Prognostic discrimination among younger patients with chronic granulocytic leukemia: relevance to bone marrow transplantation. Blood 66: 1352-1357. Speck B, Gratwohl A, Nissen C et al (1982) Allogeneic bone marrow transplantation for chronic granulocytic leukemia. Blut 45: 237-242. Speck B, Bortin MM, Champlin R et al (1984) Allogeneic marrow transplantation for chronic myelogenous leukaemia. Lancet i: 665-668. Storb R, Epstein RB, Graham TC et al (1970) Methotrexate regimens for control of graft-versushost disease in dogs with allogeneic marrow grafts. Transplantation 9: 240-246. Storb R, Weiden PL, Graham TC, Lerner KG & Thomas ED (1977) Marrow grafts between DLA-identical and homozygous unrelated dogs: evidence for an additional Incus involved in graft versus host disease. Transplantation 24: 165-174. Stnrb R, Deeg I t J, Thomas ED et al (1983) Preliminary results of prospective randomized trials comparing methotrexate and cyclosporin for prophylaxis ofgraft-vs-host disease after HLA identical marrow transplantations. Transplant Proceedings 15: 2620-2623. Storb R, Deeg HJ, Whitehead J e t al (1986) Melhotrexate and cyclosporin compared with cyclosporin alone for prophylaxis of acute graft versus host disease after marrow transplantation for leukemia. New England Journal of Medicine 314: 729-735. Sullivan KM, Shulman HM, Storb R et al (198 I) Chronic graft-versus-host disease in 52 patients: adverse natural course and successful treatment with combination immunosuppression. Blood 57: 267-276. Sullivan KM, Deeg H J, Sanders JE et al (i 984) Late complications after marrow transplantation. Seminars in Hematology 21: 53-63. Talpaz M, Kantarjian JM, McCredie K et al (1986) Hematologic remission and cytogenetic improvement induced by recombinant human interferon alphaA in chronic myelogenous leukemia. New England Journal of ~ledicbze 314:1065-1069. Thomas ED, Buckner CD, Clift RA et al (1979) Marrow transplantation for acute nonlymphoblastic leukemia in first remission. New England Journal of Medicine 301: 597-599. Thomas ED, Cliff RA, Fefer A e t al (1986) Marrow transplantation for the treatment of chronic myelogenous leukemia. Annals ofhlternal Medicine 104: 155-163. 9Truitt RL, Shih CY & Lefever AV (1986) Manipulation of graft versus host disease for a graft versus leukemia effect after allogeneic bone marrow transplantation in AKR mice. Transplantation 41: 301-310. Tura S, Baccarani M, Corbelli G et al (1981) Staging of chronic myeloid leukaemia. British Journal of tlaematology 47:105-119. Tutschka PJ,Copelan EA & Klein JP (1987) Bone marrow transplantation for leukemia following a new busulfan and cyclophosphamide regimen. Blood 70: 1382-1388. Wareham N J, Johnson SA & Goldman JM (1982) Relationship of the duration of chronic phase in chronic granulocytic leukaemia to the need for treatment during the first year after diagnosis. Cancer Chemotherapy and Pharmacology 8: 205-210. Weiden PL, Flournoy N, Thomas ED et al (1979) Antileukemic effect o fgraff-versus-host disease in recipients of allogeneic marrow grafts. New England Journal of Medicine 300: 1068-1073.

1076

S. MACKINNON AND J. M. GOLDMAN

Weiden PL, Sullivan KM, Flournoy ND et al (198 I) Antileukemic effect of chronic graft-versushost disease: contribution to improved survival after allogeneic bone marrow transplantation. New England Journal of Medichze 304: 1529-1533. Wyatt S, Nunn P, Yin JAL et al (1984) Airways obstruction associated with graft versus host disease after bone marrow transplantation. Thorax 39" 887-894. Zaccaria A, Rosti G, Testoni M et al (1987) Chromosome studies in patients with Philadelphia chromosome positive chronic myeloid leukemia submitted to bone marrow transplantation. Results of a European cooperative study. Cancer Genetics and Cytogenetics 25: 5-13. Zaccaria A, Rosti G, Testoni M e t al (1988) Cytogenetic and clinical follow-up of 100 patients submitted to bone marrow transplantation for Philadelphia chromosome positive chronic myeloid leukaemia. European Journal of Haematology 40: 50-57.