Graft-versus-host reactions and bone-marrow transplantation

Graft-versus-host

reactions

and bone-marrow

transplantation Malcolm

K. Brenner

St Jude Children’s Memphis

Three

Research Hospital,

during

transplants members

and University

College of Medicine, Memphis,

areas of bone-marrow

rapidly

and Helen E. Heslop

the

transplantation

past year.

using matched

unrelated

have been successfully

hemopoietic

growth

hemopoietic

recovery

factors

infections

of

potentially

the most important which

anti-leukemic

activity

and

Current

other

of an allograft

Opinion

these

This review, however, will focus on the relationship between graft versus leukemia (GVL) effects and GVHD because over the past year a number of apparently unrelated discoveries have indicated how these two interrelated phenomena may be separable from each other to the considerable benefit of allograft recipients.

agents

transplant

can and

accelerate reduce

complications.

mechanisms

may be separated

in Immunology

A number of pre-existing trends in graft-versus-host disease (GVHD) prevention and bone-marrow transplanta tion have continued over the past year. For example, matched unrelated donor (MUD) bone-marrow transplants (BMTs) are being performed with increasing frequency and success [ 1*,2*] and data have now been published showing the benefits of recombinant hemopoietic growth factors after BMT [3*,4*]. Interestingly, these growth factors have a much greater effect on overall patient survival than predicted from the relatively modest reduction in duration of neutropenia and frequency of febrile neutropenia. Improvement in survival may relate instead to their ability to reduce endotoxemia and subsequent initiation or aggravation of GVHD. Preliminary reports from a Phase II granulocyte-macrophage colonystimulating factor (GM-CSF) trial in MUD BMT recipients in Seattle document a sign&ant reduction in acute GVHD in patients receiving GM-CSF [4*].

family

the But

have come in a series of separate

suggest

graft-versus-host

Introduction

particularly

of bone-marrow

or HLA-mismatched

post-transplant

advances

in conjunction induce

shown

developed

numbers

USA

Second, trials of recombinant

bone-marrow

incidence

observations,

donors

performed.

have

after

have

First, increasing

of Tennessee,

Tennessee,

by which

from

its ability

the to

disease.

1991, 3:752-757

GVHD has always been seen as a major obstruction to increasing the applicability and safety of allogeneic BMT [5*]. As a consequence, during the 1980s much time was spent trying to prevent this complication, using cyclosporin and later T-cell depletion. But ironically, by the end of the decade, the success of these attempts had revealed that GVHD could be associated with a significant benefit, because it contributed to disease eradication when BMT was undertaken to treat leukemia - the GVL effect [6]. Although GVL appeared to be closely related to the alloreactivity of the graft with the recipient - and therefore to GVHD itself - deliberate augmentation of GVHD [7] or induction of the phenomenon after autografting [8,9] did not help to eradicate malignant disease and served instead to increase the morbidity and mortality of BMT. Thus one of the most important challenges remaining in the 1990s is to retain the anti-leukemic properties of an allogeneic marrow graft and eradicate its ability to induce GVHD, thereby optimizing the therapeutic benefit of BMT. During the past year we have learned much more about the molecular abnormalities underlying leukemia, the mechanisms by which immune system effector cells may recognize these abnormalities and about the most appropriate way to use recombinant immune system growth factors to enhance the anti-leukemic response.

Abbreviations AK-activated killer; ALL-acute lymphoblastic leukemia; BMT-bone-marrow transplant; CWellular adhesion molecule; CMCSF-granulocyte-macrophage colony-stimulating factor; GVHD_sraft-versus-host disease; GVL-graft versus leukemia; LFA-lymphocyte function-associated antigen; MUD--matched unrelated donor; MHC-major histocompatibility complex; NK-natural killer. 752

@ Current Biology Ltd ISSN0952-7915

Graft-versus-host reactions and bone-marrow

These advances have begun to show how the separation of GVL from GVHD will be achieved.

transplantation Brenner and Heslop

Table 1. Fusion proteins and point mutations in hematologic malignancy. Fusion proteins

leukemia-specific killing by MHC-restricted T cells that recognize leukemia-specific antigens Many different models have shown that major histocompatibility complex (MHC)-restricted antigen-specific T lymphocytes can protect animals against transplantable leukemias. For these effects to be relevant to the successful eradication of human leukemia, it is necessary to show that all leukemic cells express unique antigens that are critical to the leukemic behavior of the cell. Expression of leukemia-specific antigens per se is probably insufficient. For example, many leukemia/lymphomas derived from mature B cells express a unique immunoglobulin idiotype. Although anti-idiotypic responses can be generated against these unique tumor epitopes they rarely succeed in eradicating the malignancy, because subclones are generated which either express immunoglobulin of modified idiotype or no immunoglobulin at all [lo]. Fortunately, a substantial number of leukemias have been found to express proteins that are both unique and apparently important in the leukemic process. These include the fusion proteins formed following gene translocations and the abnormal oncogenes produced following point mutations in the encoding genes (Table 1). Both types of protein contain unique peptide sequences and thereby provide the potential for the leukemic cells to be recognized by antigen-specific T-lymphocyte clones. Because these leukemia-specific products are all internal proteins, the reason why they should be recognized by antigen-specific T cells is not instinctively obvious. However, many internal proteins are processed to peptides in the pre-golgi compartment, where they become associated with nascent MHC molecules. The complex of processed peptide and MHC antigen subsequently appears on the cell surface. It is this complex of specific peptide and specific MHC polymorphism that is recognized by the CD3 T-cell receptor on the classic MHC-restricted T-effector cell. Before we can conclude that the same happens to leukemia-specific antigens we have to answer two critical questions: first, are point mutated or fusion peptides processed and presented by leukemic cells? and second, can T cells distinguish such mutants from the wild-type peptides? During the past year, evidence has been produced favoring a positive response to both. Sosman et al. [ 11.1 have suggested that leukemia-specilic antigens appear on leukemia cell surfaces. They described the generation of CD3 + ,CD4 + T-cell clones that react with allogeneic acute lymphoblastic leukemia (ALL) cells. These ALLcells do not react with remission lymphocytes from the same patient implying that these clones may recognize an antigen expressed on leukemic but not normal cells. This evidence, of course, is not definitive, but active efforts are being made by a number of groups to consolidate the issue.

Disease

Fusion protein

Translocation

References

CML

t(9 : 22)

bcr-abl ~210

[231

ALL

t(9 : 22)

bcr-abl p190

[24,251

ALL

t(1 :19)

E2apbxl

c26.1

AML

t05 : 17)

RAR-my/

[27*1

AML

t(6 : 9)

dek-can

12iw

Point mutation Point mutation

Disease

References

N-ras

Codon 12 or 13

AML, ALL, MDS

129,30,31*1

c-fms

Codon 969 or 301

MDS

1321

Oncogene

ALL, acute lymphoblastic leukemia; AML, acute myelocytic leukemia; CML, chronic myelogenous leukemia; MDS, myelodysplastic syndrome.

We are probably on firmer ground with the suggestion that mutant peptides may be distinguished from the wild-type products by antigen-specific T cells. Jung and Schluesner [ 12.1 synthesized a Ras-derived peptide in which valine was substituted for glycine at residue 12, a substitution associated with transforming ability in the intact protein. They were able to generate an MHCrestricted CD4+ T-cell line that proliferated only in response to mutant peptide and had no response to stimulation with wild-type peptide. Mutant-specific responses may also be generated in vivo. Peace et al. [ 13.01 used a similar Ras peptide - but with arginine substituted at residue 12 - to immunize ~57BL/b mice. Again MHCrestricted CDfi+ specific T cells were generated in viva. These cells recognized both mutant peptide and mutant was protein processed by antigen-presenting cells, but did not respond to wild-type peptide or protein. The above observations may mean that a specific GVL effect can be generated after BMT and that the previously discredited concept of leukemia-specific vaccines may be gaining a new legitimacy.

leukemia-selective killing

but MHC-unrestricted

Whether or not MHC-restricted, antigen-spectic recognition of leukemia blast cells genuinely exists, an alternative mechanism of anti-leukemia effector function has been emphasized during the past year. Natural killer (NK) cells are MHC-unrestricted effector cells that inhibit clonogenic leukemia growth in vitro and are particularly numerous and active, activated killer (AK) cells for the

753

754

Transplantation

first few weeks following both autologous and allogeneic BMT [ 141. Although these cells were known to be plentiful after BMT and do inhibit leukemic growth in vitro, it was uncertain whether they could discriminate between normal and leukemic progenitors to produce a selective anti-leukemia effector function in vim Most NIQ’AKcells are CD3- and therefore lack the only known antigen-specific receptor present on cytotoxic lymphocytes. Thus, even if leukemic cells do express specific antigens, it is unclear how these CD3- effecters recognize them. In addition, although a subpopulation of NK/AK cells are in fact CD3+, there has been a problem in understanding how these T-cell receptor positive AK cells distinguish normal cells from malignant cells. NK and AK lymphocytes are by definition MHC unrestricted. Because the CD3 receptor classically only ret ognizes specific antigen complexed with a specific MHC polymorphism, the MI-K-unrestricted killing of CD3+ AK cells had been thought to mean that target-cell recognition could not involve the antigen-specific CD3+ receptor and therefore by definition could not be antigen specific. Two articles [15*,16-l have now demonstrated how both CD3- and CD3 + AK cells may in fact selectively kill leukemic blasts despite their lack of a conventionally functioning MHC-restricted antigen-specific CD3 receptor.

with newly synthesized MHC molecules, antigens also exist which bypass this route. Although these ‘superantigens’ may be processed, they associate directly with a range of non-polymorphic determinants on the cell surface where they bind a family of T-cell receptors (see be low). Because they are not associated with specific MHC molecules CD3 receptor binding is MHC unrestricted.

CD34+ normal myeloid progenitor cell

CD34+ malign;t gel;eloid -

Activated killer cell

CD3-

killer cells

In order to kill their target cells effectively, CD3-

AK lymphocytes must first bind to them, an effect achieved by a variety of cell-adhesion molecules (CAMS). Oblakowski et al. [ 15.1 showed that normal and malignant CD34+ myeloid progenitor cells expressed different patterns of CAM (Fig.1). Normal CD34+ cells express lymphocyte function-associated antigen-3 (CD58), which is the ligand for lymphocyte function-associated antigen-2 (CDZ), but no detectable intercellular adhesion molecule-l (CD54), the l&and for a second AK cell-adhesion molecule LFA-1 (CDlla/18). Killing of normal progenitors by CD3- AK cells is therefore largely dependent on the interaction of the CD2-CD58 &and-receptor pathway and monoclonal antibodies to CD58 block cytotoxicity. In contrast, CD34+ myeloid blasts express large quantities of the ligands CD54 and CD58, so that binding of effecters may occur through both the CD1 la/l&CD54 and CD2CD58 pathways. Thus, killing of malignant blasts is not prevented by a monoclonal antibody to the CD58 ligand alone. The authors postulate that because of in vivo competition from erythrocytes - which express high levels of CD58 - AK cells will preferentially bind to and therefore preferentially kill malignant blasts (Fig.1). Although this suggestion is tentative, differences in patterns of CAM expression clearly provide an opportunity for selective killing by CD3- AK subsets. leukemia-specific killing by MHC-unrestricted CD3+ activated killer cells

but

Although conventional protein antigens are processed intracellularly and are recognized following association

Fig. 1. Mechanism by which AK cells may selectively kill malignant blasts. CD34+ malignant myeloid blasts express the ligands CD54 and CD58, which may be recognized by the cell-adhesion molecules CDlla/l8 and CD2 expressed on activated killer cells. Binding of AK cells to blasts, therefore, may potentially occur through two cell-adhesion systems. In contrast CD34+ normal progenitors only express CD58, and so binding to AK cells may only occur through one cell-adhesion system. Furthermore, CD58 is expressed by red cells, which may compete for the CD2 ligand and block this system.

Although bacterial products were the first superantigens described, a number of cellular products can behave in the same way, including proteins of the heat-shock family. Fisch et al. [ l6**] were able to generate CD3+ T-cell lines using Vr9 and V62 T-cell receptor proteins that recognized ligands homologous to heat-shock superantigens on the surface of Daudi, a Burkitt lymphoma line. Cross-reactive antisera to GroEL, an Escbericbiu cd protein homologous to mycobacterial heat-shock proteins, blocked the proliferative response of these fines, but antibody to MHC products had no effect. In other words, proliferation was antigen specific (to the heat-shock superantigens), but was also MHC-unrestricted. If other leukemia/‘lymphoma cells express superantigens that are qualitatively or even quantitatively different from their normal equivalents, then the CD3+ MHC-unrestricted AK cells appearing after BMT could contribute to leukemiaspecific killing.

Graft-versus-host reactions and bone-marrow

marrow and T-celldepleted 1 Conditioning including monoclonal antibodies to immune system cells

autologous marrow

Fig. 2. Schema for future bone marrow transplant (BMT) treatment regimens. Patients will receive conditioning that will include monoclonal antibodies to deplete residual host immune system cells. Patients who receive mismatched allogeneic marrow would also receive autologous T-cell-depleted marrow and interleukin (IL)-2, to prevent graft-versus-host disease while preserving graft-versus leukemia. To facilitate engraftment, all marrow recipients will be given hemopoietic growth factors that act on early progenitors, such as the recently cloned stem cell growth factor (SCF) and IL-3, followed by factors such as granulocyte colony-stimulating factor GCSF), which act on later progenitors. Following engraftment, the recipient may be immunized with a peptide vaccine specific for a fusion protein or point mutation in the original malignancy.

Immunize with oncogene fusion peptides

Mismatched allogeneic

I?

G-CSF

1

IL-2 v r\ 1/

-1

SCF and IL-3 m

G-CSF

#

I

Marrow from HLA-matched sibling or matched unrelated donor

>

Enhancement

Relative time

of GVL mechanisms

The evidence that the immune system may contribute to leukemia eradication after BMT has led to a renewal of interest in the use of immunomodulation after the procedure. However, attempts to augment GVL after allogeneic BMT using cytokines such as interleukin (IL)-2 or pharmacological agents such as linomide, have been constrained by a concern that these efforts would simply augment the growth of alloreactive donor T lymphocytes and so exacerbate GVHD. To date, therefore, immunomodulation has only been attempted in patients following autologous BMT or chemotherapy alone [ 17,18,19.]. Over the past year an approach was described that appears to allow enhancement of anti-leukemic effector function af ter allo-BMT, without exacerbating GVHD. If lethally irradiated mice receiving allogeneic T-cell replete BMT are also given IL-2 post grafting, then GVHD is both accelerated and intensified [20]. But if the mice are simultaneously given syngeneic T-cell-depleted marrow, GVHD is absent - even when donor and recipient are MHC disparate, and there is full donor engraftment [21]. Moreover, the new graft retains ‘GVL’ activity because it can eradicate leukemic cells given at the same time [22**]. Although the mechanism for this effect has not been established, it is likely that the proliferating mature T cells in the incoming graft are anergized by exposure to recipient immune system cells and high doses of IL-2. The specilicity of this anergy has been demonstrated by the capacity of T cells in the incoming immune system to prevent engraftment of a transplantable leukemia. If this approach can be demonstrated to be safe and effective in larger animals, it is reasonable to hope that we may be able to prevent GVHD even after MI-K nonidentical BMT, and yet retain or even enhance both the MIX-restricted and non-restricted GVL effects that have

transplantation Brenner and Heslop

been described. We conclude with a speculative schema to illustrate how the advances outlined in this review may modify future BMT treatment regimens (Fig.2).

AcknowledPments This work was supportedby grant CA 20180 and cancer center support (CORE) grant CA-21765 from NIH and AISAC (American

Syrian Lebanese Associated Charities).

References

and recommended

reading

Papers of special interest, published within the annual period of review, have been highlighted as: . of interest .. of outstanding interest 1. .

MCGLWE PB, BEATPI P, ASH R, HOW JM: Therapy for Chronic Myelogenous Leukemia with Unrelated Donor Bone Marrow Transplantation: Results in 102 Cases. Blo& 1990, 75:1728-1732. Describes the outcome of 102 patients with chronic myelogenous leukemia receiving MUD BMT at four centers. A high incidence of medium fo severe GVHD was seen and the Kaplan-Meier probability estimate of disease free sunival was 29% after 2.5 years. 2.

Bum

.

FE, MARTIN PJ, i%fICKELsoNEM,

PG,

JA, ILINGTON GM, THOW ED, SANDERS SI, ANASETI'Ic, %TJS6DoIW I?&', BEARMAN ET AL: Marrow Transplantation from HLAmatched Unrelated Donors for Treatment of Hematologic Malignancies. Tran.pkantution 1991, 51443447. Reviews 52 patients receiving MUD BhIT and compares their outcome with a matched cohort of 104 patients receiving HIA-matched sibling allograft. MUD recipients had a higher inci~ce of grade II-lV GVHD (79% versus 36%) but disease free survival was similar at 41% compared with 46%. The authors conclude that MUD BMT should be considered for all patients in whom HIA-matched sibling allograft would be recommended HANSEN

755

756

Transplantation 3. .

J, SINGER JW, BUCKNERCD, DURNAMD, EPSTEIN C, HIU R, STORE R, THOMAS ED, A~PELBAUM FR Use of Recom-

NEMUNAITIS

binant Factor

Human Granulocyte-macropbage Colony-stimulating in Graft Failure After Bone Marrow Transplantation. Bload 1990, 76:245-253. Describes the effect of GM-CSF administered to patients with graft failure post autologous or allogeneic BMT. Twenty one of 37 patients had an inctie in neutrophil count to > 500 and the overall sutvival was 59% compared with the historical rate of 23% in patients who met the selection criteria. 4. .

SINGERJW, NEMUNAITIS J: Recombinant

Growth Factors in Bone Marrow TrampkantaMarrow Transplantation. tion 1991, 7(suppl l):lo-12. Reviews Phase I and II trials of granulocyte colony-stimulating factor, GM-CSF and macrophage colony-stimulating factor in BMT recipients and reports provisional data on the Phase III Seattle GM-CSF trial post autograft. Patients receiving GM-CSF following autologous, allogeneic or MUD BMT had earlier hematologic recovery and aLso a reduced incidence of other post BMT complications. Bone

FERRARA JLM, DEEG HJ: Mechanisms of Disease: hostdisease. N Engl J Med 1991, 324667-674. i good ovenicw of GVHD. 5.

6.

Graft-versus-

HOROW~ MM, GALERP, ~ONDELPM, GOIJNAN JM, KERSEY J, KOLB H-J, RIMMAA, RINGDEN 0, RO~J~ANC, SPECKB, ET AL:

Graft-versus-leukemia Reactions After Bone Marrow plantation. Blood 1990, 75:55F562. 7.

15. .

HAZIEHURSTG, HOFFBRANDAV, BRENNERMK: Possible Mechanism of Selective Killing of Myeloid Leukemic Blast Cells by Lymphokine-activated Killer Cells. Blood 1991, 77:1996-2001. Proposes a mechanism by which acute myeloblastic leukemia blasts may be selectively killed by AK cells. Although > 85% of CD34+ acute myeloblastic leukemia blasts express CD54, less than 15% of normal CD34+ progenitors express this cell-adhesion molecule. Therefore, binding of AK cells to acute myelocytic leukemic blasts may occur via CD54LFA-1 or CD2XD58. In comparison, AK cells may only bind to normal progenitors via CD2XD58 and this system may be blocked by autologous red cells that express CD58. 16. ..

9.

10.

17.

JONES RJ, VOGELSANGGB, HE%~AD, FARMERER, MANN RB, GEUER RB, PUNTAWSI S, SANTOSGW: Induction of Graftversus-host Disease After Autologous Bone Marrow Transplantation. Lancer 1989, i:754-757. TAIBOT DC, POWLESRL, SLOANEJP, ROSEJ, TREIEAVEN J, ALOUD H, HELENGU\SSG, PARIKH P, SMITH C, ROWXEYM, ET AL: Cyclosporine-induced Graft-versus-host Disease Following Autologous Bone Marrow Transplantation in Acute Myeloid Leukemia. Bone Marrow Tran.pkant 1990, 6:17-20.

18.

19. .

20.

12.

JUNGS, SCHLUESNER HJ: Human

Peptide

of Single Point-mutated,

E%p Med

T Lymphocytes Recognize Oncogenic ras Proteins.

a

J

1991, 173:273-276.

Shows that T cells can specifically recognize a mutation of glycine to valine at position 12 in a synthetic peptide product of the ru.s gene. 13. ..

PFXE DJ, CHEN W, NEL‘N

14.

21.

SYKESM, RO~XK ML, HOYIIS KA, SACHSDH: In Viva Administration of Interleukin 2 Plus T Celldepleted Syngeneic Marrow Prevents Graft-versus-host Disease Mortality and Permits AUoengraftment. J E.ap Med 1990, 171:64%58.

SYKES M, ROMICKML, SACHS DH: Interleukin 2 Prevents Graft-versus-host Disease While Preserving the Graft-versusleukemia ElTect of Allogeneic T Cells. Proc Natl Acud Sci USA 1990, 87:5633-5637. Demonstrates that the GVL effect is preselved when GVHD is abrogated by co-administration of IL-2 and T-cell-depleted syngeneic marrow. Therefore the beneficial effect of allogeneic T cells can be maintained while GVHD is avoided. 23.

BEN-NERIAHY, DALF~ GQ MES-MASSONA-M, W~TE ON, BALTIMORE D: The Chronic Myelogenous Leukemia-specific

P210

Protein

is the Product

of the

bcrlabl Hybrid

Gene.

Science 1986, 233:212-214. 24.

REITIX JE, &YITLIEBD, HES~~P HE, IEGER0, DREXLERHG, HAZIEHUR~T G, HOFFBRANDAV, PRENXE HG, BRENNERMK: Endogenously Generated Activated Killer Cells Circulate After Autologous and Allogeneic Marrow Transplantation but Not After Chemotherapy. Bkmi 1989, 73:1351-1358.

C, BROWNS, NORTHME, &HERSONGL, PRENTICE HG, MEDAWAR PB: T-cell Depletion of Allogeneic Bone Marrow Prevents

22. ..

H, CHEEVERMA: T Cell Recog-

nition of Transforming Proteins Encoded by Mutated ras Proto-oncogenes. J Immunol 1991, 146:20592065. Immunization of mice with a Ras peptide containing a single amino acid substitution results in the generation of pepride-specific T cells.

MALKO~KY M, BRENNERMK, HUNT R, RA.STANS, Dow

Acceleration of Graft-versus-host Disease Induced by Exogenous Interleukin 2. Cell Immunol 1986, 103:476-480.

11.

.

BWSE D, OLIVED, STOPPAAM, VIENSP, POURRFZAU C, LOPEZM, Hematologic ATTALM, JA~MINC, MONGESG, MAWASC ET&

and Immunologic Effects of the Systemic Administration of Recombinant Interleukin-2 After Autologous Bone Marrow Transplantation. Blood 1990, 76:1092-1097. Confirms previous observations [ 17,181 that IL-2 can induce immunomodulation when administered following autologous BMT.

Oncol 1989, 16:199-210.

SOWAN JA, OE’ITELKR, SMITHSD, HANK J& FITCHP, S~NDEL . PM: Specilic Recognition of Human Leukemic Cells by Allogeneic T Cells: II Evidence for HLA-D Restricted Determinants on Leukemic Cells that are Crossreactive with Determinants Present on Unrelated Non-leukemic Cells. Blood 1990, 75:20052016. Demonstrates that in vitro activation of allogeneic T cells with leukemic blasts can result in the generation of clones that recognize leukemic targets but not remission lymphocytes from the same patient.

HESLOPHE, G~TII_IEBDJ, BIANCHIACM, MEAGERA, PRENTICE HG, MEHTAAB, HOFFBRAND AV, BRENNERMK: In Vivo In-

duction of Gamma Interferon and Tumor Necrosis Factor by Interleukin 2 Infusion Following Intensive Chemotherapy or Autologous Marrow Transplantation. Blood 1989, 74:1374-1380.

BROWNSL, MILLER RA, LRiy R: Antiidiotype Antibody Therapy

Semin

GO-I-IXIEB DJ, PRENTICE HG, HESLOPHE, BELLO-FERNANDEZ C, B~ANCHIAC, GAIAZKAA, BRENNERMK: Effects of Recombi-

nant Interleukin-2 Administration on Cytotoxic Function Following High Dose Chemo-radiotherapy for Hematological Malignancy. Bkmi 1989, 74:23352342.

Trans-

SULWANKM, STOREI R, BUCKNER CD, FEFERA, FISHER L, WEIDEN PL, WITHERSPOON RP, APPELBAUM FR, BANAJIM, HANSEN J, ET AL: Graft-versus-host Disease as Adoptive Immunotherapy in Patients with Advanced Hematologic Neoplasms. N Engf

of B-cell Lymphoma.

FISCH P, MAIKO~~KYM, KOVATS S, S’IIJRME, BRMKMANE, KLEINBS, Voss SD, MORISSN LW, DEMA% R, WELCH WJ, ET

AL: Recognition by Human V-@/vSZ T Cells of a GroEL Homolog on Daudi Burkitt’s Lymphoma Cells. Science 1990, 250:126%1273. Describes CD3+ T-cell lines using Vu9 and Vg2 T-cell receptors able to recognize a product on Daudi cells homologous to the groEL heatshock protein family. Recognition does not require antigen presentation by class I or class II MHC.

J Med 1989, 320:82&834. 8.

OBIAKOWSKI P, BEW-FERNAM)EZ C, R!XTIE JE, HESLOP S, PREN~CE HG, HE, GAJATOWICZG, VEYS P, WIWS

CHAN LC, KARHIKK, RAYTERSI, HE~STERKAMP N, ERIDANIS, PO~LES R, IAWIER SD, GROFFEN J, FOULKESJG, GRFAVESMF, WEIDERMANN LM: A Novel abl Protein Expressed in Phiiadelphia Chromosome Positive Acute Lymphoblastic Leukemia.

Nature 1987, 325:63%37. 25.

SC, MCIAUGHLINJ, GRIST WM, C~UN R, WITIEI ON: Unique Forms of the abl ‘Qmshe Kinase Distin-

CLW

Craft-versus-host reactions and bone-marrow guish Pht-positive 235:85-88. 26. .

CML from Pbl-positive

ALL. Science 1987,

THE H, CHOMIENNE C, LAN~TTEM, DEGOS 1 DEJEANA: The t(15;17) Translocation of Acute Promyelocytic Leukaemia Fuses the Retinoic Acid Receptor a Gene to a Novel Transcribed Locus. Nature 1990, 347~558-561. Reports the molecular basis of the t(15:17) of acute myelocytic leukemia. The authors describe translocation of the retinoic acid receptor locus on chromosome 17 to a novel locus my1 on chromosome 15 resulting in the generation of a chiieric transcript.

27. .

28. .

DE

VON LINDERN M, POUSTKA A, LERACH H, GRO~VELDG: Tbe (6;9)

Chromosome Tram&cation, Associated With a Specific Subtype of Acute Nonlymphocytic Leukemia, Leads to Aberrant Transcription of a Target Gene on 9q34. Mol Cell Bioll990, 1040164126. Describes t(6;9) translocation that results in the translwation of the &k gene on chromosome 6 to the can gene on chromosome 9 resulting in a fusion transcript.

and Heslop

29.

ACM, LYONSJ, ANGERB, BOHIJCE JAN~SENJWG, STEENVQOFXIEN CR: Ras Gene Mutations in JU, Bos JL, SEUGER H, BAKIIV&% Acute and Chronic Myelocytic Leukemias, Chronic Myeloproliferative Disorders, and Myelodysplastic Syndromes. Proc Nat1 Acud Sci USA 1987, 84~9228-9232.

30.

BROWETT PJ, NORTON JD: Analysis of ras Gene Mutations and Methylation State in Human Leukemias. Oncogaze 1989, 4:10291036.

HUNGERSP, GAUU N, CARROLLAJ, CRIS’~WM, LINK MP, CIEARY

ML: The t(1;19)(q23;p13) Results in Consistent Fusion of E2A and PBXl Coding Sequences in Acute Lymphoblastic Leukemias. Blood 1991, 77687-693. Demonstrates that E2&PBXl fused transcripts detected by an RNAbased polymerax chain reaction (PCR) protocol occur in 97% of cases of preB ALLwith the t(l:19) translocation, and the junction of E2A and PBXl occurs at precisely the same location in alI PCR positive cases.

transplantation Brenner

31. .

AHUJAHG, FOTI A, BAR-EII M, CUNE MJ: The

32.

RIDGESA, WORWOOD M, OSCIER D, JACOBS A, PADUA RA: FMS

Pattern of Mutational Involvement of Ras Genes in Human Hematologic Malignancies Determined by DNA Amplification and Direct Sequencing. Blood 1990, 75:1684-1690. One hundred and sixty one patients with hematologic malignancy were investigated for ras mutations by DNA amplification and direct sequencing. Eighteen patients with acute myelocytic leukemia, ALL or myelodysplasia were found to have mutations in codons, 11, 12 or 13 of N-ras

Mutations in Myelodysplastic, Leukemic and Normal jects. Proc Nail Acad Sci USA 1990, 87:1377-1380.

Sub-

MK Brenner and HE Heslop, Department of Hematology/Oncology, St Jude Children’s Research Hospital, 332 North Lauderdale, Memphis, Tennessee 38105, USA

757