IS ANAEMIA DURING CONTINUOUS AMBULATORY PERITONEAL DIALYSIS REALLY BETTER THAN DURING HAEMODIALYSIS?

1046 We conclude that metronidazole is as effective as vancomycin for the treatment of C-difficile-associated colitis and diarrhoea. Patients tolerate both drugs equally well and relapse rates are similar. Cost of treatment with metronidazole in our institution was less than one-thirtieth that with vancomycin. The remote risk that metronidazole may be carcinogenic in man must be weighed against its potential value and cost saving in the treatment of C difficile diarrhoea and colitis.

IS ANAEMIA DURING CONTINUOUS AMBULATORY PERITONEAL DIALYSIS REALLY BETTER THAN DURING HAEMODIALYSIS? A. K. SALAHUDEEN T. HAWKINS

P. M. KEAVEY R. WILKINSON

Departments of Medicine and Nephrology and Medical Physics, Freeman Hospital, Newcastle upon Tyne The level of anaemia in 22 patients on continuous ambulatory peritoneal dialysis (CAPD) was compared with that in 12 patients maintained on intermittent haemodialysis. Contrary to previous reports, the haematocrit did not differ between these groups, nor did it increase progressively with time in those on CAPD. Total red cell volume (RCV) and plasma volume were also similar in the two groups. Clearance of radioactive iron from plasma (plasma iron turnover) was higher in haemodialysis than in CAPD patients but erythrocyte radioiron utilisation (FeU) did not differ in the two groups. RCV in both CAPD and haemodialysis patients correlated positively with erythrocyte iron turnover and FeU but not with red cell survival, suggesting that the rate of production rather than destruction of red cells is the major determinant of total RCV in dialysis patients. Red cell survival was slightly but significantly higher in CAPD than in haemodialysis patients and increased with time on dialysis, but this difference was insufficient to increase total RCV in CAPD patients above that in

Summary This study was supported by the Veterans Administration and Searle Laboratories, Chicago, Illinois. It was presented in part at the 22nd Interscience Conference on Antimicrobial Agents and Chemotherapy, October 4-6, 1982, Miami, Florida.

Correspondence should be addressed to D. N. G., Infectious Disease Section, Veterans Administration Medical Center, 54th Street and 48th Avenue South, Minneapolis, Minnesota 55417, USA.

REFERENCES 1.

2.

George WL, Sutter VL, Goldstein EJC, Ludwig SL, Finegold SM. Aetiology of antimicrobial-agent-associated colitis Lancet 1979; i: 802-03. Bartlett JG, Chang TW, Gurwith M, Gorbach SL, Onderdonk AB. Antibioticassociated pseudomembranous colitis due to toxin-producing clostridia. N Engl J

Med 1978; 298: 531-34. 3. Rifkin GD, Fekety FR, Silva J Jr, Sack RB. Antibiotic-induced colitis implication ofa toxin neutralised by Clostridium sordellii antitoxin. Lancet 1977; ii: 1103-06. 4. Larson HE, Price AB. Pseudomembranous colitis: presence of clostridial toxin. Lancet

1977; ii: 1312-14. 5. Bartlett JG. Antibiotic-associated

pseudomembranous colitis.

Rev

Infect Dis 1979; 1:

530-39. 6.

7.

8. 9.

10.

George WL, Rolfe RD, Finegold SM.

Clostridium difficile and its cytotoxin in feces of patients with antimicrobial agent-associated diarrhea and miscellaneous conditions. J Clin Microbiol 1982; 15: 1049-53. Fekety R, Silva J Jr, Armstrong J, et al. Treatment of antibiotic-associated enterocolitis with vancomycin. Rev Infect Dis 1981; 3: S273-81. Tedesco F, Markham R, Gurwith M, Christie D, Bartlett JG. Oral vancomycin for antibiotic-associated pseudomembranous colitis. Lancet 1978; ii: 226-28. George WL, Rolfe RD, Harding GKM, Klein R, Putnam CW, Finegold SM. Clostridium difficile and cytotoxin in feces of patients with antimicrobial agentassociated pseudomembranous colitis. Infection 1982; 10: 205-07. Silva J Jr, Batts DH, Fekety R, Plouffe JF, Rifkin GD, Baird I. Treatment of Clostridium difficile colitis and diarrhea with vancomycin. Am J Med 1981; 71: 815-21.

11. 12.

George WL, Volpicelli NA, Stiner DB, et al. Relapse of pseudomembranous colitis after vancomycin therapy. N Engl J Med 1979; 301: 414-15. George WL, Sutter VL, Finegold SM. Toxigenicity and antimicrobial susceptibility of Clostridium difficile, a cause of antimicrobial agent-associated colitis. Curr Microbiol 1978; 1: 55-58.

13.

Dzink J, Bartlett JG. In vitro susceptibility of Clostridium difficile isolated from patients with antibiotic-associated diarrhea or colitis. Antimicrob Ag Chemother 1980; 17: 695-98.

Pashby NL, Bolton RP, Sherrif RJ. Oral metronidazole in Clostridium difficile colitis. Br Med J 1979; i: 1605-06. 15. Cherry RD, Portnoy D, Jabbari M, Daly DS, Kinnear DG, Goresky CA. Metronidazole: An alternate therapy for antibiotic-associated colitis. Gastroenterology 1982; 82: 849-951. 16. Saginur R, Hawley CR, Bartlett JG. Colitis associated with metronidazole therapy. J Infect Dis 1980; 141: 772-74. 17. Thomson G, Clark AH, Hare K, Spilg WGS. Pseudomembranous colitis after treatment with metromdazole. Br Med J 1981; 282: 864-65. 18. George WL, Sutter VL, Citron D, Finegold SM. Selective and differential medium for isolation of Clostridium difficile. J Clin Microbiol 1979; 9: 214-19. 19. Holdeman LV, Cato EP, Moore WEC. Anaerobe Laboratory Manual, 4th ed. Virginia Polytechnic Institute and State University, Blacksburg. 20. Shanholtzer CJ, Peterson LR, Olson MM, Gerding DN. Prospective study of Gram stain stool smears in diagnosis of Clostridium difficile. J Clin Microbiol 1983; 17: 14.

haemodialysis patients. Introduction ANAEMIA improves to a certain extent when a patient with renal failure is stabilised on haemodialysis or intermittent peritoneal dialysis. The rise in haematocrit in these patients is associated with an increase in effective erythropoiesis as indicated by ferrokinetic studies. 1-3 The initial rise in haematocrit or haemoglobin (Hb) that follows the first few months of continuous ambulatory peritoneal dialysis (CAPD)4-6 seems to be higher than that with haemodialysis or peritoneal dialysis. The anaemia in patients on CAPD is less severe than that in patients on other types of dialysis and the suggestion7,8 is that this difference is related to efficient removal by CAPD of uraemic toxins in the middle molecular weight range that inhibit haemoglobin synthesis9-11and encourage haemolysis.10 However, it has not been clearly established that CAPD improves production or reduces breakdown of red cells when compared with haemodialysis. We have compared anaemia in CAPD and haemodialysis patients by measuring total red cell volume (RCV), plasma volume (PV), ferrokinetics, and red cell survival (RCS). Patients and Methods

Patients

906-08.

NM, Aquino TI. Isolation of Clostridium difficile from hospitalized patients without antibiotic associated diarrhea or colitis. J Clin Microbiol 1982; 16: 659-62. 22. Tedesco FJ. Antibiotic associated pseudomembranous colitis with negative proctosigmoidoscopy examination. Gastroenterology 1979; 77: 295-97. 23. Bartlett JG. Metronidazole Johns Hopkins Med J 1981; 149: 89-92. 24. Nielson NL, Justesen T. Excretion of metronidazole in human bile. Scand J Gastroenterol 1977, 12: 1003-08. 25. Krook A, Danielsson D, Kjellander J, Jarnerot G. The effect of metronidazole and sulfasalazine on the fecal flora in patients with Crohn’s disease. Scand J Gastroenterol 1981; 16: 183-92. 26. Goldman P Metronidazole: Proven benefits and potential risks Johns Hopkins Med J 21. Varki

1980; 147: 1-9. CM, Noller KL, O’Fallon WM, Kurland LT, Dockerty MB. Lack of evidence for cancer due to use of metronidazole. N Engl Med 1979; 301: 519-22. J 28. Furman RH. Is vancomycin overpriced? N Engl J Med 1983; 308: 1542. 27. Beard

34

patients were investigated. 22 (12 male) were on CAPD, using exchanges per day, and 12 (9 male) were on haemodialysis, dialysing three times a week for 4-6 h. The mean agf of those on CAPD was 48 years and that of those on haemodialysis was 46 years. None of the patients underwent nephrectomy and only 1 had been previously transplanted. The graft had failed and he had been on regular haemodialysis for 4 months before the study. None of the patients had a multisystem disorder likely to influence the degree of anaemia. The mean duration on dialysis was 10 months for patients on CAPD and 37 months for patients on haemodialysis. The mean serum creatinine was 954 (SD 245) in the CAPD group and 881 (SD 115) mol/1 in the haemodialysis group four 2-litre

1047

(the value for this

group being the mean of pre-dialysis and postdialysis values). The mean residual creatinine clearance was 2-99 (SD 2 . 5) in CAPD and 1-88 (SD 2-9) ml/min in haemodialysis patients. Serum iron was also similar in the two groups, 13 -6(SD 4’ 2) in CAPD and 12 - 2 (SD 4 - 0) jmol/l in haemodialysis patients. None of these patients were deficient in iron as judged by plasma ferritin levels, nor in vitamin B12 or folate. During the study the patients were stable clinically, biochemically, and haematologically. None of the patients received blood transfusions within 2 months of the study and iron supplements, if any, were stopped 2 weeks before the study.

Methods Total RCV and RCS measurements using 51 Cr and iron (PIT), iron utilisation (FeU), and PV using 9Fe closely followed the methods recommended by the International Committee for Standardisation in Haematology (ICSH).12-14 Patients attended the outpatients department fasting on day 0. For patients on haemodialysis day 0 was the day before the next dialysis. For chromium labelling, 10 ml whole blood was collected in a sterile vial containing 1 -5ml acid citrate dextrose solution. Plasma was removed and 1-8MBq sodium chromate (5’Cr, specific activity 3’7-11.1 GBq/mg Cr) was used to label the packed red cells. A further 10 ml heparinised whole blood was obtained from the patient and the plasma was labelled with 0- 18 MBq iron citrate specific activity 0 -49 GBq/mg iron). After labelling, the red cells and plasma were reinjected intravenously in succession. Four blood samples of 8 ml each were taken at 15,30,45, and 90 min after injection. Further 4 ml samples were taken approximately 1, 3, 7, 10, 14, 21, and 28 days after day 0. From each sample, a small volume (0 - 5 ml) was taken for haematocrit estimation by the micro method. The volume dilution technique was used to calculate total RCV and PV. The method of least squares was used to obtain the regression line for the disappearance of59Fe from the plasma on day 0. This line provided data from which PV, PIT, and FeU could be calculated. In each patient, the value recorded for FeU was obtained from the blood sample which gave the highest 59Fe activity after day 0 (usually 14 days after injection). The least squares technique was also applied to the 51 Cr data obtained from the whole blood samples from day 1 onwards and the slope of the regression line was used to determine RCS half time (T/2). No correction was made for elution of 5’Cr from the red cells. Values for erythrocyte iron turnover (BIT) and non-EIT were derived from PIT and FeU for each patient. Non-EIT includes iron going to non-erythroid tissues, iron lost with haemoglobin when normoblast denucleation occurs, iron associated with "ineffective" erythropoiesis, and iron involved in reflux. Blood lost during haemodialysis was measured in 7 patients (2 of whom were not part of the present study) to estimate any effect this may have had on RCS. The volume of blood lost in dialysers, tubing, and swabs collected after each dialysis was calculated from the 51 Cr and 59Fe activity measured on a whole body monitor. Each measurement was referenced to a blood sample taken immediately before the start of dialysis. RCS was subsequently determined for these patients with and without correction for blood loss. Each patient underwent an average of 11dialyses over the period of the study. The mean volume of blood lost per dialysis per patient ranged from 4,55 (SD 2 - 2) ml to 10’77 (SD 6-9) ml. When RCS for haemodialysis patients was calculated with and without blood loss correction, the mean difference in halftime, T/2, was 0 -9±0 -5(SD) days. The data for RCS presented here are uncorrected.

plasma

turnover

The PIT (normal value 125 -3 mol/1 blood/day’6) was but significantly higher for haemodialysis (111-8, SD 29 - 8) than for CAPD patients (94 -2, SD 19 - 7; p<0 - 05). The non-EIT (normal value 25 mol/1 blood/dayI6) was also higher in the haemodialysis group (75 - 2, SD 23 - 7) than in the CAPD group (64 -8, SD 13 -9), but the difference did not reach significance. The mean FeU (normal value 80% of injected radioironl6) in the CAPD and haemodialysis groups did not differ significantly-30 - 7 (SD 8 - 2) and 31 - 7% (SD

slightly

13 - 2) of injected radioiron, respectively. The EIT (normal value 100-3 mol/1 blood/dayl6) in patients on haemodialysis (36 - 6, SD 19 - 9) was higher than in the patients on CAPD (29 - 4, SD 11 - 8), but the difference did not reach significance. The total RCV in both CAPD and showed a significant positive haemodialysis groups correlation with FeU (r+0-48, p=0-02 and r+0-94, respectively) (fig 1) and with EIT (r+0-53, p<0-001, p<0-02 and r + 0 - 89, p<0 - 001, respectively).

(59Fe,

.

;

-

.

Results The mean total RCV in CAPD was 539% (SD 87) of the normal valuel5and in haemodialysis 56 - 5% (SD 14-7) of normal (p<0 05, Student’st test). Mean PV was 109% (SD 13.2) of normal15 in 10 haemodialysis patients and 10 1 % (SD 14) of normal in the CAPD group (p>O. 05). (PV measurements in 2 haemodialysis patients were omitted for technical reasons.)

10

I ç

Fig la-Red cell volume vs 59Fe utilisation in continuous ambulatory peritoneal dialysis patients.

Fig lb-Red cell volume vs 59Fe utilisation in patients on intermittent haemodialysis. The RCS was lower than the normal range of 25-32 days17 in 7 of the 11 patients on haemodialysis and in 6 of the 22 patients on CAPD. The mean RCS in CAPD patients (26 - 4, SD 2’ 7 days) was slightly but significantly higher (p<0 . 02) than that in haemodialysis patients (23-4, SD 3’ 9 days) (fig 2). Moreover, the RCS in CAPD showed a weak but

1048

with relation between total RCV and RCS. None of the other measurements in CAPD showed any significant relation with duration on CAPD.

significant positive correlation (r+0-46, p<0’05) months on dialysis (fig 3). There was no significant

pig 2-Red cell survival in patients .

peritoneal dialysis (CAPD) (HD) (mean±1 SD).

and

on

continuous ambulatory intermittent haemodialysis

on

Hefti et al recently reported a shortened mean RCS of 20’ 0 (SD 4-9) days in 11 CAPD patients.19 Their finding was based on examination of 5-6 blood samples taken over 2 weeks, unlike our study, in which the sampling period extended over 4 weeks. 2 weeks is not generally considered adequate and it is recommended that frequent samples be taken over an interval equivalent to at least the RCS half-time. 20 Interestingly, when RCS was recalculated using data from samples (usually 5) taken over the first 14 days, the mean RCS was 24 - 2 (SD 4 - 3) days, which was shorter than results based on data from a 4 week sampling period (p<0. 05). Thus the shortness of the sampling period may well have produced a significant underestimate of RCS in the patients of Hefti et al. The slightly higher RCS in CAPD, which increases with duration on dialysis, suggests that the improvement in RCS in these patients may be related to effective removal of uraemic toxins in the middle molecular range by CAPD. An alternative explanation would be that blood in CAPD patients is not exposed, as in haemodialysis, to substances such as chloramine or formaldehyde, which are thought to induce haemolysis,21,22 or to an extracorporeal circulation which may adversely affect the erythrocyte life span. However, the slight improvement in RCS seen in our CAPD patients neither relates to nor increases the RCV. We conclude that the severity of anaemia in patients on these two types of dialysis is little different. Furthermore, there is evidence that it is the rate of erythropoiesis rather than the rate of red cell destruction which determines the degree of anaemia. The effective erythropoiesis is the same in each, but the RCS may be slightly longer in CAPD. We thank Prof D. N. S. Kerr for his criticism of the study, Dr R. W. Elliot and Dr M. K. Ward for allowing us to study some of their patients, Sister P. Buckley for her help with the haemodialysis patients, and Miss D. E. Lenaghan for secretarial help.

Fig 3-Red cell survival vs time on continuous ambulatory peritoneal

dialysis.

at

the Renal Association

meeting held

in London

Correspondence should be addressed to P. K., Department Physics, Freeman Hospital, Newcastle upon Tyne NE7 7DN.

Discussion

significant difference between CAPD and haemodialysis patients in Hb, haematocrit, or total RCV. Although the mean PV in CAPD patients was near normal, the initial rise of haematocrit seen in some CAPD patients soon after starting the dialysis may have been related to haemoconcentration.18 The PV in these patients depends partly on how vigorously fluid is removed by dialysis, a factor that would vary from centre to centre. The effective erythropoiesis, as measured by FeU and EIT, differs little between CAPD and haemodialysis patients. The total RCV in CAPD and haemodialysis patients did not relate to RCS but showed a positive correlation with FeU and EIT in both groups. This suggests that the primary factor determining the degree of anaemia in both types of dialysis is reduced red-cell production rather than reduced RCS, as suggested by another report.19 The higher PIT seen in haemodialysis patients does not seem to be related to greater erythropoiesis in haemodialysis than in CAPD patients. The mean RCS in CAPD patients was within the normal range and was significantly higher than that in the haemodialysis patients. However, if the mean blood loss factor of 0 - 9 days is applied to the RCS data for all the haemodialysis patients, the mean RCS is then 24 - 3 (SD 3 - 9) days, which is no longer significantly different (p>0 . 05) from the mean RCS for CAPD patients. We found

This paper was read 1983.

no

on

May 26,

of Medical

REFERENCES 1. Kurtides ES, Rambach WA, Alt HL, Greco DL Effect of haemodialysis or erythrokinetics in anaemia of uraemia J Lab Clin Med 1964, 63: 469-79 2. Eschbach JW, Funk D, Adamson J, Kuhn I, Scribner BH, Finch CA. Erythropoiesis in patients with renal failure undergoing chronic dialysis. N Engl J Med 1967, 276: 653-58. 3. Mann DL, Donati RM, Gallagher NI Erythropoietin assay and ferrokinetic measurements in anaemic uraemic patients. JAMA 1965; 194: 1321-22. 4. Oreopoulos DG, Dombros N, Robson M, Pierratos A. First year’s experience with continuous ambulatory peritoneal dialysis(CAPD). Proc Dialysis Transplant Forum 1978; 8: 242-44. 5. Moncrief JW, Nolph KD, Rubin J, Popovich RP. Additional experience with continuous ambulatory peritoneal dialysis (CAPD). Trans Am Soc Artif Intern Organs 1978; 24: 476-82. 6. Gokal R, McHugh M, Fryer R, Ward MK, Kerr DNS. One year’s experience in a UK dialysis unit. Br Med J 1980; 281: 494-97. 7. Editorial Anaemia in chronic renal failure. Lancet 1983; i: 965-66. 8. Bergstrom J. Serum middle molecules and continuous ambulatory peritoneal dialysis Perit Dial Bull 1982; 2: 59-61. 9. Bergstrom J, Furst P. Uraemic middle molecules. Clin Nephrol 1976; 5: 143-52. 10. Leber HW, Spiegelhalton R, Ulm A, Groubeaud G, Rawer P. Influence of middle molecules on the anaemia of uraemic patients Artif Organs 1978; 2: 378-81 11. Ohno Y, Fisher JW Inhibition of bone marrow erythroid colony forming cells (CFU-E) by serum from chronic anaemic uraemic rabbits. Proc Soc Exp Biol Med 1977; 156: 56-58. 12. ICSH. Standard techniques for the measurement of red-cell and plasma volume Br J Haematol 1973; 25: 801-14. 13. ICSH. Recommended methods for radioisotope red-cell survival studies. Br J Haematol 1971; 21: 241-50. 14. ICSH. Recommended methods for ferrokinetic studies. ICSH tentative standard EP 8/4: 1977. 15. Hurley PJ. Red cell and plasma volumes in normal adults .J Nucl Med 1975; 16:46-52 16. Wintrobe MM, Lee GR, Boggs DR, Bithell TC, Athens JW, Foerster J. Clinical Hematology. Philadelphia: Lea and Febiger, 1974: 165.

1049

UNIQUE PATTERN OF EPSTEIN-BARR VIRUS

Determination

SPECIFIC ANTIBODIES IN RECURRENT

Antibodies to EBV capsid antigen (VCA) and D and/or R component of early antigen (EA) were determined by the indirect immunofluorescence technique described previously.4Antibodies to EBV-associated nuclear antigen (EBNA) were detected by the anti-complement immunofluorescence technique.5P3HR-1 cells were used for VCA antigen, P3HR- EBV infected Raji cells for EA, and uninfected Raji cells for EBNA antigen. Cell smears for EA were prepared and fixed in acetone (which preserves both D and R components) or in methanol (which denatures R but not D). EA-DR complex and EA-R were by the method of Henle and Henle described earlier. Fluorescein (FITC)-conjugated rabbit immunoglobulins to human IgG (y-chain), IgA (a-chain), IgM (-chain), and complement (C3) were purchased from DAKO immunoglobulins (Denmark). Titres of antibody were expressed as reciprocals of the maximum dilutions of serum (2-fold from the initial 1/10 dilution) that gave fluorescence.

PAROTITIS IZUMI AKABOSHI

TAKATO KATSUKI ICHIRO MATSUDA

JIRO JAMAMOTO Departments of Paediatrics and Microbiology,

Kumamoto

University Medical School, Kumamoto, Japan Sera from 34 children with recurrent parotitis were measured by indirect immunofluorescence technique for antibody levels to several Epstein-Barr virus (EBV) antigens. IgG antibodies to EBVcapsid antigen (VCA) and EBV-associated nuclear antigen, often at high titres, were found in 29 of these patients, of whom 20 also had IgA antibody to VCA. Antibody level to early antigen complex (R and D) rose in 19 patients, of whom 18 had antibody to the R component alone. The abnormal patterns of EBV antibodies persisted for 3-14 months during and after the illness in 8 patients. These observations suggest that EBV infection may be important in the pathogenesis of

Summary

recurrent

of Antibodies to EB V

estimated

Determination

of Antibody to Mumps

Virus

Haemagglutination inhibition antibody by the conventional procedure.

for mumps virus

Results

parotitis.

-

The incidence of positive anti-EBV antibodies in the RP patients and healthy age-matched controls is listed in table I.

Introduction RECURRENT parotitis (RP) occurs mostly in children less than ten years old. In most of them, punctuate shadows, ascribed to changes in the peripheral duct, are seen in sialograms, but these changes are not unique to recurrent parotitis in children. There is a tendency to spontaneous remission at puberty. The frequency and severity of are recurrences variable and are not of prognostic The cause of the disease is still unknown. significance. include Suggestions congenital malformation of the parotid or glands, primary secondary infection, allergy, or local manifestation of systemic immunological diseases.I,2 Our study, reported here, was planned to test the hypothesis that RP might be related to Epstein-Barr virus (EBV) infection. After the start of our study there was a report that the salivary glands are the site of EBV production in the oropharynx.3

Patients and Methods

During 1979-82 sera were collected from 34 patients (19 male, 15 female) with recurrent parotid swelling and 40 age-matched controls. They were residents of Kumamoto district (southern part of Japan), and they ranged in age from 2 to 12 years. They had unilateral or bilateral recurrent (more than 4 times) swelling of the parotid gland, accompanied by slight fever and tenderness. The swelling always subsided completely within a month. Levels of immunoglobulin, C-reactive protein, rheumatoid factor, anti-DNA antibodies, and antinuclear antibodies were either normal or negative. 8 patients were followed up in our outpatient clinic for 3-14 months. Punctuate shadows were seen in sialograms taken during the symptom-free period.

TABLE I-EBV-SPECIFIC ANTIBODY RESPONSES IN

Controls = healthy children aged 4-7

34 PATIENTS

yr. ND=not done.

‘

5/34 patients (15%) were seronegative for IgG class antibody VCA (VCA-IgG), suggesting that they had not had experience of primary infection with EBV. There were no differences between the seropositive and the seronegative patients in clinical features. Among 29 seropositive patients, 3 patients had IgM antibody to VCA (VCA-IgM) and also IgG antibody to EA-DR complex (EA[R+D]-IgG). 19/34 patients were positive for EA(R+D)-IgG, and all except 1 had higher titre to R than to D. 20/34 patients had IgA class antibody to VCA (VCA-IgA). High titres (>640) ofVCA-IgG and EBNA antibody were found in 18 (53%) and 14 (41%) RP patients, respectively (fig 1). Among these, 3 and 4 patients, respectively, were negative for EA (R+D)-IgG. Fig 2 shows the relation between EA(R+D)-IgG and EAIgG to D. Among the 19 patients with positive EA(R + D)-IgG, 14 were

to

17 Szur L. Blood cell survival studies. In: Belcher

EH, Vetter H, eds. Radioisotopes in Diagnosis. London: Butterworth 1971: 342-82. De Paepe M, Lameire N, Schelstraete K, Ringoir S. Evolution of red cell mass and haematocrit readings in patients on continuous ambulatory peritoneal dialysis. In: Crahl GM, Kessel M, Nolph KD, eds. Amsterdam: Excerpta Medica, 1981. Hefti JE, Blumberg A, Martin HR. Red cell survival and red cell enzymes in patients on continuous peritoneal dialysis (CAPD). Clin Nephrol 1983; 19: 232-35. Bentley SA. Red cell survival studies reinterpreted. In: Lewis SM, ed. Radioisotopes in haematology (Clinics in haematology, vol 6/no 3). Philadelphia and Eastbourne: WB Saunders, 1977: 601-23. Eaton JW, Kolpin CF, Swofford HS. Chlorinated urban water. Science 1973; 181: Medical

18

19 20

21.

463-67. 22

was

measured

Orringer EP, Mattern WP. Formaldehyde induced haemolysis during chronic dialysis. N Engl J Med 1976; 294: 1416-18.

---

Fig 1-Titres of Epstein-Barr virus associated antibodies. *= patients, &Dgr;= controls.