Recurrent anemia in kidney transplant recipients with parvovirus B19 infection.

Parvovirus B19 (PV B19) infection is known to cause acute anemia in solid organ transplant recipients. Intravenous immunoglobulin combined with reduction of immunosuppression may be of benefit to clear the infection. However, PV B19-associated anemia can be recurrent. We describe three renal transplant recipients with a PV B19 infection. These patients showed recurrent anemia with episodes separated by as much as several months.

Factors influencing the onset of diabetes mellitus after kidney transplantation: a single French center experience.

Posttransplantation diabetes mellitus (PTDM) is a complication arising mostly during the first 6 months after kidney transplantation. Considering the serious outcomes of chronic hyperglycemia in kidney transplant patients, the recognition of factors that contribute to the onset of PTDM is of particular relevance. A retrospective analysis was performed to document the incidence of and the risk factors for diabetes mellitus occurring in the first year after kidney transplantation among 177 adult patients, without previously known diabetes transplanted between January 1998 and December 2000. PTDM, defined as fasting plasma glucose > or = 126 mg/dL confirmed by repeat testing on a different day, occurred in 48 (27.12%) patients of whom 36 showed transient changes during the first year after transplantation. Univariate analysis identified variables to be associated with the onset of PTDM: older recipient age (P = .05), male gender (P = .03), family history of diabetes (P = .04), advanced donor age (P = .008), absence of induction immunosuppression (P = .04), use of tacrolimus (vs cyclosporine; P = .01), one or more than one (steroid-treated) acute rejection episode(s) (P = .000001), cytomegalovirus infection (P = .02), and use of beta-blockers or diuretics (P = .05). By multivariate analysis, five factors were independently associated with the onset of PTDM: two episodes of rejection (odds ratio = 42.69, P = .000025), one episode of rejection (5.01, P = .007), older recipient age (1.06, P = .017), family history of diabetes (7.24, P = .011), and weight at transplantation (1.03, P = .048). Tacrolimus treatment remained of borderline significance (2.77, P = .05). In addition to traditional risk factors predisposing to the development of type 2 diabetes in the general population, episodes of acute rejection significantly influence the incidence of PTDM.

A renal allograft recipient with late recurrence of focal and segmental glomerulosclerosis after switching from cyclosporine to tacrolimus.

BACKGROUND: Focal and segmental glomerulosclerosis (FSGS) is one of the most frequent and severe primary glomerulonephritis that recurs in transplanted kidneys. Although cyclosporine seems to have no effect on the frequency of FSGS recurrence, there is evidence that cyclosporine reduces proteinuria and prolongs graft survival in patients with recurrent glomerulonephritis after renal transplantation. The effect of tacrolimus on nephrotic syndrome after renal transplantation is controversial. METHODS: We describe the case of a 30-year-old man with steroid-resistant nephrotic syndrome due to FSGS who developed nephrotic syndrome 5 years after renal transplantation due to recurrent disease when he was switched from cyclosporine to tacrolimus. RESULTS: He was given pulses of methylprednisolone and returned to cyclosporine. His proteinuria decreased, but he rapidly developed chronic renal failure. CONCLUSIONS: This observation strongly suggests that tacrolimus should be given with considerable care in renal transplant recipients with FSGS.

Early increase of peripheral B cell levels in kidney transplant recipients with CMV infection or reactivation.

BACKGROUND: Cytomegalovirus (CMV) infection or reactivation is a frequent complication of renal transplantation. Diagnosis of these conditions relies on the detection of circulating antigen, or of specific IgM and/or IgG, which develop over several weeks. Evocative clinical features may be detected earlier, but lack specificity. Rapid and early changes in the partition of lymphocyte subsets could be an additional indication of pending CMV infection. METHODS: A systematic follow-up of peripheral B lymphocytes identified immunophenotypically by the determination of surface immunoglobulins (sIg), performed in 97 kidney transplant recipients, allowed to identify transient increases apparently predictive of CMV primo-infection or reactivation over the next 3 months. To better define the nature of these B cells, an extended investigation was performed for 14 prospective patients. In addition to surface Ig, membrane CD19, HLA-DR, and CD80 expression were explored. The cytoplasmic presence of mu, kappa, and lambda chains was also examined. B cell function was investigated using the ELISPOT technique, which allows an enumeration of the populations of IgG, IgA, and IgM secreting B cells. RESULTS: Retrospective analysis of the clinical outcome of the cohort of 97 patients evidenced that early transient increases in B cell levels were significantly (P<0.0001) associated with CMV infection. The same trend was noted in the smaller series of patients who benefited from a more extensive investigation of B cells, 10 of whom presented clinical or biological signs of CMV infection. Mature B cells, expressing surface Ig, CD19, DR, and CD80 are those presenting transient increases. No significant variation of preB (cmu+/kappalambda-) or activated (spot-forming) cells was evidenced in these patients. CONCLUSION: Individual examination of each patient's immune reconstitution profile allows to detect transient peaks of mature B cell during the initial immunosuppressive therapy, that appear to be predictive of oncoming CMV infection or reactivation.

A randomized multicenter trial comparing leukocyte function-associated antigen-1 monoclonal antibody with rabbit antithymocyte globulin as induction treatment in first kidney transplantations.

Adhesion molecules are involved in several steps in the immune response: leukocyte adhesion to the endothelium, transendothelial migration, cooperation between immunocompetent cells, and cytotoxicity. Leukocyte function-associated antigen-1 plays a central role among adhesion molecules. In a multicenter randomized open trial, we compared a monoclonal antibody directed against the alpha chain of LFA-1 (Oduli-momab; IMTIX/Pasteur Mérieux Sérums et Vaccins) with rabbit antithymocyte globulin (rATG; IMTIX/Pasteur Mérieux Sérums et Vaccins), as part of a quadruple sequential protocol in 101 patients receiving a first kidney transplant. Clinical tolerance of anti-LFA-1 mAb was better than that of rATG. Short-term rejection rates (< 15 days) were not significantly different (15% and 16% for anti-LFA-1 mAb and rATG, respectively). However, 11% of the anti-LFA-1 mAb patients experienced rejection during the first 10 days of the treatment course compared with none of the patients treated with rATG. The incidence and severity of acute rejection in the first 3 months was not significantly different between groups. Of the LFA-1 and rATG patients, 96% and 92% of the grafts, respectively, were functioning at 12 months. The incidence and severity of infection, whatever the origin, were comparable in both groups. In addition, it was observed that fewer patients required posttransplantation dialysis in the anti-LFA-1 mAb group (19%, vs. 35% for rATG), although the difference was not statistically significant. Altogether, the beneficial action of this monoclonal antibody on short-term renal function recovery makes it a useful tool in the management of renal patients undergoing kidney transplantation.

Increased usage of TCR V-beta8 in kidney transplant recipients with aberrant immune reconstitution and clinical complications.

BACKGROUND: The efficiency of immunosuppressive drugs prescribed after organ transplantation is mostly monitored through clinical and biological signs of organ rejection or infection. However, it may be expected that some patients develop subtle alterations of their reconstituting immune system, not immediately associated with clinical events. Identification of such anomalies could be useful to alert clinicians for possible future complications. METHODS: A systematic follow-up of peripheral lymphocyte subsets, performed in a cohort of 89 kidney transplant recipients, identified severely skewed CD4/CD8 ratios in 32 patients. For 19 patients, the expression of specific T cell receptor fragments was examined using a panel of 10 monoclonal antibodies. Abnormal control of spontaneously Epstein Barr virus-infected B cells was tested by investigating for the generation of spontaneous lymphoblastoid cell lines in 17 cases. The incidence of rejection and infectious episodes was monitored. RESULTS: A bias in T cell receptor fragments usage was detected in 14/19 cases, involving Vbeta8 in all cases. Spontaneous lymphoblastoid cell lines of Epstein Barr positive B blasts developed in 9 of 17 cases. Eleven patients had early rejection episodes and 16 presented with viral primo-infection or reactivation. The incidence of rejection and infectious episodes was higher in the group of 32 patients who developed such abnormal patterns than in the 57 who did not. CONCLUSION: Transient bias in the T cell receptor repertoire may be observed during immune reconstitution after kidney transplantation, perhaps related to abnormal lymphocyte functions and associated to an impaired control of rejection and/or infectious agents.

Induction versus noninduction in renal transplant recipients with tacrolimus-based immunosuppression.

BACKGROUND: The aim of this study was to compare the efficacy and safety of induction treatment with antithymocyte globulins (ATG) followed by tacrolimus therapy with immediate tacrolimus therapy in renal transplant recipients. METHODS: This 12-month, open, prospective study was conducted in 15 centers in France and 1 center in Belgium; 309 patients were randomized to receive either induction therapy with ATG (n=151) followed by initiation of tacrolimus on day 9 or immediate tacrolimus-based triple therapy (n=158). In both study arms, the initial daily tacrolimus dose was 0.2 mg/kg. Steroid boluses were given in the first 2 days and tapered thereafter from 20 mg/day to 5 mg/day. Azathioprine was administered at 1-2 mg/kg per day. RESULTS: At month 12, biopsy-confirmed acute rejections were reported for 15.2% (induction) and 30.4% (noninduction) of patients (P=0.001). The incidence of steroid-sensitive acute rejections was 7.9% (induction) and 22.2% (noninduction)(P=0.001). Steroid-resistant acute rejections were reported for 8.6% (induction) and 8.9% (noninduction) of patients. A total of nine patients died. Patient survival and graft survival at month 12 was similar in both treatment groups (97.4% vs. 96.8% and 92.1% vs. 91.1%, respectively). Statistically significant differences in the incidence of adverse events were found for cytomegalovirus (CMV) infection (induction, 32.5% vs. noninduction, 19.0%, P=0.009), leukopenia (37.3% vs. 9.5%, P<0.001), fever (25.2% vs. 10.1%, P=0.001), herpes simplex (17.9% vs. 5.7%, P=0.001), and thrombocytopenia (11.3% vs. 3.2%, P=0.007). In the induction group, serum sickness was observed in 10.6% of patients. The incidence of new onset diabetes mellitus was 3.4% (induction) and 4.5% (noninduction). CONCLUSION: Low incidences of acute rejection were found in both treatment arms. Induction treatment with ATG has the advantage of a lower incidence of acute rejection, but it significantly increases adverse events, particularly CMV infection.

Successful surgical thrombectomy of renal allograft vein thrombosis in the early postoperative period.

We report the successful surgical treatment of two cases of renal vein thrombosis, each occurring early after kidney transplantation. Prompt intervention was a result of accurate diagnosis by color Doppler ultrasonography. Invasive radiological procedures were not useful. Although recent advances in thrombolytic therapy have created several alternatives to open surgery, the rationale for surgical exploration in these cases was to remove the thrombus quickly, to avoid the postoperative bleeding complications of thrombolytic therapy, and to correct any technical or anatomic problems.

Factors predisposing to post-renal transplant erythrocytosis. A prospective matched-pair control study.

We conducted a prospective study on 81 consecutive patients who had a kidney transplant with graft function for over 3 months to evaluate the prevalence of erythrocytosis following renal transplantation (PTE) and its potential risk factors. True PTE was defined as a RBC mass > 120% of the theoretical value allowing for sex, weight and height. 18 patients (22.2%) developed PTE (RBC mass = 157 +/- 21%) with no evidence of polycythemia vera (PV), or secondary polycythemia due to reduced arterial oxygen, kidney or hepatic tumors. PTE was more common in males (p = 0.041) and less common in patients treated with recombinant erythropoietin (rHEPO) prior to transplantation. 18 non-polycythemic patients (Hb 12.6 +/- 1.3 g/dl) matched for sex, age and renal function were used as case controls. Fewer PTE patients were transfused post-transplantation (p = 0.026). At the time of diagnosis, mean serum EPO was normal and similar to that of controls. PTE patients had lower serum ferritin (p = 0.005) and more commonly received iron supplementation when PTE occurred (p = 0.003). Other clinical factors did not differ significantly between the two groups. Two patients had a thrombotic event, 6 recovered spontaneously and 11 were successfully treated with angiotensin-converting enzyme inhibitors (ACEI). The normalization of Hb, hematocrit and RBC mass in ACEI treated patients was accompanied by a decline in serum EPO (p = 0.008). We conclude that true erythrocytosis is prevalent in cyclosporine-treated renal transplant patients. PTE seems to be an idiopathic erythrocytosis. Pretransplant rHEPO treatment may limit PTE by blunting the increased sensitivity of erythroid precursors to EPO and iron supplementation, which stimulates the development of PTE. ACEI treatment is effective and safe.

Renal transplantation in patients over sixty years of age.

The aim of this study was to analyze whether old age affects the outcome of renal transplantation. Data were presented on all 337 renal allografts performed from January 1, 1987 to November 30, 1992 in the department of Nephrology and Urology, University Hospital of Nancy. Of these, 32 (9.5%) were performed in patients over 60 years old at the time of transplantation (mean duration of follow-up 22.3 +/- 17.1 months). No significant difference was noted in patient and graft survivals between the two groups at 36 months (respectively 83.8% and 76.1% in elderly patients; 96% and 82.8% in younger recipients). In the older group, all grafts were lost due to death (2/5) or nephrectomy (3/5) with a functional transplant (3/5) whereas chronic rejection accounted for the majority of graft loss in the younger group (23/43, p < 0.05). Episodes of acute rejection occurred with a very low incidence in elderly patients (15.6%). Infections were infrequent in this group and did not represent serious complications. Functional rehabilitation and quality of life were as good in elderly as in younger recipients. These results suggest that renal transplantation is an acceptable form of treatment for patients older than 60 years with end-stage renal disease in the absence of obvious contraindication.

Relationship between blood pressure and renin, angiotensin II and atrial natriuretic factor after renal transplantation.

The objective of the study was to assess the evolution of renin, angiotensin II, atrial natriuretic factor (ANF) and blood pressure (BP) in the first trimester following renal transplantation in man Thirty-two recipients were investigated for 3 months post-transplantation. Twenty had a history of hypertension with moderate cardiac hypertrophy. Thirty-one retained their native kidneys. Five kidney donors had a history of mild hypertension. The recipients were perioperatively volume-expanded with 0.9% saline and diuresis was maintained for 48 h with furosemide and dopamine. The sodium intake was 25 mEq/24 hours. Prophylactic immunosuppressive therapy was antilymphocyteglobulins (25 cases), or anti-LFA1 (7 cases) and maintenance therapy was cyclosporine-prednisone (8 cases), or cyclosporine-prednisone-azathioprine (24 cases). Mean BP, serum creatinine, urinary sodium excretion (UNA) and hormonal (renin, angiotensin II and ANF) parameters were collected every other day for the first week after transplantation and then twice monthly. Twenty (62.5%) patients developed hypertension and hypertension was more frequent in patients with a delayed graft function, than in patients with immediate good graft function (10/20 vs. 4/12, p < 0.05%). Both hypertensive (group HBP) and normotensive (group NBP) patients had similar very low renin and angiotensin II plasma levels, after an initial early peak. Analysis of covariance with multiple regression analysis showed that in the HBP patients, BP was negatively correlated with UNA (p = 0.02) and positively with plasma ANF (p < 0.01). The normal BP patients also showed a correlation between BP and UNA, although it was limit of statistical significance (p = 0.05); there was no correlation between ANF and BP. We conclude that the RAS is rapidly depressed after renal transplantation and does not interfere with BP regulation. The hypertension in the early stage of post-transplantation varies inversely with the urinary sodium excretion. The defective sodium excretion, which dominates the effect of the low sodium diet, results in volume overload, increased ANF and volume-dependent hypertension.

[Cardiac pheochromocytoma. Failure of classic non-invasive diagnostic methods]. / Phéochromocytome à localisation cardiaque. Echec des méthodes diagnostiques non invasives classiques.

We report an exceptional case of cardiac pheochromocytoma which raised problems of localization. A 30-year old man who for several years had been hypertensive was admitted for attacks of paroxysmal hypertension. Very high levels of urinary catecholamines suggested a diagnosis of pheochromocytoma, but no tumour was found at computerized tomography (CT) and metaiodobenzylguanidine (MIBG) scintigraphy. However, regional venous samplings detected two para-carotid phaeochromocytomas which were surgically removed. Thereafter, the symptoms persisted and investigations were resumed. As new regional venous samplings persisted and investigations were resumed. As new regional venous samplings showed high levels of catecholamines in the right atrium, a mediastinal and, chiefly, cardiac phaeochromocytomas was suspected. No tumour was visible at CT or ultrasonography and another MIBG scintigraphy proved negative. Coronary angiography showed a very large tumour behind the left atrium, well supplied by the circumflex artery and by a branch of the right coronary artery. The patient was operated upon and is now totally asymptomatic after a 9-month follow-up. This case emphasizes the value of invasive methods (i.e. regional venous sampling and coronary angiography) in the localization of this ectopic tumour. In most cases, however, phaeochromocytomas can be localized by MIBG scintigraphy.

[Is enoxaparine (PK 10169) a good anticoagulant in chronic hemodialysis?]. / L'énoxaparine (PK 10,169) est-elle un bon anticoagulant dans l'hémodialyse itérative?

Tolerance and efficacy of single i. v. injections of PK 10169 (1 mg/kg) during installation were evaluated in 10 patients with stable chronic renal insufficiency treated with 3 sessions of hemodialysis weekly (sessions of 4 and 5 hours). Tolerance was good in all cases. Efficacy was globally satisfactory (no complete coagulation) but by the 4th hour in 7 out of 30 sessions coagulation was apparent in the bubble trap with elevation of residual blood volume, recurring in the same patient but not affecting result of dialysis. In these cases anti-Xa activity was reduced from the 2nd hour and at end of dialysis, with a markedly elevated FPA level. For most patients it is possible to envisage 5-hour sessions, but in those few susceptible to develop coagulation repeated clinical surveillance of all circuit elements is necessary.

[Indications and results of parathyroidectomy in the treatment of hyperparathyroidism in dialyzed and kidney transplant patients. Apropos of 68 cases]. / Indications et résultats de la parathyroïdectomie dans le traitement de l'hyperparathyroïdie du dialysé et du transplanté rénal. A propos de 68 observations.

Between 1972 and 1985, 78 parathyroidectomies were performed in 60 patients under chronic haemodialysis and in 6 recipients of renal transplants. These patients had severe hyperparathyroidism and radiological evidence of fibrous osteitis. This series shows a recrudescence of tertiary hyperparathyroidism in renal transplant recipients under ciclosporin. The post-operative course was favourable in 55 cases; 13 patients had to be reoperated upon, revealing the presence of supernumerary glands in 6 of them.

[Mesangial IgA deposits nephropathy]. / La néphropathie à dépôts mésangiaux d'IgA.

Idiopathic IgA nephropathy of Berger's disease is characterized by prominent and diffuse IgA deposits in the mesangium. In many countries, it is the most common type of primary chronic glomerulonephritis. Typically, it is revealed by recurrent episodes of gross hematuria in association with ENT infection, but it can progress insidiously with microscopic hematuria and proteinuria. Serum IgA levels are increased in about 50% of cases. IgA nephropathy is not a minor condition: 20% of patients develop end-stage chronic renal failure 10 years after diagnosis and 50% after 20 years. IgA nephropathy can recur in a transplanted kidney suggesting that this disease is a systemic disorder although it has a remarkable tropism for the kidney. Even though many points remain to be elucidated, its pathogenesis appears to be linked to a genetic factor responsible for a lymphocyte dysfunction and an acquired environmental factor such as penetration of an antigen via the mucosa which may give rise to an excessive and inappropriate IgA immune response with the deposition of IgA in the mesangium and the development of progressive renal alterations. No treatment has been shown to be effective but tonsillectomy advised in case of a recurrent tonsillar focal infection is most often accompanied by a decrease in the incidence of gross hematuria. Corticosteroid therapy can be of benefit in cases involving a nephrotic syndrome associated with minimal glomerular lesions. In all cases, control of possible hypertension is of value in slowing the progression of this disease.

[Carcinoma of the native kidney in patients with renal transplantation. A French multicenter study]. / Carcinomes des reins propres chez le transplanté rénal. Etude multicentrique française.

A study was undertaken to investigate the development of carcinoma in patients' own kidneys after renal transplantation. Twenty carcinomas were diagnosed among 16,755 patients grafted from 1952 to February 1993. It was possible to collect data for 17 detected carcinomas. These tumours developed in 17 patients, 14 male and 3 female, aged 31 to 64 years old. They appeared an average of 40 (range 1-204) months after transplantation. The maintenance treatment consisted of cyclosporine in 15 recipients. Four patients demonstrated clinical signs. The other 13 carcinomas were diagnosed as an incidental finding on ultrasound (n = 10), at autopsy (n = 1) or by examination of kidneys from nephrectomy (n = 2). In the patient group with incidental diagnosis, tumors were larger than 4 cm in 3 out of the 9 cases studied; they were confined to the kidney in 5 cases and lymph node invasion or renal vein involvement were noted in 1 case. Distant metastases were present in 3 symptomatic patients and in 1 "incidental" case. Except for tumours discovered on nephrectomies or autopsy, a nephrectomy was performed in all cases. Death occurred 1 to 12 months after diagnosis in the recipients with metastatic tumours. A colic carcinoma was diagnosed 6 months after nephrectomy in one patient. The other 11 patients are doing well as the immunosuppressive treatment is being continued.

[Lymphoproliferative lesions localized in the renal graft. A French multicenter study]. / Lésions lymphoprolifératives localisées au greffon rénal. Enquête multicentrique française.

Thirty-two French transplant centers participated in the study of lymphoproliferative disease (LPD) confined to the renal allograft. For the period from 1952 to February 1993, 16 cases were recognized from 16,755 renal transplant recipients. The mean age of the patients was 44 years (range 19-67 years). Fourteen of these recipients received anti-lymphocyte globulin as induction therapy and 13 received cyclosporine as their maintenance immunosuppressive treatment. Acute rejection was reported in 9 cases and was treated with methylprednisolone in 6 cases and with mono- or polyclonal antibodies for 3 episodes. The mean interval from transplantation to development of LPD was 14 months (range, 1-144 months). Most of the patient (12/15) showed symptoms. Renal failure was noted in 7 recipients. Renal ultrasound demonstrated hydronephrosis in 4 cases, a hilar mass in 5 cases, a mass lesion within the graft in 2 cases. Pathological examination showed a high grade malignant lymphoma with extensive necrosis and atypical large cells. Immunohistochemical study was consistent with B-cell lymphoma in all of the 8 cases analyzed and monotypia was noted in 4 cases. The presence of Epstein-Barr virus genome in the LPD was demonstrated in 5 of the 6 cases studied. Nine patients were managed with discontinuation of immunosuppression and transplant nephrectomies. Four patients died. The remaining recipients are alive with no evidence of recurrence after 25 months (range 3-68 months).

[Acute postoperative renal insufficiency in renal transplantation. Incidence and risk factors]. / Insuffisance rénale aiguë post-opératoire en transplantation rénale. Fréquence et facteurs de risque.

Delayed renal function (DFG) is known to influence both the short and long-term outcome of transplanted kidneys. Data collected retrospectively on all 129 cadaveric renal transplants performed between January 1991 and January 1993 within a single center were analyzed. 42 (32.55%) cases of acute renal failure (ARF) occurred during the immediate postoperative period and 28 patients required dialysis. When compared with immediate good allograft function, DGF was associated with previous failed transplant (7/15 vs 35/114, p = 0.01), donor age (39.2 +/- 13 vs 30.1 +/- 12 years, p = 0.01), and episodes of collapsus of the donor (11/25 vs 31/104, p < 0.01). The graft function of the recipient was not correlated with the serum creatinine of the donor. There was no apparent relationship between the cold ischemia or the anastomosis time and the occurrence of DGF. One-year patient and graft survival were similar in the two groups (respectively for the group ARF and without ARF: 96.4% and 96.5%; 88.8% and 89%), but patients with DGF had higher serum creatinine values at 12 months post DGF (185.6 +/- 44.8 mumol/l vs 157.5 +/- 30.8 mumol/l, p = 0.06). This study suggests that DGF is related to the characteristics of the donor graft and is more frequently encountered in previously transplanted recipients.

[Bladder candidosis after renal transplantation: contribution of ultrasonography]. / Candidose vésicale chez le transplanté rénal : apport de l'Echographie.

Candidosis of the ureter and the bladder is an infrequent complication after renal transplantation. A case occurring early after kidney transplantation is reported in a patient presenting with candiduria. Ultrasound examination detected several fungal bezoars, presenting as a proliferating, avascular lesions, located within the ureter and the bladder. It allowed to demonstrate the rapid extension of lesions, in spite of a medical treatment, leading to a successful endoscopic removal of fungus balls.

[Polycythemia after kidney transplantation]. / Polyglobulie après transplantation rénale.

Between 1971 and 1990, 251 kidney transplanted patients with a well functioning graft were evaluated to determine the frequency of post-transplant erythrocytosis (PTE). Thirty-one patients (13 percent) developed polycythaemia 10.6 +/- 10 months after transplantation. Thromboembolic complications occurred in 22 percent of the cases. The frequency of PTE was higher in males than in females (sex ratio: 7.2 vs 2.1; P < 0.05). Patients with renal dysplasia had a lower incidence of PTE (3 vs 22 percent; P < 0.05) as did those who had been treated with azathioprine (9.4 vs 19 percent; P < 0.05). None of the patients treated with recombinant erythropoietin before transplantation developed PTE during a mean follow-up of 15.1 +/- 4.5 months. The majority of polycythaemic patients had normal erythropoietin levels. These results show that there is an erythropoietin-independent proliferation due to an increased sensitivity of erythroid progenitors or to an erythroid stem cell stimulation by cytokines.