Monitored high-dose azathioprine treatment reduces acute rejection episodes after renal transplantation.

BACKGROUND: Azathioprine (AZA) is widely used in organ transplantation. Common practice is to adjust dose according to body weight only, despite documented pharmacokinetic variability. The purpose of this study was to investigate whether high-dose AZA treatment monitored by 6-thioguanine nucleotides (6-TGN) levels reduces the incidence of rejection episodes in renal transplantation without a corresponding increase in myelotoxicity. METHODS: Patients receiving cyclosporine, steroids, and AZA were randomized into either the low-dose AZA group (3 mg/kg on day 0, then 2 mg/kg/day the first week and 1 mg/kg/day thereafter) or the high-dose AZA group. In the latter, AZA was started at 5 mg/kg/day and then adjusted to keep 6-TGN concentrations (measured twice weekly) between 100 and 200 pmol/8 x 10(8) RBCs. RESULTS: A total of 360 transplant recipients were included in the final analysis. The cumulative incidence of first rejection episodes was reduced by 21%, from 62.8% in the low-dose group to 49.4% in the high-dose group (difference: 13.3%; 95% confidence interval: 3.2-23.5). Similar results were found in subgroups according to HLA-DR match. The 6-TGN concentration was significantly higher in the high-dose AZA group during the first month, and the reduction in rejection episodes was achieved in the same period. A larger proportion of patients in the high-dose group had nadir white blood cell count below 2.0 x 10(9) leukocytes/L (13.3% vs. 4.4%; difference: 8.9%; confidence interval: 3.1-14.7). CONCLUSIONS: High-dose AZA therapy in a triple-drug regimen, monitored by 6-TGN, will keep myelotoxicity within acceptable limits with the benefit of a reduction in acute rejection episodes.

Unrelated living donors in 141 kidney transplantations: a one-center study.

BACKGROUND: Kidney transplantation is the optimal treatment for the majority of patients with end-stage renal disease. However, the shortage of kidneys for transplantation is a global problem, and any attempt to improve the donor situation would be of benefit to the growing number of patients on transplant waiting lists. PATIENTS AND METHODS: Since 1984, we have transplanted 141 kidneys from genetically unrelated living donors. Donors were most often spouses and were accepted regardless of HLA match grade. Preemptive transplantation was performed in 39% of the patients. Standard triple-drug immunosuppression with prednisolone, cyclosporine, and azathioprine was used. The patients were followed from 6 months to 13 years. RESULTS: The incidence of acute rejection during the first 3 months after transplantation was higher in recipients of grafts from unrelated donors than in recipients of grafts from related living donors or cadaveric donors. However, unrelated living donor grafts survived significantly better than did cadaveric grafts (P < 0.02) and had a survival rate similar to that of living-related donor grafts mismatched for one or both HLA haplotypes. The perioperative complication rate for the donor was low. CONCLUSION: We consider unrelated living donors an excellent source for alleviating the shortage of donor kidneys.

Morphological studies of baseline needle biopsies from living donor kidneys: light microscopic, immunohistochemical and ultrastructural findings.

Fifty-seven consecutive living donors (31 women and 26 men aged 20.7-72.3 years, mean 50.6 years) were subjected to needle biopsy during nephrectomy, immediately before removal of the kidney. By light microscopy, semiquantitative scoring (0-3) was performed for arteriosclerosis, arteriolar hyalinosis (hyalin arteriolosclerosis), glomerulosclerosis, interstitial mononuclear cell infiltration, and interstitial fibrosis/tubular atrophy. Whereas vascular changes were striking in many biopsies (arteriosclerosis grades 2-3: 28/54 cases, arteriolar hyalinosis grades 2-3: 15/55 cases), glomerular and tubulointerstitial changes were mostly low grade. The morphological changes tended to be more pronounced in middle-aged and older individuals, but, in particular, vascular changes were seen also in the younger age group. Immunofluorescence microscopy revealed glomerular granular staining for IgM in 52.7% of the cases, IgA in 9.1%), IgG in 1.8%, and C3 in 12.7%. The main ultrastructural finding was glomerulosclerosis; one case with diffuse glomerular IgA showed distinct dense deposits, and one case showed similar dense deposits without IgA deposition. Arteriolar wall deposition of C3 was found in 58.2% of the cases, and IgM in 10.9%. Especially C3 occurred both with arteriolar hyalinosis and in arterioles without light microscopic alterations. The observation of significant vascular changes in baseline biopsies is relevant especially in the differential diagnosis of chronic rejection and cyclosporine nephropathy. The immunohistochemical findings strongly indicate the occurrence of immunoglobulins and complement factor C3 in both glomeruli and arterioles without clinical or morphological signs of renal disease. The possible pathophysiological significance of such deposits remains, however, uncertain.

The national kidney transplant program in Norway still results in unchanged waiting lists.

1. Of 2,670 patients starting renal replacement therapy for end-stage renal disease in Norway from 1989-1997, 76% were candidates for transplantation. The annual need for transplantations increased from 47 to 64 grafts PMP as the number of elderly patients increased. The national waiting list has remained almost stable during the period from 1989-1997 at levels of 25-30 PMP, but the dialysis population has increased from 57-105 PMP. 2. A total of 1,681 transplants was performed at an annual rate varying between 38 and 46 grafts PMP. The grafts were procured from LDs in 41% and CDs in 59% of cases. Totally 69% of all patients in need were transplanted and 54% of all patients requiring replacement therapy for end-stage renal disease received a transplant. 3. Graft survival rates in recipients of first LD grafts (n = 641) were 91% and 77% at one and 5 years, respectively. One-year graft survival was 97% in HLA-identical grafts (n = 71), 92% in haploidentical grafts (n = 419), 88% in 2 haplotype-mismatched related grafts (n = 43), and 87% in spousal donor grafts (n = 108). 4. Graft survival rates in recipients of first CD grafts (n = 801) were 84% and 65% at one and 5 years, respectively. The rates were 86% and 74% in younger (n = 557) versus 78% and 46% in older (> 65 years) (n = 244) patients. Death with a functioning graft caused approximately 45% and 75% of all graft losses in younger and older patients, respectively. Cardiovascular disease was the major cause of death. 5. A significant beneficial effect of HLA-DR matching was observed in CD grafts performed after 1989, in particular in patients older than age 65.

Patterns of azathioprine metabolites in neutrophils, lymphocytes, reticulocytes, and erythrocytes: relevance to toxicity and monitoring in recipients of renal allografts.

Monitoring of azathioprine (AZA) therapy by the measurement of 6-thioguanine nucleotides (6-TGN) concentrations in red blood cells (RBC) may improve safety and ensure optimal immunosuppressive effects of AZA in organ transplantation. The authors explored the rationale for such monitoring by measuring thiopurine metabolites in peripheral blood cell types that are more relevant to the effects and kinetics of AZA and its active metabolites. Neutrophil granulocytes were isolated by density gradient centrifugation, and CD4+ lymphocytes and reticulocytes by using specific immunomagnetic beads. In neutrophils, 6-TGN concentrations had median measurements 31 times higher than in RBCs. In contrast to the high methylated mercaptopurine (me-MP) concentrations in RBCs, these metabolites were not detected in the neutrophils. Thiopurine metabolite levels were lower than the analytic limit of detection in all the CD4+ samples. The concentrations of 6-TGN and me-MPs were lower in reticulocytes than in RBCs in general, indicating that thiopurine metabolites are taken up by RBCs in the circulation. This study's findings, that 6-TGN concentrations are very high in neutrophils, whereas me-MPs are undetectable, many explain the specific neutropenic adverse effect of AZA. The results also add support to monitoring AZA through measurements of 6-TGN and me-MPs in RBCs.

Possibilities for therapeutic drug monitoring of azathioprine: 6-thioguanine nucleotide concentrations and thiopurine methyltransferase activity in red blood cells.

The objectives of this study were to establish monitoring of azathioprine (AZA) treatment in renal allograft recipients by red blood cell (RBC) 6-thioguanine nucleotide (6-TGN) measurements and to characterize the variability of RBC thiopurine methyltransferase (TPMT) activity and the effects on 6-TGN levels and the incidence of rejection episodes. In 82 renal allograft recipients, the effect of standard AZA dosage (3 mg/kg tapered to 1 mg/kg) was compared with higher dosages (3 mg/kg for several days) under 6-TGN monitoring. The authors measured TPMT in these patients and in a group not receiving AZA. The authors did not find an inverse correlation between RBC TPMT activity and 6-TGN concentrations, and baseline TPMT activity did not predict the incidence of rejection episodes The slight increase in RBC TPMT activity after transplant was associated with the use of furosemide rather than AZA; in the five patients receiving furosemide for less than 10 days, TPMT activity declined. The higher AZA dosage in the 6-TGN monitored group was not sufficient to increase RBC 6-TGN to target levels (100 to 200 pmol/8 x 10(8) RBC); median 6-TGN levels were similar in the two groups, as was the incidence of rejection episodes. Based on these findings, the authors suggest that higher dosages be studied in conjunction with 6-TGN monitoring, to explore the possibilities for therapeutic improvements.

Half dose of OKT3 is efficient in treatment of steroid-resistant renal allograft rejection.

Rejection episodes in renal allograft recipients are usually efficiently treated with high doses of intravenous methylprednisolone. Rejection therapy with OKT3 is often reserved for steroid-resistant episodes. However, the optimal dose of OKT3 in the treatment of steroid-resistant rejection is not known. Therefore, we randomized renal transplant recipients with steroid-resistant rejection to treatment with a standard daily intravenous dose of either 5 mg of OKT3 (n=15) or 2.5 mg of OKT3 (n=15) for 10 days. Circulating T cells (measured as CD2+ cells) were adequately and equally depleted in the two groups. Three grafts were lost due to rejection within the first 3 months following OKT3 administration, one in the 2.5 mg OKT3 group and two in the 5 mg OKT3 group. Two nonimmunologic graft losses occurred in the 2.5 mg OKT3 group. Median serum creatinine values were not different between the two groups, neither at the start (median values: 200 micormol/L in the 5 mg OKT3 group vs. 188 micromol/L in the 2.5 mg group) nor immediately after OKT3 rescue therapy (202 micromol/L vs. 185 micromol/L, respectively). Eight cytomegalovirus infections occurred in each group. Two re-rejection episodes occurred in the 5 mg OKT3 group and one occurred in the 2.5 mg OKT3 group. All responded to treatment. Function of the remaining grafts estimated by serum creatinine after a mean long-term follow-up of 18 months (range, 6-36 months) revealed no differences (185 micromol/L in the 5 mg OKT3 group vs. 170 micromol/L in the 2.5 mg OKT3 group). We conclude that OKT3 treatment of steroid-resistant rejections in renal transplant recipients is equally effective in daily doses of 2.5 mg and 5 mg with respect to reversal rate and long-term outcome.

[Liver transplantation in Norway. Results after 10 years and 114 transplantations]. / Levertransplantasjon i Norge. Resultater etter ti års aktivitet og 114 transplantasjoner.

A total of 114 liver transplantations were performed in 106 patients in Norway during 1984-1994. Survival after one year was 65% and after three years 57%. The most frequent causes of death were infections and rejections. The survival rate improved considerably during the period, and after 1990 the 1 year survival was 70%. Approximately 2/3 of the patients return to work or education. Very few patients die later than 12 months after the transplantation. The most frequent indications were primary biliary cirrhosis, metabolic liver disease, primary sclerosing cholangitis, autoimmune cirrhosis and fulminant liver failure. The number of liver transplantations (approximately 4 per million inhabitants) is lower in Norway than in the other Nordic countries. The number should be increased to 7-8 per million inhabitants.

Pharmacokinetics and immunodynamics of chimeric IL-2 receptor monoclonal antibody SDZ CHI 621 in renal allograft recipients.

SDZ CHI 621 is a murine-human chimeric monoclonal antibody (mAb) to the interleukin-2 (IL-2) receptor (CD25) intended for prophylactic immunosuppression against acute rejection in the first several weeks following kidney transplantation. A multicentre, prospective, dose-finding study was conducted in 37 primary, mismatched cadaver kidney transplant patients to assess its tolerability, pharmacokinetics and immunodynamics. Successive cohorts of patients were stratified to receive total doses of 20, 30, 40 or 60 mg (n = 4, 4, 14, 15, respectively) administered as 15- or 20-mg intravenous infusions with the first dose given preoperatively and subsequent doses within the first 10 days posttransplant. Daily mAb serum concentrations were analysed by a radioimmunoassay method and the percentage of peripheral T-lymphocytes expressing CD25 from serial blood samples was determined by FACScan. Intravenous administrations were well tolerated. mAb concentration profiles exhibited a biphasic decline with an initial t1/2 of 14.4 +/- 14.2 h, terminal t1/2 of 13.4 +/- 6.0 days, distribution volume (Vss) of 6.9 +/- 3.31 and clearance of 17.4 +/- 7.8 ml/h. The concentration-effect (mAb-CD25) relationship indicated that mAb concentrations exceeding a threshold of about 0.7 microgram/ml corresponded to complete suppression of CD25 (< or = 3% CD25+ T-cells). The threshold mAb concentration was exceeded at all dose levels, whereas the duration above the threshold (and thus of CD25 suppression) rose with increasing dose: 20 mg, 20 +/- 7 days; 30 mg, 32 +/- 6 days; 40 mg, 37 +/- 10 days; and 60 mg, 53 +/- 17 days. As mAb concentrations declined below the threshold following the last dose, CD25 expression returned to baseline (18-44% CD25+ T-cells) within a few days.

Pretransplant plasma exchange or immunoadsorption facilitates renal transplantation in immunized patients.

Patients with preformed antibodies against HLA molecules accumulate on renal transplant waiting lists and have inferior graft survival compared with nonsensitized patients. One hundred patients were included in a program of pretransplant removal of antibodies by plasma exchange (n = 90) or immunoadsorption (n = 10) in addition to prednisolone and cyclophosphamide medication. After plasma exchange, the panel reactivity and the antibody titer were reduced in about half of the patients, and after immunoadsorption the panel reactivity fell in 6 of 10 patients. Of the 83 patients who received grafts, 17 received a graft from a living donor (LD) and 66 received a graft from a cadaver donor (CD). Patients with a positive crossmatch against their LD were included in the program and were thus grafted with a recent positive, current negative crossmatched organ. Fifteen CD graft recipients had a pretreatment positive crossmatch toward their donor. No episodes of hyperacute rejection were seen. One- and 4-year graft survival rates in LD transplants with a recent positive and current negative crossmatch were 77% and 64%, respectively. At 1 and 4 years, graft survival rates were 70% and 57% in pretreated first CD graft recipients (n = 27) and 61% and 47% in pretreated regrafted patients (n = 39), respectively. In this program, a high rate of transplantation among the sensitized patients was achieved. Graft survival was inferior to that seen in nonsensitized patients, but was comparable to graft survival in sensitized patients at other centers.

Autonomous hyperparathyroidism in X-linked hypophosphataemia.

Four patients with familial hypophosphataemic rickets developed significant hypercalcaemia which persisted after discontinuation of vitamin D therapy. They had increased PTH levels and were operated for hyperparathyroidism at the ages of 18, 20, 24 and 45 years, respectively. Three of the patients had previously received phosphate treatment and one patient developed hyperparathyroidism 7 years after treatment with calcitriol. Histological evaluation revealed different degrees of parathyroid hyperplasia in all patients, with persistently increased PTH and/or calcium levels after surgery. The possibility of autonomous hyperparathyroidism should be evaluated in the follow-up of patients with X-linked hypophosphataemic rickets.

[Pancreas transplantation. A 10-year material]. / Pancreastransplantasjon. Et tiårsmateriale.

A programme for pancreas transplantation was initiated in Oslo in 1983. Of a total of 100 transplants so far, 14 were performed as pancreas transplantation alone (PTA) in non-uremic diabetics (n = 9), or as pancreas after kidney (PAK), i.e. in diabetic patients with a functioning renal transplant (n = 5). Duct occluded segmental grafts were used until 1988, when the pancreaticoduodenal technique with bladder drainage was introduced. Since 1991, owing to a low graft survival rate in PAK and PTA cases, all pancreas transplantations have been performed simultaneously with a renal transplant, giving a one-year survival of 82%, 83% and 93% for kidney, pancreas and patient respectively. The authors give a brief overview of the experience gained during ten years, with a pancreas transplant rate of ten/year.

Pregnancy outcome in renal allograft recipients in Norway. The importance of immunosuppressive drug regimen and health status before pregnancy.

BACKGROUND: To study the influence of pre-conceptional health status and immunosuppressive drug regimen on pregnancy outcome in renal allograft recipients. METHODS: The study includes all pregnancies in renal allograft recipients in Norway in the period 1973-1991. The data were collected from the patient records. Serum-creatinine values, proteinuria, blood pressure, recent graft rejection, and immunosuppressive drug regimen before pregnancy as well as the interval from transplantation until pregnancy were related to the frequency of deliveries at term, preterm deliveries, and of induced and spontaneous abortions. RESULTS: 54 pregnancies in 37 renal allograft recipients resulted in 31 term deliveries, 12 preterm deliveries, four spontaneous, and seven induced abortions. One induced abortion due to psychosocial reasons was excluded from the calculations. Post-transplant intervals less than two years as compared to longer intervals were associated with an increased frequency of spontaneous and induced abortions (6/13 vs 4/40, p < 0.01) and a non-significant increase in the relation between preterm and term deliveries (3/4 vs 9/27). The few women with proteinuria, elevated serum-creatinine values, and hypertension before pregnancy had an increased number of adverse pregnancy results. The women receiving cyclosporine A experienced a larger frequency of spontaneous and induced abortions (7/18 vs 3/35, p < 0.05) and an increase in the relation between preterm and term deliveries (7/4 vs 5/27, p < 0.01) as compared to the women who received prednisolone and azathioprine only. CONCLUSIONS: The results demonstrate the importance of pre-conceptional consultation and may indicate a harmful effect of cyclosporine A on pregnancy outcome.