Triple therapy in cadaver renal transplantation

Anti-thymocyte globulin for treatment of T-cell-mediated allograft rejection

Anti-thymocyte globulin (ATG) is a pivotal immunosuppressive therapy utilized in the management of T-cell-mediated rejection and steroid-resistant rejection among renal transplant recipients. Commercially available as Thymoglobulin (rabbit-derived, Sanofi, United States), ATG-Fresenius S (rabbit-derived), and ATGAM (equine-derived, Pfizer, United States), these formulations share a common mechanism of action centered on their interaction with cell surface markers of immune cells, imparting immunosuppressive effects. Although the prevailing mechanism predominantly involves T-cell depletion via the com plement-mediated pathway, alternate mechanisms have been elucidated. Optimal dosing and treatment duration of ATG have exhibited variance across ran domised trials and clinical reports, rendering the establishment of standardized guidelines a challenge. The spectrum of risks associated with ATG administration spans from transient adverse effects such as fever, chills, and skin rash in the acute phase to long-term concerns related to immunosuppression, including susceptibility to infections and malignancies. This comprehensive review aims to provide a thorough exploration of the current understanding of ATG, encom passing its mechanism of action, clinical utility in the treatment of acute renal graft rejections, specifically steroid-resistant cases, efficacy in rejection episode reversal, and a synthesis of findings from different eras of maintenance immunosuppression. Additionally, it delves into the adverse effects associated with ATG therapy and its impact on long-term graft function. Furthermore, the review underscores the existing gaps in evidence, particularly in the context of the Banff classification of rejections, and highlights the challenges faced by clinicians when navigating the available literature to strike the optimal balance between the risks and benefits of ATG utilization in renal transplantation.

Renal Transplantation: Experience at a Single Centre

BACKGROUND

Renal transplantation program in the Armed Forces commenced in Feb 1991 and till date 245 patients have undergone renal transplantation at INHS Asvini. We describe our protocols for donor and recipient evaluation and immunosuppression.

METHODS

245 patients received renal transplants during this period, 243 (99.2%) being from live donors. Most of them were started on triple immunosuppression comprising of cyclosporine, azathioprine and prednisolone. Newer drugs like mycophenolate, tacrolimus and sirolimus were administered in a select population.

RESULT

69 (28.1%) of them had at least one episode of acute rejection, most of which were steroid responsive and 13 (18.8%) of them required either anti CD3 monoclonal or anti-thymocyte globulin (ATG). Complete recovery with normal renal function occurred in 54 (78.2%) cases and 15 (21.7%) recovered with residual dysfunction with maximum serum creatinine being 2.1mg/dl. There were three (1.2%) cases of accelerated rejection during the first week of transplantation and one had graft rupture. All three lost their grafts. There were eight (3.2%) cases of acute tubular necrosis, who recovered completely within 8-14 days. Immediate infections included wound sepsis, lower respiratory tract infection, disseminated candidiasis and disseminated aspergillosis. Late infections included pulmonary tuberculosis, disseminated tuberculosis, cytomegalovirus infection and recurrent urinary tract infection. 28 (11.4%) patients developed post transplant diabetes mellitus. At the end of one year and five years, graft and patient survival were 97.2%, 93%, 80.9% and 85.7% respectively.

CONCLUSION

Our outcomes show that the transplantation is a viable mode of renal replacement therapy in patients of end stage kidney disease with a near normal rehabilitation.

C4d Deposition in Early Renal Allograft Protocol Biopsies

BACKGROUND

Deposition of the complement protein C4d in renal allograft biopsies obtained during graft dysfunction and rejection has been proposed to be a sensitive marker of antibody-mediated acute rejection. To determine the diagnostic specificity of C4d deposition, it is important to study biopsies from allografts with no evidence of dysfunction. In this study, we examined C4d deposition in protocol biopsies obtained irrespective of clinical status.

METHODS

Immunohistochemistry for C4d was performed on routine protocol biopsies preimplantation and on day 7 posttransplantation from 48 unselected renal allografts. Serum samples obtained up to 1 month after transplantation were assayed for donor-reactive antibodies (DRA). Results were correlated with histopathology and clinical outcome measures.

RESULTS

Diffuse C4d deposition was detected in the peritubular capillaries of 6 of 48 (13%) biopsies. C4d deposition was present in 5 of 15 (33%) biopsies that showed acute rejection (Banff 97, category 4) but only in 1 of 33 (3%) biopsies with no rejection (P=0.003, 97% specificity). Posttransplant DRAs were detected in 21 of 48 (44%) patients. All five recipients with C4d deposition and rejection had posttransplant DRA; the recipient whose biopsy showed C4d positivity, but not rejection, did not have detectable DRA. C4d deposition was not treated with plasmapheresis or intravenous immunoglobulin and was not associated with poor posttransplant graft outcome at 1-year follow-up.

CONCLUSIONS

Our results show that in early posttransplant protocol biopsies, C4d is a specific marker for the presence of humoral rejection, as indicated by its association with DRA and acute histologic rejection.

Use of cyclosporine in renal transplantation

The first cyclosporine trials in renal transplantation began in Cambridge in 1978. Between 1982 and 1985 several large multicenter trials and the reports from large series of patients evidenced that cyclosporine was a major advance in the prevention of acute rejection episodes and in improving short-term and long-term graft survival. Cyclosporine also showed the capacity to mitigate immunologic risk factors, HLA mismatching, and lack of pretransplant transfusions. However, cyclosporine has the serious defect of being nephrotoxic. Induction therapy with OKT3, polyclonal antibodies, and more recently with anti IL-2R monoclonal antibodies allowed the delay of introduction cyclosporine in patients showing posttransplant graft dysfunction. Other relatively unsuccessful attempts for overcoming cyclosporine nephrotoxicity were made before the association of new xenobiotics such as mycophenolate mofetil or sirolimus permitted cyclosporine doses to be reduced. These combinations reduce acute rejection incidence to below 20%, with its consequent positive impact on long-term graft outcome and also allow a safer steroid sparing and withdrawal early posttransplantation. Also, the association of cyclosporine with other new compounds such as the lymphocyte homing FTY20 or the peripheral lymphocyte-depleting Campath-1-IgG is currently under clinical investigation. Cyclosporine's future place is yet to be established in the new era of immunosuppression.

Chronic allograft failure in human renal transplantation: a multivariate risk factor analysis

OBJECTIVE

To identify potential risk factors for the development of chronic renal allograft failure.

SUMMARY BACKGROUND DATA

Chronic allograft failure (CAF) is the leading cause of late graft loss in renal transplantation. The authors studied the risk factors for the development of CAF in a single center during a period in which a consistent baseline immunosuppression regimen (cyclosporine, azathioprine, and prednisolone) was used.

METHODS

Data from the Oxford Transplant Center Database were assessed on 862 renal allografts during a 10-year period. Risk factors were identified using multivariate logistic regression analysis.

RESULTS

Biopsy-proven CAF occurred in 77 patients (9.2%) in the entire group. Multivariate risk factor analysis revealed that early and late acute rejection episodes, proteinuria, and serum triglycerides were significant factors. Acute rejection after 3 months was more important than early acute rejection. Serum triglyceride level and proteinuria at 1 year were both elevated in the CAF group. Male sex provided a protective effect. Serum creatinine levels at 6 months after the transplant were not predictive of the risk of developing CAF.

CONCLUSIONS

These results from the largest single-center review to date suggest that both antigen-dependent and -independent factors are involved in the pathogenesis of CAF. Acute rejection at all time points has a significant impact on the development of CAF.

Cadaver versus living donor kidneys: impact of donor factors on antigen induction before transplantation

BACKGROUND

It is widely recognized that living-related donor (LRD) renal allografts have a higher overall graft survival than cadaver donor transplants. We tested the hypothesis that part of this is attributable to LRD kidneys being obtained under optimal conditions from healthy donors, whereas cadaveric kidneys may have experienced injury as a result of inflammatory events around the time of brain death.

METHODS

We have performed a comparative immunohistochemical analysis of pretransplant donor biopsies from cadaveric (N = 65) and LRD (N = 29) kidneys to determine any differences that may predispose them to subsequent damage. Cryostat sections were stained with antibodies to leukocytes, adhesion molecules, and human leukocyte antigen (HLA)-DR antigens, and the expression was assessed semiquantitatively.

RESULTS

High levels of endothelial E-selectin and proximal tubular expression of HLA-DR antigens, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1 were detected in biopsies from cadaveric kidneys, whereas expression of these markers was markedly reduced in LRD kidneys. High levels of tubular antigen expression were significantly associated with traumatic death, prolonged ventilation, and episodes of infection in cadaver donors. Furthermore, the expression of pretransplant tubular antigens in cadaver donor kidneys was significantly associated with early acute rejection following transplantation, suggesting that such kidneys are predisposed to subsequent immune-mediated attack following transplantation.

CONCLUSIONS

These results may explain, in part, the superior outcome of LRD allografts compared with cadaver renal allografts.

Delayed graft function: risk factors and the relative effects of early function and acute rejection on long-term survival in cadaveric renal transplantation

Delayed graft function (DGF) and acute rejection have both been associated with reduced renal allograft survival. In some studies, they have been shown to have an interactive effect. We studied the risk factors for DGF and the relative impact of DGF and rejection on both short- and long-term survival in recipients of cadaveric renal transplants. Data from the Oxford Transplant Centre Database were assessed on 710 cadaver allografts over a 10-yr period, during which time all recipients received cyclosporin-based immunosuppressive protocols. The interaction between DGF and acute rejection was examined using logistic and Cox multivariate regression. Long cold ischaemia time (CIT), sensitisation and older donor age were found to be independent predictors of DGF. The occurrence of DGF resulted in a reduced 5-yr survival (56 vs. 75%). However, the effect of DGF was confined to the first year post-transplant, as there was no significant difference in survival, as measured by half-life (t1/2) of grafts functioning at 1 yr, with DGF alone and a group with good early function (t1/2 = 21.3 vs. 20.0 yr). There was no increase in acute rejection in grafts with DGF. However, the combination of DGF and acute rejection resulted in the worst short-term graft survival (68% at 1 yr, compared to 92.3% in those grafts with no DGF or acute rejection) and this continued over the long term (t1/2 = 10.5 yr). These data suggest that early function is critical to the success of renal transplantation. The effects of DGF are limited to the first year post-transplant. Long-term graft survival may be improved by efforts to limit CITs, particularly for grafts from older donors and sensitised recipients.

Ischemia/reperfusion injury in human kidney transplantation: an immunohistochemical analysis of changes after reperfusion

Organs used for transplantation undergo varying degrees of cold ischemia and reperfusion injury after transplantation. In renal transplantation, prolonged cold ischemia is strongly associated with delayed graft function, an event that contributes to inferior graft survival. At present, the pathophysiological changes associated with ischemia/reperfusion injury in clinical renal transplantation are poorly understood. We have performed an immunohistochemical analysis of pre- and postreperfusion biopsies obtained from cadaver (n = 55) and living/related donor (LRD) (n = 11) renal allografts using antibodies to adhesion molecules and leukocyte markers to investigate the intragraft changes after cold preservation and reperfusion. Neutrophil infiltration and P-selectin expression were detected after reperfusion in 29 of 55 (53%) and 24 of 55 (44%) cadaver renal allografts, respectively. In marked contrast, neutrophil infiltration was not observed in LRD allografts, and only 1 of 11 (9%) had an increased level of P-selectin after reperfusion. Immunofluorescent double-staining demonstrated that P-selectin expression resulted from platelet deposition and not from endothelial activation. No statistically significant association was observed between neutrophil infiltration and P-selectin expression in the glomeruli or intertubular capillaries despite the large number of cadaver renal allografts with postreperfusion changes. Neutrophil infiltration into the glomeruli was significantly associated with long cold ischemia times and delayed graft function. Elevated serum creatinine levels at 3 and 6 months after transplantation were also associated with the presence of neutrophils and platelets after reperfusion. Our results suggest that graft function may be influenced by early inflammatory events after reperfusion, which can be targeted for future therapeutic intervention.

A randomized trial comparing cyclosporine and steroids with cyclosporine, azathioprine, and steroids in cadaveric renal transplantation

BACKGROUND

In renal transplantation, triple-drug therapy (low-dose cyclosporine [CsA] combined with azathioprine plus steroids) has been replacing double-drug therapy (CsA plus steroids) in clinical practice without much evidence in favor of either therapy. Previous trials comparing the two immunosuppressive regimens gave conflicting results. We attempted to determine whether triple therapy is at least equivalent to double therapy.

METHODS

A randomized trial was performed in 250 adult cadaveric renal transplant recipients, comparing double therapy (CsA [10 mg/kg/day] plus prednisone) with triple therapy (CsA [6 mg/kg/day] plus azathioprine plus prednisone). The median follow-up time was 930 days.

RESULTS

The incidence of acute rejection episodes refractory to treatment was 11% in double therapy and 4% in triple therapy (relative risk reduction: 64%; 95% confidence interval: 5-100%; P=0.035). Patients in the double therapy group required more intensive antirejection treatment, and their pathologic lesions were more severe. The proportion of patients with acute rejection was similar (double therapy: 45% vs. triple therapy: 40%) as was the incidence of chronic renal dysfunction (double therapy: 17% vs. triple therapy: 15.5%), the 4-year graft survival (double therapy: 71% vs. triple therapy: 83%, P=0.089), and patient survival (double therapy: 94% vs. triple therapy: 93%). In 29 patients (23%), 35 episodes of azathioprine-induced leukopenia were recorded, and in 9 of them azathioprine had to be discontinued. The incidence of other adverse events did not differ between the groups.

CONCLUSIONS

Triple therapy caused fewer episodes of refractory acute rejection episodes and was as efficacious and safe as double therapy.

Preemptive cadaveric renal transplantation--clinical outcome

Preemptive cadaveric renal transplantation (PCRT) maximizes the chance of maintaining high quality of life and may avoid the morbidity of dialysis and the associated financial costs. These benefits are offset by disadvantages, which include the possibility of transplantation many months before the need for dialysis, resulting in wasted organ function; an immediate risk of graft failure with conversion to a dialysis-dependent state; and uncertainty of the safety of PCRT. Patients who underwent PCRT between June 1976 and December 1994 at the Oxford Transplant Centre were compared with a matched cohort of first cadaveric transplant recipients who were dialysis-dependent when transplanted. The 116 patients in the PCRT cohort were well matched to the control group with respect to sex, age, blood group, HLA match, degree of sensitization, donor age, immunosuppression, and year of transplantation. Patient and graft survival were significantly better in the PCRT group. The difference in graft survival did not appear to be completely explained by better patient survival, as suggested by a trend toward better graft survival after excluding death with a functioning graft as a cause of failure. Among surviving grafts there were no significant differences in graft function as assessed by 1, 2, and 3 year plasma creatinine levels. In conclusion, PCRT appears to be safe and may even be associated with superior graft survival when compared with conventional transplantation. Early inclusion on a transplant waiting list with a view to PCRT can be justified with respect to the clinical outcome but the financial costs and implications for the utilization of cadaveric donor kidneys must also be considered.

The quality of function of renal allografts is associated with donor age

The quality of renal allograft function was assessed by prospective measurement of creatinine clearance at 1 year (n = 197) and at 3 years (n = 115) after cadaveric renal transplantation in a cohort of 268 patients treated with triple therapy immunosuppression. Donor age (P < 0.0012) and recipient age (P < 0.01) were independently associated with creatinine clearance both at 1 and at 3 years. In patients with donor age above 50 years and recipient age above 45 years, the mean creatinine clearance was 32.7 (SD 10.4) ml/min (n = 27). When the donor age was below 30 years and recipient age below 45 years, the mean creatinine clearance was 55.6 (SD 14.4) ml/min (n = 47, P < 0.001). However, in these patients there was no significant association between graft function and many of the factors known to influence graft survival, such as HLA matching, sensitisation of the recipient, and the occurrence of rejection. In conclusion, the quality of renal allograft function declined with increasing donor and recipient age in our patients, whilst immunological factors were not significantly associated with function in surviving grafts.

Urological complications in 1,000 consecutive renal transplant recipients

The urological complications in the first consecutive 1,000 renal transplants at our transplant center are reported with a minimum followup of 12 months. The kidney was implanted in the iliac fossa in all cases and in all but 3 the ureter was inserted into the bladder with a Politano-Leadbetter technique. Overall, there were 71 primary complications in 68 patients (7.1%), which included 36 ureteral obstructions, 25 ureteral or bladder leaks (including ureteral necrosis), 7 bladder outflow obstructions, 2 ureteral stones and 1 case of symptomatic vesicoureteral reflux. The use of high dose steroids in the early years was associated with a 10% urological complication rate, which decreased to 4% in patients receiving low dose steroids thereafter combined with azathioprine or cyclosporine. The urological complication was corrected after 1 procedure in 65 cases and after 2 procedures in 4. No grafts were lost due to urological complications. Two patients died, 1 of sepsis following transurethral resection of the prostate and subsequent ureteral necrosis, and 1 of hemorrhage following nephrostomy tube insertion. Most ureteral complications were treated by an open operation, although in recent years endoscopic techniques have become more common. Meticulous retrieval technique, low dose steroid protocols and rapid diagnosis are the crucial factors associated with a minimal incidence of urological complications after renal transplantation.

Cyclosporin A (CsA) and azathioprine (AZA) combination in renal allografts with CsA nephrotoxicity

Cyclosporin A (CsA) is a potent immunosuppressive drug whose effect is well known in the organ transplantation field. Treatment with CsA reduces the incidence of rejection and improves graft survival after renal transplantation (RT). However, to set against the clear advantages of CsA, a most important problem is nephrotoxicity. Scientists are therefore seeking new non-nephrotoxic Cs derivatives, but the search has not yet borne fruit. Teams working in organ transplantation attempt to avoid nephrotoxicity by switching to conventional treatment with azathioprine (AZA), starting 1, 3 or 6 months after transplantation. Conversion from CsA to AZA has not always been successful due to the high incidence of rejection. AZA has also been started immediately after transplantation in combination with CsA at low doses, and in some instances no CsA is administered when oliguric acute tubular necrosis is present. In a previous report, we presented the short-term results of the treatment with a CsA-AZA combination, reducing the CsA dose and giving a moderate dose of AZA in 21 transplanted patients not achieving acceptable graft function. In the present study we analysed the long-term results in a group of patients whose kidney biopsy examination results were compatible with CsA nephrotoxicity.

Decreased incidence of infection after renal transplantation with the use of cyclosporine

The incidence of infection within six months of cadaveric kidney transplantation was reviewed in 183 consecutive patients. Prior to June, 1985, 91 patients received azathioprine 2 mg/kg/day and prednisone 0.5 mg/kg/day; 63 patients (group A1) also received antilymphocyte globulin 15 mg/kg/day for the first ten days, whereas for the 28 other patients (group A2) antilymphocyte globulin had to be withdrawn before 72 hours because of general intolerance. The next 92 patients received cyclosporine 5-8 mg/kg/day and prednisone 0.25 mg/kg/day (group B). The three groups were similar for all studied parameters except for the number of patients with anti-HLA antibodies. At six months the mortality rate was not significantly different between the three groups. After six months the number of infections per patient was 1.47, 1.03 and 0.84 (p less than 0.01) in groups A1, A2 and B respectively; the percentage of patients developing one or more infections was 81, 58 and 57% (p less than 0.01); bacterial infections: 57, 50 and 34% (p less than 0.01); viral infections: 40, 14 and 10% (p less than 0.01); cytomegalovirus infections: 27, 11 and 4% (p less than 0.001). After adjustment with logistic regression upon factors which might facilitate infections, the results showed a significantly lower incidence of infection for the cyclosporine-treated group, especially for cytomegalovirus, as compared with the antilymphocyte globulin-treated group.

Renal transplantation without steroids

Cyclosporin has been in use in our unit since 1982 to treat renal transplant recipients. In two controlled clinical trials cyclosporin monotherapy was compared with cyclosporin with steroids, and with cyclosporin with azathioprine. The addition of steroids did not improve graft survival but did increase the incidence of infection. The addition of azathioprine also had no effect upon graft outcome. We conclude that cyclosporin monotherapy provides very adequate immunosuppression in the majority of cases giving an 80% survival rate for cadaveric kidney transplants at 1 year. Triple therapy has been used successfully by other centres although graft survival rates are no different from our own. Such treatment does, however, provide more powerful immunosuppression and is appropriate for previously sensitised patients and for children. Under this regimen steroids can be withdrawn at a later date. Sequential therapy with four agents is highly immunosuppressive. The long-term results are uncertain at the present time, and this expensive treatment needs careful evaluation. In our experience it is perfectly possible to undertake cadaveric renal transplantation without having to prescribe regular steroid therapy for the majority of patients. We have been impressed by the lack of serious side effects with this treatment and would still regard cyclosporin monotherapy as the treatment of choice for unsensitised renal transplant patients.

The lens after renal transplantation

A single masked observer examined 55 non-diabetic patients chosen randomly from a population of patients who had undergone renal transplant. The mean age was 41 years and mean time from transplant was 4.4 years (1-10 years). Fourteen patients were found to have a posterior subcapsular cataract (PSC). The axial thickness of the right lens of the renal transplant population, even in the presence of a PSC, was significantly larger than in a control population of 99 patients with clear lenses. The PSC of renal transplantation is readily distinguished from age related PSC because the opacity lies in the superficial cortex at a depth proportional to time from transplant and the lens maintains a normal anterior clear zone. It is proposed that this type of cataract be called 'recovering' PSC. It is concluded that the cataractogenic insult occurs mainly during the peritransplant period. Maintenance doses of immunosuppressives or steroids are therefore probably not cataractogenic.

Triple therapy immunosuppression in cadaveric renal transplantation

One hundred and ninety-two patients received 200 consecutive cadaver renal transplants (158 first and 42 regrafts) and were treated with triple therapy immunosuppression consisting of low-dose cyclosporin, azathioprine and prednisolone. One-year patient and graft survival rates were 95% and 82%, respectively. Against this low rate of graft loss, the proportion of rejection-free patients in the first 3 months was strongly related to matching for HLA-DR (P less than 0.01), although HLA-DR matching was not associated with improved graft survival. More grafts were lost to nonimmunological causes than to rejection, and these losses fell into three main categories, namely, losses in elderly and diabetic patients and losses due to renal vascular thrombosis. Thus, triple therapy immunosuppression appears to offer effective immunosuppression, resulting in good graft and patient survival, especially in highly sensitised patients or patients receiving regrafts. There are relatively few serious adverse effects, although elderly and diabetic patients experienced significant morbidity and mortality after transplantation.

Spontaneous rupture of renal allografts: the importance of renal vein thrombosis in the cyclosporin era

Spontaneous renal allograft rupture occurring within 14 days of transplantation occurred in 15 patients from 791 consecutive transplants. In each of eight patients treated with azathioprine and prednisolone there was pathological evidence of rejection and only two patients had thrombosis of the renal vein. Of the seven cases occurring in patients treated with triple therapy regimen (low dose cyclosporin, prednisolone and azathioprine), histological evidence of rejection was present in only three cases, but renal vein thrombosis was found in all seven. Spontaneous rupture of a transplanted kidney, a relatively uncommon complication, is more likely to be due to renal vein thrombosis than to rejection in the cyclosporin era.

HLA-DQ mismatches between donor and recipient in the presence of HLA-DR compatibility do not influence the function or outcome of renal transplants

Although matching of kidney donors and recipients for antigens of the HLA-DR series is considered to have a significant influence on graft outcome, the independent effects of incompatibilities for the closely linked HLA-DQ series of antigens are unknown largely because serological compatibility for HLA-DR usually ensures a corresponding compatibility for HLA-DQ. In a retrospective study using restriction fragment analysis we have identified clear HLA-DQ mismatches in 25 out of 62 recipients of HLA-DR-compatible kidney grafts. Though these incompatibilities correspond to differences at the cell surface and hence potential alloantigenic stimuli, none of the eight clinical parameters examined indicate that HLA-DQ mismatches in the presence of compatibility for HLA-DR have any significant effect on either graft function or outcome.

Skin cancer in renal transplant recipients

Skin cancer was found in 31 of 598 patients transplanted in Oxford. No cases occurred during the first 3 years after transplantation but the prevalence rose after 12 years to 18.2 per cent. The main risk factors predisposing to skin cancer were the time after transplantation and male sex. Comparison with data from other centres suggests that exposure to ultraviolet light is a major aetiological factor in the speed of development of skin cancer. As the incidence of new cases rose progressively with time in our patients, it would seem that skin cancer is likely to become a major clinical problem as more patients enjoy prolonged survival after renal transplantation. Preventative and screening measures should be taken by transplant units both in the UK and in other countries with similar temperate climates.

Discriminating rejection from CMV infection in renal allograft recipients using flow cytometry

The ability to distinguish among rejection, cytomegalovirus (CMV) infection, and cyclosporin toxicity in the symptomatic renal allograft recipient remains one of the major issues in clinical transplantation. The practical application of immunologic monitoring of peripheral blood lymphocytes through the use of fluorescently labeled monoclonal antibodies and single-color flow cytometry has been limited by the inability to demonstrate significant correlations between the levels of specific T-cell subset populations and the cause of impaired renal function. In the present study using two-color analysis, we monitored the expression of interleukin-2 receptor (IL-2R) and HLA-DR antigen on the T-cells of a group of 51 renal cadaveric allograft recipients receiving cyclosporin, azathioprine, and prednisone for an average of 4 months after transplantation. We found that the proportion of CD3+ cells coexpressing IL-2R increased above baseline during 12 out of 14 rejection episodes that took place during the course of the study (P less than 10(-6)). Alternatively, we found that the proportion of cells coexpressing HLA-DR antigen on CD2+ cells increased above baseline during 11 out of 11 CMV infections (P less than 10(-6)). There was no correlation between the level of IL-2R+CD3+ cells and CMV infection or between the level of CD2+DR+ cells and rejection. These relationships showed a high degree of sensitivity and specificity when used to discriminate among possible etiologies for decreased renal function in the symptomatic patient.

Genomic analysis identifies class II mismatches in serologically DR-compatible human renal allografts

Many studies, including those from our own center, have shown that matching the donor and recipient for HLA-DR antigens has a beneficial effect on the outcome of cadaveric renal transplantation. However, cases of irreversible graft rejection are sometimes seen in patients who have received an HLA-DR-compatible kidney, suggesting that serologic compatibility for HLA-DR may not always ensure reduced alloreactivity toward the graft. We have examined a number of recipients and their serologically DR-compatible cadaveric donors by Southern blotting and hybridization with locus specific HLA class II probes in order to determine whether in these patients there were class II mismatches that had been undetected by serology. The results show that the analysis of DR beta restriction fragment patterns does little more than complement and confirm the serologic identification of HLA-DR. Hybridization with DQ alpha and DQ beta probes, however, significantly extends the number of DQ specificities that can be detected and suggests that DQ mismatches in DR-compatible donor-recipient pairs may be more common than previously supposed, although it is not possible to draw any conclusions on the influence of DQ incompatibilities in the presence of DR compatibility on graft outcome.

Renal transplantation in patients over 55 years old

From 1975 to 1987, 507 patients, of whom 63 (12.4 per cent) were over 55 years old at the time of operation, received first cadaver renal transplants. The annual percentage of recipients given transplants after the age of 55 has risen from 0 per cent in 1975 to 44 per cent in 1987. Of the 63 older patients, 41 had at least one serious non-renal disease at the time of transplantation. Perioperative mortality rate was 3 per cent. After successful transplantation these patients remained subject to a significant number of serious complications, even in the cyclosporin era. Despite these adverse factors, actuarial graft survival for the population over 55 years of age was no worse than for those patients receiving first cadaver grafts who were under 55 years old, although patient survival was poorer in the former group (P = 0.027). Analysis of the subgroup of 56 patients treated with an immunosuppression protocol containing cyclosporin failed to show any adverse effect of age on either graft or patient survival. It is concluded that renal transplantation can be as successful in patients over 55 years of age as it is in younger patients and, given an adequate supply of kidneys, should be considered the treatment of choice for the elderly patient with end-stage renal failure.