Long-term Renal Allograft Recipients Research Articles

Impact of HLA Antibodies on Graft Survival in Long-Term Renal Recipients with Functional Grafts

Objectives: Accumulating evidence supports the hypothesis that HLA antibodies play an important role in early renal allograft injury. However, the effects of HLA antibodies on long-term graft survival are still poorly understood. In this study, we examined the impact of HLA antibodies on graft survival in long-term renal recipients with functional grafts for 10 years. Material and Methods: In this retrospective study, long-term renal recipients were defined as kidney transplant recipients who had normally functioning renal grafts (serum creatinine level <2.0 mg/dl) for 10 years. Posttransplant serum samples from a total of 92 long-term renal allograft recipients on cyclosporine-based triple maintenance drug therapy (121.6 ± 0.886 months) were screened for the specificities of anti-HLA antibodies. The results of HLA antibodies before the transplantation, assessed using the same test method, were compared with those after their transplantations. Moreover, these 92 patients who received cadaveric renal transplant between January 2000 and December 2002 were followed up for about 10 years (range 107-135 months). Results: 27 patients had HLA-I antibodies and 16 patients had HLA-II antibodies before the transplantation, whereas 12 patients had HLA-I antibodies and 18 patients had HLA-II antibodies after the transplantation. Moreover, the types of HLA antibodies were different from those found before the transplantation. In these renal recipients with functioning renal grafts, the estimated glomerular filtration rate was 66.52 ± 14.52 ml/min/1.73 m² in the HLA antibody-positive group (n = 23) and 69.09 ± 25.54 ml/min/1.73 m² negative in the HLA antibody-negative group (n = 69, p > 0.05). Three patients (3.26%) (3 out of 92) had donor-specific anti-HLA antibodies (DSA). The frequency of DSA in this study was lower than that in the general Chinese Han renal recipient population. Conclusions: We find that all HLA antibodies in the long-term renal grafts are newly formed after the transplantation. The HLA antibody status has little impact on the renal graft function in the long-term renal recipients.

66-P: Correlation of immune function monitoring with tapering of Tacrolimus in long-term renal allograft recipients

66-P: Correlation of immune function monitoring with tapering of Tacrolimus in long-term renal allograft recipients

Cyclosporine dose reduction in stable renal transplant patients with high C2 level: simplified method of single C2 measurement and individualization of C0 target

It is recommended that cyclosporine dosing should be based on the whole blood level 2 h after a dose (C2), not the trough level (C0). Initial studies did not however establish the outcome of dosing according to C2 levels in long-term patients previously managed by C0 levels. C0 and C2 were measured in 152 stable patients receiving Neoral therapy, mean 86.9 months after transplantation. This showed that 38 (25%) had C2 levels above a target range of 700-900 microg/l. Higher C2 levels were associated with higher cholesterol levels (P = 0.0058) and higher diastolic blood pressure (P = 0.0163). Cyclosporine dose reduction was undertaken in 32 patients with high C2 levels. For logistical reasons, C2 was not performed regularly, but an individualized C0 level was set for each patient. A 16% reduction in mean cyclosporine dose was achieved, associated with a 28% fall in mean C0, from 212 to 153 microg/l, and a 25% fall in mean C2, from 1075 to 820 microg/l. There was no excess in adverse events in the dose reduction cohort, compared with patients with initial C2 levels <900 microg/l. Over a mean 15 month follow-up period in the dose reduction cohort, there was a 4.4% reduction in mean diastolic blood pressure, from 84.9 (SEM 2.1) to 80.2 (1.9) mmHg, P = 0.023; and a 10.4% reduction in mean cholesterol, from 5.71 (0.27) to 5.11 (0.25), P = 0.005 (patients starting on statin during follow-up excluded). In patients with initial C2 <900 microg/l, blood pressure did not fall and the cholesterol fell by 3.9%, from 5.27 (0.14) to 5.07 (0.15) mmol/l (P = 0.0405). In conclusion, cyclosporine dose reduction was safe in stable long-term renal allograft recipients with high C2 levels. There was an improvement cholesterol levels and a small improvement in blood pressure after cyclosporine dose reduction.

Evaluation of cyclosporine C 2 levels in long-term stable renal allograft recipients

Background The use of cyclosporine was traditionally monitored by the trough level (C 0). However, the immunosuppressive effects of cyclosporine correlate with its drug exposure, represented by the area under curve (AUC). It was also noted that cyclosporine C 0 level correlated with AUC poorly, while C 2 level (concentration at 2 hours after drug administration) satisfactorily correlated with AUC. Most recent studies concern the use of C 2 levels in de novo renal transplant patients; target levels of C 2 have been suggested. There is rare discussion about the C 2 target level for long-term cyclosporine-maintenance patients. Our objectives were to analyze the cyclosporine C 2 levels of patients more than 12 months after transplantation as well as changes in C 2 with time and the correlation between C 2 level and renal function. Methods and patients This was a cross-sectional case-controlled study of 101 kidney recipients immunosuppressed with a cyclosporine-based regimen for at least 12 months. Both C 0 and C 2 levels were examined at various time points during outpatient clinic follow-up. The patients were stratified according to the time after transplant surgery, or to their renal function. Results The 101 patients were divided into three groups based on the time after renal transplant surgery. Groups 1, 2, and 3 represented patients transplanted for 1 to 3 years ( n = 16), 4 to 6 years ( n = 35), and more than 6 years ( n = 50), respectively. The C 2 levels for each group were 657 ± 232, 561 ± 186, and 580 ± 243 ng/mL, respectively, ( P = NS). When stratified into low versus high C 2 groups, there were no significant differences in renal function both at the beginning and at the end of 1 year follow-up. Seven of 67 patients shifted to stronger immunosuppression in the low C 2 group, but only 2/34 in the high C 2 group, a difference that was not significant ( P = .234 by Fisher Exact Test). Patients with creatinine levels greater than 1.5 mg/dL or lower than 1.5 mg/dL showed no difference in C 2 on C 0 levels. Patients with deterioration of renal function during this period had no different C 2 levels as those with no deterioration of renal function. Conclusion The average C 2 levels among long-term cyclosporine-maintained patients were significantly lower than those previously suggested. C 2 levels did not correlate with the long-term outcome of renal function in patients at least 1 year after renal transplantation.

The value of C2 monitoring in stable renal allograft recipients on maintenance immunosuppression.

Cyclosporin A (CyA) is a drug with a narrow therapeutic window and highly variable pharmacokinetics. Therapeutic drug monitoring is essential and conventionally has been guided by trough levels (C0). Recent evidence indicates that a single blood concentration measurement 2 h after CyA administration (C2) is a more accurate predictor of drug exposure and clinical events than determination of C0. To date, limited prospective data are available with respect to risks and benefits of C2 monitoring in renal transplant recipients, and little experience exists with C2 monitoring in maintenance patients. In 127 long-term renal allograft recipients, we determined C2 levels in addition to conventional C0 and observed clinical outcome over a period of 13.6 +/- 3.1 months. To determine the precision of monitoring, we repeatedly determined C0 and C2 levels in 46 stable patients without dose change. Clinical outcome was excellent (patient survival 100%, graft survival 97%), with only two borderline rejections, although C2 levels (564 +/- 186 ng/ml) were lower than recommended so far for maintenance patients. We found no significant differences in C2 levels between patients with rejection and CyA toxicity. Receiver operating characteristic (ROC) analysis showed no prediction for risk of rejection, toxicity or infection by C2 levels. Repeated determinations of both C0 and C2 levels in 46 patients revealed a high intra-patient variability. In these patients, the coefficient of variation for C2 was only marginally better compared with C0. We conclude that in maintenance patients, C2 concentrations between 500 and 600 ng/ml are well tolerated and provide effective and safe rejection prophylaxis. Although mean C2 levels do not seem to be helpful in identifying patients at risk for rejection, they may be useful to detect over-immunosuppression and to improve long-term allograft survival further by reducing CyA nephrotoxicity.

Cyclosporin C2hour monitoring after renal transplantation.

Therapeutic drug monitoring of cyclosporin A (CsA) is essential because of its variable pharmacokinetics in individual patients and its narrow therapeutic window. In the past, standard trough level (C0) monitoring has been used, and although this method is currently the routine strategy, it has been shown that a single blood concentration measurement 2 hours after CsA administration (C2hour) is a significantly more accurate predictor of drug exposure and clinical events than trough concentrations. The CsA absorption profiling, in particular the measurement of C2hour, is a much more sensitive approach to assessing the pharmacokinetics and predicting the clinical effect in the individual patient. However, there are limited prospective data available examining the risks and benefits of C2hour monitoring in renal transplant recipients. Most studies focus on the early post-transplant phase, but there is little experience with C2hour monitoring in maintenance patients. Our experience in 127 stable long-term renal allograft recipients suggests that the therapeutic window for C2hour levels in patients during maintenance is lower than previously anticipated. Repeat determinations of both C0 and C2hour levels in 46 patients to determine precision of C2hour monitoring showed a high intrapatient variability. We observed only a slightly better coefficient of variation for C2hour than for C0 in repeat determinations. This suggests that drug monitoring using C2hour levels in transplant patients may provide a more accurate and reliable measure of drug exposure in the individual patient. However, CsA absorption showed only a weak correlation with dose during repeated measurements, suggesting high variability in absorption in these stable patients. We conclude that an adequate C2hour level soon after transplantation is associated with a reduced risk of acute rejection in adult renal transplant recipients. It is important to identify slow and poor absorbers in the initial phase after transplantation in order to avoid inappropriate increases in CsA dose. In maintenance patients, C2hour values between 500 and 600 ng/ml are effective and safe for providing effective rejection prophylaxis. Although mean C2hour levels do not seem to identify patients at risk of rejection, they may help to identify excessive immunosuppression and to improve long-term survival by reducing CsA toxicity.

Long-term Renal Allograft Recipients from South-East Asia in the Pre-Cyclosporin Era

The clinical outcome of long-term renal allograft recipients in the Chinese population has not been reported previously. We analysed patients from the pre-cyclosporin era who had grafts that functioned for > 10 years. Forty-five patients (31 men, 14 women; mean age 30, follow-up duration 13.3 years), representing a 10-year graft survival of 53%, were included. Thirty-six patients (80%) received living-related allografts and 9 (20%) received cadaveric or living-unrelated renal transplantation. The mean serum creatinine at last follow-up was 1.36 mg/dl (range, 0.83-4.08). Major posttransplantation complications included: hypertension in 25 (56%), infection in 16 (36%), acute rejection in 15 (33%), lipid disorder in 13 (29%), liver disease in 7 (16%), osteonecrosis in 5 (11%), malignancy in 4 (9%), coronary artery disease in 3 (7%), and diabetes mellitus in 3 (7%). Five grafts were lost: 3 to chronic rejection, and 2 to patients with stable function who died of non-renal causes. Proteinuria correlated strongly with graft function and survival, and marginally with hypertension. In hepatitis B carriers, serum alpha-feto protein is useful in the early detection of hepatocellular carcinoma. We conclude that while patients in the pre-cyclosporin era can survive with excellent graft function beyond the first decade, the risk of complications leading to significant morbidity still remains even when patients are receiving minimal doses of immunosuppression in the second decade.

Low-dose cyclosporine and mycophenolate mofetil in renal allograft recipients with suboptimal renal function.

Cyclosporine (CsA) nephrotoxicity can be identified by functional changes and chronic renal damage. CsA-associated renal fibrosis has been related to the overproduction of transforming growth factor (TGF)-beta1, a fibrogenic cytokine. Mycophenolate mofetil (MMF) may allow CsA dose reduction without increasing the risk of rejection. We studied the impact of CsA dose reduction in association with MMF on renal function and TGF-beta1, production in 16 long-term renal allograft recipients with suspected CsA nephrotoxicity. Two grams/day of MMF were introduced, and CsA dose was reduced to reach whole-blood levels between 40 and 60 ng/ml within 1 month. CsA dose and levels, renal function parameters, and platelet-poor plasma TGF-beta1 levels were evaluated before and 6 months thereafter. MMF allowed a decrease in both the mean dose of CsA (3.8+/-1.35 vs. 2.2+/-0.73 mg/kg/day; P<0.01) and CsA levels (148+/-36 vs. 53+/-19 ng/ml; P<0.001). The reduction of CsA was associated with a decrement of serum creatinine levels (210+/-46 vs. 172+/-41 micromol/L; P<0.001) and an increase in both the glomerular filtration rate (32.9+/-12 vs. 39.1+/-14 ml/min/1.73 m2; P<0.02) and renal plasma flow (195+/-79 to 218.6+/-74.02 ml/min/1.73 m2; P<0.02). There was a reduction in plasma TGF-beta1 levels (4.6+/-4.2 vs. 2.0+/-1.4 ng/ml; P=0.003) and CsA levels correlated with TGF-beta1 (r=0.536, P=0.002). No rejection episodes occurred, and an improvement in both systolic (149+/-13 vs. 137+/-12 mmHg; P<0.01) and diastolic blood pressure (89+/-14 vs. 83+/-10 mmHg; P<0.04) were observed. These short-term results show that MMF introduction allows a CsA dose reduction, which improves renal function, reduces TGF-beta1 production, and improves the control of hypertension, without increasing the incidence of acute rejection.

LOW-DOSE CYCLOSPORINE AND MYCOPHENOLATE MOFETIL IN RENAL ALLOGRAFT RECIPIENTS WITH SUBOPTIMAL RENAL FUNCTION.

417 Cyclosporine (CsA) nephrotoxicity can be identified by functional changes and chronic renal damage. CsA-associated renal fibrosis has been related to the overproduction of TGF-ß, a fibrogenic cytokine. CsA dose reduction may improve renal function but may increase the risk for rejection. We have studied the impact of CsA dose reduction in association with mycophenolate mofetil (MMF) on renal function and TGF-ß production in long-term (> 12 months after transplantation) renal allograft recipients with suspected CsA nephrotoxicity (serum creatinine 140-300 μmol/l, proteinuria < 1 g/day). In these patients MMF was introduced at 2 g/day and CsA dose was reduced to reach CsA whole blood levels between 40-60 ng/ml in one month. Before and 6 months after the introduction of MMF, CsA dose and levels, renal function parameters, and TGF-ß in platelet-free plasma, were evaluated. Eighteen patients were entered in this study, and 2 of them were withdrawn because of MMF intolerance. The results obtained in the remaining 16 cases (10 M/6F, mean age 44 y) are summarized in the next table:CsA levels correlated with TGF-ß values (r= 0.536, p= 0.0016). No rejection episodes occurred in these patients. These results show that MMF introduction allows CsA dose reduction which ameliorates renal function and reduces TGF-ß production.

Pattern of cytokine expression in circulation CD57 + T cells from long-term renal allograft recipients

We made a quantitative analysis of the lymphokine mRNA and of proteins produced by CD57 + and CD57 − circulating T cells isolated from long-term kidney-transplanted patients with expanded CD4 +/CD57 + and CD8 +/CD57 + T cells, and from normal individuals. We concentrated on IL-2 and IFN-γ, which define a Th1-like type of lymphokine production, and on IL-4 which defines a Th-2-like type. We also analysed the production of IL-10 which is endowed with inhibitory effects on IL-2 and IFN-γ-synthesis, and of TNF-α, a pleiotropic inflammatory cytokine. On ionomycin + PMA stimulation, which reveals the intrinsic potential of lymphokine production by T cells, the CD57 + T cell subsets from all individuals produced high amounts of IFN-γ and TNF-α mRNA and protein. They also produced IL-2, but to a much lesser extend than their CD57 − counterparts, and little IL-4 and IL-10. They were no more capable of producing IL-2 when stimulated through the CD3/TCR in the presence of monocytes, yet still synthesized IFN-γ. Our data suggest that the in vivo expansion of CD57 + T cells in stable allograft renal recipients might correspond to Th1 energized cells which on triggering of cell surface receptors hardly secrete lymphokines involved in cell cycle progression, but can still exert some effector functions, including IFN-γ secretion.

Delayed-type hypersensitivity-like mechanisms dominate late acute rejection episodes in renal allograft recipients.

Episodes of acute rejection (aRx) may occur in functional renal allografts even at a very late stage post-Tx. Histopathology in early and late aRx looks quite similar--however, there is a slower deterioration of graft function in late aRx, suggesting that pathogenetic immune mechanisms are different. In order to investigate this phenomenon we studied the gene expression pattern (IL-1beta, 2, 4, 8, 10, IFNgamma, TNFalpha, GrnA, IL-2R p55/p75) in PBMC and core biopsies from long-term renal allograft recipients with histologically proven late aRx and compared it with transplant and non-transplant controls using a semiquantitative RT-PCR technique. PBMC and graft-infiltrating cells of patients with late aRx showed an upregulation, especially of IFN-gamma, IL-4, IL-10, and TNFalpha transcripts. While IL-2 mRNA was only detected in PBMC of two patients with late aRx who were not on cyclosporine, upregulation of intragraft IL-2 mRNA allowed the best discrimination between aRx and the other groups (sensitivity: 83%, specificity: 93%). In contrast to several reports on early Rx we did not notice an elevation of granzyme A transcripts in comparison with the controls, suggesting that cell-mediated inflammatory processes (CD4+ T cell-mediated DTH) dominate the late aRx, while early aRx is characterized by the additional involvement of cytotoxic T cell response. This may explain the distinct clinical course. Additionally, in a pilot study we successfully treated late aRx in 10/12 patients with the anti-CD 4 mAb, 16H5. Our encouraging therapeutic results underline the pathogenetic role of CD4+ T cells and support our hypothesis on DTH-like mechanisms in late aRx.

CORRECTION OF POSTTRANSPLANT ERYTHROCYTOSIS WITH ENALAPRIL

Erythrocytosis (i.e., elevation in red cell mass) frequently develops after renal transplantation and is associated with increased risk of thromboembolic incidents and hypertension. Because it has been reported that enalapril may induce anemia in renal allograft recipients, we have undertaken a prospective study to estimate the efficacy and safety of enalapril therapy for erythrocytosis and to establish the mechanism by which enalapril reduces red cell mass. Seventeen (12 male and 5 female) long-term renal allograft recipients with increased hematocrit value (> 55% for male and > 50% for female) and elevated red cell mass as determined with 51Cr-labeled autologous erythrocytes were treated with enalapril. After 3 months of therapy, enalapril was withdrawn and patients were observed in order to differentiate spontaneous remission of erythrocytosis from effects of enalapril therapy. After 3 months of the treatment, mean hematocrit decreased from 51.1% (range 47–56%) to 42.9% (range 37–51%; P<0.01). Red cell mass significantly decreased during this period (from 46.7 ml/kg, range 32.5–60.7 ml/kg, to 32.9 ml/kg, range 20.1–60.1 ml/kg; P<0.01). Serum erythropoietin levels also changed from 12.2 mlU/ml (range 1.0–33.0 mlU/ml) at baseline to 5.4 mlU/ml (range 0.7–24.2 mlU/ml; P<0.05). During the following 3 months without enalapril treatment, an increase in hematocrit was noted, reaching 51.7% (range 46–58%; P<0.05). No serious side effects of enalapril were observed during the study, but there was a need to reduce other hypotensive drugs in some patients. Serum creatinine did not change significantly during enalapril therapy (1.49 mg/dl, range 0.9–2.3 mg/dl, and 1.55 mg/dl, range 1.0–2.3 mg/dl; before and after 3 months of therapy, respectively). Our study proves that enalapril can be safely and effectively used to treat posttransplant erythrocytosis. The effect of enalapril on red cell mass results from reducing erythropoietin production.

CORRECTION OF POSTTRANSPLANT ERYTHROCYTOSIS WITH ENALAPRIL

Erythrocytosis (i.e., elevation in red cell mass) frequently develops after renal transplantation and is associated with increased risk of thromboembolic incidents and hypertension. Because it has been reported that enalapril may induce anemia in renal allograft recipients, we have undertaken a prospective study to estimate the efficacy and safety of enalapril therapy for erythrocytosis and to establish the mechanism by which enalapril reduces red cell mass. Seventeen (12 male and 5 female) long-term renal allograft recipients with increased hematocrit value (> 55% for male and > 50% for female) and elevated red cell mass as determined with 51Cr-labeled autologous erythrocytes were treated with enalapril. After 3 months of therapy, enalapril was withdrawn and patients were observed in order to differentiate spontaneous remission of erythrocytosis from effects of enalapril therapy. After 3 months of the treatment, mean hematocrit decreased from 51.1% (range 47-56%) to 42.9% (range 37-51%; P < 0.01). Red cell mass significantly decreased during this period (from 46.7 ml/kg, range 32.5-60.7 ml/kg, to 32.9 ml/kg, range 20.1-60.1 ml/kg; P < 0.01). Serum erythropoietin levels also changed from 12.2 mIU/ml (range 1.0-33.0 mIU/ml) at baseline to 5.4 mIU/ml (range 0.7-24.2 mIU/ml; P < 0.05). During the following 3 months without enalapril treatment, an increase in hematocrit was noted, reaching 51.7% (range 46-58%; P < 0.05). No serious side effects of enalapril were observed during the study, but there was a need to reduce other hypotensive drugs in some patients. Serum creatinine did not change significantly during enalapril therapy (1.49 mg/dl, range 0.9-2.3 mg/dl, and 1.55 mg/dl, range 1.0-2.3 mg/dl; before and after 3 months of therapy, respectively). Our study proves that enalapril can be safely and effectively used to treat posttransplant erythrocytosis. The effect of enalapril on red cell mass results from reducing erythropoietin production.

Identification of natural suppressor cells in long-term renal allograft recipients.

We have previously reported an abnormal expansion of CD3+Leu7+ (CD57+) large granular lymphocytes in long-term renal allograft recipients. These cells lacked NK activity, T-helper activity and did not respond to T cell mitogens. The following studies were done in order to further define the functional characteristics of these cells. We sorted CD3+Leu7+ T cells from the peripheral blood of 45 recipients (all with good renal allograft function), and found that these cells suppress mixed lymphocyte culture responses and pokeweed mitogen-induced IgG secretion in a non-genetically restricted manner. PWM-induced IgG secretion assays are suppressed by 60-100%, and MLC responses are suppressed by 20-85% at a ratio of 1:10 CD3+Leu7+ cells to responder/effector cells. Supernatants from CD3+Leu7+ cell cultures are also suppressive. On the other hand, unsorted cells and non-CD3+Leu7+ sorted cells either enhance responses or produce less than 10% suppression under the same conditions. Patients who were tested more than once showed a relatively stable percentage and suppressive effect of their CD3+Leu7+ cells over an interval of 6-12 months. These nonspecifically suppressive CD3+Leu7+ large granular lymphocytes are similar in many ways to the natural suppressor cells that have been identified in hematopoietic tissues, in graft-vs.-host disease, and in the lymphoid organs of neonates.

Diagnostic and predictive value of an immune monitoring program for complications after kidney transplantation.

We have tested an immune monitoring program consisting of cytofluorometric analysis of lymphocytic and monocytic markers, using a set of different monoclonal antibodies (mAb), in about 500 transplant patients including about 300 long-term renal allograft recipients. The high sensitivity (95%) of these cytofluorometric analyses in the peripheral blood allows to discriminate between acute rejection and other causes of deteriorated kidney transplant function (infection, toxicity, arteriopathy), especially in the late phase (> 1 year) after transplantation. Additionally, the immune monitoring is sufficient to predict success of antirejection therapy as early as a few days after onset of treatment. A life-threatening complication in allograft recipients is septic disease. Proceeding from immune parameters, septic patients were found to fall into two categories: those with decreased expression of HLA-DR on monocytes (< 20%, termed as 'immunoparalysis') and patients with nearly normal HLA-DR+ monocytes. Septic immunoparalysis requires drastic reduction of immunosuppression (mortality after drastic reduction: 8%; after marginal reduction or without reduction: 90%). We have not observed severe rejection as a consequence of reduced immunosuppression in such patients. Our immune monitoring seems to be useful for management of immunosuppression in patients with unclear deterioration in graft function as well as patients with septic complications in order to minimize two risks, i.e. death by sepsis or loss of graft.

The Effect of Nifedipine on Renal Function in Normotensive Cyclosporin-A-Treated Renal Allograft Recipients

Intrarenal vasoconstriction is a characteristic feature of CsA nephrotoxicity. The influence of nifedipine, a dihydropyridine calcium channel blocker and potent renal vasodilator, on renal haemodynamics was investigated in 11 cyclosporin A (CsA)- and 9 azathioprine (Aza)-treated normotensive long-term renal allograft recipients. Baseline Cr51-EDTA clearance and effective renal plasma flow (ERPF) were similar in both groups. Nifedipine 20 mg twice daily for 28 days significantly increased Cr51-EDTA clearance (+14.8%) in the CsA group; however, ERPF, renal vascular resistance (RVR), and filtration fraction did not change. Nifedipine did not influence renal haemodynamics in the azathioprine group. The increase in Cr51-EDTA clearance in the CsA group did not correlate with baseline renal function, CsA dose or whole blood levels, donor age, duration of graft, or renal functional reserve capacity. This study suggests that nifedipine confers a beneficial effect on renal haemodynamics in long-term CsA-treated renal allograft recipients and appears to improve renal function by a non-haemodynamic mechanism.

CD4+/Leu-7+ LARGE GRANULAR LYMPHOCYTES IN LONG-TERM RENAL ALLOGRAFT RECIPIENTS A SUBSET OF ATYPICAL T CELLS1

In long-term renal allograft recipients on conventional immunosuppression, we have previously reported an abnormal expansion of CD3+/Leu-7+ cells. These cells are large granular lymphocytes without any natural killer activity. About 20% of these CD3+/Leu-7+ cells coexpress the CD4 differentiation antigen. In 65 transplant recipients at risk for more than 6 months, the mean percentage of peripheral blood CD4+/Leu-7+ cells is significantly increased compared with 34 normals (5.0 +/- 0.6% versus 1.0 +/- 0.1%, P less than 0.0001). Patients who never received azathioprine do not show such an abnormality. We carried out this study to further define the phenotype, morphology, and function of these cells. As to phenotype, they coexpress CD2, CD3 but do not coexpress CD1, CD8, CD11, CD16, CD19, CD25, HLA-DR, Leu-M3. Morphologically, CD4+/Leu-7+ cells are typical large granular lymphocytes undistinguishable from CD16+ effector NK cells. CD4+/Leu-7+ cells do not exhibit any natural killer cell activity. In contrast to CD4+/Leu-7- cells, CD4+/Leu-7+ cells do not proliferate when stimulated with either lectins (Con A, PHA) or allogeneic cells. When stimulated for 3 days with PHA, sorted CD4+/Leu-7+ cells do not express IL-2 receptors as detected with a PE-conjugated anti-CD25 monoclonal antibody, whereas 40% of CD4+-Leu-7- cells do so. Finally, when stimulated with PHA, CD4+-Leu-7+ cells are not able to produce detectable levels of IL-2, while CD4+-Leu-7- cells do so. In long-term renal allograft recipients on conventional immunosuppression, Leu-7 antigen identifies a subset of CD4+ cells that do not behave like regular T helper cells. We speculate that these cells represent an alteration in the cellular environment in transplant recipients, perhaps leading to long-term complications such as cancers and chronic viral infections.

Two-color Immunofluorescence Flow Cytometric Analysis of Lymphocytes in Long-term Renal Allograft Recipients

We used 2-color immunofluorescence flow cytometry (FACS 440) and monoclonal antibodies (Becton-Dickinson) to study peripheral blood lymphocyte subsets from 26 patients with well functioning renal allografts for longer than 5 years. Comparisons were made to a group of 25 healthy volunteers and 25 dialysis patients awaiting renal transplantation. As anticipated, there was no significant difference with respect to the absolute number or percentage of activated (T11+ and HLA-DR+) and cytotoxic (Leu-2+ and Leu-15−) T lymphocytes among the 3 groups. However, there was a significantly decreased absolute number (p equals 0.0001) and percentage (p equals 0.0001) of suppressor cells (Leu-2+ and Leu-15+) in the transplant patients compared to the healthy control group. No significant difference existed between the transplant and dialysis groups. There also was an increase in the percentage (p equals 0.002) but not in the absolute number of T helper lymphocytes (Leu-3+ and Leu-8−) in the transplant population compared to healthy controls. No significant difference existed between the transplant and dialysis groups. These findings suggest that a normal value of cytotoxic (Leu-2+ and Leu-15−) and activated (T11+ and HLA-Dr+) T lymphocytes may be a good prognostic indicator of long-term survival of renal allografts. Also, the highly significant decrease in the number of Leu-2+ and Leu-15+ cells in long-term, well functioning allografts indicates that additional functional characterization of this subset may be necessary.

Growth and Sexual Maturation in Children After Kidney Transplantation

Linear growth and sexual maturation were assessed in 68 long-term pediatric renal allograft recipients (43 boys) receiving dally or alternate-day prednisone therapy. Growth was analyzed both during the prepubertal period and during pubertly. Height at transplantation was >2 SD below the mean in 34.2% of prepubertal children. After the first posttransplant year, 59.2% of the prepubertal children had a normal height increment (>4.8 cm/yr). Onset of pubertly was recorded at a chronologic age of 14.6±1.9 years in boys and 13.3±1.9 years In grils. Height at onset of puberty related to chronologic age was −2.4±1.3 SD. Height velocity during puberty was within normal limits in 62.5% of the children. No significant difference in pubertal growth was detected in patients who had received transplants before and after the onset of puberty. Duration of pubertal development was within normal limits. In grils,menarche was achieved at a mean chronologic age of 15.9 years and bone age 12.9 years. Adult height was attained at an average age of 20.3 years in boys and 18.7 years in girls. Overall, one third of the children attained anadult height >2 SD below the mean. Our data indicate that although poor growth before kidney transplantation has a great inffuence on adult height, the loss of growth potential during pubertal development seems even more important.

Growth and sexual maturation in children after kidney transplantation

Linear growth and sexual maturation were assessed in 68 long-term pediatric renal allograft recipients (43 boys) receiving daily or alternate-day prednisone therapy. Growth was analyzed both during the prepubertal period and during puberty. Height at transplantation was greater than 2 SD below the mean in 34.2% of prepubertal children. After the first posttransplant year, 59.2% of the prepubertal children had a normal height increment (greater than 4.8 cm/yr). Onset of puberty was recorded at a chronologic age of 14.6 +/- 1.9 years in boys and 13.3 +/- 1.9 years in girls. Height at onset of puberty related to chronologic age was -2.4 +/- 1.3 SD. Height velocity during puberty was within normal limits in 62.5% of the children. No significant difference in pubertal growth was detected in patients who had received transplants before and after the onset of puberty. Duration of pubertal development was within normal limits. In girls, menarche was achieved at a mean chronologic age of 15.9 years and bone age 12.9 years. Adult height was attained at an average age of 20.3 years in boys and 18.7 years in girls. Overall, one third of the children attained an adult height greater than 2 SD below the mean. Our data indicate that although poor growth before kidney transplantation has a great influence on adult height, the loss of growth potential during pubertal development seems even more important.