Failure of Calcineurin Inhibitor (Tacrolimus) Weaning Randomized Trial in Long-Term Stable Kidney Transplant Recipients.

Long-term renal transplant outcome is limited by side effects of immunosuppressive drugs, particularly calcineurin inhibitor (CNI). We assumed that some patients selected for a "low immunological risk of rejection" could be eligible and benefit from a CNI weaning strategy. We designed a prospective, randomized, multicenter, double-blind placebo-controlled clinical study (Eudract: 2010-019574-33) to analyze the benefit-risk ratio of tacrolimus weaning on highly selected patients (≥4 years of transplantation, normal histology, stable graft function, no anti-HLA immunization). The primary endpoint was improvement of renal function. Fifty-two patients were scheduled in each treatment arm, placebo compared to the CNI maintenance arm. Only 10 patients were eligible and randomized. Five patients were assigned to the placebo arm and five were assigned to the tacrolimus maintenance arm. In the tacrolimus maintenance arm, all patients maintained stable graft function and no immunological events occurred. Contrastingly, in the placebo arm, all five patients had to reintroduce a full dose of tacrolimus since three of them presented an acute rejection episode (one humoral, one mixed, and one borderline) and two displayed anti-HLA antibodies without histological lesion (one donor-specific antibodies [DSA] and one non-DSA). Clearly, tacrolimus withdrawal must be avoided even in long-term highly selective stable kidney recipients.

The natural history of clinical operational tolerance after kidney transplantation through twenty-seven cases.

We report here on a European cohort of 27 kidney transplant recipients displaying operational tolerance, compared to two cohorts of matched kidney transplant recipients under immunosuppression and patients who stopped immunosuppressive drugs and presented with rejection. We report that a lower proportion of operationally tolerant patients received induction therapy (52% without induction therapy vs. 78.3%[p = 0.0455] and 96.7%[p = 0.0001], respectively), a difference likely due to the higher proportion (18.5%) of HLA matched recipients in the tolerant cohort. These patients were also significantly older at the time of transplantation (p = 0.0211) and immunosuppression withdrawal (p = 0.0002) than recipients who rejected their graft after weaning. Finally, these patients were at lower risk of infectious disease. Among the 27 patients defined as operationally tolerant at the time of inclusion, 19 still display stable graft function (mean 9 ± 4 years after transplantation) whereas 30% presented slow deterioration of graft function. Six of these patients tested positive for pre-graft anti-HLA antibodies. Biopsy histology studies revealed an active immunologically driven mechanism for half of them, associated with DSA in the absence of C4d. This study suggests that operational tolerance can persist as a robust phenomenon, although eventual graft loss does occur in some patients, particularly in the setting of donor-specific alloantibody.

BAFF and BAFF-R levels are associated with risk of long-term kidney graft dysfunction and development of donor-specific antibodies.

There are lines of evidence that B cells may play a role in transplantation. B cell activating factor, BAFF, is a homotrimer that has been shown to play a role in B cell survival, maturation and activation. To date, little is known of the role of BAFF and its receptors in transplantation. We analyzed the level of BAFF mRNA and its soluble protein, as well as transcripts coding for its receptors, BAFF-R, TACI and BCMA, in the blood of 143 patients with stable kidney transplant function 5 years or more posttransplantation. Three endpoints were analyzed: the time to renal dysfunction, the time to appearance of anti-HLA antibodies and the time to development of donor-specific antibodies. We established threshold values for BAFF and BAFF-R and showed that (1) stable patients with high BAFF-R levels had a higher risk of developing graft dysfunction, (2) patients with lower levels of BAFF transcripts or a higher level of soluble BAFF had a significantly higher risk of developing donor-specific antibodies. These data suggest that BAFF constitutes a risk factor for renal graft dysfunction and development of donor-specific antibodies. They also suggest that agents targeting BAFF-R interactions may offer new therapeutic opportunities in transplantation.

[Results and surgical complications of living donor nephrectomy: open vs hand-assisted laparoscopic nephrectomy]. / Résultats et complications chirurgicales de la néphrectomie donneur vivant : lombotomie vs laparoscopie manuellement assistée.

PURPOSE: Hand-assisted laparoscopic nephrectomy in living donors is a minimally invasive surgical modality. Laparoscopic nephrectomy is now a routine procedure. This study compares an initial group of patients undergoing laparoscopic live donor nephrectomy to a group of patients undergoing open donor. Donor morbidity and graft function in the laparoscopic group were compared with those in the open group. MATERIALS AND METHODS: We retrospectively reviewed the medical records of 53 consecutive laparoscopic nephrectomy and compared them with 60 consecutive open donor nephrectomies. RESULTS: Demographic data of donors and recipients were similar in the two groups. No conversion to open surgery was necessary. Laparoscopic group patients had a shorter hospital stay compared to those undergoing open surgery. Long-term follow-up of serum creatinine levels revealed no significant differences among the two groups: at 3.6 and 12 months: 112 (+/-27) versus 122 (+/-11), 111 (+/-25) versus 119 (+/-19), 114 (+/-23) versus 122 (+/-25). There was no difference between hand-assisted laparoscopic nephrectomy (two vesico ureteral leak, three hematoma (one needed a surgical revision) and lombotomy (one vesico ureteral leak, one hematoma needed a surgical revision, two arteries stenosis). The rate of recipient ureteral stenosis in the laparoscopic and open nephrectomy groups was 0 of 39 cases and two of 60, respectively. Two vesico ureteral leak versus none appear in the lapararoscopic group. CONCLUSION: Hand-assisted laparoscopic nephrectomy in living donors is a safe procedure which presented low morbidity after surgery. This provides equal graft function equal urological complications compared to open live donor nephrectomy. This is our reference method.

Controlling the incidence of infection and malignancy by modifying immunosuppression.

Long-term outcomes in renal transplantation have improved over the years but are still a matter of concern. Because patients typically require lifelong immunosuppression, the risks of cancer and infection associated with immunosuppressive agents continue to demand attention. Physicians strive endlessly to find the right balance between the level of immunosuppression required to prevent rejection and the level that will minimize dose-dependent side effects. Data presented in this paper suggest that some renal transplant recipients might have more than necessary immunosuppression during maintenance therapy and that reducing the immunosuppressant dose can decrease cancer incidence, without worsening long-term patient or allograft survival. Additionally, data were examined suggesting that immunosuppressive agents might be associated with different risks for cancer, specifically, the potential advantage of reduced cancer risk for sirolimus and sirolimus derivatives in comparison with standard immunosuppressive agents. Although promising, these preliminary results are from preclinical studies, and further study is warranted.

Highly altered V beta repertoire of T cells infiltrating long-term rejected kidney allografts.

Chronic rejection represents a major cause of long-term kidney graft loss. T cells that are predominant in long-term rejected kidney allografts (35 +/- 10% of area infiltrate) may thus be instrumental in this phenomenon, which is likely to be dependent on the indirect pathway of allorecognition only. We have analyzed the variations in T cell repertoire usage of the V beta chain at the complementary determining region 3 (CDR3) level in 18 human kidney grafts lost due to chronic rejection. We observed a strongly biased intragraft TCR V beta usage for the majority of V beta families and also a very high percentage (55%) of V beta families exhibiting common and oligoclonal V beta-C beta rearrangements in the grafts of patients with chronic rejection associated with superimposed histologically acute lesions. Furthermore, V beta 8 and V beta 23 families exhibited common and oligoclonal V beta-J beta rearrangements in 4 of 18 patients (22%). Several CDR3 amino acid sequences were found for the common and oligoclonal V beta 8-J beta 1.4 rearrangement. Quantitative PCR showed that biased V beta transcripts were also overexpressed in chronically rejected kidneys with superimposed acute lesions. In contrast, T lymphocytes infiltrating rejected allografts with chronic rejection only showed an unaltered Gaussian-type CDR3 length distribution. This pattern suggests that late graft failure associated with histological lesions restricted to Banff-defined chronic rejection does not involve T cell-mediated injury. Thus, our observation suggests that a limited number of determinants stimulates the recipient immune system in long-term allograft failure. The possibility of a local response against viral or parenchymatous cell-derived determinants is discussed.

Impact of the MHC-encoded HLA-DMA, DMB, and LMP2 gene polymorphisms on kidney graft outcome.

We previously studied the relationship between TAP1 and TAP2 gene polymorphism and compatibility in kidney graft outcome and reported that the currently described TAP1 and TAP2 gene polymorphisms did not influence the incidence of acute rejection episodes. In this study, we report on the effect of polymorphism and matching of HLA-DMA, -DMB, and LMP2 genes on kidney graft outcome. This study was performed on 102 selected kidney recipients who experienced two or more acute rejection episodes (rejection group) during follow up and who were compared to a group of 150 patients who never had rejection (non rejection group). Although a significant effect of HLA-DR matching was observed between these two groups, our data suggest that matching for all the new genes located in the HLA class II region (TAP1, TAP2, LMP2, HLA-DMA and -DMB) does not influence the kidney graft outcome. However, a significant increase (pc < 0.05) of DMA*0102 allele was observed in the recipients of the rejection group as compared to those of the non rejection group. This effect was not due to a linkage disequilibrium between DMA and HLA-DR loci and suggests that this specific HLA-DMA allele could play a role in the indirect pathway of class II presentation of donor antigens.

Effect of long-term immunosuppression in kidney-graft recipients on cancer incidence: randomised comparison of two cyclosporin regimens.

BACKGROUND: Long-term administration of cyclosporin carries a risk of renal toxicity, and immunosuppressants are associated with an increased rate of malignant disorders. We undertook an open randomised study of the risks and benefits of two long-term maintenance regimens of cyclosporin in kidney-allograft recipients. The primary endpoint was graft function; secondary endpoints were survival and occurrence of cancer and rejection. METHODS: 231 recipients of a first allograft with at most one previous rejection episode were randomised 1 year after transplantation. Most were receiving cyclosporin and azathioprine. One group received cyclosporin doses adjusted to yield trough blood concentrations of 75-125 ng/mL (low-dose group); the second received doses that yielded trough concentrations of 150-250 ng/mL (normal-dose group). Analysis was by intention to treat. FINDINGS: At 66 months' follow-up, the low-dose and normal-dose groups were similar in mean serum creatinine (182 [SD 160] vs 184 [157] micromol/L; p=0.9) and mean creatinine clearance (47.5 [25.1] vs 45.3 (22.5] mL/min; p=0.6). Nine of 116 patients in the low-dose group and one of 115 in the normal-dose group had symptoms of rejection (p<0.02). There was no difference between the low-dose and normal-dose groups in survival (95 vs 92%; p=0.7) or graft survival (89 vs 82%; p=0.17) at 6 years. 60 patients developed cancers, 37 in the normal-dose group and 23 in the low-dose group (p<0.034); 66% were skin cancers (26 vs 17; p<0.05). INTERPRETATION: We found no evidence that halving of trough blood cyclosporin concentrations significantly changes graft function or graft survival. The low-dose regimen was associated with fewer malignant disorders but more frequent rejection. The design of long-term maintenance protocols for transplant recipients based on powerful immunosuppressant combinations should take these potential risks into account.

Decreased cytotoxic activity of natural killer cells in kidney allograft recipients treated with human HLA-derived peptide.

Peptides derived from a conserved region (aa 75-84) of HLA class I, overlapping the supertypic HLA-BW4/BW6 antigen region, have been shown to exhibit nonallele restricted immunosuppressive properties in rats and mice, prolonging survival of major histocompatibility complex-mismatched allografts. Furthermore, HLA-B7 peptides inhibit alloreactive cytotoxic cells, and both HLA-B7 and HLA-B2702 peptides inhibit natural killer (NK) cytotoxicity in vivo. In this article, we report on a randomized, controlled study of the safety and pharmacokinetics of HLA-B2702-derived peptide in human recipients of a first kidney allograft. Escalating doses of HLA-B2702 were compared with doses of placebo controls. No toxicity and no immunization against the peptide were noted. Although the study was not designed as an efficacy trial, patients who received the high-dose protocol (7 mg/kg) did experience more rejection episodes, but this was not statistically significant when compared with control patients. Interestingly, in human recipients, as previously observed in rodents, administration of the peptide was associated with a statistically significant decrease in the cytotoxicity of NK cells against K562 targets (P<0.001). As these peptides correspond to a region of the HLA class I molecule that interacts with the newly described NK receptors for class I, their mode of action through interaction with such receptors is discussed. As a peptide of the same sequence from HLA-B7 blocks both NK and alloreactive T cell cytotoxicity, it is possible that, in humans too, both types of cytotoxic cells are affected by this peptide. The biological significance of these observations should be confirmed in future controlled studies with a larger patient population.

Single-center analysis of 468 first cadaveric kidney allografts with a uniform ATG-CsA sequential therapy.

Progress in clinical management and sophistication of immunological treatment of kidney allografts depend upon continuous reassessment of the risk factors related to pre- and post-graft information according to the therapeutical strategies used. We studied predictive factors of long-term graft survival (up to 9 years) and of kidney graft function at one year after surgery in a single-center population of 468 first cadaveric kidney recipients treated with a uniform immunosuppression induction regimen of anti-thymocyte globulin, followed by cyclosporine A. The statistical analysis showed that long-term graft survival was highly correlated with the occurrence of one or more acute cellular rejections and with the timing of these episodes. In addition, this uniformly treated series of patients confirmed the potential importance of gender matching. The magnitude of anti-HLA immunization and delayed graft function were also strongly linked to low graft survival rates. We found no significant influence of HLA matching, with serological HLA typing, on graft loss. The quality of graft function at one year was found to be a strong prognostic factor of long-term graft survival. In addition, the impact of pre- and post-graft parameters were studied in terms of prediction of one-year graft function. A stepwise multivariate analysis showed that graft function at one year was a multivariate phenomenon strongly correlated with a history of acute rejection episodes and with donor and recipient age. However, these 3 factors could account for only 15% of the graft function deterioration, the remaining 85% might be explained in part by chronic cyclosporine toxicity and/or chronic rejection.

[Anti-cytokines and anti-cytokine receptors]. / Anticytokines et antirécepteurs de cytokine.

Cytokines play a key-role in the immune response. The best known of them is interleukin-2 and its specific receptors. Monoclonal antibodies directed against the interleukin-2 receptor have initially enabled this receptor to be characterized; then they served to confirm the major role played by this cytokine in immune responses, where it proved effective in many animal models such as allograft reaction, delayed hypersensitivity reaction and some experimental auto-immune diseases. These results have been confirmed in man, particularly in kidney transplantation (but also in bone marrow transplantation), and they encourage to develop new bioreagents (chimeral antibodies, "humanized" antibodies, fusion proteins). Some of these reagents are now undergoing evaluation in renal transplantation. The principles of these bioreagents, issued from molecular biology, can be applied to other cytokines involved in the immunopathological mechanisms of certain diseases such as, for example, IL-6 and its role in the development of myeloma. Data from immune intervention directed against other cytokines are, for the moment, preliminary, but many potential targets (IL-1, IL-4, TNF alpha, INF gamma) are emerging.

Soluble interleukin 2 receptor (Tac chain) is not a reliable marker in kidney transplant recipient monitoring.

T lymphocyte expansion is triggered through interaction of interleukin 2 (IL-2) with its high-affinity receptor (IL-2R). This molecule is a heterodimer comprising an antigen-inducible component, the Tac chain (P55). Activation of T lymphocytes also generates a soluble form of this P55 called S-IL-2R. S-IL-2R is elevated in many T-cell-related pathologies (leukemia, autoimmunity, etc.). In graft recipients, rejection is a result of T-cell activation by graft antigens and therefore might induce a release of S-IL-2R in the circulation; this parameter is now said to be a good indicator of rejection. We have performed a study in renal graft recipients in order to assess the usefulness of circulating S-IL-2R particularly to discriminate the origin of renal failure in cases of rejection or of cyclosporin-A (CsA)-induced nephrotoxicity. We demonstrated that there are no differences between isolated values in the clinical groups at the time of diagnosis. Variations in S-IL-2R are increased compared to steady-state periods during rejection and cytomegalovirus infections, although not in CsA toxicity episodes. However, at the individual level there are too many false-positive and false-negative results, making this parameter no more meaningful than serum creatinine levels alone or even in association (as tested in logistic discriminant analysis). In addition, it seems that the variations in S-IL-2R are partly related to renal function itself, as suggested by the correlation between S-IL-2R levels and serum creatinine levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-interleukin 2 receptor monoclonal antibody in the treatment of ongoing acute rejection episodes of human kidney graft--a pilot study.

Monoclonal antibodies (MoAbs) against human interleukin 2 receptor (IL-2-R) have been shown to prevent early kidney rejection in animals and humans. We report here the effect of an anti-IL-2-R MoAb (33B3.1) inhibiting IL-2 binding high-affinity sites on activated lymphocytes in 10 declared acute rejection episodes of first cadaveric kidney grafts. Six patients were under cyclosporine treatment only at the time of diagnosis of the rejection. All rejection episodes but one were biopsy-proved cellular rejections. Treatment consisted of intravenous infusions of 33B3.1 at 20 mg/day x 2 days, followed by 10 mg/day for 8 additional days. In case of MoAb ineffectiveness at day 5, anti-IL-2-R MoAb was discontinued and a rescue treatment of corticosteroid boluses (CSb) was given. If not, in all cases corticosteroids (CS) were given (1 mg/kg) at the end of MoAb treatment (day 10) and tapered off thereafter. Two rejection episodes immediately responded to 33B3.1 treatment. During 33B3.1 treatment four other patients had only a stabilization of their blood creatinine concentration, which nevertheless returned to prerejection levels after day 10 when anti-IL-2-R was discontinued and CS administered at 1 mg/kg (no rescue treatment). The four remaining patients had an increase of their blood creatinin levels at day 5 despite 33B3.1 treatment, and their renal function only improved with CSb rescue treatment. One of these patients lost the graft despite rescue treatment, as well as a 9-day course of antithymocyte globulin. Trough levels of MoAb reached a plateau as early as day 2 (approximately 6 micrograms/ml). All patients developed antibodies (IgM and IgG) after day 14. In no instance could unresponsiveness be related to low circulating 33B3.1 trough levels or to early host anti-MoAb immune response (IgM or IgG). We conclude that 33B3.1, known to be effective in preventing early rejection, has only inconsistent and/or incomplete effects on the ongoing rejection process. Our data suggest that once IL-2-dependent clones are expanded in the rejected graft, interference with IL-2/IL-2-R signals does not block the effector mechanisms sustaining acute rejection.