Complement genes strongly predict recurrence and graft outcome in adult renal transplant recipients with atypical hemolytic and uremic syndrome.

Atypical hemolytic and uremic syndrome (aHUS) is a severe disease strongly associated with genetic abnormalities in the complement alternative pathway. In renal posttransplantation, few data are available on recurrence risk and graft outcome according to genetic background in aHUS patients. The aim of this study was to identify risk factors for recurrence and transplant outcome and, in particular, the role of complement gene abnormalities. We retrospectively studied 57 aHUS patients who had received 71 renal transplants. A mutation in complement gene was identified in 39 (68%), in factor H (CFH), factor I (CFI), membrane cofactor-protein (MCP), C3 and factor B (CFB). At 5 years, death-censored graft survival was 51%. Disease recurrence was associated with graft loss (p = 0.001). Mutations in complement genes were associated with higher risk of recurrence (p = 0.009). Patients with CFH or gain of function (C3, CFB) mutations had a highest risk of recurrence. M-TOR inhibitor was associated with significant risk of recurrence (p = 0.043) but not calcineurin inhibitor immunosuppressive treatment (p = 0.29). Preemptive plasmatherapy was associated with a trend to decrease recurrence (p = 0.07). Our study highlights that characterization of complement genetic abnormalities predicts the risk of recurrence-related graft loss and paves the way for future genetically based individualized prophylactic therapeutic strategies.

Complement mutation-associated de novo thrombotic microangiopathy following kidney transplantation.

Mutations in one or more genes encoding complement-regulatory proteins predispose to atypical hemolytic uremic syndrome (aHUS) and its recurrence following kidney transplantation. We evaluated plasma complement level and performed a screening for mutations in genes encoding complement Factors H and I (CFH, CFI) and membrane cofactor protein (MCP) in 24 kidney transplant recipients experiencing de novo thrombotic microangiopathy (TMA). Six patients presented with low C3 and/or low Factor B levels suggestive complement alternative pathway. A mutation in the CFH or CFI gene was found in 7/24 patients (29%), two of whom had a mutation in both genes. On the contrary, no mutation was identified in a control kidney transplant patients group (n = 25) without TMA. Patients with or without mutations were similar with regard to clinical features. Eight out of 24 patients lost their graft within 1 year of posttransplantation including six patients with a CFH mutation or a decrease of C3 or CFB in plasma. To conclude, kidney transplant patients with de novo TMA exhibit an unexpectedly high frequency of CFH and CFI mutations. These results suggest that genetic abnormalities may represent risk factors for de novo TMA after kidney transplantation and raise the question of the best therapeutic strategy.

[Immunosuppressive strategies and chronic graft dysfunction in kidney transplantation]. / Stratégies immunosuppressives et dysfonction chronique du greffon en transplantation rénale.

Chronic graft dysfunction is a major cause of return to dialysis. In the majority of cases, it is correlated with histological signs of cellular and/or humoral rejection, the nephrotoxicity of anticalcineurins, or nonspecific lesions of interstitial fibrosis and tubular atrophy. Although the incidence of acute rejection has considerably decreased, renal toxicity of the calcineurin inhibitors remains problematic. In cases of established nephrotoxicity, the use of non-nephrotoxic immunosuppressors such as mycophenolic acid or the proliferation signal inhibitors makes it possible to reduce or even stop the anticalcineurins. In prevention of anticalcineurin nephrotoxicity, many attempts to minimize or wean patients from them have shown that improvement in renal function is only obtained at the cost of an increase in the incidence of acute rejection. This makes it necessary to select patients who may benefit from anticalcineurin-sparing treatment, based on clinical, histological, and biological markers. Finally, long-term follow-up is also fundamental in order to validate the positive impact on renal function of this strategy in terms of graft survival.

[Buschke's scleredema successfully treated with extracorporeal photopheresis]. / Sclérœdème de Buschke traité efficacement par photophérèse extracorporelle.

BACKGROUND: Scleredema adultorum (Buschke's scleredema) is a cutaneous mucinosis of unknown origin, clinically characterized by a diffuse induration of the skin usually involving the neck, shoulders and back, which limits patients' mobility. CASE REPORT: We report a case of a 50-year-old woman who presented a chronic sclerodermiform syndrome for 2 years associated with type 1 diabetes. Physical examination revealed an extensive skin induration involving the shoulders, neck and back. Histologic examination confirmed the diagnosis of scleredema adultorum. The patient was treated with extracorporeal photopheresis (EPP) twice a month for two months. At follow-up, mobility was highly improved after two months. Beneficial effect of EPP was maintained on the long term while sessions were spaced. DISCUSSION: EPP is an unconventional treatment of Buschke's scleredema. We described a case of Buschke's scleredema successfully treated with EPP which may represent a therapeutic option for the treatment of scleredema.

[Weaning from corticosteroid therapy after kidney transplantation]. / Sevrage de la corticothérapie après transplantation rénale.

For years, the numerous side effects of long term steroid administration have motivated their elimination from the immunosuppressive regimen in renal transplantation. However until the 90's, steroid withdrawal induced an increase in the incidence of acute rejection episodes, and some studies described a significant risk of graft loss. New immunosuppressive drugs (tacrolimus, mycophenolate and mTOR inhibitors) have led to reevaluate steroid discontinuation. Recent trials with these drugs have shown that late steroid withdrawal (3 months post-transplant) was no more associated with a higher risk of acute rejection or graft loss. Some studies have demonstrated an improvement in the cardiovascular risk factors and a decreased incidence of infections and osteoporosis. Its positive impact on patient survival remains to be confirmed in long term follow-up studies.

Long-term kinetics of a T-lymphocytes subset in kidney transplant recipients: relationship with posttransplant malignancies.

UNLABELLED: Immunosuppression is associated with a high incidence of malignancies among renal transplant patients. In this study, we investigated the relationship between CD4 lymphopenia and the development of posttransplant malignancy (PTM) after induction therapies in renal transplant recipients (RTR). PATIENTS AND METHODS: This retrospective study included 966 RTR who were transplanted between 1993 and 2005 and had a mean follow-up of 83 +/- 46 months. Induction with antithymocyte globulin (ATG) was employed in 747 patients, while remaining 219 recipients received anti-CD25 antibodies. CD4 T-cell counts determined yearly were correlated with the occurrence of PTM. RESULTS: Eighty-five (8.8%) patients developed a PTM: cutaneous neoplasia (n = 33), lymphoma (n = 14), noncutaneous solid cancer (n = 36). Only age was observed to be significantly different among patients with versus without PTM (48 +/- 10 vs 41 +/- 12 years; P < .001). An early CD4 lymphopenia (<300/mm(3)) was frequent after ATG as compared with anti-CD25 induction (69.8% vs 12.1% at 3 months; P < .0001). The proportion of T CD4 lymphopenic patients progressively decreased over time remaining stable at 5- and 10-year follow-ups (12% and 10.8%, respectively). However, CD4 lymphopenia was not associated with a greater incidence of PTM. CONCLUSION: ATG induced CD4 lymphopenia, which persisted in a small proportion of patients in the long term, but did not seem to be correlated with the occurrence of PTM.

[Thyrotoxic hypokalaemic periodic paralysis in a Caucasian male]. / Paralysie périodique hypokaliémique thyréotoxique chez un Caucasien.

We report the case of a caucasian patient with a presentation of a periodic paralysis associated with hypokalaemia disclosing Graves' disease. Major pathophysiologics hypothesis are discused in order to explain relationships between hyperthyroidism and paralysis through a disturbance of the excitability of the muscle fibres. A genetic predisposition explain the high incidence of this affection in asiatic population while it is uncommon in caucasian race. Potassium supplementation is not needed in order to correct hypokalaemia except in case of cardiac disturbances. Treatment by beta-blockers is advisable with the specific treatment of hyperthyroidism.