Expression of VE-Cadherin in Peritubular Endothelial Cells during Acute Rejection after Human Renal Transplantation.

Genes involved in acute rejection (AR) after organ transplantation remain to be further elucidated. In a previous work we have demonstrated the under-expression of VE-Cadherin by endothelial cells (EC) in AR following murine and human heart transplantation. Serial sections from 15 human kidney Banff-graded transplant biopsies were examined for the presence of VE-Cadherin and CD34 staining by immunohistochemistry (no AR (n = 5), AR grade IA (n = 5), or AR grade IIA (n = 5)). Quantification of peritubular EC staining were evaluated and results were expressed by the percentage of stained cells per surface analysed. There was no difference in CD34 staining between the 3 groups. VE-Cadherin expression was significantly reduced in AR Grade IIA when compared to no AR (P = .01) and to AR grade IA (P = .02). This study demonstrates a reduced VE-Cadherin expression by EC in AR after renal transplantation. The down-regulation of VE-Cadherin may strongly participate in human AR.

Association of human leukocyte antigen haplotypes with posttransplant lymphoproliferative disease after solid organ transplantation.

BACKGROUND: Posttransplant lymphoproliferative disease (PTLD) after solid organ transplantation (SOT) is commonly characterized by Epstein-Barr virus (EBV)-driven proliferation of recipient B cells due to impaired immune surveillance in the context of immunosuppression. Because EBV-specific T-cell responses are focused on the level of EBV antigen and epitope choice depending on the individual human leukocyte antigen (HLA) alleles, we hypothesized that certain HLA alleles or a distinct HLA haplotype may influence the risk of development of PTLD after SOT. METHODS: A multicenter case-control study was performed comparing a group of 155 recipients after SOT with development of PTLD with a group of 1996 recipients after SOT without development of PTLD. Alleles, genotypes, and three locus haplotypes were compared of SOT recipients with and without PTLD. RESULTS: The bivariate analysis showed that carrying HLA-A03 was negatively associated (odds ratio [OR] 0.61, confidence interval [CI] 0.40-0.92, P < 0.02) whereas carrying of HLA-B18 (OR 1.79, CI 1.18-2.73, P < 0.006) and HLA-B21 (OR 2.08, CI 1.14-3.77, P < 0.02) were positively associated with PTLD after SOT. HLA-DR analysis demonstrated a significant negative association between the expression of HLA-DR7 (OR 0.46, CI 0.28-0.78, P < 0.004) and PTLD. Three locus haplotype analysis underlined the relevance of a dominant protective effect of HLA-DR7 expression concerning the risk of PTLD development. CONCLUSIONS: Our data suggest an influence of HLA variants on the risk of the development of PTLD. We hypothesize that HLA genes or non-HLA genes within the HLA loci confer a risk modification for the individual patient.

Subsequent skin cancers in kidney and heart transplant recipients after the first squamous cell carcinoma.

BACKGROUND: The increased incidence of skin cancers in transplant patients is well documented; however, few data exist on the risk of subsequent skin tumors in a given patient after the first skin cancer. The aim of this study was to compare the individual rate of subsequent skin cancers in kidney (KTR) and heart transplant recipients (HTR) after the first squamous cell carcinoma (SCC) and to assess risk factors for tumor multiplicity. METHODS: In all, 188 patients (121 KTR/67 HTR) were studied for up to 5 years. The cumulative number of SCC, basal cell carcinomas, Bowen's diseases, premalignant keratoses, and keratoacanthomas was recorded yearly after the first SCC. RESULTS: Overall, 71% of patients developed 757 new skin tumors. At 5 years, 100% of HTR and 88% of KTR had presented new tumors. However, the mean number of all tumors was significantly higher in KTR (3.4 vs. 2.0, 4.8 vs. 2.6, 6.6 vs. 2.9, 8.5 vs. 3.5, and 9.7 vs. 4.6 at 1, 2, 3, 4, and 5 years, respectively). Transplantation before 1984, multiple tumors at first consultation, eye and hair color, and skin type were predictive of multiple tumors. Early minimization of immunosuppression and of sun exposure tended to be associated with a reduced rate of all tumors and of SCC, respectively. CONCLUSIONS: Although the proportion of HTR developing new tumors is greater as compared with KTR, the mean number of tumors per patient is higher in KTR. This could be due to a longer immunosuppression in patients younger at transplantation.

Efficacy and safety of rituximab in B-cell post-transplantation lymphoproliferative disorders: results of a prospective multicenter phase 2 study.

B-cell posttransplantation lymphoproliferative disorder (B-PTLD) is a rare but severe complication of transplantation, with no consensus on best treatment practice. This prospective trial, the first to test a treatment for PTLD, was designed to evaluate the efficacy and safety of rituximab in patients with B-PTLD after solid organ transplantation (SOT). Forty-six patients were included and 43 patients were analyzed. Patients were eligible if they had untreated B-PTLD that was not responding to tapering of immunosuppression. Treatment consisted of 4 weekly injections of rituximab at 375 mg/m2. At day (d) 80, 37 (86%) patients were alive, and the response rate was 44.2%, including 12 complete response/unconfirmed complete response (CR/CRu). The only factor predictive of a response at d80 was a normal lactate dehydrogenase level (P = .007, odds ratio [OR] = 6.9). At d360, responses were maintained in 68% of patients, and 56% of patients were alive. The overall survival rate at 1 year was 67%. We conclude that rituximab is effective and safe in PTLD, with stable responses at 1 year. The response rate and overall survival might be improved by combining rituximab with other treatments.

No recurrence of posttransplantation Kaposi's sarcoma three years after renal retransplantation.

Kaposi's sarcoma (KS) develops in 0.5-5% of organ transplant patients; it usually regresses upon treatment reduction, but this may result in graft loss necessitating return to dialysis and/or retransplantation. Until now posttransplantation KS is considered to recur upon reintroduction of immunosuppressive treatment, a fact that has limited retransplantation of patients with previous KS. We report a patient with posttransplantation KS who received a second renal transplantation after having been off immunosuppressive treatment for 10 years, in whom KS has not recurred more than 3 years after retransplantation. This unique observation suggests that retransplantation of patients with previous posttransplantation KS is possible.