Evidence for genetic susceptibility towards development of posttransplant lymphoproliferative disorder in solid organ recipients.

BACKGROUND: Posttransplant lymphoproliferative disorder (PTLD) is a life-threatening complication after organ transplantation. The identification of risk factors for PTLD development is important for disease management. It has been shown that cytokine gene polymorphisms are associated with lymphoma and Epstein-Barr virus (EBV)-associated diseases in nonimmunosuppressed patients. In the present case-control study, we analyzed the impact of -1082 interleukin (IL)-10, -308 tumor necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta1 (codon 10, 25), and +874 interferon (IFN)-gamma gene single-nucleotide polymorphisms on the late onset EBV-associated PTLD. METHODS: Out of 1,765 solid organ recipients, 38 patients with late-onset EBV-associated PTLD and 408 matched solid organ recipients were selected and enrolled in the study. Single nucleotide polymorphisms (SNPs) for -1082IL-10, -308TNF-alpha, TGF-beta1 (codon 10, 25), and +874IFN-gamma genes were analyzed by a sequence specific primer polymerase chain reaction and were related to the PTLD development, and the disease course and outcome. RESULTS: The TGF-beta1 (codon 25) GG genotype was detected more frequently in controls than in PTLD patients (odds ratio=0.34, 95% confidence interval: 0.17-0.69, P=0.0022). The frequency of -1082 IL-10 GG genotype was also significantly higher in controls than in PTLD patients (odds ratio=0.5, 95% confidence interval: 0.25-1.0, P=0.044). There were no associations between -308TNF-alpha, TGF-beta1 codon 10, and +874IFN-gamma SNPs and PTLD. Disease course and outcome were not associated with any cytokine SNPs. CONCLUSIONS: Polymorphisms in two key anti-inflammatory cytokines, IL-10 and TGF-beta, are associated with susceptibility to EBV-associated PTLD, suggesting that a shift in pro-/anti-inflammatory response is involved in the pathogenesis of PTLD.

Salvage chemotherapy for refractory and relapsed posttransplant lymphoproliferative disorders (PTLD) after treatment with single-agent rituximab.

BACKGROUND: Single-agent rituximab has demonstrated encouraging efficacy and tolerability in posttransplant lymphoproliferative disorders (PTLDs) failing to respond to immunosuppression reduction (IR). This retrospective analysis was undertaken to determine the efficacy and safety of salvage therapy in recipients of solid organ transplants with progression of PTLD after rituximab first-line therapy. METHODS: Eleven patients who had received IR and single-agent rituximab were analyzed. Of these, 10 had received CHOP salvage chemotherapy. One patient with limited disease received tumor irradiation and further IR. Most patients (73%) had late PTLD (median onset of disease 145 months posttransplant), and most (83%) had monomorphic histology; 36% had EBV-association. RESULTS: IR and irradiation therapy re-induced complete remission (CR) and allowed long-term disease control in a patient with polymorphic PTLD relapse. CHOP therapy achieved CR in five (50%) and partial remission (PR) in two (20%) patients. Four of five (80%) patients achieving CR remained in CR at a median follow-up of 44.2 months. Of the patients achieving PR, one is currently alive, and the second died from transplant rejection after converting to CR after consolidative chemotherapy. Patients with stable disease (two) and progressive disease (one) have died from PTLD. There was one possible CHOP-associated death (acute cardiac event) and two patients had to be switched to less-toxic monotherapies. Median overall survival was 46.5 months (95% confidence interval: 23.6-49.1 months). CONCLUSIONS: CHOP salvage therapy achieved a favorable overall response rate of 70% in this setting, indicating that PTLD generally remains chemotherapy-sensitive after progression following first-line rituximab.

Quantitative analysis of EBV-specific CD4/CD8 T cell numbers, absolute CD4/CD8 T cell numbers and EBV load in solid organ transplant recipients with PLTD.

Post transplant lymphoproliferative disease (PTLD) in solid organ transplant (SOT) recipients is assumed to be the result of impaired Epstein-Barr Virus (EBV)-specific cellular immunity. We analyzed the absolute CD4 and CD8 T cell counts as well as the EBV-specific CD4 and CD8 T cell responses in relation to EBV load in SOT recipients with PTLD. A prospective, single center study was initiated and 10 immunosuppressed patients with diagnosis of PTLD were analyzed and compared to 3 patients without PTLD (2 SOT recipients with EBV-reactivation, 1 patient with Infectious Mononucleosis) and 6 healthy EBV positive controls. EBV-specific CD8 T cells were enumerated using HLA class I tetramers and the IFN-gamma cytokine secretion assay. EBNA1-specific CD4 T cells were analyzed after protein stimulation and EBV load was quantified by real-time PCR. Absolute CD8 T cell counts were highly variable in all 19 cases analyzed. In contrast, the absolute EBV-specific CD8 T cell count was found to be low in 7/9 patients with PTLD (<5/microl whole blood). These frequencies were similar to absolute EBV-specific CD8 T cell numbers observed in healthy EBV positive donors, but much lower compared to patients with EBV reactivation but no PTLD. Absolute CD4 T cell counts were significantly lower in PTLD patients (mean: 336/microl+/-161 vs. controls 1008/microl+/-424, p=0.0001), with EBNA1-specific CD4 T cell responses being also low, but highly variable. Moreover, low absolute CD4 T cell counts (<230/microl) were associated with an elevated EBV load (>1000 copies/microg DNA). We conclude that SOT recipients with PTLD have an inadequate functional EBV-specific T cell response. Our data suggest that the frequency and function of circulating EBV-specific CD8 T cells are dependent on absolute CD4 T cell counts. Further studies are needed to verify if a low absolute CD4 T cell count presents a risk factor for the development of PTLD in SOT recipients.

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.

Epstein-Barr viral load in whole blood of adults with posttransplant lymphoproliferative disorder after solid organ transplantation does not correlate with clinical course.

Posttransplant lymphoproliferative disease (PTLD) is closely linked to primary Epstein-Barr virus (EBV) infection. A defect of EBV specific cellular immunity is postulated to play a pivotal role in the etiology of PTLD, but there is some debate as to whether EBV load in the peripheral blood of transplant patients predicts onset of PTLD or relapse after treatment. The current prospective, single-center study was undertaken to investigate the impact of therapy on EBV load in adult patients with PTLD. Fifteen patients with PTLD after solid organ transplantation were included and of these, seven had EBV-associated PTLD. All 15 patients received Rituximab as primary therapy. In cases of treatment failure or relapse after Rituximab treatment, patients received polychemotherapy according to the cyclophosphamide, vincristine, doxorubicin, and prednisone regimen. At onset of PTLD, the median EBV load in the peripheral blood of patients was higher in EBV-associated PTLD than PTLD with no associated EBV infection. After Rituximab therapy, four of seven patients with EBV-associated PTLD achieved long-lasting complete remissions. However, in two of these patients, EBV load increased to reach levels as high as those recorded at onset of PTLD. Another patient showed a dramatic decline of EBV load after the first dose of Rituximab while suffering from progressive disease. The other patient relapsed after Rituximab monotherapy, but his viral load stayed low. In total, discordance in EBV load and clinical course was observed in five of the seven patients with EBV-associated PTLD. We conclude that in adult patients with PTLD, EBV load does not correlate with treatment response and is not suitable as a predictive marker for PTLD relapse.

Salvage chemotherapy for refractory or relapsed post-transplant lymphoproliferative disorder in patients after solid organ transplantation with a combination of carboplatin and etoposide.

This pilot study assessed the feasibility and efficacy of salvage chemotherapy (carboplatin and etoposide; CE) supported by granulocyte colony-stimulating factor (GCSF) in patients with refractory or relapsed post-transplant lymphoproliferative disorder (PTLD) following solid organ transplantation. Intensified salvage regimens were not feasible for these patients, due to their immunosuppressive conditions and potential organ (especially kidney and bone marrow) malfunctions. Salvage chemotherapy consisted of carboplatin [area under the curve (AUC) 4], on day 1, etoposide (120 mg/m2), on days 1-3 and GCSF (5 microg/kg) starting on day 5. This therapeutic regimen was planned to be repeated every 21 d. Nine patients (seven with refractory, two with relapsed disease) were enrolled. Five patients were heart transplant recipients, three liver transplant recipients and one patient had been a double lung transplant recipient. Five patients achieved a complete remission (CR), with follow-up at 92, 39, 55+, 17 and 9+ months. One patient showed stable disease after two cycles of CE and one patient had progressive disease. Two patients experienced early deaths, after the first and third cycles of chemotherapy respectively. One died of septic complications and one because of a perforated intestine, which had been infiltrated by lymphoma. In respect of the difficulties experienced in treating patients with refractory or relapsed PTLD after solid organ transplantation, the combination of carboplatin and etopoide with GCSF support (filgrastim) proved to be an effective regimen.