Neil A. Haldar

The impact of recipient cytokine genotype on acute rejection after renal transplantation.

Background. Acute allograft rejection remains an important cause of morbidity after kidney transplantation, and has been shown to be a crucial determinant of long-term graft function. As cytokines are major regulators of the immune system, genetic variation in cytokine production or activity may influence susceptibility to acute rejection. This study sought to determine the impact of recipient cytokine and cytokine receptor polymorphisms on acute rejection after renal transplantation. Methods. A total of 209 cadaveric renal transplant recipients were selected for analysis according to the presence or absence of graft rejection in the first 30 days after transplantation. DNA was genotyped for 22 polymorphisms in 11 cytokine and cytokine receptor genes using the polymerase chain reaction with sequence specific primers. Results were stratified by incidence and severity of rejection, and by HLA-DR mismatching. Results. No association between any polymorphism and the incidence or severity of acute rejection was detected. In particular, no association was seen with tumor necrosis factor or interleukin-10 genotype, either alone or in combination. Conclusions. We have failed to demonstrate any association between recipient cytokine genotype and acute rejection after cadaveric renal transplantation. Although more extensive studies may disprove these findings, it would seem premature to use recipient cytokine genotyping to predict transplant outcome, or to guide immunosuppressive therapy after transplantation.

DONOR CYTOKINE GENOTYPE INFLUENCES THE DEVELOPMENT OF ACUTE REJECTION AFTER RENAL TRANSPLANTATION

Background. Acute allograft rejection remains an important cause of morbidity after kidney transplantation, and has been shown to be a crucial determinant of long-term graft function. Although rejection is mediated by recipient lymphocytes, both donor and recipient factors contribute to the local environment that influences the nature, severity, and duration of the rejection response. Cytokines are a major determinant of this milieu, and this study sought to explore the impact of donor cytokine and cytokine receptor gene polymorphisms on acute rejection after renal transplantation. Methods. A total of 145 cadaveric renal allograft donors were selected for analysis according to the presence or absence of graft rejection in the first 30 days after transplantation. DNA was genotyped for 20 polymorphisms in 11 cytokine and cytokine receptor genes using the polymerase chain reaction with sequence specific primers. Associations were assessed using contingency table analysis and the &khgr;2 test, using a two-set design. Results. A polymorphism at position −174 of the donor IL-6 gene was associated with the incidence (P =0.0002) and severity (P =0.000007) of recipient acute rejection. This finding was independent of HLA-DR matching. Acute rejection was not influenced by recipient IL-6 genotype, or by donor-recipient matching of IL-6 genotype. Conclusion. This study identifies donor IL-6 genotype as a major genetic risk factor for the development of acute rejection after renal transplantation. This provides evidence that donor-derived cytokines play a major role in determining outcome after transplantation, and will contribute to the development of therapeutic algorithms to predict individuals at particularly high risk of acute rejection.

Polymorphisms in tumour necrosis factor (TNF) are associated with risk of bladder cancer and grade of tumour at presentation

The purpose of this study is to assess the role of tumour necrosis factor (TNF) polymorphisms in the risk of developing bladder cancer and effect on tumour stage, grade and progression. In all, seven single-nucleotide polymorphisms in TNF were studied in 196 bladder cancer patients and 208 controls using a PCR-SSP genotyping technique. It was seen that there was a significant association of two polymorphisms in TNF with bladder cancer: the TNF+488A allele was found in 28.1% of patients compared with 14.9% of controls (P=0.0012). In addition, TNF−859T was found in 26.0% of patients compared with 14.4% of the controls (P=0.0036). The two loci were in tight linkage disequilibrium, that is, almost all the individuals having TNF+488A also had TNF−859T. Patients with the TNF+488A or TNF−859T were more likely to present with a moderately differentiated tumour than those patients without the uncommon allele. In all, 16.7% of patients with TNF+488A and 29.9% of patients without TNF+488A presented with a G1 tumour (P=0.015). A total of 14% of patients with TNF−859T and 30.5% of patients without TNF−859T presented with a G1 tumour (P=0.0043). There was no significant effect on time to first recurrence, stage progression or grade progression. In conclusion, a significant association between TNF polymorphisms TNF+488A and TNF−859T and risk of bladder cancer was detected in this study. Both these polymorphisms were associated with grade of tumour at presentation although there was no significant effect on subsequent tumour behaviour.