Cytokine gene polymorphisms in acute cellular rejection following living donor liver transplantation: analysis of 155 donor-recipient pairs

Cytokines in Liver Transplantation

Cytokines, soluble mediators of the immune system, play a critical role in the pathogenesis of autoimmune, allergic and infectious diseases. They are also implicated in the initiation and development of allograft rejection. During recent years, there have been considerable advances in generating novel anti-cytokine agents with promoted efficacy and safety, which could be administrated for managing dysregulated cytokine secretion; besides, gene therapy for overexpression of immunomodulatory cytokines has shown substantial improvements. Liver transplantation has been established as a life-saving treatment for end-stage hepatic diseases but the growing number of recipients urge for improved post-transplant care including tolerance induction, infection control and resolving immunosuppressant drugs adverse effects. Cytokines with a wide range of proinflammatory and regulatory properties might be considered as potential therapeutic targets for selective suppression or enhancement of the immune responses in recipients. In the present review, we aimed to summarize the positive and negative effects of cytokines on liver allograft in addition to their prognostic and therapeutic values.

Biopsy-proven acute cellular rejection as an efficacy endpoint of randomized trials in liver transplantation: a systematic review and critical appraisal

Biopsy-proven acute cellular rejection (ACR) is the primary efficacy endpoint in most randomized trials evaluating immunosuppression in liver transplantation. However, ACR is not a major cause of graft loss, and a certain grade of immune activation may be even beneficial for long-term graft acceptance. Validated criteria to select candidates for liver biopsy are lacking, and routine clinical practice relies on liver tests, which are inaccurate markers of ACR. Indeed, both the agreement among clinicians to select candidates for liver biopsy and the correlation between the clinical suspicion of ACR and histological findings are poor. In randomized trials evaluating immunosuppression protocols, this concern grows exponentially due to the open-label and multicenter nature of most studies. Therefore, biopsy-proven ACR is a suboptimal efficacy endpoint given its limited impact on prognosis and the heterogeneous diagnosis, which may increase the risk of bias. Chronic rejection and/or graft loss would be more appropriate endpoints, but would certainly require larger studies with prolonged surveillances. An objective method to select candidates for liver biopsy is therefore urgently needed, and only severe episodes of histological ACR should be considered as potentially harmful. Emerging surrogate markers of ACR and antibody-mediated rejection require further investigation to determine their clinical role.

Role of cytokine gene polymorphisms in acute and chronic kidney disease following liver transplantation

PURPOSE

Development of renal dysfunction, including acute kidney injury (AKI) and chronic kidney disease (CKD), after liver transplantation (LT) remains a critical issue adversely affecting patient survival in both the short and long term. Previous reports have suggested that inflammatory and antiinflammatory cytokines and their functionally relevant gene polymorphisms may play critical roles in the development of AKI and CKD. However, the involvement of these cytokines and their gene polymorphisms in renal deterioration following LT remains unclear.

METHODS

We examined 62 recipients who underwent LT at Nagoya University between 2004 and 2009 and who had survived for at least 1 year. The following gene polymorphisms in recipients were analyzed: tumor necrosis factor-A (TNFA) T-1031C, interleukin-2 (IL2) T-330G, IL10 C-819T, IL13 C-1111T, transforming growth factor-B (TGFB) T29C, and IL4 T-33C.

RESULTS

Thirteen patients (21 %) developed AKI within 4 weeks after LT. Of the investigated gene polymorphisms, the IL4 -33 T/T genotype was significantly associated with higher incidence of AKI compared with the other two genotypes [hazard ratio (HR) = 5.48, 95 % confidence interval (CI) 1.18-25.52, p = 0.03]. On the other hand, 16 patients (26 %) had developed CKD at median follow-up of 9.2 years after LT. We showed the lack of association between investigated gene polymorphisms in recipients and CKD development.

CONCLUSIONS

The IL4 -33 T/T genotype might be a risk factor for AKI in LT, and this might contribute to earlier withdrawal of immunosuppressive agents to minimize renal toxicity. In contrast, none of the investigated cytokine gene polymorphisms were associated with CKD.