Thrombotic microangiopathy caused by severe graft dysfunction after living donor liver transplantation: report of a case

The outcomes of thrombotic microangiopathy after liver transplantation: A nationwide survey in Japan

BACKGROUND

Although thrombotic microangiopathy (TMA) is recognized as one of the poor-prognosis factors after liver transplantation, the precise outcome of TMA is unclear. We sought to elucidate the factors affecting the outcome of TMA after liver transplantation in Japan, based on the data from a nationwide survey.

METHODS

One hundred cases of post-transplant TMA were accumulated from 17 Japanese centers of which two cases were excluded because the cause of death was obviously not related to TMA (recurrence of original diseases as primary sclerosing cholangitis and hepatocellular carcinoma), and the remaining 98 cases were enrolled in this study. The patient survival after the development of TMA and the factors that affected the patients' outcomes were retrospectively analyzed.

RESULTS

All cases were living-donor liver transplant cases, and the 1-, 3-, and 5-year patient survival rates after transplantation were 66.9%, 64.6%, and 62.2%, respectively. In a multivariate analysis, the requirement of renal replacement therapy during TMA treatment was the only factor that was significantly related to poor outcome after the development of TMA.

CONCLUSION

The outcomes of TMA were generally poor. The progression of renal dysfunction despite intensive treatment might be the only factor related to the poor prognosis after the development of TMA.

Potential Antigens Involved in Delayed Xenograft Rejection in a Ggta1/Cmah Dko Pig-to-Monkey Model

When hyperacute rejection is avoided by deletion of Gal expression in the pig, delayed xenograft rejection (DXR) becomes a major immunologic barrier to successful xenotransplantation. This study was to investigate the potential antigens involved in DXR. We isolated primary renal microvascular endothelial cells (RMEC) and aortic endothelial cells (AEC) from a GGTA1/CMAH double-knockout (DKO) pig (and a GGTA1-KO pig) and immunized cynomolgus monkeys with both of these cells. After sensitization, monkey serum antibody binding and cytotoxicity to RMEC was significantly higher than to AEC(p < 0.05), suggesting that RMEC are more immunogenic than AEC. Transcriptome sequencing of GGTA1/CMAH DKO pigs indicated that the expression of 1,500 genes was higher in RMEC than in AEC, while expression of 896 genes was lower. Next, we selected 101 candidate genes expressed only in pig RMEC, but not in pig AEC or in monkey or human RMEC. When these genes were knocked out individually in GGTA1/CMAH DKO RMEC, 32 genes were associated with reduced antibody binding, indicating that these genes might be primary immunologic targets involved in DXR. These genes may be important candidates for deletion in producing pigs against which there is a reduced primate immune response in pig kidney xenograft.

A Case Report of Drug-Induced Thrombocytopenia after Living Donor Liver Transplantation

There are few descriptions of severe thrombocytopenia during the early postoperative period after liver transplantation, and these have not been fully documented in the literature. Here, we report a case of drug-induced thrombocytopenia requiring transfusion of blood products after living donor liver transplantation. We determined that this was not caused by the interferon-free anti-viral therapy but by tacrolimus A 61-year-old woman with hepatitis C-related cirrhosis and hepatorenal syndrome underwent living donor liver transplantation using a left lobe graft from her son. After transplantation, immunosuppression consisted of tacrolimus and steroid. Seven weeks after transplantation, interferon-free therapy with daclatasvir and asunaprevir was started. Thirteen days thereafter, hepatitis C virus tested negative. However, the platelet count had begun to gradually decrease just before starting anti-viral therapy. Daclatasvir and asunaprevir were stopped because this was suspected to be a side-effect of these drugs, but the patient nonetheless went on to develop severe thrombocytopenia (platelet count 17,000/μL), which needed transfusions. Now suspecting tacrolimus as the inducer of this side effect, we changed to cyclosporin, after which the platelet count gradually recovered. Viral markers were still not detectable up to 2 months after discontinuation of the antiviral drugs. We conclude that when severe thrombocytopenia occurs, possible drug-induced thrombocytopenia as well as other disorders must be investigated.