Background:In solid organ transplantation (SOT), CMV is commonly transmitted from seropositive organ donors (D+) to seronegative recipients (R-), despite the use of antiviral prophylaxis. The epidemiology of CMV transmission in islet transplantation (IT) is not well defined.

Methods:This is a single center retrospective review of IT recipients at the University of Alberta Hospital transplanted from March 1999 to May 2014. Antiviral prophylaxis with ganciclovir or valganciclovir was given for 3 months for all D+/R- and CMV seropositive recipients (R+) that received antilymphocyte globulin (ALG) induction with alemtuzumab or thymoglobulin. R+ recipients without ALG induction received pre-emptive therapy. Outcomes assessed included CMV seroconversion and viremia.

Results:We analyzed 100 patients (63 CMV R-, 37 CMV R +) receiving 256 IT (mean 2.56 transplants per patient). Out of 256 transplants, 154 were performed in CMV R-, 98 in CMV R+ patients, and in 4 cases the serology was unknown or indeterminate. Out of the 154 CMV R, 77 had at least 1 CMV D+ and 77 had exclusively CMV D-. The islets were obtained from a single donor in 240 IT, 2 donors in 15 and 3 donors in 1 case. Seroconversion was documented in 7 patients in the follow-up (11%) of R- recipients. Seroconversion occurred at a median of 1,292 days after the last transplant (IQR 490.5-1733.5) in these 7 patients; 6 of them receiving IT from a single CMV D+ and 1 from a single CMV D-. Only 1 D+/R- patient had seroconversion within 1 year of transplant, 2 within 2 years and 3 beyond 2 years of transplantation making community acquired CMV more likely than islet transmission. Of the 100 patients analyzed, 72 had CMV viral load monitored post-transplant. Viremia was detected in 5 of 37 (14%) of CMV R+ and in 3 of 60 (5%) CMV R- (p=0.253). Three (of 7 patients) who had seroconversion, also had detectable CMV viral load. Only 4 patients had at least one CMV viral load higher than 1,000 IU/ml and 3 of them were CMV R- pre-transplant with seroconversion.

Conclusion:CMV seroconversion rates in CMV D+/R- islet transplants are low compared to SOT. The majority of seroconversion occurred beyond 1 year after IT suggesting community exposure and making CMV transmission through islets less likely. Our findings support a pre-emptive approach to CMV in R- islet transplants receiving islet transfusion from CMV D+ rather than universal prophylaxis.

CITATION INFORMATION: Kabbani D, Cheung K, Senior P, Cervera C, Doucette K, Preiksaitis J. Low Risk of Cytomegalovirus (CMV) Transmission in Clinical Islet Transplantation. Am J Transplant. 2016;16 (suppl 3).

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