Prolonged islet allograft function is associated with female sex in patients after islet transplantation.

BACKGROUND Islet transplantation (ITx) has proved to be effective in preventing severe hypoglycemia and improving metabolic control in selected subjects with T1D. Long-term graft function remains a challenge. Estrogens have been shown to protect β-cells from metabolic stresses and improve revascularization of transplanted human islets in the mouse. We aimed to evaluate the influence of sex in allograft survival of ITx recipients. METHODS We analyzed a retrospective cohort of ITx recipients (n=56) followed-up for up to 20 years. Allograft failure was defined as a stimulated C-peptide <0.3 ng/ml during a mixed-meal tolerance test. Subjects were divided into recipients of at least one female donor (Group 1) and recipients of male donors only (Group 2). RESULTS Group 1 subjects (n=25) were aged 41.5 ± 8.4 years and Group 2 subjects (n=22) 45.9 ± 7.3 years (P= 0.062). Female recipient frequency was 44.8% (n=13) in Group 1 and 55.2% (n=16) in Group 2 (P=0.145). Group 2 developed graft failure earlier than Group 1 [680 (286 - 1624) vs. 1906 (756 - 3256) days, P= 0.038]. We performed additional analyses on female recipients only from each group (Group 1, n= 16, Group 2, n=20). Female recipients in Group 1 exhibited prolonged allograft function compared to Group 2, after adjustment for confounders (OR: 28.6, CI: 1.3 - 619.1; P < 0.05). CONCLUSION Recipients of islets from at least one female donor exhibited prolonged graft survival compared to recipients of islets from exclusively male donors. In addition, female recipients exhibited prolonged survival compared to male recipients following ITx of at least one female donor.