Impact of preformed donor-specific anti-HLA antibodies on pancreatic islet transplantation outcomes: do they matter as they do in solid organ transplantation?

Background: Preformed donor-specific anti-HLA antibodies (DSA) are a major risk factor for antibody-mediated rejection and graft failure in kidney, heart, lung, and other vascularized solid organ transplants. Their clinical significance in pancreatic islet transplantation, however, remains uncertain. Methods: We conducted a SANRA-guided narrative review using a focused PubMed search (January 1, 2000, to June 9, 2026) supplemented by citation chasing. Of 104 records identified, 11 directly evaluating islet transplantation formed the core evidence base, complemented by 38 references providing mechanistic, immunologic, and solid-organ context. Results: The available islet-specific evidence is dominated by small single-center studies, registry analyses, and case series, with few reports directly evaluating preformed DSA. Across these reports, preformed DSA have not shown the consistent adverse effect expected from kidney transplantation, but the evidence is insufficient to establish safety. In the largest focused cohort, Piemonti et al. reported no clear association between preformed DSA and graft failure, whereas post-transplant antibody evolution was more closely linked to impaired graft survival. Brooks et al. similarly found rapid graft dysfunction after Conclusions: The limited evidence is insufficient to support a universal policy of automatic exclusion of otherwise suitable islet candidates solely because of low-level preformed DSA; nor does it establish that such antibodies are safe. Because the evidence derives mainly from small single-center cohorts, registry analyses, and case series, this conclusion is provisional and may not be generalized across programs.