Two Cases of Solitary Renal Transplant Associated Shellfish Sensitization from the Same Allergic Donor

Abstract Background Since the first case of transplant-acquired food allergy (TAFA) reported in the 1990s, TAFA has been increasingly recognized in solid organ and bone marrow transplantation, especially in pediatric liver transplant recipients. Due to the concern of allergic reactions, including anaphylaxis, food allergies can significantly impact patients’ lives. While IgE-mediated allergy transmission has been documented across multiple organ types, TAFA following solitary renal transplantation remains rare. The mechanisms underlying TAFA and the impact of donor allergy, immunosuppressive therapy, and recipient-specific factors remain incompletely understood. Case Presentation: We report two cases of TAFA following solitary renal transplantation from the same donor with documented severe shellfish allergy. Both recipients underwent renal transplantation for end-stage diabetic nephropathy and were maintained on identical post-transplant immunosuppressive regimens including tacrolimus, prednisone, and mycophenolate mofetil. Following transplantation, both recipients avoided consumption of shellfish until they were evaluated in the allergy clinic. Neither recipient had a prior shellfish allergy; one had prior dust-mite sensitization with no clinical symptoms, while the other had no history of allergy. Despite their shared variables, the recipients showed markedly different sensitization profiles: both had positive skin prick testing to shrimp, but one showed a large immediate and delayed-phase reaction (wheal over 80 mm) while the other exhibited a comparatively modest reaction. Over a 9-month period, both patients showed progressive attenuation of their sensitization, with a decrease in wheal size; therefore, supervised oral challenge was successfully performed. Both were initially prescribed an epinephrine autoinjector and advised not to consume shellfish until a successful oral challenge could be completed. Conclusion Based on the paucity of published cases, the incidence of TAFA in solitary renal transplantation is exceedingly rare, and the long-term outcomes remain poorly defined. In our cases, both recipients received organs from the same allergic donor and identical immunosuppression regimens, yet demonstrated markedly different sensitization patterns, suggesting that TAFA cannot be explained by donor allergy or immunosuppression alone and highlighting the role of recipient-specific immune factors. Notably, the unusually large size of the wheal occurred in the mite-sensitized recipient despite regular crustacean consumption prior to the transplant. The gradual diminution with repeated testing raises questions about transient sensitization, the duration of TAFA, and the sensitivity and specificity of post-transplant skin testing. Due to the serious consequences of allergic reactions, these findings reinforce the importance of donor allergy disclosure during transplant screening, patient counselling, precautionary avoidance, and support a cautious longitudinal approach of close follow-ups to reduce the risk to these recipients.