Case Report: Kidney allograft recovery after conversion to belatacept-based immunosuppression in simultaneous heart-kidney transplantation.

Renal allograft dysfunction after simultaneous heart-kidney transplantation (SHKT) is often multifactorial, reflecting perioperative hemodynamic instability, ischemia-reperfusion injury, alloimmune activation, and calcineurin inhibitor exposure. The therapeutic role of belatacept in this dual-organ setting remains poorly defined. We report the case of a 47-year-old woman with systemic lupus erythematosus, antiphospholipid syndrome, previous kidney allograft loss and heart failure, who underwent SHKT. The post-transplant course was complicated by persistent anuria requiring prolonged dialysis dependence, a high-titer de novo class II donor-specific antibody (DSA), and biopsy-proven cardiac antibody-mediated and cellular rejection. Despite intensive anti-rejection treatment, cardiac histology improved and DSA levels decreased, but renal allograft function did not recover. Belatacept was introduced at post-transplant week 12 with tacrolimus minimization. Thereafter, diuresis progressively resumed and dialysis was discontinued, with progressive improvement in renal function, while DSA became progressively undetectable. At 6 months, both grafts are functioning, serum creatinine is 1.4 mg/dL and no DSA rebound occurred. This case highlights the potential role of belatacept-based immunosuppression in the complex setting of SHKT with prolonged kidney allograft dysfunction.