Early Antibody-Mediated Rejection in Non-Pre-Sensitized Heart Transplant Recipient

Introduction Antibody-mediated rejection (AMR) is an important cause of allograft dysfunction. It usually occurs after the first month of heart transplant (HT), but an early presentation is possible. We present an unusual case of a female HT recipient who had early AMR with no evidence of pre-sensitization to the donor. Case Report A woman, 45 years old, idiopathic dilated cardiomyopathy, two kids, with previous negative panel reactive antibody (PRA) was submitted to HT with success. The prospective crossmatch was negative and she did not receive blood cells during the surgery. The donor was a woman, 47 years old, who had a hemorrhagic stroke. After the procedure, she needed low doses of vasoactive drugs, received immunosuppression therapy according to institutional protocol and maintained normal ventricular function. On the 5th day, she developed biventricular graft dysfunction (left ventricular ejection fraction of 40%) requiring inotropes. The PRA revealed a donor specific antibody (DSA) not previously detected and the result of endomyocardial biopsy (EMB) confirmed acute AMR (pAMR2). Patient was successfully treated with methylprednisolone, plasmapheresis, immunoglobulin and rituximab. Biventricular function recovered; no DSA was detected and new EMB showed no rejection findings. Summary AMR results from recipient antibodies against donor-HLA antigens, causing complement activation, inflammation and injury to the allograft endothelium. In general, it occurs in the first two months after HT due to a rise in DSA by the contact with donor-HLA antigens. Early AMR, that occurs in the first week, is related to pre-sensitization to donor HLA antigens and associated with graft dysfunction. In this case report, no previous antibody had been detected. Two possibilities could explain such findings: the presence of non-HLA antibodies or the presence of memory B cells with levels of DSA too low to be detected on PRA. This case highlights the importance of monitoring antibodies in HT recipients with early allograft dysfunction even with previous negative PRA.