BACKGROUND: Donor-specific anti-HLA antibody (DSA) detected on Luminex-based single antigen assay (LSA) has become the subject of desensitization based upon the results of previous studies. We retrospectively investigated the impact of preoperative DSA on the incidence of antibody mediated rejection (AMR) in patients desensitized using a protocol based on rituximab and rabbit antithymocyte globulin (rATG).

MATERIAL AND METHODS: Nine patients (Group 1, 9/327, 2.8%) were complement dependent cytotoxicity crossmatch (CDC-XM) positive and underwent desensitization with rituximab (375 mg/m²), intravenous immunoglobulin (IVIG; 400 mg/kg), plasmapheresis, and rATG. Twenty-two patients (Group 2, 22/327, 6.7%) were CDC-XM negative but DSA positive on LSA and had received desensitization with rituximab and rATG, while 55 patients (Group 3, 55/327, 16.8%) were CDC-XM and DSA negative with a calculated panel reactive antibody (cPRA) ≥50%. Another 241 patients (Group 4, 241/327, 73.7%) were CDC-XM and DSA negative with a cPRA <50%.

RESULTS: Recipients with DSA (Group 2) experienced more AMR than other groups (p<0.01). More de novo DSAs also developed in Group 2 (p<0.001). The mean fluorescence intensity (MFI) of DSA of patients with AMR tended to rebound (p=0.01).

CONCLUSIONS: Patients who were CDC-XM negative but DSA positive status were at a higher risk of developing AMR even though they had received desensitization with rATG and rituximab. A more intense desensitization protocol is needed for these recipients. Patients with MFI rebound of DSA should be carefully monitored for the risk of AMR.

Keywords: Desensitization, Immunologic, Graft Rejection, HLA Antigens, Kidney Transplantation