Older kidney transplant patients experience less antibody-mediated rejection: a retrospective study of patients with mild to moderate sensitization

Background: There is a paucity of data stratifying by age the incidence of antibody-mediated rejection (AMR) in kidney transplant patients. Methods: We performed a retrospective study of all adult, renal transplant recipients at a single institution between December 12, 2009, and March 16, 2011. Mildly and moderately sensitized patients were defined as patients with positive donor-specific antibody (DSA) and negative flow cross-match. Results: One hundred and forty-six patients were determined to have mild to moderate pre-transplantation sensitization. Thirty percent of patients younger than 40 yr of age experienced AMR vs. 15% in the older group (p = 0.04). There was a disproportionate increase in DSA for younger patients at 12 months, particularly for antibodies to class II. Histologic presence of C4d deposition was independently associated with AMR on multivariate analysis. Conclusions: Following renal transplantation, moderately sensitized patients aged 40 yr old and older were less likely to develop AMR when compared with younger patients.