51-P: C4d STAINING AND HISTOLOGICAL FEATURES OF PROTOCOL LUNG BIOPSIES IN PATIENTS WHO DEVELOP DE NOVO DONOR HLA SPECIFIC ANTIBODIES

Abstract

Aim In this study we aimed to compare the frequency of histological findings commonly evaluated in transplant lung biopsies and immunofluorescent staining for C4d among transplant recipients with de novo donor HLA specific antibodies (dDSA). Methods We retrospectively analyzed the records of 103 lung transplant biopsies obtained from 36 recipients transplanted at our institute in 2011-2012 and were on routine post-transplant monitoring for dDSA within ±1 week of the a biopsy date (paired biopsies). dDSA testing was performed using Luminex single antigen beads (Thermo Fisher Scientific, Canoga Park, CA). All recipients had protocol bronchial biopsies at 2 weeks, 1, 3, 6, 12 months and for cause thereafter. Results Eighteen biopsies were obtained from patients with only class I dDSA, 47 from patients with only class II dDSAand 38 from those with both class I and class II dDSA. Interestingly, of the 47 biopsies with class II dDSA 35 presented with DQ and 30 of them had DQ dDSA only. We compared dDSA status with the following histological findings: C4d staining, acute rejection ⩾ISHLT grade 2A & B, and acute lung injury (ALI/OALI with/out PMNs). The distribution of histological findings in biopsies in association with dDSA characteristics in terms of class I versus class II is shown in the following: [ Table 1 ] Conclusions dDSA to DQ seems to be disproportionately more frequent than dDSA to other loci and was the only dDSA detected in the majority of patients with class II dDSA only. However, in this cohort, there was no evidence of an association between any of the evaluated biopsy findings and dDSA characteristics in terms of class I versus class II dDSA.