51-P C4d STAINING AND HISTOLOGICAL FEATURES OF PROTOCOL LUNG BIOPSIES IN PATIENTS WHO DEVELOP DENOVO DONOR HLA SPECIFIC ANTIBODIES. Medhat Askar a, Marie Budev b, Lynne Klingman a, Aiwen Zhang a,Kenneth McCurry c, Carol Farver d. a Allogen Laboratories, Cleveland Clinic, Cleveland, OH, USA; b Allergy andCritical Care Medicine, Cleveland Clinic, Cleveland, OH, USA; c Thoracic and Cardiovascular Surgery, ClevelandClinic, Cleveland, OH, USA; d Anatomic Pathology, Cleveland Clinic, Cleveland, OH, USA.

Aim: In this study we aimed to compare the frequency of histological findings commonly evaluated intransplant lung biopsies and immunofluorescent staining for C4d among transplant recipients with de novodonor HLA specific antibodies (dDSA).

Methods: We retrospectively analyzed the records of 103 lung transplant biopsies obtained from 36 recip-ients transplanted at our institute in 2011-2012 and were on routine post-transplant monitoring for dDSAwithin ±1 week of the a biopsy date (paired biopsies). dDSA testing was performed using Luminex single anti-gen beads (Thermo Fisher Scientific, Canoga Park, CA). All recipients had protocol bronchial biopsies at 2weeks, 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 onlyclass II dDSAand 38 from those with both class I and class II dDSA. Interestingly, of the 47 biopsies with class IIdDSA 35 presented with DQ and 30 of them had DQ dDSA only. We compared dDSA status with the followinghistological findings: C4d staining, acute rejection PISHLT grade 2A & B, and acute lung injury (ALI/OALI with/out PMNs). The distribution of histological findings in biopsies in association with dDSA characteristics interms 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 wasthe only dDSA detected in the majority of patients with class II dDSA only. However, in this cohort, there wasno evidence of an association between any of the evaluated biopsy findings and dDSA characteristics in termsof class I versus class II dDSA.

Pub #: 51-P Order: 1

52-P DE NOVO DEVELOPMENT OF DONOR SPECIFIC HLA ANTIBODIES IS STRONGLY ASSOCIATED WITH ANTIBODYMEDIATED REJECTION FOLLOWING LIVE DONOR RENAL TRANSPLANTATION. Ajay K. Baranwal, Jamshaid A.Siddiqui, Sanjeev Goswami, Deepali K. Bhat, Narinder K. Mehra. Transplant Immunology and Immunogenetics,All India Institute of Medical Sciences, New Delhi, Delhi, India.

Aim: The harmful effects of preformed and de novo development of donor specific anti HLA antibodies insolid organ transplantation have been extensively reviewed and are found to be associated with allograft dys-function. The spectrum of antibody mediated insult ranges from hyperacute rejection to chronic antibodymediated rejection (AMR) leading ultimately to graft loss. With the advent of solid phase assays, the sensitiv-ity and specificity of antibody detection have increased.

Methods: We studied 105 renal transplant recipients who had undergone live donor renal transplantationat this hospital. None of the recipients were sensitized. The recipients were longitudinally followed-up for aperiod of 60 months after transplantation. Serum samples collected serially at pre-transplant, at least onetime during the post-transplant period and at the time of rejection were analyzed by the solid-phase immu-noassay system on a Luminex 200 Platform using OneLambda SAB kits.

Results: Of the total patients, 79 did not show any evidence of AMR. The remaining 26 (24.7%) recipientshad evidence of AMR as characterized by donor specific antibodies, histopathological changes and C4D stain-ing on biopsy as per the Banff 2007 criteria. Luminex SAB analysis revealed that out of the 26 patients expe-riencing AMR, 80.7% had DSA compared to recipients who had no evidence of AMR (12.6%).

Conclusions: The study highlights the relevance of de novo development of donor specific HLA antibodieswith AMR in the renal allograft recipients.

Table 1The distribution of histological findings in biopsies in association with dDSA characteristics

P 2A P B C4d ALI/OALI with/out PMNs

Class I dDSA 3/16 1/13 1/17 7/18Class II dDSA 8/43 1/41 1/43 8/47Class I + Class II dDSA 9/36 0/32 1/37 13/38

Abstracts / Human Immunology 74 (2013) 51–173 87