72-P

Abstract

Aim The association between HLA-DQ Donor Specific Antigen (DSA) and chronic antibody mediated rejection (AMR) has been reported in several cohort studies, and anti-DQ is the most frequent detected DSA after solid organ transplantation. Unlike Class I or HLA-DR DSA, anti-DQ DSA show little improvement with current antibody removal protocols as demonstrated by persistently elevated IgG Mean Fluorescent Intensity (MFI) values (MFI > 7000). Here we compare IgG and C1q single antigen measurements to monitor the response to antibody removal therapy. Methods Post transplant de novo anti-DQ DSA in one kidney and one lung recipient were tested by single antigen IgG and C1q binding assay (One Lambda). Samples were collected before, during and after antibody removal treatment with plasmapheresis and IVIG. Results were correlated with organ function by creatinine level and FEV1 in the kidney and lung recipients, respectively. Results Changes in IgG and C1q MFI measurements during treatment are represented in the Table 1 and Fig. 1. Both patients IgG levels remain over MFI > 10,000 after treatment. In contrast, the values of C1q show a decline with treatment that correlates with improving creatinine in the kidney recipient. FEV1appears to stabilize when the C1q MFI is Download : Download full-size image Conclusions Based on these results, C1q MFI measurements is superior to IgG MFI monitoring during antibody removal therapy to reduce anti–DQ DSA. The combination of these two assays may improve the characterization and the management of AMR due to anti-DQ DSA.