Anti-HLA-DQ antibodies are highly and independently related to the C1q-binding capacity of HLA antibodies

The complement-binding capacity of anti-HLA antibodies (HLAabs) is recognized as a key pathogenic factor. The aim of this study is to describe the patient characteristics associated to the presence of C1q+ as well as those of the Abs per se when associated to C1q binding. Methodology: This is a cross-sectional, observational, descriptive study of patients with previous sensitizing factors and awaiting a kidney transplant (KT). We determined anti-HLA antibodies and their C1q binding capacity with the C1q assay. Results: Among the 55 included patients, 26 (47.2%) had at least one C1q + anti-HLAab. A previous transplant history, a greater number of HLAabs, a greater % of class I or class II PRA, the average MR of all HLAabs, the MR of the dominant HLAab and the HLAab antigenic specificities against HLA-B,-C and-DQ all proved to be risk factors associated to the presence of Cl q binding HLAabs (Clq +). In the total population, were detected 1268 HLAabs, 230 (18.1%) of which were Cl q +. On multivariate analysis, both HLAabs against the HLA-DQantigenic specificity (OR 9.82 95% CI 5.4-17.6, p < 0.001) and the MR documented by LABScreen (R) SAB (OR 12% Cl 1.22-1.3, p < 0.001), proved to be risk factors. Conclusion: Anti-HLA-DQ antibodies and the MFI (LABScreen (R) SAB) are highly and independently related to the C1q-binding capacity of HLA antibodies. (C) 2017 Elsevier B.V. All rights reserved.