TY - JOUR AU - Johana Hrdinová, AU - Fabian C. Verbij, AU - Paul H.P. Kaijen, AU - Robin B. Hartholt, AU - Floris van Alphen, AU - Neubury Lardy, AU - Anja ten Brinke, AU - Karen Vanhoorelbeke, AU - Pooja J. Hindocha, AU - Anne S. De Groot, AU - Alexander B. Meijer, AU - Jan Voorberg, AU - Ivan Peyron, PY - 2018/06/03 Y2 - 2024/03/28 TI - Mass spectrometry-assisted identification of ADAMTS13-derived peptides presented on HLA-DR and HLA-DQ JF - Haematologica JA - haematol VL - 103 IS - 6 SE - Articles DO - 10.3324/haematol.2017.179119 UR - https://haematologica.org/article/view/8484 SP - 1083-1092 AB - Formation of microthrombi is a hallmark of acquired thrombotic thrombocytopenic purpura. These microthrombi originate from insufficient processing of ultra large von Willebrand factor multimers by ADAMTS13 due to the development of anti-ADAMTS13 autoantibodies. Several studies have identified the major histocompatibility complex class II alleles HLA-DRB1*11, HLA-DQB1*03 and HLA-DQB1*02:02 as risk factors for acquired thrombotic thrombocytopenic purpura development. Previous research in our department indicated that ADAMTS13 CUB2 domain-derived peptides FINVAPHAR and LIRDTHSLR are presented on HLA-DRB1*11 and HLA-DRB1*03, respectively. Here, we describe the repertoire of ADAMTS13 peptides presented on HLA-DQ. In parallel, the repertoire of ADAMTS13-derived peptides presented on HLA-DR was monitored. Using HLA-DR- and HLA-DQ-specific antibodies, we purified HLA/peptide complexes from ADAMTS13-pulsed monocyte-derived dendritic cells. Using this approach, we identified ADAMTS13-derived peptides presented on HLA-DR for all 9 samples analyzed; ADAMTS13-derived peptides presented on HLA-DQ were identified in 4 out of 9 samples. We were able to confirm the presentation of the CUB2 domain-derived peptides FINVAPHAR and LIRDTHSLR on HLA-DR. In total, 12 different core-peptide sequences were identified on HLA-DR and 8 on HLA-DQ. For HLA-DR11, several potential new core-peptides were found; 4 novel core-peptides were exclusively identified on HLA-DQ. Furthermore, an in silico analysis was performed using the EpiMatrix and JanusMatrix tools to evaluate the eluted peptides, in the context of HLA-DR, for putative effector or regulatory T-cell responses at the population level. The results from this study provide a basis for the identification of immuno-dominant epitopes on ADAMTS13 involved in the onset of acquired thrombotic thrombocytopenic purpura. ER -