Screening novel autoantigens targeted by serum IgG autoantibodies in immunorelated pancytopenia by SEREX

Immunorelated pancytopenia (IRP) is characterized by pancytopenia caused by autoantibody-mediated destruction or suppression of bone marrow. However, the autoantigens targeted by autoantibodies in IRP remain unclear. In the present study, we screened novel autoantigens in IRP by serological analysis of recombinant cDNA expression libraries and compared anti-UQCR10 antibody levels between IRP and normal controls detected by immunoblotting. Our results indicate that we successfully constructed the K562 cDNA library, which we used to screen seven candidate autoantigens expressed in haematopoietic cells of IRP: ferritin, light polypeptide, ubiquinol-cytochrome c reductase, complex III subunit X (UQCR10), multifunctional methyl-transferase subunit TRM112-like protein isoform 1 (TRMT112), hemoglobin gamma-G, stathmin 1 (STMN1), transcript variant 3, phosphoglycerate kinase 1 (PGK1), and trafficking protein particle complex subunit 4 (TRAPPC4). Six of 17 (35.29%) IRP patients exhibited positive reactivity to UQCR10 antigen, while only one of 10 (10%) of normal controls reacted to UQCR10 antigen. The IRP patients with positive reactivity to UQCR10 antigen exhibited significantly improved total efficiency (6/6) compared with those with negative reactivity (5/11). Thus, UQCR10 may be implicated as one of the autoantigens involved in development of IRP.