IGHA1 and Henoch-Schoenlein purpura: We previously developed a monoclonal antibody (KM55 mAb) that specifically recognizes Gd-IgA1, and demonstrated that glomerular Gd-IgA1 was specifically detected in IgAN and IgA vasculitis by immunohistochemical analysis using KM55 mAb [10,11].