1. From the Department of Rheumatology (W.L., H.Y., X.T., Q.L., C.G., X.L., G.W., Q.P.), Key Myositis Laboratories, China-Japan Friendship Hospital; Department of Rheumatology and Clinical Immunology (C.D.), Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College; and Department of Blood Transfusion (L.C.), China-Japan Friendship Hospital, Beijing.