Takahisa Gono1, Masataka Kuwana2. 1. Department of Rheumatology, Jichi Medical University Saitama Medical Centre, 1-847 Amanuma-cho, Omiya-ku, Saitama-shi, Saitama-ken, 330-8503, Japan. 2. Department of Allergy and Rheumatology, Nippon Medical School Graduate School of Medicine, 1-1-5 Sendagi, Bunkyo-ku, 113-8603, Tokyo, Japan.