1 Division of Hematology and Rheumatology, Teikyo University Chiba Medical Center, 3426-3 Anesaki, Ichihara, Chiba, 299-0111, Japan. nagahata.ken@sapmed.ac.jp.
2 Division of Hematology and Rheumatology, Teikyo University Chiba Medical Center, 3426-3 Anesaki, Ichihara, Chiba, 299-0111, Japan.