1. Inflammatory Bowel Disease Center, Yokohama City University Medical Center, Yokohama, Japan;
2. Department of Gastroenterology, Yokohama City University Graduate School of Medicine, Yokohama, Japan;
3. Department of Laboratory Medicine and Clinical Investigation, Yokohama City University Medical Center, Yokohama, Japan;
4. Department of Biostatistics and Epidemiology, Graduate School of Medicine, Yokohama City University, Yokohama, Japan;
5. Department of Pathology, Yokohama City University Graduate School of Medicine, Yokohama, Japan;
6. Gastroenterological Center, Yokohama City University Medical Center, Yokohama, Japan