Fig. (1) Case 1: A 66-year-old man with retroperitoneal fibrosis. The abdomen CT scan and the gallium scintigraphy. Case 2: A 53-year-old man with retroperitoneal fibrosis. The gallium scintigraphy and the abdomen MR image (T2-wtighted). Case 3: A 38-year-old man with lymphadenopathy. Whole body CT scan, histological finding and immunohistochemistry (IgG4+/IgG+ cells=50%) of lymph nodes. Case 4: A 60-year-old man with interstitial nephritis. Immunohistochemistry of the renal biopsy (IgG4+/IgG+ cells > 50%) and the gallium scintigraphy. The representative flow cytometric profiles and percentages of RP105-negative B cells in peripheral blood before and after the treatment.