FIGURE 1.

Patient's trend in estimated GFR over a 3-year period. Initially, his decline in renal function was treated with prednisone (60 mg/day). Attempts to taper prednisone resulted in rebound elevations in serum creatinine. After his third relapse in renal function, a repeat renal biopsy confirmed the diagnosis of IgG4-related renal disease. He was treated again with prednisone, but his renal function failed to improve and was subsequently treated with Rituximab (4 weekly doses of 375 mg/m² (900 mg)). Corticosteroids were stopped 9 weeks after the 2nd renal biopsy. One year after treatment with Rituximab, estimated GFR was 50 mL/min/1.73 m² and he was corticosteroid-free. CST =  corticosteroids; GFR = glomerular filtration rate.