The effect of rituximab on median immunoglobulin levels. Median immunoglobulin levels are represented as a continuous line and interquartile ranges as dashed lines, according to time after first rituximab treatment, from 0 to 60 months. A. IgG, IgM and IgA levels for all 177 patients. B. Comparison of IgG levels for all patients with those patients with IgG <6 g/L before first rituximab (N = 18). C. Comparison of IgG levels for patients who received <6 g of rituximab in total (N = 79) and patients who received ≥6 g of rituximab (N = 98). D. Comparison of IgG levels for patients with (N = 71) and without (N = 106) severe infection.