Correlative studies of peripheral blood lymphocyte populations and serum Ig levels. *P < .001, compared with pretreatment values. (A) Serum IgG measurements as a percentage change from baseline. There is a significant increase in serum IgG from 3-9 cycles of therapy. Lines represent median percentage change in serum IgG; boxes, interquartile range; and outer spread lines, 10th to 90th percentiles. (B) Serum IgM measurements as a percentage change from baseline. There is a significant increase in serum IgM from by 3 cycles and from 3-9 cycles of therapy. Lines represent median percentage change in serum IgM; boxes, interquartile range; and outer spread lines, 10th to 90th percentiles. (C) Peripheral blood total lymphocyte and CD3⁺ T-lymphocyte counts for patients who completed at least 15 cycles of therapy (n = 38), including 31 patients who have completed 21 cycles. Range bars represent the interquartile range.