B-cell replication history and SHM levels in 5 different B-cell patterns compared with controls. (A) The in vivo replication history of B-cell subsets as determined by KREC assay in sorted peripheral B-cell subsets of patients and controls (c; n = 10) is given in number of cell divisions. In patients with B-cell pattern 1, proliferation of marginal zone–like and memory B cells was above the detection limit of the KREC assay in 7 patients. (B) The SHM frequency given in percentage mutated hot spot in a rearranged Vk3-20 gene segment was determined by the IgκREHMA assay and compared with 10 healthy controls (c). The 5 B-cell patterns are: (1) low transitional and memory B cells; (2) low naive mature, marginal zone–like, and memory B cells; (3) low marginal zone–like and memory B cells; (4) low memory B cells; and (5) normal marginal zone–like and memory B cells. Individual data points are displayed and bars indicate medians. Groups are compared with controls using the Mann-Whitney test. Significant values compared with healthy controls are indicated. ***P < .0005; **P < .005; *P < .05.