Phylogenetic analysis of V_H (left) and V_κ (right) from subject 1432's IgM⁺κ⁺ CD27⁺CD21^low B cells. Trees were constructed using neighbor-joining analysis of Tamura-Nei distances calculated from pairwise comparisons of Ig DNA sequences. Percentages of bootstrap support (> 50%) from 1000 replicate samples (analyzed by the neighbor joining method) are indicated to the left of the support node. V_H and V_κ from B cell A5 of patient 1403 serve as reference sequences.