In addition to the clonal rearrangements amplified at least twice and listed above, rearrangements were amplified once from several clonally related cells. Patient 2, C3, from the cell with the unmutated V_H rearrangement, an unmutated V_κ and a mutated V_λ (2.5% mutation frequency) rearrangement. Patient 4, C1, from one cell an unmutated in-frame V_λ 2e rearrangement, from the second cell an unmutated out-of-frame V_K A17 and an unmutated out-of-frame V_λ1g, and from the third cell an unmutated out-of-frame V_κ O11/1 rearrangement; C2, from one cell an unmutated, potentially functional V_H rearrangement; C3, from one cell a potentially functional, mutated (3%) V_κ O12/2 rearrangement; C4, from one cell a potentially functional mutated (3.1%) V_λ 1b rearrangement. Patient 5, C1, from 2 cells an unmutated, potentially functional V_Krearrangement, each; C2, from one cell an unmutated out-of-frame V_κ and a mutated, potentially functional V_H(0.8%) rearrangement; C3, an unmutated, potentially functional V_H rearrangement.

Because nonproductive V_κJ_κ joints are usually inactivated by deletion of the C_κ gene and the κ enhancers and are thereby exempted from somatic hypermutation, the finding of unmutated V_κ genes in clones with otherwise mutated immunoglobulin rearrangements is not unusual.

Pt indicates patient; PTCG, progressively transformed germinal center.

Rearranged without N-nucleotide insertion. Thus, it cannot be excluded that these two rearrangements originated from two clonally unrelated cells.