MOLECULAR ANALYSIS OF THE IMMUNOGLOBULIN V-H GENE REARRANGEMENT IN A PRIMARY CUTANEOUS IMMUNOBLASTIC B-CELL LYMPHOMA BY MICROMANIPULATION AND SINGLE-CELL PCR

The immunoglobulin V-H gene rearrangement in a primary cutaneous, larg e-cell (centroblastic and immunoblastic) B-cell lymphoma was analyzed using a micromanipulation/single-cell polymerase chain reaction techni que. In all single B cells obtained from CD20-stained skin sections th at gave a polymerase chain reaction product (eight of 27 in biopsy I), the same V(H)DJ(H) rearrangement, consisting of DP-54-DIR1-J(H)3a gen es, was detected, with no intraclonal nucleotide diversity. Comparison with the most closely related germline counterpart showed significant ly altered complementarity determining gene regions as a result of som atic mutations, suggesting an antigen-driven selection and expansion o f this particular B-cell clone. Interestingly, in a biopsy obtained fr om the patient 9 mo later, during disease progression (deep muscle inf iltration), the lymphoma cells again contained the same V(H)DJ(H) gene rearrangement (six of 18 in biopsy II) without any further somatic mu tations. Therefore, it is suggested that the cutaneous lymphoma charac terized throughout this study descended from postgerminal center B-cel ls.