Mutated V-H genes and preferential V(H)3-21 use define new subsets of mantle cell lymphoma

Mantle cell lymphoma (MCL) is believed to originate from a naive B cell. However, we recently demonstrated that a subset of MCL displayed mutated V-H genes. We also reported restricted use of certain V-H genes. To assess the prognostic impact of these new findings, we performed V-H gene analysis of 110 patients, revealing that 18 (16%) patients had mutated and 92 (84%) patients had unmutated V-H genes. Because the mutation rate was low in the mutated group (2.2%-6.7%), further investigation of the germline V-H gene in T cells from 5 patients with mutated V-H genes was carried out; results showed that the unrearranged V-H gene was identical to the published sequence. These data confirm that the base pair substitutions within the rearranged V-H genes represent hyper-mutations, and indicate germinal center exposure. However, V-H gene mutation status did not correlate with prognosis because there was no difference in clinical outcome between the unmutated and mutated groups. The most frequently used V-H genes were V(H)3-21 (21 patients) and V(H)4-34 (19 patients). A novel finding was that V(H)3-21(+) MCL almost exclusively ex-pressed X light chains and displayed highly restricted use of the V(lambda)3-19 gene. V(H)3-21(+) patients had longer median survival than the remaining patients (53 vs 34 months; P = .03), but they tended to be younger at diagnosis. The combined use Of V(H)3-21/V(lambda)3-19 suggests a possible role for antigen(s) in the pathogenesis of these tumors and indicates that V(H)3-21(+) patients constitute a new MCL entity. (C) 2003 by The American Society of Hematology.