Isotype switching in human B lymphocyte malignancies occurs by DNA deletion: evidence for nonspecific switch recombination.

摘要: The mechanism and specificity of isotype switching operative in human B lymphocytes was investigated by a determination immunophenotype immunoglobulin heavy light chain gene status panel Ig-, IgM, IgG, IgA cell malignancies. Regardless specific tumor type or switched immunophenotype, accompanied the rearrangement expressed CH downstream VDJH, with concomitant deletion upstream genes all cases. On allelically excluded chromosome, 25% IgG tumors have retained C mu, 75% deleted mu. 5' recombination breakpoints for both productive alleles lie within near S 3' enhancer. No correlation between extent deletions produced observed. Excluded chromosome endpoints were found 5', equal to, endpoints. Furthermore, we identified at least one IgM+ that has undergone abortive observed several unanticipated switch region potential translocations. data suggest cells occurs nonsubclass- nonclass-specific recombinase.