Molecular Ig gene analysis reveals that monocytoid B cell lymphoma is a malignancy of mature B cells carrying somatically mutated V region genes and suggests that rearrangement of the kappa‐deleting element (resulting in deletion of the Ig kappa enhancers) abolishes somatic hypermutation in the human

摘要

AbstractFive cases of monocytoid B cell lymphoma (MBCL) were analyzed for somatic mutations in the rearranged V region genes. Somatic mutations were found in four of the five cases, whereas one unusual CD5+lymphoma harbored unmutated V region genes. Since somatic mutations are introduced into V regiongenes of antigen‐activated B cells in the course of T cell‐dependent immune responses, these results suggest a derivation of the tumor B cells in MBCL from antigen‐experienced mature B cells. An analysis of the ϰ‐deleting element in two of the cases in which mutated VHbut unmutated and nonfunctional Vϰgene rearrangements were found suggests that somatic hypermutation does not take place in human rearranged Vϰregion genes when the Cϰgene and the ϰ enhancers have been deleted incisby rearrangement of the ϰ‐d