Immunogenotypes of Lymphoid Malignancies; the Rearrangement of T Cell Receptor β Chain Gene Can Occur before the γ Chain Gene Rearrangement

Immunoglobulin (Ig) and T cell receptor (TcR) gene rearrangements were analyzed in 101 cases of lymphoid malignancies in association with a surface phenotype study. In leukemias/lymphomas with mature phenotype, there is a good correlation between phenotypes and genotypes. However, in leukemias/lymphomas with immature phenotype, we found many discordances between phenotypes and genotypes, suggesting the stochastic nature of hematopoietic cell differentiation at the early stage. As for TcR β and γ chains, the rearrangement of γ chain gene is considered to occur slightly prior to that of β chain gene. However, we observed a mature T cell malignancy, adult T‐cell leukemia, with rearranged β chain gene and germ line γ chain gene, showing the possible existence of another pathway of T cell differentiation.