Heterogeneity of Acute Undifferentiated Leukemia at the Immunoglobulin and T-cell Receptor Genes Level

Abstract

Phenotypic markers of leukemic cells from 76 children with acute leukemia were examined. Of these cases, 7 were diagnosed as acute undifferentiated leukemia (AUL) whose leukemic cells were negative for myeloperoxidase and did not react with lineage-specific or lineage-associated monoclonal antibodies. Then, we analyzed the configuration of both immunoglobulin (Ig) and T-cell receptor β-chain (Tβ) gene in these 7 AUL cases. Three cases had no rearrangement of Ig or Tβ genes which was suggestive of non-lymphoid origin of these cases. In contrast, 4 cases showed rearrangements of Ig and/or Tβ genes. One of these 4 cases demonstrated Tβ gene rearrangement with retention of the germline configuration of Ig genes. Two cases with both Ig and Tβ gene rearrangements also showed kappa-chain gene rearrangements. These findings indicate the heterogeneity of AUL at the DNA level, and may cast new light on the early differentiation of hematopoietic progenitor cells.