T-cell receptor beta-chain gene expression in B-lineage acute lymphoblastic leukemia.

The T-cell receptor beta-chain (T beta) gene expression was examined in 16 children with B-lineage acute lymphoblastic leukemia (ALL), including eight patients with rearrangement of the T beta gene as well as immunoglobulin (Ig) heavy chain gene rearrangement. In contrast to the 1.3 kb full-length transcripts of the T beta observed in T-lineage leukemia and lymphoma cells, no transcript of the T beta gene was detected in 10 patients, including four with T beta gene rearrangement. Low levels of T beta transcripts were found in three patients with T beta gene rearrangement and two patients without T beta gene rearrangement, but those transcripts were truncated. In contrast to those findings, a single patient with T beta gene rearrangement showed abundant 1.3 kb T beta transcripts. These data indicate that T beta gene expression is not restricted to T-lineage cells and demonstrate the heterogeneity of B-lineage ALL at the expression level of the T beta gene. Our findings also suggest that T beta gene expression is not always accompanied with T beta gene rearrangement.