Pattern of immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements in childhood acute lymphoblastic leukemia in India

In 120 cases of acute lymphoblastic leukemia (median age 8 years), IgH chain gene was rearranged in 99% B-Cell Precursor (BCP) ALLs and 13% T-ALLs. One or the other TCR locus was rearranged not only in all T-ALLs, but also in 87% of BCP-ALLs. TCR-beta rearrangement in BCP-ALL was associated with a higher mean age at presentation (8.7 vs. 6.2 years, P = 0.008), lower mean platelet counts (61.2 x 109/l vs. 103.7 x 109/1, P = 0.003) and a poorer DFS (% cummulative survival 0 vs. 88.9 +/- 10.5, P = 0.004). TCR-gamma rearrangement in T-ALL was associated with a higher mean WBC count (186.3 x 10(9)/l vs. 63.4 x 109/l, P = 0.002). Also, the pattern of rearrangement of these genes appeared to be different from the West; viz. TCR-beta rearrangement in a higher proportion of BCP-ALLs (58%, 95% confidence intervals 45-69%), invariable deletion of C gamma 1 and only monoallelic rearrangement for TCR-delta locus. This repertoire of gene rearrangement may have a bearing on the poor treatment outcome reported previously from our geographic region. (C) 2000 Elsevier Science Ltd. All rights reserved.