분자생물학적 방법을 이용한 소아 급성 림프구성 백혈병의 분류

Abstract

Acute lymphocytic leukemia(ALL) is derived from clonally expanded, developmentally arrested cells of B or T lymphocyte lineage. Childhood ALL has been divided into four immunophenotypically distinct categories. Nowadays recombinant DNA technology has provided the means to characterize childhood ALL at the immunoglobulin(Ig) and T cell receptor(TCR) gene level. Ig heavy chain(IgH), IgK light chain(IgK), TCRβ, and TCRγ genes were examined in the lymphoblasts of 21 childhood ALL with immunophenotyping. The most frequent phenotype were early pre-B(57% ), followed by pre-B(14% ), and T ALL(14% ), There were one case in each B cell, null cell and mixed lineage leukemia. Several distinct phenotypic variants were seen with in the precursor B group. Two cases showed T lineage marker CD2 and CD7, and two cases showed myeloid antigen(CDl3). Fifteen of sixteen B lineage leukemia(94%) demonstrated rearrangement of the IgH region. Six of sixteen B lineage leukemia(38% ) demonstrated rearrangement of the IgH gene. In B lineage leukemia, four cases(25% ) showed TCRβ gene rearrangement and seven cases(44% ) showed TCRγ gene rearrangement. All T lineage leukemia demonstrated rearrangement of the TCRβ and TCRγ. No case of T lineage ALL demonstrated IgH, IgK gene rearrangement. One case of null cell ALL assigned to the germ line configuration of Ig and TCR genes. One case of mixed leukemia demonstrated only IgH chain gene rearrangement. In conclusion, the gene rearrangement correlate well with immunophenolype. And rearranged TCR genes in a relatively large proportion of B lineage ALL were observed.