小儿急性白血病IgH基因重排与白血病克隆性和免疫分型的关系

THE RELATIONSHIP BETWEEN IgH GENE REARRANGEMENT AND CLONALITY AND IMMUNOPHENOTYPE IN CHILDHOOD ACUTE LEUKEMIA

选用一对免疫球蛋白重链基因V区和J区的通用引物,进行PCR检测不同类型小儿急性白血病免疫球蛋重链基因重排。33例小儿急性白血病初诊未治骨髓标本检测结果呈单克隆条带的为U-ALL3/7例,C-ALL4/6例,单/B祖双标记白血病1/3例,T-ALL1/4例,AML1/10例。B-ALL、AMoL、髓/T双标记白血病各1例均阴性。说明免疫球蛋白重链基因重排主要见于B细胞系ALL及其与B细胞相关的双标记白血病,阳性率为47％,可以作为分析白血病细胞来源的标志之一,并辅佐基因分型。另外对20例正常人外周血单个核细胞DNA检测结果均为一片模糊,无明确条带,说明可以区分淋巴细胞系克隆增殖和反应性增生。本文尚对2例PCR产物进行DNA序列分析,结果参与重排的J区分别为J_4和J_5,DNA同源性很小,有可能设计克隆特异性引物和探针作微小残留病检测。

A pair of universal primers for amplifying the D and J regions of immunoglobulin heavy chain gene was selected, synthesized, and tested with PCR for immunoglobulin heary chain gene rearrangement in different types of childhood acute leukemias. The DNAs from leukemic cells of 33 cases with newly diagnosed chidhood acute leukemias (7 cases of U-ALL3, 6 of C-ALL4, 3 of mono-B progenitor cells double marker leukemia I, 4 of T-ALL I and 10 of of AML 1) were analyzed and the results indicated that 47% of B precursor ALL showed monoclonally rearranged band and all the 20 samples from normal peripheral blood leucocytes showed smear pattern. Therefore, this band can be used to discriminate clonal lymphoproliferative disorders from reactional proliferation. It can also aid in gene classification of acute leukemia. DNA sequences of PCR products were analyzed in two cases of leukemic DNA. It showed that the rearranged J regions were J4 and J5 respectively. There was little homology in DNA regions. It is possible to design clonal specific primers and probes to detect minimal residual disease.