AMPLIFICATION OF 3RD-COMPLEMENTARY-DETERMINING-REGION (CDR-III) OF HEAVY-CHAIN IMMUNOGLOBULIN GENE (IGH) IN 100 ADULT ACUTE LEUKEMIAS

We applied a simple polymerase chain reaction (PCR) based method for d etecting immunoglobulin heavy-chain (IgH) gene rearrangement, using it s CDR-III region to assess B-cell clonality in a series of 100 acute l ymphoblastic leukemias (ALL) (84 B-cell lineage, 4 null-ALL and 12 T-A LL). The amplified CDR-III regions can be generated in all the B-linea ge ALL and separated by size by polyacrylamide gel electrophoresis (PA GE), thereby providing a specific diagnostic marker for each B cell cl one. Size heterogeneity resulting from independent IgH rearrangement e vents and the high resolution power after electrophoresis and silver s taining of the PAGE gels can be used to generate a ''fingerprint'' of the PCR fragments representing either the spectrum of B-cell clonality in complex populations of B lymphocytes or the partially genomic conf iguration of the VH-N-DH-N-JH region. At diagnosis, we found the prese nce of one clonal IgH heavy-chain gene rearrangement in 80 B-cell line age and null ALL and a biclonal rearrangement in 8 cases. The CDR-III bands were of sizes ranging from 80 to 130 bp. The PCR analysis of the IgH gene enabled us to obtain st CDR-III leukemia specific product in all cases, thereby providing a specific and diagnostic marker for eac h B-cell clone.