Detection of immunoglobulin gene rearrangements by PCR using BIOMED-2 multiplex protocols in acute lymphoblastic leukemia patients

Abstract

Objective To investigate the sensitivity of BIOMED-2 primer system in adult acute lymphoblastic leukemia (AIJ,) patients Ig gene rearrangement, and to analyze their frequency, corearrangement pattern, utilization of V, D and J genes and composition of junctional regions. Methods Amplification of rearranged IgH (complete and incomplete), IgK, IgK-Kde and IgL was performed in standard PCR in 29 adult ALL patients. Monoclonal PCR products were subjected directly to DNA sequencing. Sequences were identified by comparison with all known human Ig germline sequences to analyze the recombination patterns, somatic mutations and germline gene segments usage. Results IgH, incomplete IgH, IgK, igK-Kde and Igl, rearrangements were found with positive rate of 70.8%, 12.5% , 29.2% , 25.0% and 0 of B-ALL patients, respectively. All B-ALL patients displayed at least one pattern of Ig gene rearrangements. In TALL, one of five patients was found with incomplete IgH rearrangement, two patients were found with IgK rearrangements and two patients were PCR-negative. The sequence analysis showed that the most frequently used V, D, J segments in adult B-ALL patients were from VH3/VH4 families, DH3 family and JH6 family, respectively. Four of five IgK rearrangement used VκI family. 23.5% B-ALL IgH contained scattered replacement mutations with replacement to silent substitution ratio < 1 in complementarity determining regions. Conclusion BIOMED-2 multiplex PCR analysis strategy is a reliable and useful technique in the adult BALL patients. Key words: BIOMED-2; Leukemia; Immunoglobuliu; Gene rearrangement