Analysis of the immunoglobulin heavy chain variable region gene expression in Iranian patients with chronic lymphocytic leukemia

Abstract

B-cell chronic lymphocytic leukemia (B-CLL) results from clonal expansion of phenotypically mature but functionally immature B-lymphocytes. The incidence of this type of leukemia is low in Asian countries, whereas it is the most frequent type of leukemia in the West. Previous investigations mainly conducted in Western populations have demonstrated non-random rearrangement of certain immunoglobulin variable region heavy (VH) and/or light (VL) chain genes in different groups of B-CLL patients. Little is known about the profile of VH gene expression in Asian patients. In the present study, we determined the frequency of VH gene family usage in 59 Iranian patients with B-CLL. VH gene family of patients was determined by reverse transcriptase-polymerase chain reaction using VH1-VH7 family specific primers. The most frequently expressed VH gene family was found to be VH3 (45.8%) followed by VH4 (32.2%), VH1 (18.6%), VH5 (1.7%) and VH6 (1.7%), with no expression of VH2 and VH7 gene families. The results indicate a lower representation of the VH1 and VH2 gene families and a higher representation of the VH4 gene family in Iranian B-CLL patients compared to Western patients, suggesting involvement of ethnic and/or environmental factors in B-CLL disease initiation.