Immunoglobulin variable heavy chain region genetic constitution and mutation status in Chinese patients with chronic lymphocytic leukemia

Abstract

To evaluate the genetic constitution and mutation status of the immunoglobulin variable heavy chain region (IGVH) gene expression in Chinese patients with chronic lymphocytic leukemia (CLL). The IGVH mutation was detected by multiplex PCR and direct sequencing of the purified PCR products from 64 CLL patients. The segments of VH, DH and JH family and mutations were analyzed by IMGT/V-QUEST and IGBlast. In the 64 patients, the most common usage was VH3 (31/64, 48%), followed by VH4 (26/64, 41%), VH1 (4/64, 6%), VH2 (2/64, 3%) and VH7 (1/64, 2%). The results also showed that 44 patients (69%) had mutated VH, 6 cases (9%) had identical germline sequences. Among the 64 sequences of DH segments, DH3 gene family was used most frequently (25/64, 39%), among which 11 cases had unmutated VH. The most frequent usage of the JH segments was JH6. There is significant difference in the frequency of the IGVH gene family in Chinese CLL patients compared to Western patients, suggesting the involvement of antigen selection in different ethnic and/or environmental factors in CLL disease initiation, and its prognostic significance needs further investigation.