Preferential Usage of Specific Immunoglobulin Heavy Chain Variable Region Genes With Unmutated Profile and Advanced Stage at Presentation Are Common Features in Patients With Chronic Lymphocytic Leukemia From Senegal

Objectives: Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in Western populations, being rarer in Asian and African people. It has been suggested that patients with CLL from Africa might have a more aggressive disease compared with white patients. In this study, we aimed to identify genetic factors that may account for this difference. Methods: We analyzed immunoglobulin heavy chain (IGH) genes' mutational status by performing next-generation sequencing in 25 Senegalese and 50 Italian patients with CLL. Results: We found that Senegalese patients more frequently had adverse prognostic factors and an unmutated profile. Furthermore, we documented that IGHV1 (IGHV1-69), IGHD3, and IGHJ6 were significantly more frequent in Senegalese patients, whereas IGHV3-30 was common and limited to the Italian cohort. Stereotyped receptors commonly detected in the white population were not recorded in our Senegalese series. Conclusions: The different IGH repertoire we observed in the Senegalese cohort may reflect the diverse genetic and microenvironmental (ie, polymicrobial stimulation) background.