IGHV Mutational Status in a Cohort of Bulgarian CLL Patients: High Unmutated CLL Prevalence in North-East Bulgaria

Chronic lymphocytic leukemia (CLL) is the most common leukemia in adults. One of the best established CLL prognostic markers is the somatic hypermutational status of the IGHV gene which is a part of the immunoglobulin heavy chain variable region. Technology for IGHV genotyping has been optimized and has been applied in routine diagnostics for the first time in Bulgaria. A total of 105 patients with CLL from different Bulgarian regions were tested. IGHV mutational status was determined by Sanger sequencing on total genomic DNA (gDNA) or RNA extracted from mononuclear cells. All sequencing profiles were analyzed with the IMGT/V-QUEST tool. Within the course of the analysis a high percentage of IGHV unmutated status was established in the Varna district on the Black Sea (Northeast Bulgaria). In addition, the IGHV genotyping performed on gDNA revealed a rare case with multiple rearrangements. The present data from IGHV genotyping will help in choosing the proper treatment for the benefit of Bulgarian CLL patients.