Prevalence of Monoclonal B Lymphocytosis in First-Degree Relatives of Chronic Lymphocytic Leukemia Patients in Turkey

OBJECTIVE Monoclonal B lymphocytosis (MBL) is considered to be a precursor state for chronic lymphocytic leukemia (CLL). This study was planned to evaluate the MBL prevalence in first-degree relatives of CLL patients in Turkey, which is considered to be an ethnic and geographic bridge between the Eastern and Western worlds. MATERIALS AND METHODS A total of 136 volunteers [median age: 40 (17-77) years; male/female: 60/76] from 61 families were included. Flow cytometry analysis by 4-colour staining was used for MBL diagnosis. RESULTS MBL was demonstrated in 17 cases (12.5%). A total of 14 cases (10.3%) were classified as CLL-like MBL, while 3 (2.2%) exhibited a non-CLL-like phenotype. The prevalence of MBL was 12.72% in subjects aged less than 40 years, 12.28% in subjects between 40 and 60 years, and 40% in subjects over 60 years, without statistical significance (p>0.05). A total of 115 cases were evaluated for intermarriage, which was observed in 19 cases (16.5%). The prevalence of MBL did not differ based on intermarriage status (p>0.05). CONCLUSION The current report is the first MBL prevalence study in a Eurasian population that demonstrates a similar distribution pattern of MBL in Anatolian CLL kindreds. Further efforts should be made to refine our understanding of the natural history and clinical outcomes of MBL.