Relationship of the phenotype of peripheral blood lymphocytes and signs of osteopenia in patients with chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most common leukemia among adults in Western countries, characterized by the development of a number of complications, including osteoporosis, which is a prerequisite for studying its predictors. The purpose of the work is to investigate the relationship between immunophenotyping indicators of blood lymphocytes and osteodensitometry indicators in CLL. The study was conducted on 48 male patients with CLL aged 50-70 years with an average disease duration of 12 months and 14 apparently healthy men of the corresponding age (group 1). In the blood, CD5+, CD19+, CD20+, CD22+, CD23+, CD43+, and CD200+ lymphocytes were differentiated in the blood using flow cytometry. The international FRAX questionnaire was used to assess the probability of fracture. Osteodensitometry assessed bone mineral density (BMD), T-score (standard deviation, SD), Z-score (SD) in the lumbar spine (LS), proximal femoral neck (FNA), proximal femoral bone (PFB). Patients with CLL were included in group 2 (n = 34) with BMD within normal limits (T- and Z-score – 1.0 SD) or group 3 (n = 14) with signs of osteopenia (OP) (T- and Z-score from – 1.0 SD up to – 2.5 SD). In patients with CLL in group 3, compared with patients with CLL in group 2, there is a significant increase in the number of lymphocytes in the blood expressing markers CD5+, CD19+, CD20+, CD22+, CD23+, CD43+, and CD200+. In patients with CLL in group 3, signs of AP in the SPBC increase with the increase in lymphocytes with the CD5+, CD19+, CD20+, CD22+, CD23+, CD43+, CD200+ phenotype in the blood. Signs of AP in the PBC increase with the increase in lymphocytes with the CD5+, CD19+, CD20+, CD23+, CD43+ phenotype in the blood. The strongest connections were found between the number of lymphocytes in the blood with the markers CD5+, CD19+, CD23+, CD43+ and the T-score, Z-score, and BMD in the FNA. The data obtained are a prerequisite for further study of the interaction between the clone of tumor lymphocytes in CLL and cells involved in bone tissue remodeling to identify the mechanism of development of OP, osteoporosis and the risk of bone fractures, and changes in the quantitative composition of the lymphocyte phenotype in the blood can be considered as potential laboratory predictors of a decrease in BMD.