CTLA4 and B-cell chronic lymphocytic leukemia: Statistical analysis of the obtained test results showed a significant increase in the concentration of soluble forms of all tested molecules in both CVID and CLL patients in relation to healthy volunteers, and the observed differences ranged from 5.81 times (for sCD86) to 17.86 times (for sCD200) for CVID patients and 14.11 fold (for CTLA-4) to 41.62 fold (for PD-L1) for CLL patients.