MS4A1 and B-cell chronic lymphocytic leukemia: As a diagnostic marker, CD200 (≥30%) revealed a sensitivity of 94.97%, a specificity of 98.11%, with considerably higher accuracy than other MS markers (CD5, CD23, FMC7, CD79b and sIgM) (99.1%) in CLL diagnosis, p value<0.001, (Table 3).