CD200 and B-cell chronic lymphocytic leukemia: In CLL cases, CD200 positive B- cells (≥ 30%) were detected in all cases [median 97.9% (50.6–100)] as opposed to a highly heterogeneous CD200 expression pattern in the non-CLL group, reported in 37.7% of cases, [median 9.8 (0.10–91.8%)],p value<0.0001 (Table 2 and Fig 1).