In humans, the anti-CD200 mAb Samalizumab has entered two phase I clinical trials: one on patients bearing solid tumors (NCT02987504) and the other on patients with B-cell chronic lymphocytic leukemia (B-CLL) or multiple myeloma (NCT00648739) (clinicaltrials.gov). This evidence concerns the gene CD200 and B-cell chronic lymphocytic leukemia.