Detailed peripheral blood phenotyping showed that B lymphocytes expressed a CLL-like antigen pattern (CD5+, CD11c+, CD19+, CD20+/low, CD23+, CD43+, CD79b+, surface IgM+/low, CD200+; CD10−, CD103−, CD38−, CD123−). The gene discussed is CD40LG; the disease is B-cell chronic lymphocytic leukemia.