CD5 and B-cell chronic lymphocytic leukemia: In contrast, studies on the pathological accumulation of CD5+ B cells, such as in chronic lymphocytic leukemia (CLL), have shown that CD1d expression and iNKT cells are not essential for the development, expansion, or IL-10 competence of CD5+ B cells in mice prone to benign or leukemic CLL-like B cell proliferation (140).