Biological Features of CD5+ CD19+ B1 Cell and Natural IgM (VH4-34) in Chronic Lymphocytic Leukemia vs. Multiple Sclerosis.

Chronic lymphocytic leukemia (CLL) is the clonal expansion of mature CD5+ B cells and the most common lymphoproliferative disease in adults (B1-CLL). B1 cells' anti-inflammatory effects include the production of natural IgM (nIgM) by the spleen and bone marrow, decreased inflammatory cytokines as a primary response to maintaining tissue homeostasis, and enhanced release of transforming growth factor β (TGFβ). We used the flow cytometry technique in peripheral blood from patients with CLL and multiple sclerosis (MS) to immunophenotype B cells and their subpopulations.