label: Decreased proportion of immature B cells
label_lc: decreased proportion of immature b cells
description: "A reduction in normal proportion of immature B cells (CD19+/ CD21low)in circulation relative to total number of B cells. Immature B cells (IgM+) are still in final stages of development within the bone marrow. Naive B cells are those which have left the bone marrow, before they bind to the antigen for which they're specific (IgM+/IgD+)."