CD19 and malnutrition: Furthermore, malnutrition reduces the number of spleen B cells as well as all subpopulations of B cells, such as mature (CD19+B220HighCD24LowIgM+), immature (CD19+B220LowCD24High IgM+), transitional 1 (IgD+IgMHighCD24High) and transitional 2 (IgD−IgMHighCD24High) B cells (36).