fraction D precursor B cell 2010-04-28T02:55:16Z fraction D pre-B cell Fraction D precursor B cells are also reportedly CD24-positive and sIgD-negative. A pre-B cell that is pre-BCR-negative, and the kappa- and lambda- light immunoglobulin light chain-negative, CD43-low, and is BP-1-positive, CD45R-positive and CD25-positive. This cell type is also described as being AA4-positive, IgM-negative, CD19-positive, CD43-low/negative, and HSA-positive. Fr. D fraction B/C precursor B cell