Absolute blood counts of mIgD⁺ (A) and mIgD⁻ (B) B cells. Data are expressed as medians (squares) and 25^th to 75^th percentiles (vertical lines), with the exception of the two 4-year-old children in which case the vertical line represents the range. The differences between each of the groups of patients or normal children and the reference group of normal adults were significant (P ≤ .05), except for the group of patients at 1 year after allogeneic BMT in case of mIgD⁺ B cells and the group of patients at 5 years after allogeneic BMT in case of mIgD⁻ B cells.