Flow cytometric gating algorithm on PB B-cell subpopulations in patients without cGVHD (no cGVHD) and BOS. Whole blood was analyzed by multicolor flow cytometry. B cells as defined by CD19 positivity and side scatter characteristics (SSC) were further stained in various combinations for IgD, CD21, CD27, CD38, and CD10. Numbers indicate percent of cells within respective gates.