Pattern of CD38 expression displayed by CLL cells.

CLL cells were analyzed for surface CD38 expression after incubation with anti-CD19, anti-CD38, and anti-CD5 conjugated with different fluorochromes. Dot plots (A-C) were obtained by gating lymphocytes (identified on side and forward scatter profiles) expressing CD19 and CD5. The intensities of CD19 and CD38 are shown on the x-axis and y-axis, respectively. The histograms in panels D-F show the profile of CD38 expression. The intensity of CD38 and the number of events are shown on the x-axis and y-axis, respectively. In panels A and D, a representative patient negative for CD38 is depicted, whereas panels B and E illustrate a representative patient homogeneously positive for CD38. A patient with a bimodal expression of CD38 is shown in panel C, with 2 distinct cell populations: one positive and the other negative (F).