Monoclonal B cells present in the blood of elderly people are phenotypically heterogeneous. Cytofluorimetric analyses of whole blood from 3 patients carrying either a classic CLL-like (A,D), or an atypical CLL-like (B,E), or a non–CLL-like (C,F) B-cell clone are presented. (A-C) Dot plots were obtained by gating lymphocytes (identified on side-scatter and forward-scatter profiles) expressing CD19. The intensity of CD20 and CD5 is shown on the x-axis and y-axis, respectively. R1, R2, and R3 gates indicate the clones. (D-F) Dot plots show κ and λ light chain expression of the B-cell clones as identified on panels A, B, and C.