Two distinct B-cell clones can coexist in the same blood sample. Cytofluorimetric analyses of whole blood from one individual (case 18) carrying 2 distinct B-cell clones is presented. (A) Dot plot was obtained by gating lymphocytes (identified on SSC and FSC profiles) expressing CD19. The intensity of CD20 and CD5 is shown on the x-axis and y-axis, respectively. R1 and R2 identify an atypical CLL-like clone and a non–CLL-like clone, respectively. (B-C) Dot plots show κ and λ light chain expression, on the x-axis and y-axis, respectively, of the atypical CLL-like clone (R1) in panel B and of the non–CLL-like clone (R2) in panel C.