Phenotypic characterization of lymphocytes recovered from human-<Balb/c chimera. Chimera were prepared by conditioning Balb/c mice with split irradiation followed by radioprotection with SCID BM; thereafter, the mice were transplanted with 100 to 1,000 × 10⁶ human PBMC from BCLL patients. Cells were recovered from the peritoneum wash 14 days after transplantation. The total population of human lymphocytes (A, B, and C) was typed by staining with anti-CD45. T cells (D, E, and F ) were typed by triple staining of CD45⁺ cells with anti-CD3 and anti-CD5. BCLL cells (G, H, and I) were typed by triple staining of CD45⁺ cells with anti-CD20 and anti-CD5. Typical FACS analysis of cells from chimeric mice generated from patients in stage 0, I to II, and III to IV disease; patients no. 5 (A, D, and G), 20 (B, E, and H), and 18 (C, F, and I), respectively.