Expression of CD19 and BAFF-R on normal and CLL lymphocytes. PBMNCs from either healthy donors (A) or individuals with CLL (pt no. 2, B) were isolated and stained with CD19-FITC and BAFF-R-PE (A-B) followed by flow cytometry analysis. The CLL patient has low circulating WBC counts (< 20 × 10⁹/L) and B-cell percent (23%) with normal cytogenetics and ZAP70 negative.