Levels of sCD52 quantified by ELISA. (A) healthy blood donors (n = 45) and patients with CLL (n = 86). (B) patients with early CLL (n = 44) and with progressive CLL (progressive CLL, n = 42). (C) patients with early CLL and progressive CLL by Binet stage grading A (n = 39 and n = 6, early CLL and progressive CLL, respectively), vs. B/C (n = 4 and n = 36, early CLL and progressive CLL, respectively). (D) Levels of sCD52 and β2-microglobulin (β2m) in patients with early CLL (n = 26) and progressive CLL (n = 30). Statistical analyses were performed as unpaired Student’s t tests and linear regression analysis, data were logarithmically transformed.