bFGF levels in sera and BM aspirates from healthy donors and HCL-patients. Sera from EDTA-drawn blood samples (n = 7) and BM aspirates (n = 7) were tested for bFGF contents by ELISA (limit of detection: 1 pg/mL). HCL-derived sera (range, 1 to 90 pg/mL; mean, 29 pg/mL) (A) and BM aspirates (range, 230 to 1,005 pg/mL; mean, 641 pg/mL) (B) contained significantly elevated amounts of bFGF. In HD, only one of seven serum samples was weakly positive (4.6 pg/mL) and BM samples showed a mean value of 39 pg/mL, range, 1 to 83 pg/mL bFGF.