In vitro bFGF production by PBMC from patients with HCL and HD. A total of 2 × 10⁶ cells were cultured in 12-well plates for 48 hours with and without PWM. Supernatants were assayed by a bFGF-specific ELISA. Unstimulated cultures from HD did not contain detectable amounts of bFGF in contrast to HCL-derived samples (mean, 55 pg/mL; range, 4 to 161 pg/mL). PWM stimulation led to an increased bFGF release in HCL (mean, 110 pg/mL; range, 8 to 262 pg/mL), while only two of seven HD showed weak positive reaction (2.4 pg/mL and 1.9 pg/mL).