CIRCULATING CYTOKINES IN SICKLE-CELL PATIENTS DURING STEADY-STATE

Plasma levels of GM-CSF, IL-3, IL-6 and IL-1(alpha,beta) were investig ated in steady-state sickle cell patients. We find that SS patients wi th low levels of HbF (< 9% [LFSS]) are characterized by elevated plasm a GM-CSF, whereas in patients with high levels of HbF (HFSS), GM-CSF i s not detectable. In contrast, HFSS patients exhibited increased plasm a IL-3 (m = 84.8 + 57 pg/ml), whereas LFSS patients had lower or no de tectable plasma IL-3. IL-1(alpha,beta) and IL-6 were also detected in plasma from some SS patients, but there was no correlation with HbF le vels. Normal controls tested negative for all cytokines, except for on e individual positive for IL-3. These results are compatible with a mo del in which the level of haemopoietic stress determines the level of participation of GM-CSF or IL-3 in the regulation of SS circulating BF U-E.