Effects of cytokines and serum (A) on the expression of CD64 on PMNs and (B) on the binding of PMNs to untreated endothelium. (A) Blood PMNs (1 × 106 cells) from 5 patients out of crisis (▪) and from 5 normal healthy subjects (▧) were incubated with cytokines (10 U/mL except for IFN-γ, which was 50 U/mL) or 100 μL patient and control serum for 24 hours and with FMLP for 3 minutes before flow cytometric analysis. Only IFN-γ significantly increased the number of CD64+ PMNs (9 experiments) by comparison with the untreated samples (normal controls, P = .02; patients, P = .03). (B) PMNs from the 5 control subjects were also examined in the adherence assay. The cells were incubated with cytokines or serum for 24 hours or with FMLP for 3 minutes and overlaid onto untreated endothelial cells. A significant increase of PMN adherence was only seen after FMLP treatment (P = .008). In both (A) and (B), data are expressed as the mean result ± SD.
