Inappropriate neutrophil activation in venous disease

Neutrophil oxygen radical production was studied in 18 limbs with class 2 or 3 venous disease and compared with that of nine normal limbs. Neutrophils were isolated from arm and leg venous samples. Free radical production was determined using chemiluminescence after stimulation with the chemotactic peptide formyl-methionyl-leucyl-phenylalanine (FMLP) or the ester phorbol myristate acetate (PMA). The ratio of leg to arm luminescence was greater after FMLP stimulation in patients with venous disease (median 1.52 (95 per cent confidence interval (c.i.) 1.27-2.60)) than in controls (median 0.97 (95 per cent c.i. 0.70-1.12); P < 0.01). These changes were not observed with PMA (venous disease 1.16 (95 per cent c.i. 1.05-1.40); controls 0.95 (95 per cent c.i. 0.78-1.24)). There were fewer FMLP receptors on activated leg neutrophils (median 20.19 (95 per cent c.i. 3.58-51.42) fluorescence units) than arm neutrophils (median 36.03 (95 per cent c.i. 13.00-65.28) fluorescence units; P < 0.05), indicating an amplification of signal transduction. Intracellular calcium imaging demonstrated a larger release of calcium after stimulation of leg neutrophils (median 25.0 per cent (95 per cent c.i. 15.7-43.9 per cent)) compared with neutrophils from the arm (median 8.0 per cent (95 per cent c.i. 5.6-16.1 per cent); P = 0.04), demonstrating calcium-dependent activation. Neutrophils in patients with chronic venous disease inappropriately produce more oxygen free radical as a result of amplification of a calcium-dependent signal pathway.