Circulating opsonic fibronectin and peripheral blood neutrophils’ activity in acute burns

Recent experimental and clinical evidence has suggested that circulating fibronectin plays an important role as a nonspecific opsonin in the phagocytosis of some bacteria The effect of circulating fibronectin levels on leukocyte phagocytosis was determined in a serial study of 20 burn patients (mean TBSA 56% range 32%–84%) and in 24 healthy donors. The metabolic activity of per-ipheral blood leukocytes as reflected by oxygen consumption after stimulation with preopsonized zymosan correlated with fibronectin levels (rocket immunoelectrophore-sis) in healthy donors (r = 0.77 P<0.05). The results showed a decrease of fibronectin level in burned patients’ serum with parallel decreased leukocyte oxygen consumption (r = 0.95 P<0.005 for the first three days postburn). Profound decrease of both values was observed especially during the septic episodes. Decrease of leukocytes’ oxygen consumption when incubated in fibronectin-depleted serum (affinity chromatography) additionally suggests participation of fibronectin in the opsonization processes of some target particles.