Effect of circulating fibronectin on stimulation of leukocyte oxygen consumption and serum opsonizing function in burned patients.

In a study of 27 thermally burned patients (mean TBSA, 58%; range, 32-96%) serum fibronectin levels were decreased with parallel decreased oxygen consumption of stimulated peripheral blood phagocytes and decreased EGTA-blocked burn serum opsonizing activity which correlated with serum fibronectin changes postburn. Normal and burn sera fibronectin content also correlated with the opsonizing times for zymosan and Staphylococcus aureus but not for Enterobacteriaceae. Although in vivo 14 cases showed circulating fibronectin 140 micrograms/ml or lower and a marked decrease in Staphylococcus aureus opsonization, only two patients from this group revealed positive Staphylococcus aureus blood cultures and serum fibronectin levels were higher in patients with Staphylococcus aureus sepsis than in patients with Enterobacteriaceae sepsis. Supplementary experiments on leukocyte oxidative response after zymosan stimulation in normal, fibronectin-depleted, and fibronectin-reconstituted serum demonstrated that the lag period of oxygen burst is a fibronectin-dependent reaction.