Effects of wound exudates on in vitro immune parameters

Although local failure of antibacterial host defenses in the surgical wound may contribute to the development of wound infections, little attention has been focused on this problem. The goals of the current study were to determine the biological activity of postsurgical wound exudates (seroma fluids) on normal neutrophil and lymphocyte function and to quantitate the levels of complement and plasma fibronectin in these wound exudates. The wound exudates did not support the opsonophagocytosis and killing of Staphylococcus aureus or Pseudomonas aeruginosa by control neutrophils as well as serum (P less than 0.01) and was inferior to serum as a neutrophil chemoattractant (P less than 0.01). Similarly, the wound exudates did not support mitogen-induced lymphocyte blastogenesis as well as normal serum (P less than 0.01). The impaired function of both neutrophils and lymphocytes incubated in the wound exudates appeared to be due to a lack of normal humoral factors, rather than to the presence of inhibitory factors, since the addition of normal serum to the wound exudates restored cellular activity to normal. The findings of decreased levels of plasma fibronectin and decreased complement hemolytic activity in the wound exudates were consistent with the concept of a local deficiency of immune-related humoral factors. Thus, this study supports the clinical concept that local collections of wound fluids may predispose to wound infections by hampering effective local host defenses.