Biologic effect of blister fluid from thermal injuries on peripheral neutrophil chemotaxis

Patients who become immunologically incompetent after major thermal injury often show in vitro defects in neutrophil function, including abnormalities of neutrophil chemotaxis. Although there is evidence suggesting that this acquired chemotactic defect is related to circulating suppressor substance(s) in the serum of these individuals, neither the etiology of this chemotactic defect nor the origin of these putative suppressors have been clarified. We report studies directed toward determining the biologic effect of blister fluid from thermally injured patients on peripheral neutrophil chemotaxis. Fifteen blister fluid samples from 12 patients were tested in attraction and inhibition assays of neutrophil chemotaxis. Chemotaxins were observed in all specimens. The biologic activity of blister fluid was similar to that produced by complement in serum and presumably was due to complement activity in the blister fluid. No inhibitors of chemotaxis were found in the blister fluid samples, although it seemed logical to expect to find suppressors in this fluid if they were generated locally by the thermal injury. Since suppressors were not found locally, other explanations must be sought to explain the etiology of the acquired defect in neutrophil chemotaxis that occurs after thermal trauma.