Effects of peritonitis exudates on chemotaxis and phagocytosis of human neutrophils

Objective: To elucidate the in vitro effects of peritoneal exudate in patients with peritonitis on the functions of normal neutrophils (chemotaxis and phagocytosis) and to correlate these findings with constituents of the exudate, severity of disease, and clinical course. Design: Open study. Selling: University hospital, Germany. Subjects: Fifty consecutive patients with secondary peritonitis and healthy volunteers. Interventions: Samples of peritoneal exudate were taken during operation and tested for their ability to stimulate or inhibit chemotaxis and phagocytosis of polymorphonuclear neutrophils (PMN). Main outcome measures: Correlation between chemotaxis and phagocytosis and concentrations of constituents of peritoneal exudate. Results: Mean (SD) exudate-induced chemotaxis was 102.5 (22.8) μm compared with 62.3 (4) in the buffer control and 116 (17) in the 1 ng/ml C5a buffer control. The mean (SD) phagocytic index (uptake of zymosan and Candida albicans) was 68.8 (28.1) % of the respective serum control. There were correlations between chemotaxis and concentrations of C3a, endotoxin, and white cell count in the exudates; between phagocytosis and concentrations of C3a, IgG, IgM, protein and granulocyte elastase activity (GE and GE-α₁ proteinase inhibitor complex) in the peritoneal exudate; concentrations of endotoxin, and tumour necrosis factor (L (TNFα), and granulocyte elastase activity in the exudate; and concentrations of C3a, IgG, IgM, and fibrinopeptide A in the exudate. There were no differences in chemotaxis and phagocytosis between patients who survived and those who died, and only the APACHE II score, the Sepsis Severity Score and the Mannheim Peritonitis Index correlated with mortality. Conclusion: It is still not clear whether other constituents of the exudate, variable conditions of resorption, inflammatory conditions within the peritoneal lining, or the individual patient's capacity to limit the systemic response, may have a critical role.