Phagocytic and chemotactic function of polymorphonuclear and mononuclear leucocytes in patients with recurrent...

From 21 patients with chronic or recurrent staphylococcal infections, phagocytosis and intracellular killing of Staphylococcus aureus by polymorphonuclear (PMN) and mononuclear (MN) leucocytes were evaluated. Also chemotactic responsiveness and the capacity of their sera to opsonize Staph. aureus was tested. The chemotactic, phagocytic and bactericidal capacity of PMN's and MN's from patients was significantly decreased. The mean uptake of Staph. aureus by patient PMN's and MN's was 65% and 44%, respectively, as compared to 85% and 75% observed with PMN's and MN's from 38 healthy donors. The phagocytic activity of 17/21 patients (81%) was below the normal range. A decreased chemotactic mobility and bactericidal capacity of patient leukocytes was also found and was always accompanied by a decreased rate of ingestion. Although a great variability was noted in the phagocytic capacity of leucocytes from patients tested repeatedly over periods up to 82 weeks, the mean value for phagocytosis remained below the normal range in 10/11 patients included in the follow-up study. Except for 1 patient with dysgammaglobulinemia, sera from the patients contained normal amounts of immunoglobulins and complement (CH50 and C3), and they all effectively opsonized Staph. aureus. The results indicate that defects in leucocyte function may be frequently involved in the pathogenesis of recurrent Staph. aureus infections.