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Suitability of techniques of P. aeruginosa DNA fingerprinting to determine risk of acquisition in cystic fibrosis. † 1829

We examined the chemiluminescence response of peripheral blood monocytes from patients with cystic fibrosis (CF) and their asymptomatic parental carriers of the CF gene to three different types of stimulation. We found that monocytes from both patients and carriers have increased luminol-dependent chemiluminescence in the first 25 min after stimulation by adherence to glass. These results are consistent with the hypothesis that monocytes from both CF heterozygotes and homozygotes respond to adhesion with increased oxygen radical formation. The increased adherence-induced monocyte chemiluminescence of the parental carriers did not vary with age or length of exposure of the parents to a child with CF. Also, repeated exposure to medications and respiratory secretions of CF patients was not associated with an increase in adherence-induced monocyte chemiluminescence of their nonbiologically related caretakers. Thus, this observed increase in chemiluminescence is not simply secondary to the medications or respiratory dysfunction seen in the patients with CF. Patients with other types of obstructive lung disease did not show increased adherence-induced monocyte chemiluminescence. We conclude that increased early phase adherence-induced monocyte chemiluminescence occurs in patients with cystic fibrosis and the obligate carriers of the CF gene independent of environmental influences.

Many Staphylococcus epidermidis (S. epi) strains isolated from patients with catheter related infections produce an extracellular "slime". This slime probably mediates adhesion of this bacterium to plastic, inhibits the lymphoproliferative response to polyclonal activators and may prevent serum opsonins or polymorphonuclear phagocytes from functioning normally. To examine its effects on opsonization, increasing amounts of staphylococcal slime were added to pooled human serum (PHS), radiolabeled S. epi (2 strains) or E. coli (ON2), and incubated in this mixture for 15 min/37°. The washed bacteria were incubated in fluid phase with PMN's for varying times and the percent of cell associated bacteria determined. Slime decreased the percent of cell associated S. epi and E. coli in a dose dependent manner and killing of E. coli was markedly decreased. To examine its effects on phagocyte function, slime was added in increasing amounts to PMN's to which radiolabeled S. epi and E. coli preopsonized in PHS alone were then added. Slime interfered in a dose dependent manner with PMN uptake of preopsonized S. epidermidis but did not alter PMN uptake nor killing of preopsonized E. coli. We conclude that slime 1) interferes with opsonization of both S. epi and E. coli and 2) that it interferes with PMN phagocytosis of preopsonized S. epi but not preopsonized E. coli. These findings may relate to the persistence of S. epi catheter associated infections.

The role of anti-neutrophil antibodies was investigated as a cause of functional abnormalities of circulating neutrophils in a child with persistent neutropenia and recurrent mouth sores. The patient's neutrophils were isolated by isopycnic centrifugation and compared with normal adult neutrophils. Functional abnormalities in the patient's PMNS included (1) decreased chemotaxis studied by under agarose method and by skin window, (2) decreased oxidative burst measured by luminol amplified chemi luminescence, and (3) decreased superoxide production measured by cytochrome C reduction assay. The ability of the patient's serum to bind normal neutrophils was determined by immunofluorescence. While the patient's serum bound normal PMNs, this binding did not interfere with their oxidative burst. In contrast, the patient's serum did not bind to his own PMNs in vitro even though his neutrophil specific antibody was anti-NAI and his PMNs were NAI positive. Therefore, the functional abnormalities of this patient's PMNs were not due to neutrophil antibody binding alone, but due to a subpopulation of dysfunctional neutrophils in circulation possibly selected out by their low affinity to the circulating autoantibodies.

Decreased peripheral blood lymphoproliferative response due to dysfunctional non-T lymphocytes and the presence of unusual antigenie structures on peripheral blood non-T cells are among the alterations in the immune system found in patients with rheumatic cardiac valvular disease. The present study examined natural killer cell activity and generation of cytotoxic lymphocytes after exposure to bklastogen A in patients with RHD and age- and socioeconomic-matched controls with recurrent tonsillitis but no rheumatic history, signs or symptoms. Peripheral blood mononuclear cells (PBMNC) were obtained by isopycnic centrifugation. Fresh PBMNC were incubated with 4 concentrations of K562 erythroleukemia cell targets. Rates of target cell lysis were measured by assay of lactate dehydrogenase using a spectrophotometric assay. Natural cytotoxic activity of freshly isolated PBMNC did not differ between RHD and controls. However, the PBMNC from RHD showed significantly less cytotoxicity after they were cultured alone in media for 6 days. In marked contrast, when cultured for 6 days in the presence of streptococcal blastogen A, PBMNCs from RHD showed greater rates of target cell lysis than controls at all target cell concentrations (P