Functional assessment of alveolar macrophages: comparison of cells from asthmatics and normal subjects

Alveolar macrophages (AM) were obtained by bronchoalveolar lavage (BAL) from seven healthy nonallergic, nonasthmatic donors, I5 patients with allergic bronchial asthma, and six patients with aspirin-sensitive asthma. AM were purified by adherence over 2 hr and cultured for an additional 24 hr. Functional assessment of viable cells was carried out for zymosan phagocytosis and for prostaglandin (PG) E 2-PGF 2α thromboxane (Tx) B2 release by resting and zymosan-stimulated AM. The eosinophil count in BAL fluid from allergic asthmatics was higher than that from control subjects (3.9% ± I.6% vs 0.4% ± 0.3%, p < 0.05) and still greater in BAL from patients with aspirin-sensitive asthma (21.7% ± 9.0%, p < 0.0I). After the 24 hr of incubation, the AM viability was inversely correlated to the percentage of eosinophils in BAL fluid (r = -0.54, n = 21, p < 0.02). Zymosan phagocytosis was significantly lower by viable cells from both allergic asthmatics and aspirin-sensitive patients as compared with cells from normal donors (p < 0.05). Zymosan phagocytosis induced a twofold to threefold increase in the release of PGE 2, PGF 2α, and TχB 2 from AM of normal subjects (p < 0.01) but only a onefold to twofold increase from AM of allergic asthmatic patients. The stimulated AM from aspirin-sensitive patients released smaller quantities of each product than AM from normal subjects or allergic asthmatic patients (p < 0.05). We conclude that the viability and functional activity of AM are impaired in asthmatic patients and that these deficits correlate with the percent eosinophilia in the BAL; it is therefore suggested that they may be due to an interaction between eosinophils and AM in the bronchoalveolar lumen.