leukotriene-b4 and Sarcoidosis

Mediators released by alveolar macrophages, as well as by T cells, play an important part in modulating local immune processes in sarcoidosis. Among alveolar macrophage secretory products, arachidonic acid metabolites are known to regulate inflammatory and immune reactions. It has been suggested that cyclo-oxygenase and lipoxygenase pathway metabolites of arachidonic acid modulate the evolution of the granulomatous inflammatory response in the lung differently.. Alveolar macrophages recovered from the bronchoalveolar lavage (BAL) fluid of 32 patients with sarcoidosis in different states of disease activity and 10 normal subjects were evaluated for their ability to release prostaglandin E2 (PGE2) and leukotriene B4 (LTB4). Alveolar macrophages were cultured in the presence or absence of opsonised zymosan (500 micrograms/ml), and PGE2 and LTB4 levels in the culture supernatants were determined by enzyme immunoassay (EIA).. Stimulated alveolar macrophages from patients with active sarcoidosis released higher LTB4 levels than those from normal subjects, but no differences in PGE2 release were observed between the two groups. The time course of LTB4 release by activated alveolar macrophages showed that normal cells produced similar levels of the hydroxyacid during the early and late times of culture while LTB4 release by activated cells from patients with sarcoidosis increased markedly after 60 minutes of culture, remaining elevated until 24 hours. Indomethacin (3 x 10(6) M) caused the expected inhibition of PGE2 formation without affecting LTB4 release.. These results suggest that alveolar macrophages from the BAL fluid of patients with active sarcoidosis are primed to release LTB4, which may contribute to the locally heightened immune response.

Topics: Adult; Bronchoalveolar Lavage Fluid; Cell Count; Cells, Cultured; Cyclooxygenase Inhibitors; Female; Humans; Indomethacin; Leukotriene B4; Lymphocyte Count; Macrophages, Alveolar; Male; Prostaglandins E; Sarcoidosis; Zymosan

Topics: Adult; Arachidonic Acid; Arachidonic Acids; Bronchoalveolar Lavage Fluid; Cells, Cultured; Dinoprostone; Humans; Leukotriene B4; Macrophage Activation; Macrophages; Middle Aged; Phagocytosis; Pulmonary Alveoli; Sarcoidosis; Zymosan

Lipoxins are biologically active trihydroxytetraene containing products derived from arachidonic acid that are formed by interactions between lipoxygenases. Although the lipoxins have been generated from mixed cell suspensions in vitro, it has not been established whether these products are synthesized in vivo. We have performed bronchoalveolar lavage (BAL) in 12 patients with lung disease (sarcoid, six; pneumonia, two; asthma, two; carcinoma, one; alveolitis of unknown cause, one) and in six normal control subjects. The BAL fluid was analyzed for lipoxin A4 (LXA4) using gas chromatography mass spectrometry with selective ion monitoring, and the levels of the sulfidopeptide leukotrienes were determined using reverse-phase high-performance liquid chromatography and radioimmunoassay. LXA4 was detected in BAL fluid from nine of the 12 patients studied. The levels of LXA4 ranged from 0.4 to 2.8 ng/ml. LXA4 was not detected in any of the six normal subjects. Sulfidopeptide leukotrienes were detected in all the BAL samples, ranging from 0.04 to 0.7 ng/ml, and there was no significant difference between the patients and the normal subjects. In patients with detectable LXA4 in BAL fluid, the ratio of the concentrations of LXA4 to those of the sulfidopeptide leukotrienes ranged from 1.9 to 62 (mean, 19.0). This is the first demonstration of the presence of LXA4 in disease.

Topics: Adult; Bronchoalveolar Lavage Fluid; Chromatography, High Pressure Liquid; Female; Gas Chromatography-Mass Spectrometry; Humans; Hydroxyeicosatetraenoic Acids; Leukotriene B4; Leukotriene E4; Lipoxins; Lung Diseases; Male; Middle Aged; Radioimmunoassay; Sarcoidosis; SRS-A

Activated macrophages can secrete a number of mediators that can attract inflammatory cells and enhance secretion of phlogistic substances from these cells. The ultimate effect of activated bronchoalveolar lavage (BAL) cells may be fibrotic lung injury. Inasmuch as pulmonary sarcoidosis is a disease associated with spontaneous activation of macrophages and lymphocytes among BAL cells, cells obtained from patients with sarcoidosis were compared with normal cells. We report that adherent BAL cells in culture from patients with sarcoidosis (n = 21) release during a resting period in vitro more chemotactic activity for neutrophils (PMNs) than do BAL cells from normal individuals (n = 14). After density fractionation of the respiratory cells by albumin gradient, cells from high-density fractions in the group with sarcoidosis secrete more chemotactic activity for neutrophils than cells from less dense fractions. The PMN chemotactic activity spontaneously released in vitro by BAL cells from patients with sarcoidosis correlates with the percentage of PMNs recovered by BAL. Immunochemical bioassay and high-performance liquid chromatographic (HPLC) analysis of BAL cell supernatants revealed a complex pattern of chemotactic factors to be present. Generally, three peaks of chemotactic activity were noted on HPLC 1-60 separations at greater than 20 kd, 8 to 10 kd, and less than 1 kd apparent molecular weights. Significantly, interleukin-1 was present in these supernatants, whereas complement components and leukotriene B4 were absent. Sarcoid BAL cells, principally alveolar macrophages, are activated in vivo as manifested by spontaneous secretion of chemotactic factors for PMNs in vitro. Interleukin-1 and other less well characterized molecules were detected. The presence of PMNs among the lavage cells of some patients with sarcoidosis appears to be an in vivo biologic correlate of this activation. These data provide additional criteria of BAL cell activation in patients with pulmonary sarcoidosis and provide further evidence concerning factors that attract inflammatory cells into the lung.

Topics: Bronchoalveolar Lavage Fluid; Cell Separation; Cells, Cultured; Centrifugation, Density Gradient; Chemotactic Factors; Chemotaxis, Leukocyte; Chromatography, High Pressure Liquid; Complement C3; Complement C3a; Complement C5; Complement C5a; Humans; Interleukin-1; Leukotriene B4; Macrophage Activation; Macrophages; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Radioimmunoassay; Sarcoidosis; Zymosan