ONO-1078 (pranlukast) is a leukotriene receptor antagonist developed in Japan. This drug has been shown to be useful in oral treatment of bronchial asthma. The present study was undertaken to assess the effects of this drug on the production of cytokines in the peripheral blood mononuclear cells of patients with asthma under stimulation with specific antigens.
Peripheral blood mononuclear cells from mite antigen-positive asthmatic patients (immunoglobulin E RAST score > 3) were incubated for 72 h in the presence of mite antigen (10 μg/mL). The supernatant of the culture was subjected to enzyme-linked immunosorbent assay (ELISA) to quantify interleukin (IL) -4, IL-3, IL-5, and granulocyte macrophage-colony stimulating factor (GM-CSF). Other peripheral blood mononuclear cells from the same patients were incubated for 72 h in the presence of both mite antigen (10 μg/mL) and ONO-1078 (0.5, 1, or 10 μg/mL), followed by ELISA of the supernatant to quantify the cytokines.
Production of IL-4, IL-5, and GM-CSF by mononuclear cells under stimulation with mite antigen was markedly suppressed when they were exposed to ONO-1078 at a concentration of 10 μg/mL.
The results suggest that ONO-1078 acts directly on peripheral blood mononuclear cells and that blockade of leukotriene receptors on blood mononuclear cells by the cysteinyl-leukotriene receptor antagonist (LTRA) pranlukast (ONO-1078) can dose-dependently inhibit release of immunoreactive TH2-type cytokines (IL-3, IL-4, GM-CSF, and possibly IL-5), but not of the TH1-type cytokine IL-2, when stimulated by mite allergen in vitro. The data may provide clues to the mechanism by which a number of LTRA including zafirulukast and montelukast can reduce airway, sputum and blood eosinophil counts in clinical asthma. It supports animal studies showing that anti-IL-5 antibodies partially block cys-LT-induced airway eosinophilia, suggesting that cys-LTs may cause secondary release of IL-5 from an unknown cell-type.
These findings indicate that ONO-1078 suppresses the production of IL-4 (a cytokine that affects IgG antibody production), IL-5, and GM-CSF (cytokines that affect eosinophil activation) by peripheral blood mononuclear cells under stimulation with specific antigens in patients with bronchial asthma. Because of its anti-inflammatory effects, ONO-1078 should be useful in the treatment of bronchial asthma.