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Histamine Stimulates Interleukin-6 Production through Histamine H1 Receptors in Human Amnion Cells

Background/Aims: Previous studies have stated that maternal allergic diseases are associated with increased risk of preterm labor/delivery, but the underlying mechanisms remain unclear. This study tested the hypothesis that histamine induces interleukin (IL)-6 production in amnion cells. Methods: Using cultured human amnion cells, we examined expression of histamine receptors and effects of histamine on IL-6 production. Results: Reverse transcription-polymerase chain reaction and Western blotting revealed expression of histamine H1 receptor (H1R) and H2 receptor (H2R) in human amnion. Histamine stimulation significantly increased concentrations of IL-6 in conditioned medium, as did tumor necrosis factor-α and IL-1β in positive controls. In addition, the H1R antagonist olopatadine significantly blocked histamine-induced production of IL-6, whereas the H2R antagonist ranitidine did not. Conclusion: Histamine appears to induce IL-6 production through H1R in human amnion cells.