Azithromycin decreases Chlamydia pneumoniae-mediated Interleukin-4 responses but not Immunoglobulin E responses

Abstract

Background Chlamydia pneumoniae is an obligate intracellular bacterium that causes respiratory infection. There may exist an association between C. pneumoniae, asthma, and production of immunoglobulin (Ig) E responses in vitro. Interleukin (IL-4) is required for IgE production. Objective We previously demonstrated that doxycycline suppresses C. pneumoniae-induced production of IgE and IL-4 responses in peripheral blood mononuclear cells (PBMC) from asthmatic subjects. Whereas macrolides have anti-chlamydial activity, their effect on in vitro antiinflammatory (IgE) and IL-4 responses to C. pneumoniae have not been studied. Methods PBMC from IgE-adult atopic subjects (N = 5) were infected +/-C. pneumoniae BAL69, +/azithromycin (0.1, 1.0 ug/mL) for 10 days. IL-4 and IgE levels were determined in supernatants by ELISA. IL-4 and IgE were detected in supernatants of PBMC (day 10). Results When azithromycin (0.1, 1.0 ug/ml) was added, IL-4 levels decreased. At low dose, IgE levels increased and at high dose, IgE levels decreased. When PBMC were infected with C. pneumoniae, both IL-4 and IgE levels decreased. Addition of azithromycin (0.1, 1.0 ug/mL) decreased IL-4 levels and had no effect on IgE levels. Conclusions These findings indicate that azithromycin decreases IL-4 responses but has a bimodal effect on IgE responses in PBMC from atopic patients in vitro.

Insights Into Host Cell Cytokines in Chlamydia Infection

“…It can elicit many responses, in particular the humoral immune response that is associated with antibody production (135,136). IL-4 can be detected in the culture supernatant of PBMCs isolated from patients with Chlamydia infection (137,138). Therefore, IL-4 is considered to play a role in Chlamydia infections.…”