Background: Inhaled corticosteroids (ICS) are widely prescribed medications. Some studies have reported that ICS may suppress the hypothalamic-pituitary-adrenal axis and induce systemic effects. Objective: To explore the possibility of a dose-dependent association between the long-term use of ICS and the risk of obesity and other markers of metabolic syndrome. Methods: A 5-year retrospective two-arm cohort study explored patients on asthma and not on ICS relative to patients with asthma who were on varying doses of ICS (low, medium, and high) and attributes such as body mass index (BMI) trajectory and prescription of antihypertensive, antidiabetic, and cholesterol-lowering medications. Results: A total of 229 subjects with asthma were in the control cohort, and 215 subjects with asthma were in the ICS cohort. The ICS cohort was subdivided into individuals on low- (n = 88), medium- (n = 107), or high- (n = 20) dose ICS throughout the 5-year study period. For every 1-year increase in time, the BMI in the high-dose ICS group increased at a rate of 0.25 kg/m2 when compared with the subjects in the control group after controlling for age and gender. Also, for every 1-year increase in time, the BMI of those on medium-dose ICS increased by 0.06 kg/m2 compared with those in the control group after controlling for age and gender. The subjects on ICS also had a statistically increased risk of being prescribed antihypertensive, antidiabetic, and cholesterol-lowering medications. Conclusion: ICS use in the subjects with asthma was associated with a dose-dependent risk of increasing BMI trajectories over time and an increased requirement for antidiabetic and cholesterol-lowering medications. One possible conclusion from this study is that long-term medium- and high-dose ICS have the potential to induce systemic effects.

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Chlamydia pneumoniae causes respiratory infection in adults and children. Previous studies in our laboratory identified significantly higher in vitro T lymphocyte responses to C. pneumoniae in children with asthma compared to healthy controls which may indicate the presence of T effector memory (TEM) lymphocytes. In the present study, we screened healthy subjects for the presence of TEM cells and their cytokines. CCR7 negative effector TEMs may indicate persistent infection with C. pneumoniae. METHODS: Peripheral blood mononuclear cells (PBMC) (1310 6 /mL) from adult non-asthmatic subjects (N55) were infected or mock-infected for 1h +/-C. pneumoniae TW-183 at a multiplicity of infection (MOI) 5 0.1 or 0.01 and cultured for 48 hrs. Distributions of lymphocytes (CD4+, CD8+) and TEM cells (CD4+CCR7+CD45RA+CD154+, CD8+CCR7+CD45RA+CD154+) were determined. Levels of intracellular Interleukin (IL)-2, IL-4, and Interferon (IFN)-gamma were measured (flow microfluorimetry). RESULTS: C. pneumoniae infection (48 hr) led to a decrease in numbers of CD8+ TEM and CD8+CD154+ cells (50%, 33%, respectively); numbers of CD4+TEM and CD4+CD154+ cells did not change. In addition, numbers of TEM cells (CD4+IL-2+, CD8+ IL-2+) decreased (;27%, 50%, respectively). However, number of TEM cells (CD4+IL4-+, CD8+ IL-4+) and (CD4+ IFN-gamma+, CD8+IFN-gamma+) did not change significantly (P<0.05). CONCLUSIONS: C. pneumoniae infection decreased CD4+ and CD8+ IL-2+ TEM cells in this study population. These findings may provide more understanding of the mechanisms of persistent C. pneumoniae infection.

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