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Background: Mechanisms underlying the association between asthma and obesity remain poorly understood. Obesity appears to be a risk factor for asthma, and obese asthmatics fare poorly compared to lean asthmatics. Objectives: To explore the possibility that reduced regulatory T cell (Treg) number and function contribute to the obesity-asthma association. We concentrated on obese females with childhood-onset asthma, since Treg may be involved in this phenotype. Methods: We recruited 64 women (ages 18–50) into four groups: lean (BMI 18–25 kg/m2) controls (n = 17) and asthmatics (n = 13), and obese (BMI ≥ 35 kg/m2) controls (n = 17) and asthmatics (n = 17). Asthmatics had atopy and childhood-diagnosed asthma. We assessed lung function, asthma control and quality of life. Peripheral blood CD4+/CD25+/FoxP3+ Treg cells were identified and counted by flow cytometry and expressed as % total CD4+ T cells. We assessed Treg cell function by the ability of CD4+/CD25+ Treg cells to suppress autologous CD4+/CD25- responder T cell (Tresp) proliferation and measured as % suppression of Tresp cell proliferation. Results: Obese asthmatics had worse lung function, asthma control, and quality of life compared to lean asthmatics. Compared to lean or obese control groups, the number of Treg cells in the obese asthmatics was approximately 1.58- or 1.73-fold higher. The ability of Treg cells from obese-asthmatics to suppress Tresp cell proliferation was reduced. Conclusions: Obese, atopic women with childhood diagnosed asthma demonstrate increased Treg cell number and mildly decreased Treg cell function. Our data do not support the view that reduced Treg cell number contributes to this obese-asthma phenotype. [ABSTRACT FROM AUTHOR]

Background. Obesity is a risk factor for asthma. Studies in mice suggest that the adipokines leptin and adiponectin affect asthmatic responses. The purpose of this study was to determine if adipokines associated with obesity are (1) altered in obese women with asthma compared to controls and (2) associated with increased cytokines and chemokines involved in allergic inflammation. Methods. We performed a cross-sectional study of asthmatic and non-asthmatic obese premenopausal women. Participants answered questionnaires and performed lung function tests. Serum and peripheral blood mononuclear cells (PBMCs) were collected for analysis of cytokines and adipokines. Results. A total of 22 asthmatic (mean body mass index 40.0 ± 5.1 kg/m2) and 20 non-asthmatic women (mean body mass index 41.3 ± 5.6 kg/m2) participated. We found no difference in serum adipokine concentrations between asthmatics and non-asthmatics. Serum adiponectin correlated positively with PBMC eotaxin (rs = 0.55, p = .0003) and RANTES (regulated upon activation, normal T-cell expressed, and secreted) (rs = 0.36, p = .03), whereas serum leptin correlated negatively with PBMC eotaxin (rs = -0.34, p = .04). There was a negative correlation between serum adiponectin and PBMC interferon-γ (rs = -0.41, p = .01). Conclusions. Perturbations of adipokines that occur in obesity were correlated with decreased cytokine production typically associated with allergic responses in PBMC of obese premenopausal women. This study suggests that although obese asthmatics may have elements of Th2-mediated inflammation, adipokine derangements in obesity are associated with Th1 rather than Th2 bias. Obesity has complex effects on allergic inflammation and is likely to be important modifier of the pathogenesis of airway disease in asthma. [ABSTRACT FROM AUTHOR]