Akram Davoodi - Student Research Committee, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
Ramin Lotfi - Lung Diseases and Allergy Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran.
Seyed Hamidreza Mortazavi - Department of Pediatrics, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
Ali Gorgin Karaji - Department of Immunology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
Alireza Rezaiemanesh - Department of Immunology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
Farhad Salari - Department of Immunology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.

Background: Retinoic acid (RA) plays a key role in naïve T cell differentiation into FOXP3+ Treg cell in the respiratory airways. The present study aims to investigate RA and Treg-related cytokine serum levels, salivary IgA levels, FOXP3 and IL-4 gene expression, and the relationships between RA serum levels and Treg-related cytokines in allergic rhinitis (AR) patients and healthy controls. Methods: Salivary IgA and serum IgE, RA, IL-10, and TGF-β concentrations were measured by ELISA in 37 AR patients and 30 age- and sex-matched healthy controls. Results: IL-10 and TGF-β concentrations were significantly less in AR patients than in healthy controls (p< 0.01 and P< 0.0001, respectively). Salivary IgA was significantly greater in patients than in controls (p< 0.05). RA was not significantly different between patients and controls (p> 0.05); however, a significant positive correlation was found between serum RA and both IL-10 and TGF-β in AR patients. Conclusions: Our data suggest that RA may influence AR risk via affecting the TGF-β and IL-10 production.

Allergic Rhinitis, Interleukin-10, Obesity, Retinoic Acid, Transforming Growth Factor-β.