CD4 and allergic rhinitis: Objectives: Given the emerging role of peroxisome proliferator-activated receptor gamma (PPARgamma) in immune regulation and the increasing prevalence of allergic rhinitis (AR), we sought to understand how modulation of the PPARgamma pathway impacts the balance of CD4+ T-cell subsets, particularly regulatory T cells (Tregs) and T helper (TH)1, TH2, and TH17 cells, which are key players in the pathogenesis of AR.