Immunopathology features of chronic rhinosinusitis in high-altitude dwelling Tibetans

Chronic rhinosinusitis (CRS) presents distinct inflammatory and remodeling patterns in different populations and environments. Tibetan ethnic groups live at high altitudes and in cold weather conditions. We sought to examine whether Tibetans exhibit distinct CRS pathology or characteristics. Sinonasal polyps and mucosal tissue were obtained from 14 Tibetan patients with CRS and nasal polyps (CRSwNPs), 13 patients with CRS without nasal polyps (CRSsNPs), and 12 Tibetan controls. Tissue homogenates and serum samples were assayed for several T-helper (TH) cell cytokines and mediators using enzyme linked immunosorbent assay profiles were measured using quantity polymerase chain reaction. Several key inflammatory cells were examined for immunohistochemical markers. CRSwNPs were characterized by increased mediator promoting eosinophilic inflammation (interleukin [IL]-5, eosinophil cationic protein, and total immunoglobulin E) and slight synergism with expression of IL-8, IL-2sRa, IL-1beta, IL-6, and myeloperoxidase, and a predominance of eosinophils, mast cells, and neutrophils. GATA-3 transcription factor was significantly increased and Foxp3 showed a tendency to be impaired in CRSwNPs compared with controls. CRSsNPs were characterized by significantly high levels of transforming growth factor beta1, increased interferon γ, and a significant enhancement of Foxp3 and T-beta compared with CRSwNPs. There were reduced numbers of inflammatory cells but increased levels of macrophages in CRSsNPs. Compared with CRSsNPs, CRSwNPs present a severe inflammatory reaction and show a TH2 milieu with apparently impaired regulatory T cells (Treg) function and increased inflammatory cells infiltration predominated by eosinophilic and mast cells. In contrast, TH1 polarization with enhanced Treg function and increased levels of macrophages appear in CRSsNPs.