The role of innate T cells in inflammatory disorders in asthma and chronic rhinosinusitis.

Chronic rhinosinusitis (CRS) and asthma are often comorbid and represent heterogeneous inflammatory disorders in the upper and lower airways, respectively. Type 2 inflammation driven by eosinophils and CD4 T cells has been recognized as central mediators in CRS with nasal polyp (CRSwNP) and asthma pathogenesis. However, recent evidence has highlighted the critical involvement of innate T cells, such as invariant natural killer T (iNKT), mucosal-associated invariant T (MAIT), and γδ T cells in airway inflammatory disorders. Innate T cells were enriched in sinonasal tissues and contributed to mucosal inflammation through cytokine production, exhibiting functional polarization influenced by local inflammatory cues. In particular, MAIT17 and Vγ1+ γδ T cells have been associated with tissue eosinophilia and disease severity in eosinophilic CRSwNP (E-NP) patients, whereas iNKT cells displayed subset-specific distribution across eosinophilic and neutrophilic endotypes. In asthma, iNKT cells consistently contributed to disease development in murine models, whereas the roles of MAIT and γδ T cells were controversial, demonstrating both pro- and anti-inflammatory roles depending on anatomical location and disease context. This review summarizes current findings on the contribution of innate T cells to the immunopathology of CRSwNP and asthma and discusses the challenges and future directions in resolving discrepancies arising from methodological and biological variability.