Gene expression profiles of nasal epithelium in long COVID and post-COVID

Recent studies suggest that chronic inflammation and immune dysregulation in the local tissues and systemically play a critical role in the pathophysiology of long COVID. Here, we report a role for nasal epithelium in mediating inflammation in a subset of long COVID patients. We demonstrate impaired barrier function of nasal epithelial cells, inadequate wound healing potential, and nasal cell hypersensitivity along with a persistent inflammatory state in long COVID. These inflamed structural cells activate type 1 innate lymphoid cells in the blood of long COVID patients and propagate systemic inflammation. We demonstrated the importance of understanding the immunological mechanisms driving long COVID to develop effective treatments. We highlight the critical role of the nasal epithelial barrier and the interplay between epithelial cells and ILCs in maintaining mucosal homeostasis and contributing to chronic inflammation in long COVID.