*3.1.9 IL-C2*

Innate lymphoid cells are a group of lymphoid cells with a recently recognized role as regulators of innate immunity, inflammation, and tissue repair at the barrier surfaces. They are a lymphoid subclass characterized by the lack of either B- or T-cell receptors but retain cytotoxic or immunomodulatory capacity [22–24].

The innate defense system contains cells that look just like B or T lymphocytes under the microscope, yet express neither B- nor T-cell receptors. These cells are known as innate lymphoid cells.

Innate lymphoid cells are classified into three groups based on their transcription factors and cytokine production patterns, which mirror helper T-cell subsets. Unlike T cells and B cells, ILCs do not have antigen receptors. They respond to innate factors released by the bronchial epithelium, such as cytokines and alarmins, including IL-33, IL-25, and thymic stromal lymphopoietin [22–24]. ILCs produce multiple pro-inflammatory and immune regulatory cytokines for the induction and regulation of inflammation.
