Stem cell factor 248 shapes ILC2 transcriptional programs and promotes mucosal inflammation in allergic asthma.

Stem cell factor (SCF), also known as Kit ligand, is a pleiotropic cytokine that signals through the c-Kit receptor to regulate cellular development, survival, and proliferation. Although SCF is classically recognized for its essential role in hematopoiesis and mast cell biology, c-Kit is also expressed by innate lymphoid cell progenitors (ILCp) and subsets of mature innate lymphoid cells (ILCs), suggesting broader immunoregulatory functions. Group 2 innate lymphoid cells (ILC2s) are critical mediators of type 2 airway inflammation and serve as an important source of type 2 cytokines during allergic responses. We previously demonstrated increased expression of the pro-inflammatory SCF248 isoform in the lungs of mice with chronic allergic inflammation, while elevated soluble SCF levels have also been reported in patients with asthma. In the present study, we further observed that SCF248 is upregulated in the bone marrow during allergic inflammation, suggesting that SCF248 may contribute to both local and systemic regulation of allergic immune responses. To define the role of SCF/c-Kit signaling in ILC2 biology, we first performed transcriptional profiling of SCF-deficient ILC2s, which revealed reduced expression of genes associated with cytokine signaling, activation, and effector function, including