Elevated cutaneous expression of stem cell factor in chronic spontaneous urticaria: a prospective cohort study

Abstract

Background Tissue expression of endothelial cell (EC) markers of microcirculatory changes in CSU is poorly investigated. Objective to explore the expression of specific EC markers (stem cell factor (SCF), vascular endothelial growth factor (VEGF) and membrane attack complex (MAC)) in CSU-L and CSU-NL skin through immunohistochemistry (IHC) and in serum. Methods Lesional (L) and non-lesional (NL) skin biopsies from CSU patients and HCs were studied for the IHC expression of SCF, VEGF and MAC in CSU patients (n = 23) and healthy controls (HCs, n = 9). In this population, we also investigated blood levels of VEGF and SCF. Patients were also assessed for clinical characteristics, disease activity, and markers of autoimmune CSU (aiCSU). Results Epidermal SCF reactivity was significantly higher in CSU-L skin compared to HC skin (p=0.026). In the dermis, SCF immunoreactivity was seen particularly on endothelial, perivascular and epithelial cells. In CSU-L skin, mean perivascular SCF stainings were significantly more intense compared to HCs (p<0.001). Furthermore, CSU-NL skin also showed significantly higher SCF stainings on dermal perivascular cells compared to HCs (p<0.001). CSU patients had the highest SCF immunoreactivity scores in the epidermis and/or on dermal ECs. These patients did not have significantly higher SCF serum levels. Conclusion This is the first study to show elevated cutaneous expression of SCF in chronic spontaneous urticaria. These findings underline the potential therapeutic possibilities of anti-KIT antibodies in CSU treatment.