Background: Bullous pemphigoid (BP) and atopic dermatitis (AD) are both type 2 inflammatory skin diseases with similar clinical features. Thymic stromal lymphopoietin (TSLP) is an epithelial-derived cytokine which is upregulated in AD. However, the expression of TSLP in BP and the correlation between TSLP and inflammatory infiltrations have not been fully studied.
Objective: To characterize the serum Th2 cytokines level and Th2 inflammatory cell infiltrations in BP and AD. To study TSLP levels in serum, blister fluids and expression in lesional skin in patients with BP and AD.
Methods: TSLP level in serum and blister fluids was measured by enzyme-linked immunosorbent assay (ELISA). Inflammatory cells (CD4+ T cells, CD8+ T cells, CD1a+ cells, eosinophils and mast cells) were stained immunohistochemically and quantified by image analysis.
Results: TSLP level was significantly increased in blister fluids of BP and was highly expressed in lesional skin of BP and AD. Serum levels of IL-6, IL-4, IL-22, IFN-γ and thymic activation regulates chemokines (TARC) were significantly higher in patients with BP and AD than in healthy controls. CD4+ T cells, CD8+ T cells and CD1a+ cells were significantly more in upper dermis of BP and AD lesions. Eosinophils were found more in BP lesions while mast cells were found more in AD lesions than in healthy controls. A distinct correlation was found between TSLP levels and the intensities of CD4+ T cells, CD1a+ cells infiltrations.
Conclusion: TSLP was significantly higher in blister fluids and skin lesions of BP, suggesting that it might contribute to the pathogenesis of BP. BP exhibited a similar type 2 immune response and a slight difference in cells infiltrations with AD.
Keywords: type 2 immunity, thymic stromal lymphopoietin, bullous pemphigoid, atopic dermatitis, Th2 cytokines, inflammatory infiltrations