Purpose: To investigate the expression of Plasmacytoid Dendritic Cells (pDCs) and TLR7/9-MyD88-IRAKs pathway in chronic eczema lesions.
Patients and Methods: Lesional tissues and the surrounding healthy tissues were collected from 25 individuals with chronic eczema, and immunohistochemistry was used to detect and comparatively analyze the expression profile of CD123, CD2AP, toll-like receptor 7 (TLR7), toll-like receptor 9 (TLR9) along with interleukin-1 receptor-associated kinase 1 (IRAK1) and interferon regulatory factor 7 (IRF7) in signaling pathways.
Results: The positive rates of CD2AP + pDC and CD123 + pDC in lesional tissues were significantly elevated compared to the surrounding healthy tissues (P < 0.05). They were distributed in both the epidermal and dermal layers of the lesional tissue, but the majority were in the dermal layer. The TLR7, TLR9, IRAK1 and IRF7 were more expressed in dermal layers of the lesional tissue with higher positive rates of expression compared to the surrounding healthy tissues (P < 0.05). IRAK1 and IRF7 were expressed in a small amount in the epidermal layer with higher positive rates of expression than in the surrounding healthy tissues (P < 0.05), while the positive rates of TLR7 and TLR9 expression in the epidermal layer were not statistically different from those in the surrounding healthy tissues (P > 0.05).
Conclusion: PDC and TLR7/9-MyD88-IRAKs pathways are actively expressed in chronic eczema lesions and may be involved in pathogenesis and disease progression.
Keywords: eczema, plasmacytoid dendritic cells, toll-like receptor 7, toll-like receptor 9, immunohistochemistry