Expression of toll-like receptor 2 on peripheral blood monocytes of patients with inflammatory and noninflammatory acne vulgaris.

The pathogenesis of acne vulgaris is multifactorial and entails the interplay of hormonal, microbial and immunological events. The bacterium Propionibacterium acnes is involved in the induction of comedogenesis and maintenance of the inflammatory phase of acne. Toll-like Receptor 2 (TLR2) expressed on mononuclear inflammatory cells and possibly on keratinocytes and sebocytes is thought to be of vital importance in mediating P. acnes-induced inflammatory response in acne vulgaris. This work aimed to study the degree of expression of TLR2 on peripheral blood monocytes (PBM) from patients with non-inflammatory and inflammatory acne and to investigate the influence of systemic isotretinoin therapy on TLR2 expression. Sixteen patients with predominantly non-inflammatory acne, 16 patients with predominantly inflammatory acne and 16 age and sex matched healthy subjects were involved in this study. Cell surface expression of CD14 and TLR2 were determined by cell surface staining and flowcytometry. TLR2 expression was analyzed for 12 patients with severe and/or scaring inflammatory acne after oral isotretinoin therapy for two months. The mean fluorescence intensity (MFI) of TLR2 on PBM reported a statistically significant difference between patients with non-inflammatory acne, patients with inflammatory acne and control subjects. MFI of TLR was significantly lower for patients with inflammatory acne after systemic isotretinoin therapy. Data obtained suggest that TLR2 expression on PBM is an important event in acne pathogenesis and targeting this molecule might be a useful therapeutic goal in the future.