Serum Toll-Like Receptor 2 Concentration in Pediatric Atopic Dermatitis: A Case-Control Study

Background and Aims: Atopic dermatitis (AD) is a chronic, relapsing inflammatory skin disease. There is increased evidence that Toll-like receptors 2 (TLR2), which are a part of innate immunity, play a role in the pathophysiological changes in AD. The study aims to estimate the serum TLR2 concentration among children with AD compared to healthy controls, and to explore the relationship between serum TLR2 concentration and AD severity and total Immunoglobin E (IgE) level. Patients and Methods: This case-control study enrolled 156 participants, with 76 atopic dermatitis (AD) cases and 80 controls. It was conducted at the outpatient clinics of Al-Fayhaa Teaching Hospital between December 2020 and March 2021. The study involved interviewing the parents of the participants, detailed clinical examination with assessment of disease severity, and laboratory tests including total IgE and serum TLR2 concentration. Results: Serum TLR-2 concentrations were lower in AD cases (median= 761.9 pg/ml) than in controls (median=1528.5 pg/ml; P=0.00002). Significantly higher TLR2 levels were seen in patients with elevated IgE (P=0.013) and severe form of AD (P=0.005). Conclusions: Although lower TLR2 concentrations could indicate their role in AD pathogenesis, higher TLR-2 levels were seen in more severe cases or patients with elevated IgE. This suggests a complex mechanism of TLR2 in the immune dysregulation that occurs in AD. This might refer to the involvement of TLR2 in both the onset and exacerbation of AD, particularly in severe forms.