Introduction : Food allergy (FA) in infants and small children is an important and rising problem. TLR4 is the main receptor recognizing lipopolysaccharide (LPS) and belonging to the Toll-like receptor (TLR) family. Triggering this receptor leads to activation of nuclear factor κB (NF-κB) and interferon regulatory factors (IRFs) and expression of genes included in immunological reactions.

Material and methods : Fifty children (aged 1-36 months) were included in this study: 35 children with food allergy (17 of them with IgE-dependent allergy, 18 with IgE-independent allergy) and 15 healthy children without any allergy. In this work mRNA expression of TLR4 receptor on neutrophils and concentrations of selected Th1/Th2 cytokines were evaluated.

Results : We observed lower mRNA TLR4 expression in children with food allergy especially IgE-independent food allergy. Furthermore, higher concentrations of IL-4, IL-5 and IL-10 in children with food allergy compared with children from the control group were found. Estimated mRNA expression of TLR4 on neutrophil surfaces was negatively correlated with serum concentration of IL-4 and positively correlated with IFN-γ serum levels in children with IgE-dependent FA.

Conclusions: Results of this study suggest a role of innate immunity in the development of food allergy and evaluation of this immunity can be helpful in diagnosis of allergy in small children. Streszczenie