Clinical Value of Toll Like Receptor 4 and CD14 in Children with Acute Lower Respiratory Tract Infection

Toll like receptors (TLRs) with a myeloid differentiation antigen (CD14) recognize and bind various structures from invading microbes and then trigger cell activation. They initiate a variety of effectors' functions, including cytokine secretion, proliferation, co-stimulation or phagocyte maturation. The aim of this study was to evaluate Toll-like receptor 4 (TLR4) and CD14 expression in children with acute lower respiratory tract infections and their relation to severity. The study  was carried on 50 children under 3 years of age; 25 of them with lower respiratory tract infection (LRTI) with mean age 11.9± 6.7 months, the other 25 children were healthy controls, age and sex matched. TLR4 and CD14 expression were assessed in both case and control groups. There was no statistical significant difference between cases and  controls regarding the  mean TLR4 level. mCD14 level among cases was significantly higher than that of the control group with more increase in bacterial LRTI. There was a  positive correlation between CD14 with TLC and ESR in bacterial group. There was a  positive correlation between respiratory distress severity  with CD14, TLC, and ESR levels in patients  group. TLR4 was not involved in the development of lower respiratory tract infection in  the studied cases. mCD14 might be involved in the development of LRTI, and changes in mCD14 expression are parallel with the levels of TLC and acute phase reactants including CRP, ESR and with  respiratory distress severity.