Clinical significance of TLR3 and TLR4 in peripheral blood mononuclear cells from children with Henoch-Schönlein purpura nephritis

The aim of the present study was to investigate the expression levels and clinical significance of Toll-like receptor (TLR) 3 and 4 in peripheral blood mononuclear cells (PBMCs) collected from children with Henoch-Schönlein purpura (HSP) nephritis. The randomized controlled trial was conducted between August 2011 and March 2013, and 105 children with a clinical diagnosis of HSP were enrolled in the study. According to the 24-h urinary protein measurements and the presence of renal damage, the 105 cases were divided into groups A, B and C as follows: Group A, children with HSP but without renal damage; group B, children with HSP nephritis but without proteinuria; group C, children with HSP nephritis and proteinuria. A total of 30 healthy children were enrolled in the normal control group (group N). The primary endpoints were the detection of TLR3 and 4 mRNA and protein expression levels in PBMCs by flow cytometry and quantitative polymerase chain reaction. The mRNA and protein expression levels of TLR4 in the PBMCs were significantly higher in groups A, B and C when compared with group N. In addition, the mRNA and protein expression levels of TLR4 in group C were much higher when compared with groups A and B. A positive correlation was identified between TLR4 protein expression and 24-h urinary protein levels in group C. The expression levels of TLR3 did not significantly differ among the groups. Protein and mRNA expression levels of TLR4 in PBMCs significantly increased and exhibited a positive correlation with urinary protein excretion. These results indicate that aberrant activation of TLR4 may be relevant to the development of HSP nephritis.