Association analysis of Toll-like receptor 7 genotypes with mRNA expression in peripheral blood mononuclear cells. Association between Toll-like receptor 7 (TLR7) single-nucleotide polymorphisms (SNPs) and TLR7 mRNA levels was examined by using the Kruskal-Wallis test. Relative quantitative levels of TLR7 mRNA were normalized to β-actin (ACTB) mRNA levels. Bars indicate median values in each group. The experiments were performed in triplicate.