TLR2 and allergic disease: Previous studies have revealed four genetic polymorphisms in human TLR2, TLR4, and CD14 [12, 13, 16, 17], such as TLR2 rs1898830, TLR2 rs4696480, TLR4 rs4986790 and CD14 rs2569190, which play a role in the pathogenic mechanism of allergic diseases and the protection mechanism of maternal exposure to farming.