TLR4 and chlamydia trachomatis infectious disease: Interestingly, recent studies in humans have revealed that genetic Variants in the TLR1 and TLR4 genes may increase inflammation and are associated with risk of chlamydial infection and development of pelvic inflammatory disease [29], raising questions over whether genetic variation at these loci may serve as a biomarker of chlamydial infection and disease in other species as well.