The data presented here show that genomic variation in the human MICA microsatellite in exon 5 and in TLR4 Asp299Gly are associated with the conjunctival inflammatory response due to the infection with the human pathogen Ct. pathogenic environment is a major determinant of the evolutionary pathway that leads to the change in the genetic makeup of the innate immune system genes. The gene discussed is TLR4; the disease is infection.