TLR9 and cytomegalovirus infection: On the other hand, the minor C allele of TLR9 (rs352139) was also associated with an increased incidence of CMV infection, either in the heterozygous (TC) or homozygous state (CC) (56.8% and 66.7%, respectively) compared with homozygous patients (TT) for the reference allele (40.7%) (P-value = 0.017).