IFNG and cytomegalovirus infection: A large Swedish study of infants up to 2 years of age with congenital CMV infection found that they had CMV-specific CD4+ T cell responses (measured by IFN-γ) that were inferior compared to adults during the first 3 months of age, though this difference was not significant by the age of 24 months (Lidehall et al., 2013).