Demonstration of IgG EA (early antigen) and IgM MA (membrane antigen) antibodies in CMV infection of healthy infants and in those with liver disease.

The sequence of antibody production to various virus-specific antigens in CMV infection in infancy was studied. In healthy infants, IgG EA antibody was demonstrated in 18% of cord sera, and disappeared within two months after birth in all cases not shedding virus. The nonmaternal EA antibody was produced following virus excretion and decreased rapidly following cessation of virus excretion. Thus, demonstration of EA antibody in infants after 2 months of age was found to indicate acquired CMV infection, even when CMV could not be isolated. IgM MA antibody did not persist as long as EA antibody, disappearing before cessation of virus excretion. Both IgG EA and IgM MA antibodies were more frequently demonstrated in infants with hepatitis than in healthy infants. These findings suggest the possible association of CMV with hepatitis in infants.