An enzyme linked immunoassay using recombinant antigens for differentiation of primary from secondary or past CMV infections in pregnancy

Background: As primary cytomegalovirus (CMV) infection in pregnancy may be associated with severe fetal outcome, the serological differentiation of primary infection from recurrent or previous infection is of major importance. Objectives: This differentiation was attempted with a CMV IgG enzyme immunoassay (EIA), which investigated the differential IgG immune response to recombinant proteins p52 and pp150. To express the IgG reactivity to either protein a ratio was calculated by OD p52/OD pp150. Study design: Serial samples from groups of pregnant women with primary infection (n = 18) were compared to those with recurrent (n = 7) or previous CMV infection (n = 189). Results: In primary infected women a predominant IgG response to p52 (p52 alone or ratio greater than or equal to 1.5) was observed in early sera less than 4 weeks after seroconversion, whereas the IgG response to recombinant protein pp150 was delayed and appeared after 2-7 weeks. Women with secondary and those with past infection had either IgG antibodies to pp150 alone or a ratio of less than 1.5 in 85 and 89.1% respectively with no remarkable change of ratio over time. Conclusions: The IgG recombinant EIA was shown to be a useful supplementary assay for differentiation of primary up to 8 weeks after seroconversion from recurrent or past infections. (C) 1998 Elsevier Science B.V. All rights reserved.