The usefulness of IgG avidity for determining primary cytomegalovirus infection in pregnant women

Abstract number: R2336

Karachristou C., Armelidou A., Dinopoulou V., Traki M., Minopoulos I.

Objectives: The diagnosis of infection with human cytomegalovirus remains difficult on symptoms alone as many of them are mild and asymptomatic. Primary CMV infection in early pregnancy bears a high risk of fetal damage. The prenatal diagnosis of CMV has focused on first-trimester screening since the time of maternal CMV infection is an important variable and the rate of transmission from mother to fetus is much higher. If fetal infection occurs earlier in gestation, it appears to present a greater threat to the fetus.

Methods: 8.768 pregnant women in the first trimester of the pregnancy were tested for CMV during the last 18 months May 2008 – Oct 2009 in "Mitera" general, maternity & children hospital. Women were aged between 23 and 44 (mean age 33.5 years). Samples positive for CMV IgG were tested farther for IgM antibodies. Finally samples positive in both CMV IgG and IgM antibodies were farther tested for CMV IgG avidity. All tests were performed by chemiluminescent microparticle immunoassay (CMIA, Abbott Park, US).

Results: Of the 8.768 women tested, 3.558 (40.6%) had never been infected with CMV, 5.082 (58.0%) found to be positive in CMV IgG and negative in IgM. 117 (1.3%) samples found to be positive in both CMV IgG and IgM and 11 (0.1%) were in the CMV IgM grayzone. Of the 117 positive samples, 23 (19.7%) had a low avidity and 93 (79.5%) had a high avidity. One sample (0.8%) was in the grayzone. All samples with CMV IgM in the grayzone had high avidity.

Conclusions: Measurement of CMV IgG avidity may help to improve the serodiagnosis of CMV infected women by determining the time of infection. The presence of high avidity indicates that primary infection occurred well before conception and the fetus is most likely protected against debilitating CMV infection. This information is important in the clinical management of pregnant women found to be positive for CMV antibodies at their first-trimester of gestation when the risk of fetal damage is greater.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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