Background: CMV is the most common cause of congenital infection, non-genetic sensorineural hearing loss, and important cause of neurodevelopmental delay. The diagnostic method for cCMV infection is viral identification in urine and/or saliva within the first 2-3 weeks of life (culture/PCR). Identification of cCMV by detection of CMV IgM in serum has low sensitivity.
Objective Assess sensitivity, clinical characterization and prognostic factor of positive IgM at birth in a large cohort of infants with cCMV.
Methods Data of infants with cCMV in our pediatric clinic, born between 01/2005 and 07/2015 with serology test for CMV during the first two weeks of life was collected.
Outcome after birth, symptomatic CNS involvement vs. asymptomatic (no CNS involvement) was compared between infants with positive or negative results of IgM.
Results IgM test was obtained in 199 children with cCMV; 178 after maternal primary infection, 13 non-primary and 8 unknown. The sensitivity of positive IgM in the diagnosis of cCMV was 40.7%. Among these 199 infants, rate of symptomatic disease in positive IgM neonates was higher than negative IgM (67.7% vs. 35.8%, p<0.001). Among 172 infants born after maternal primary infection (known trimester of infection), those with positive IgM had symptomatic disease in 40.8% of cases compared with only 15% of infants with negative result (p=0.005). Odds ratio for symptomatic disease in infants born after maternal primary infection with positive IgM compared to borderline or negative was 3.47 (95% CI: 1.7 to 7.1). Nevertheless, positive IgM was found in only 48.8% of symptomatic and also in 22.1% of asymptomatic children.
Conclusions Our results show the low sensitivity of IgM in diagnosis of cCMV. However, while positive CMV IgM antibody is associated with more symptomatic disease in maternal primary infection, it cannot serve as a strict laboratory marker for symptomatic disease.
