Baseline antibody level may help predict the risk of active human cytomegalovirus infection in a HCMV seropositive population.

Recurrent human cytomegalovirus (HCMV) infection during pregnancy could lead to congenital HCMV infection and permanent sequelae. However, knowledge regarding the risk factors associated with recurrent HCMV infection is limited. In the present study, 1,659 paired serum samples from the natural population were collected in Guangxi Province, China, from 2003 to 2004 with a 1-year interval. The serum anti-pp150 titre was quantitatively determined using a homemade recombinant pp150-based ELISA, and the IgG titre that increased at least 4-fold was defined as a recurrent infection. The HCMV seroprevalence was above 98.6% (1,636/1,659) in Guangxi in 2003, and the infection rate during the 1-year follow-up was approximately 10% (171/1,659). The seronegative population has the highest infection risk, while the risk of recurrent infection in the seropositive population was negatively correlated with the baseline anti-pp150 titre. With a cutoff of 1:80 (the baseline anti-pp150 IgG titre), the sensitivity and specificity were 73.1% (125/171) and 85.7% (1,275/1,488) respectively, and the relative risk of infection in the high-risk group compared to the low-risk group was 10.6 (95% CI: 7.7-14.6). In conclusion, the baseline anti-pp150 IgG was negatively correlated with the risk of HCMV infection and could be an excellent predictor of HCMV infection in HCMV seropositive populations.