Diagnosis of dengue virus infection with IgA anti Dengue rapid tests

Abstract

Background: Dengue IgM, IgG Capture ELISAs and NS1 Ag ELISA have become the most widely used serological methods for dengue diagnosis until now. Previous studies reported a possible use of IgA antibodies for dengue virus as a new serologic marker to make dengue infection active. In the present study, the performance of IgA anti-dengue rapid test as a new marker of dengue infection was assessed. Methods: In this study, sera were obtained from 70 dengue virus infection patients and 30 non dengue virus infection patients. Seventy dengue paired sera were collected twice, at the time of hospital admission (acute) and discharge (convalescent). All sera samples were characterized using dengue reference ELISAs (NS1 Ag, Dengue IgM and IgG capture ELISAs). All of the dengue and non dengue samples were evaluated by Dengue IgA Rapid Test. Results: The results of IgA anti-dengue rapid test were compared with the coresponding dengue reference tests. The sensitivity and specificity of IgA anti-dengue rapid test respectively were 82.9% (95%CI:72.4-89.9), and 73.3%(95%CI: 55.6%-85.8%). Meanwhile, from acute sera, sensitivity of IgA anti-dengue rapid test was 83.3%(95%CI:64.5-93.7), higher than IgM (73.3%,95%CI:53.8-87.0), IgG (66.7%,95%CI:47.1-82.1) and NS1 Ag ELISAs (60%,95%CI:40.7-76.8). Based on the day of fever, sensitivity of IgA anti-dengue from day 1-2 was 66.7%, day 3-4 was 84.8%, day 5-7 was 76.2% respectively. Positive IgA anti-dengue rapid test results in acute sera was higher in secondary (84.6%) than primary infection (77.7%). Conclusion: IgA anti-dengue rapid test can be considered as a new marker of dengue infection, because it gives a high sensitivity, especially in the acute phase and in the secondary infections as well.