Specific IgA antibody response in Ross River virus infection.

Sera were collected over a period of several years from the onset of initial symptoms from 77 patients with Ross River virus infection. When tested for virus-specific IgA antibodies, using an enzyme-linked immunosorbent assay (ELISA) based on antibody class capture, 245 out of 704 sera were antibody-positive. Although Ross River virus IgA antibodies were present in the serum of all patients soon after onset of symptoms, the IgA response was relatively short-lived in comparison with specific IgM antibodies. The results suggested that the detection of high levels of Ross River virus IgA antibodies was of potential value in differentiating between recent and past infection, especially in those patients with persisting IgM antibodies.