Immunoglobulin class-specific serological responses to adenovirus in respiratory infections of young adult men.

Complement fixation and enzyme immunoassay (EIA) were used for measuring viral antibodies in 103 military conscripts with pneumonia and 98 conscripts with other respiratory infections. Diagnostic rises in antibody to adenovirus were found in 23 (22%) patients with pneumonia and in 42 (43%) patients with other respiratory infections. EIA detected more diagnostic rises than did complement fixation (22 versus 17 for pneumonia and 42 versus 40 in other infections). Adenovirus antibodies were analyzed for different immunoglobulin classes by EIA. Diagnostic rises in immunoglobulin G (IgG) and IgA isotypes were observed in 89 and 77% of the cases, respectively. IgM antibodies were positive in 39% of the cases. In five cases (8%), the demonstration of adenovirus antibodies of the IgM class was the only serological evidence for adenovirus infection. The present study demonstrates that the immunoglobulin class-specific EIA is a sensitive method for the diagnosis of respiratory adenovirus infections.