[Detection of influenza virus A antigens by radioimmunological methods in patients' nasopharyngeal washings].

9olid-phase radioimmunoassay (SPRIA) was used for the detection of influenza A (H3N2,H1N1) and B viruses in nasopharyngeal washings of patients admitted in January-March, 1983, to the 1st Clinical Hospital of Moscow City with acute respiratory diseases. The solid phase consisted of nitrocellulose filters and plastic plates which were coated with nasopharyngeal washings of the patients. Rabbit or horse antiviral immunoglobulins were used as antibodies. 125I-labeled protein A was the indicator system. In 61 out of 211 patients examined influenza A (H3N2) virus was detected; from 20 of the influenza A (H3N2), from 7 influenza A (H1N1) virus was isolated, but no influenza B virus was ever found. Comparisons of the results of SPRIA and IF techniques yielded similar but not identical data. Diagnostic rises of antibodies were demonstrated in 48 out of 61 patients. The lack of complete correlation between antibody rises and detection of influenza A virus antigen appears to be due to early discharge of the patients when humoral immunity had not reached its peak. The SPRIA is a highly sensitive and specific technique for influenza A virus detection in nasopharyngeal washings of the patients and may be recommended for use in properly equipped laboratories where highly specific hyperimmune sera are available. It gives an objective information on the proportion of influenza in the period of epidemic rise of ARD incidence.