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[Immunofluorescent method of studying autopsy material in acute pneumonia]
Abstract:
The immunofluorescent procedure in examinations of the autopsy material from 304 fatal cases hospitalized for acute pneumonia permitted to diagnose influenza A2 in 29.0%, influenza B in 18.1%, parainfluenza in 3.5%, adenovirus infection in 9.2% and respiratory syncytial virus infection in 3.5% of the cases. In the period of a high incidence of acute respiratory infection, influenza A2 was detected by this method in 40.9% and influenza B in 50% of the cases. Simultaneous examinations of the material in the influenza epidemic period by virological and immunofluorescent methods (63 cases) in 13 cases positive results were obtained with both methods, in 6 cases where influenza viruses were detected the immunofluorescent test was negative, and in 28 cases the positive diagnosis by the immunofluorescent test could not be confirmed virologically. Among the cases examined, 33 were found by the immunofluorescence test to have a mixed respiratory infection, including influenza A2 with other forms of respiratory infection in 18, and influenza B with other respiratory infections in 19 cases. Serological examinations by the complement fixation and hemagglutination inhibition tests on the blood from fatal cases irrespective of the time of examination, as a rule, revealed antibody in low titres which did not confirm the diagnosis.
Insights
Immunofluorescent testing aids in diagnosing respiratory infections like influenza A2 and B in fatal pneumonia cases. This method identified mixed infections but showed discrepancies with virological and serological tests.
Area of Science:
- Virology
- Immunology
- Pathology
Context:
- Autopsy material from 304 fatal pneumonia cases was analyzed.
- Focus on identifying causative agents of acute respiratory infections, particularly influenza.
- Evaluation of diagnostic methods during periods of high respiratory illness incidence.
Purpose:
- To assess the utility of immunofluorescence (IF) in diagnosing viral respiratory infections, including influenza A2 and B, parainfluenza, adenovirus, and respiratory syncytial virus.
- To compare IF results with virological and serological methods (complement fixation, hemagglutination inhibition).
- To identify mixed respiratory infections.
Summary:
- Immunofluorescence detected influenza A2 in 29.0% and influenza B in 18.1% of cases, with higher detection rates (40.9% and 50%, respectively) during peak incidence.
- Simultaneous testing showed discordance between IF and virological methods, with 28 IF-positive cases unconfirmed virologically.
- IF identified 33 mixed infections, but serological tests yielded low antibody titers, failing to confirm diagnoses.
Impact:
- Highlights the potential of immunofluorescence for rapid viral diagnosis in post-mortem samples.
- Reveals limitations and discrepancies when comparing IF with traditional virological and serological techniques.
- Underscores the complexity of diagnosing viral respiratory infections, especially mixed infections, in fatal cases.