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[Serologic response measured by complement fixation in children with acute respiratory infection]
B Ebekian1, G Carballal, C Cerqueiro
1Departamento de Microbiología, FAcultad de Medicina, Universidad de Buenos Aires, Argentina.
Revista Argentina De Microbiologia
|April 1, 1990
Summary
Complement fixation testing shows low sensitivity for diagnosing acute respiratory infections (ARI) in young children, especially those under six months. Direct diagnostic methods are more effective, though complement fixation aids epidemiological studies in older children.
Area of Science:
- Virology
- Immunology
- Pediatrics
Background:
- Acute respiratory infections (ARI) are a significant cause of morbidity in young children.
- Accurate and sensitive diagnostic methods are crucial for effective management and epidemiological surveillance of viral ARI.
- Complement fixation (CF) is a serological method for detecting viral antibodies, but its sensitivity in pediatric ARI requires evaluation.
Purpose of the Study:
- To evaluate the diagnostic sensitivity of the complement fixation (CF) test for lower acute respiratory infections (ARI) in young children.
- To compare the efficacy of CF testing with direct diagnostic methods like indirect immunofluorescence (IIF) and tissue culture isolation.
- To assess the utility of CF serology for epidemiological studies of viral respiratory infections in different age groups.
Main Methods:
- Sera from 264 children under five with ARI were tested using complement fixation for six respiratory viruses: RSV, adenovirus, influenza A and B, and parainfluenza 1 and 3.
- Direct methods, including indirect immunofluorescence (IIF) on nasopharyngeal aspirate and tissue culture isolation, were used for comparison.
- Serum samples were analyzed for seroconversion, indicating a recent infection.
Main Results:
- Complement fixation testing detected seroconversion in 38% of confirmed viral ARI cases, significantly lower than direct methods (38.5% sensitivity).
- Sensitivity was particularly low in children under six months (20% overall, 25% for RSV), increasing to over 60% for RSV in children older than six months.
- Adenovirus showed 50% seroconversion, while RSV showed 39% seroconversion in confirmed viral ARI patients.
Conclusions:
- Complement fixation testing demonstrates low sensitivity for diagnosing viral ARI in young children, especially infants under six months.
- Direct diagnostic methods (IIF and culture) are more effective for rapid and sensitive diagnosis of viral ARI in this age group.
- Despite its limitations, complement fixation serology remains valuable for epidemiological surveillance of respiratory viruses, particularly RSV, in children over six months of age.