Lower respiratory tract infection caused by respiratory syncytial virus in infants: the role played by specific antibodies.
BACKGROUND
Respiratory syncytial virus (RSV) is a major etiological agent of lower respiratory tract infection in infants. Genotypes of this virus and the role of the infants' serum antibodies have yet to be fully clarified. This knowledge is important for the development of effective therapeutic and prophylactic measures.


OBJECTIVE
To evaluate the types and genotypes of RSV causing respiratory tract infection in infants, to analyze the association of subtype-specific serum antibodies with the occurrence of infection and to evaluate the presence of subtype-specific antibodies in the infants' mothers and their association with the profile of the childrens' serum antibodies.


METHODS
This was a prospective study on infants hospitalized with respiratory infection. Nasopharyngeal secretions were collected for viral investigation using indirect immunofluorescence and viral culture and blood was collected to test for antibodies using the Luminex Multiplex system.


RESULTS
192 infants were evaluated, with 60.9% having RSV (73.5%- A and 20.5% B). Six genotypes of the virus were identified: A5, A2, B3, B5, A7 and B4. The seroprevalence of the subtype-specific serum antibodies was high. The presence and levels of subtype-specific antibodies were similar, irrespective of the presence of infection or the viral type or genotype. The mothers' antibody profiles were similar to their infants'.


CONCLUSIONS
Although the prevalence of subtype-specific antibodies was elevated, these antibodies did not provide protection independently of virus type/genotype. The similarity in the profiles of subtype-specific antibodies presented by the mothers and their children was consistent with transplacental passage.
Vieira
Sandra E
SE
Department of Pediatrics, Faculdade de Medicina, Universidade de São Paulo, SP, Brazil. sandra@hu.usp.br
Gilio
Alfredo E
AE
Durigon
Edison L
EL
Ejzenberg
Bernardo
B
D000914:Antibodies, Viral / Q000097:blood* / Q000276:immunology; D000918:Antibody Specificity / Q000235:genetics / Q000276:immunology*; D001938:Brazil / Q000453:epidemiology; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology / Q000276:immunology*; D012136:Respiratory Syncytial Viruses / Q000235:genetics / Q000276:immunology*; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000517:prevention & control / Q000821:virology*
D000914:Antibodies, Viral