Secretory IgM and IgA antibodies to respiratory syncytial virus in nasopharyngeal aspirates: a diagnostic supplement to antigen detection.
BACKGROUND
RSV-shedding during an RSV-infection declines dramatically after the first week of infection. It could be of interest to be able to diagnose RSV-infection for a longer period of time by detection of specific RSV-IgM and RSV-IgA in nasopharyngeal aspirates (NPA) in order to minimize unnecessary antibiotics.


OBJECTIVE
To evaluate an ELISA to detect specific RSV-IgM and RSV-IgA in NPA as a supplement to RSV-antigen detection.


METHODS
A total of 104 NPA from 101 children (median age 9 months) with acute respiratory disease (group 1) admitted to hospital and consecutive NPA (collected on day 0, 7, 14, 30 and 60) from 11 children (median age 3 months) with a proven RSV infection (group 2) were collected. All NPA from group 1 were analysed for RSV-antigen, RSV-IgM and RSV-IgA. NPA from group 2 were analysed for RSV-IgM and RSV-IgA.


RESULTS
Thirty-five NPA in group 1 were positive for RSV-antigen and 64 were positive for RSV-antigen test alone found 44% and the RSV-IgM test alone found 80%. In group 2 8/11 (73%) has an excellent RSV-IgM response day 7, the rest responded later. Only 5/11 (46%) had a less pronounced RSV-IgA response on day 7, three cases responded later and three did not respond at all. RSV-IgM disappeared in 8/11 (73%) and RSV-IgA in 7/8 (88%) between day 30-60.


CONCLUSIONS
Specific RSV-IgM is a valuable supplement to RSV-antigen detection for the diagnosis of acute and recent RSV infection.
Jensen
I P
IP
Department of Virology, Statens Serum Institut, Copenhagen, Denmark. ipj@ssi.dk
Thisted
E
E
Glikmann
G
G
Obel
N
N
Kofoed
P E
PE
Sambo
M
M
Valerius
N H
NH
Mordhorst
C H
CH
D000914:Antibodies, Viral / Q000032:analysis* / Q000276:immunology; D000956:Antigens, Viral / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005069:Evaluation Studies as Topic; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000032:analysis / Q000276:immunology; D007075:Immunoglobulin M / Q000032:analysis / Q000276:immunology; D007223:Infant; D007231:Infant, Newborn; D009302:Nasopharyngeal Diseases / Q000175:diagnosis* / Q000821:virology; D018357:Respiratory Syncytial Virus Infections / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D018113:Respiratory Syncytial Virus, Human / Q000276:immunology*
D000914:Antibodies, Viral; D000956:Antigens, Viral; D007071:Immunoglobulin A, Secretory; D007075:Immunoglobulin M; C033027:secretory IgM