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 ord er to minimize unnecessary antibiotics. Objectives: To evaluate an ELI SA to detect specific RSV-IgM and RSV-IEA in NPA as a supplement to RS V-antigen detection. Study design: A total of 104 NPA from 101 childre n (median age 9 months) with acute respiratory disease (group 1) admit ted 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 infectio n (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-IgM. When 'true' RSV infecti on was defined by the detection of RSV-antigen and/or RSV-IgM the RSV- antigen test alone found 44% and the RSV-IgM test alone found 80%. In group 2 8/11 (73%) had an excellent RSV-IgM response day 7, the rest r esponded 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 al l. 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 R SV-antigen detection for the diagnosis of acute and recent RSV infecti on. (C) 1997 Elsevier Science B.V.