Serum immunoglobulin A (IgA) as a biomarker for respiratory syncytial virus (RSV) infection in children aged below 2 years
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Published version (early view)
Author(s)
Type
Journal Article
Abstract
Question
Past research suggested respiratory syncytial virus (RSV) specific serum immunoglobulin A (IgA) antibodies as a biomarker of previous RSV infections in young infants accounting for maternal immunity. This study aimed to confirm this association, and to establish a serological threshold for discriminating RSV-naïve infants from those who have experienced RSV.
Material and Methods
This study involves 135 infants from the LoewenKIDS Study with nasal swabs collected at each acute respiratory infection, and serum samples collected at ages 1 and 2. RSV presence in swabs was ascertained by RT-PCR; RSV-specific IgG and IgA antibody levels against five different structural proteins and RSV neutralising antibodies were measured in sera. Robust Mixture Discriminant Analysis was used to determine the cut-off values and account for false negatives.
Results
Of 135 included infants, 131 had available data at year 1 (Y1), and 95 at year 2 (Y2). Pre-F IgA concentrations were higher in infants with PCR-confirmed RSV infections. There was a further increase in IgA, IgG and NT concentrations from Y1 to Y2 consistent with reinfections. Based on RMDA, the cut-off values of pre-F IgA level indicative of past RSV infection were 0.23 AU·mL−1 at Y1 and 0.22 AU·mL−1 at Y2.
Answer to the question
This study shows that in children aged <2 years, a previous RSV infection is accompanied by pre-F IgA antibody levels above 0.22 AU·mL−1, a value close to a previously proposed cut-off (0.19 AU·mL−1) based on seroresponse data only. The confirmed threshold can be of use in studies assessing vaccination strategies.
Past research suggested respiratory syncytial virus (RSV) specific serum immunoglobulin A (IgA) antibodies as a biomarker of previous RSV infections in young infants accounting for maternal immunity. This study aimed to confirm this association, and to establish a serological threshold for discriminating RSV-naïve infants from those who have experienced RSV.
Material and Methods
This study involves 135 infants from the LoewenKIDS Study with nasal swabs collected at each acute respiratory infection, and serum samples collected at ages 1 and 2. RSV presence in swabs was ascertained by RT-PCR; RSV-specific IgG and IgA antibody levels against five different structural proteins and RSV neutralising antibodies were measured in sera. Robust Mixture Discriminant Analysis was used to determine the cut-off values and account for false negatives.
Results
Of 135 included infants, 131 had available data at year 1 (Y1), and 95 at year 2 (Y2). Pre-F IgA concentrations were higher in infants with PCR-confirmed RSV infections. There was a further increase in IgA, IgG and NT concentrations from Y1 to Y2 consistent with reinfections. Based on RMDA, the cut-off values of pre-F IgA level indicative of past RSV infection were 0.23 AU·mL−1 at Y1 and 0.22 AU·mL−1 at Y2.
Answer to the question
This study shows that in children aged <2 years, a previous RSV infection is accompanied by pre-F IgA antibody levels above 0.22 AU·mL−1, a value close to a previously proposed cut-off (0.19 AU·mL−1) based on seroresponse data only. The confirmed threshold can be of use in studies assessing vaccination strategies.
Date Issued
2025-02-27
Date Acceptance
2025-02-08
Citation
ERJ Open Research, 2025
ISSN
2312-0541
Publisher
European Respiratory Society
Journal / Book Title
ERJ Open Research
Copyright Statement
Copyright ©The authors 2025. This version is distributed under the terms of the Creative Commons Attribution Non-Commercial Licence 4.0. For commercial reproduction rights and permissions contact permissions@ersnet.org
License URL
Identifier
10.1183/23120541.01288-2024)
Publication Status
Published online
Date Publish Online
2025-02-27