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MxA protein in infants and children with respiratory tract infection
J Forster1, M Schweizer, R F Schumacher
1University Children's Hospital, Freiburg, Germany.
Abstract:
MxA protein--a stable product of cells stimulated by type I interferons--was examined prospectively for its ability to discriminate between viral and bacterial respiratory tract infections (RTIs) in 182 infants and children. The nasopharyngeal secretions (NPSs) of all of them were tested for MxA using enzyme-linked immunosorbent assay (ELISA), and the whole blood of 92. Seventy-three children undergoing elective surgery served as controls. These apparently healthy children had higher levels of serum MxA than adult controls. Using antigen detection and serology, a viral aetiology was diagnosed in 81/182 cases. The sensitivity and specificity of MxA ELISA were assessed at 92 and 76% for the blood test and at 40 and 91% for the NPS, respectively. The positive predictive value for a viral RTI was superior to a leucocyte count or C-reactive protein when determined only once.
Insights
MxA protein shows promise in distinguishing viral from bacterial respiratory infections in children. Blood MxA levels offer better sensitivity and specificity than nasopharyngeal MxA for diagnosing viral respiratory tract infections.
Area of Science:
- Immunology
- Virology
- Pediatrics
Background:
- Distinguishing viral from bacterial respiratory tract infections (RTIs) in children is clinically important.
- MxA protein, induced by type I interferons, is a potential biomarker for viral infections.
Purpose of the Study:
- To evaluate the MxA protein's efficacy in differentiating viral from bacterial RTIs in pediatric patients.
- To assess the diagnostic performance of MxA protein in nasopharyngeal secretions (NPSs) and whole blood.
Main Methods:
- Prospective study of 182 infants and children with RTIs.
- MxA protein levels measured in NPSs and whole blood using enzyme-linked immunosorbent assay (ELISA).
- Comparison with viral etiology diagnosis, leucocyte count, and C-reactive protein.
Main Results:
- Viral etiology confirmed in 81/182 cases.
- MxA ELISA in blood showed 92% sensitivity and 76% specificity for viral RTIs.
- MxA ELISA in NPS demonstrated 40% sensitivity and 91% specificity.
- Positive predictive value of MxA was superior to leucocyte count or C-reactive protein.
Conclusions:
- MxA protein, particularly in whole blood, is a valuable biomarker for diagnosing viral RTIs in children.
- Blood MxA ELISA offers a sensitive and specific method for differentiating viral from bacterial respiratory infections.