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Antipolysaccharide group-specific antibodies of Streptococcus pyogenes in children
Insights
A new microtest for Streptococcus pyogenes group A antipolysaccharide antibodies (MSK) shows superior diagnostic accuracy compared to ASO, especially in young children and specific infection types.
Area of Science:
- Pediatric Infectious Diseases
- Immunology
- Microbiology
Background:
- Streptococcus pyogenes (Group A Strep) infections are common in children.
- Accurate and timely diagnosis is crucial for effective treatment and preventing complications.
- Current diagnostic methods like Anti-Streptolysin O (ASO) have limitations, particularly in young children.
Purpose of the Study:
- To evaluate a new microtest for detecting Streptococcus pyogenes group A antipolysaccharide antibodies (MSK).
- To compare the diagnostic performance of MSK with the traditional ASO test in children aged 0-12 years.
- To establish age-related normal value ranges for the MSK test.
Main Methods:
- A study involving 996 control children and 562 children with streptococcal infections.
- Division of participants into four age groups (0-2, 2-4, 4-8, 8-12 years).
- Evaluation of MSK and ASO antibody levels in various streptococcal infection types and related conditions.
Main Results:
- The MSK test demonstrated higher positivity rates (85-95%) across all age groups compared to ASO, especially in children under 4 years.
- MSK showed clear diagnostic superiority over ASO in acute conditions like adenitis, pyodermic infections, bronchopneumopathies, and acute tonsillitis.
- In rheumatic disease, MSK and ASO showed similar positivity, while MSK was superior in post-streptococcal glomerulonephritis and Schoenlein-Henoch syndrome.
Conclusions:
- The MSK test is a valuable diagnostic tool for Streptococcus pyogenes infections in children, particularly those under 4 years old.
- MSK offers improved sensitivity for infections with low or slow antigenic load, outperforming ASO.
- Routine use of the MSK test is recommended for enhanced diagnosis of streptococcal infections in pediatric populations.
Abstract:
Evaluation of a new microtest for the detection of Streptococcus pyogenes group A antipolysaccharide antibodies in 996 control children and 562 streptococcal infections from 0 to 12 years. The case-list was divided in 4 groups, years 0-2. 2-4. 4-8. 8-12 for the evaluation of the age-related normality range. Under 2 years normal values between 60 and 120 U, from 2 to 12 years normal values under 240 U. In streptococcal infections identical patterns for the pathological values in the 4 age-ranges considered, with positivity percentage from 85% to 95%, thus confirming the same antibody response also in breast-fed children, unlike what occurs for ASO under 2 years, when the response is present only in 25% of the cases and in the 2-4 years age-range in 33.3%. Evident diagnostic superiority of MSK as compared with ASO in adenitis, pyodermic infections, bronchopneumopathies, acute tonsillitis at the onset of symptomatology. In rheumatic disease the percentage of positivity for MSK and ASO is similar, in post-streptococcal glomerulonephritis and in Schoenlein-Henoch syndrome the percentage of positivity for MSK is higher than for ASO. It is suggested the utility of insertion of MSK test in the routine assay for streptococcal infections diagnosis above all in children under 4 years and in infections with low or slow antigenic charge for 0-streptolysin.