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Group A streptococcal infections and tic disorders in an Italian pediatric population
1Department of Developmental Neuropsychiatry, University "La Sapienza" and Istituto Superiore di Sanità, Rome, Italy.
Insights
Children with tic disorders show higher antistreptolysin O (ASO) titers, suggesting a link between group A streptococcal (GAS) infections and tics. Higher ASO levels correlate with tic severity.
Area of Science:
- Neuroscience
- Immunology
- Pediatrics
Background:
- Childhood tic disorders are common neurodevelopmental conditions.
- A potential link between group A streptococcal (GAS) infections and tic disorders has been suggested.
- Previous research lacked systematic evaluation of laboratory indicators for GAS in children with tics.
Purpose of the Study:
- To investigate clinical and laboratory evidence of GAS infections in children with tic disorders.
- To compare GAS infection indicators between children with and without tic disorders.
Main Methods:
- A case-control study involving 150 children with tics and 150 controls without tics.
- Assessment included clinical signs and laboratory indicators of streptococcal infections.
- Laboratory tests included antistreptolysin O (ASO) titers and throat cultures for GAS.
Main Results:
- Children with tics had significantly higher mean ASO titers (434 IU) compared to controls (155 IU).
- 38% of children with tics had ASO titers >=500 IU, versus 2% in controls (P <.001).
- A positive correlation was found between ASO titers and the severity of tic disorder.
Conclusions:
- Children with tic disorders may represent a unique population where GAS infection exposure correlates with the neurobehavioral disorder.
- The magnitude of the serologic response to GAS antigens is related to the severity of tic disorder.
Background:
The relationship between childhood tic disorders and group A streptococcal (GAS) infections has been recently investigated by several research groups, but no systematic evaluation of laboratory indicators of GAS infections has been provided.
Objective:
The aim of our study was to seek clinical and laboratory evidence of GAS infections in a large population of children affected with tic disorders.
Study Design:
This investigation was a case-control study: 150 consecutive children presenting with tics were investigated for clinical and laboratory signs of streptococcal infections on the occasion of their first neuropsychiatric consultation. To compare the rate of exposition to GAS in a similar population, a control group of 150 children without tic disorders was examined during the same period.
Results:
In children with tics, mean antistreptolysin O (ASO) titer (434 +/- 338 IU) was significantly higher compared with that of control subjects (155 +/- 126 IU); 38% of the children with tics compared with 2% of the control subjects (P <.001) had ASO titers > or =500 IU. Twenty-six children with tics (17%) had throat cultures positive for GAS, but in all cases, only few colonies per plate were isolated. Among the strains isolated, no prevalent T pattern or M type was observed. In children with tics a positive correlation between ASO titers and severity of tic disorder (measured by the Yale Global Tic Severity Scale) was found.
Conclusion:
Our results suggest that children with tic disorder could be a unique population in which GAS infection, or at least the exposure to streptococcal antigens, is correlated to the neurobehavioral disorder. Moreover, our data indicate a relationship between the severity of tic disorder and the magnitude of the serologic response to GAS antigens.