title: A lack of association between elevated serum levels of S100B protein and autoimmunity in autistic children.
abstract: BACKGROUND
  S100B is a calcium-binding protein that is produced primarily by astrocytes. Increased serum S100B protein levels reflect neurological damage. Autoimmunity may have a role in the pathogenesis of autism in some patients. Autoantibodies may cross the blood-brain barrier and combine with brain tissue antigens, forming immune complexes and resulting in neurological damage. We are the first to investigate the relationship between serum levels of S100B protein, a marker of neuronal damage, and antiribosomal P protein antibodies in autistic children.
  
  
  METHODS
  Serum S100B protein and antiribosomal P antibodies were measured in 64 autistic children in comparison to 46 matched healthy children.
  
  
  RESULTS
  Autistic children had significantly higher serum S100B protein levels than healthy controls (P < 0.001). Children with severe autism had significantly higher serum S100B protein than patients with mild to moderate autism (P = 0.01). Increased serum levels of antiribosomal P antibodies were found in 40.6% of autistic children. There were no significant correlations between serum levels of S100B protein and antiribosomal P antibodies (P = 0.29).
  
  
  CONCLUSIONS
  S100B protein levels were elevated in autistic children and significantly correlated to autistic severity. This may indicate the presence of an underlying neuropathological condition in autistic patients. Antiribosomal P antibodies may not be a possible contributing factor to the elevated serum levels of S100B protein in some autistic children. However, further research is warranted to investigate the possible link between serum S100B protein levels and other autoantibodies, which are possible indicators of autoimmunity to central nervous system in autism.
authors.affiliation: Autism Research and Treatment Center, Al-Amodi Autism Research Chair, Department of Physiology, Faculty of Medicine, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Laila Yousef
authors.initials: LY
authors.lastname: Al-Ayadhi
authors.forename: Gehan Ahmed
authors.initials: GA
authors.lastname: Mostafa
mesh_terms: D000906:Antibodies / Q000097:blood; D001321:Autistic Disorder / Q000097:blood* / Q000276:immunology*; D015551:Autoimmunity / Q000502:physiology*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D009414:Nerve Growth Factors / Q000097:blood* / Q000276:immunology; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000097:blood* / Q000276:immunology; D012720:Severity of Illness Index; D013223:Statistics as Topic
chemical_list: D000906:Antibodies; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C579160:S100B protein, human