title: High prevalence of antiphosphatidylinositol antibodies in young patients with cerebral ischemia of undetermined cause.
abstract: OBJECTIVE
  Anticardiolipin antibodies (aCL) are associated with thrombotic phenomena including cerebral ischemia in young adults. Although aCL are directed to a neoepitope formed by phospholipid and beta2-glycoprotein I (beta2-GPI), immunoassays based on cardiolipin as target antigen are widely used. We previously demonstrated that 47% of aCL-negative systemic lupus erythematosus (SLE) patients had antiphospholipid antibodies (aPL) to epitopes other than cardiolipin, and we found an association between aPL to noncardiolipin antigens and thrombosis. We now assess the prevalence and clinical significance of noncardiolipin aPL in young adults with cerebrovascular disease of undetermined etiology.
  
  
  METHODS
  Seventy-seven non-SLE patients, aged <51 years, with cerebral ischemia were studied. Specificity of aPL were characterized by ELISAs using 7 different phospholipids: cardiolipin (CL), phosphatidylserine (PS), phosphatidylinositol (PI), phosphatidylglycerol (PG), phosphatidic acid (PA), phosphatidylcholine, and phosphatidylethanolamine.
  
  
  RESULTS
  Thirty-four patients (44.1%), had aPL to 1 or more of the following antigens: 23.4% to CL, 18.2% to PS, 15.6% to PG, 14.3% to PA, and 28.6% to PI. Fifty-nine patients (76.6%) were aCL negative. Of these subjects 23.4% showed aPL to noncardiolipin epitopes. PI was the specificity with highest prevalence in all subgroups, and in 6 patients anti-PI antibodies were the only detectable aPL. The binding of aPL to the different antigens was beta2-GPI dependent.
  
  
  CONCLUSIONS
  Our data demonstrate a high prevalence of aPL in young adults with cerebral ischemia of undetermined cause. PI was the specificity with highest prevalence, suggesting that anti-PI antibodies may be an immunological marker in young patients with cerebrovascular disease.
authors.affiliation: Department of Hematology and Blood Transfusion, San Carlo Borromeo Hospital, Milan, Italy. vitoschi@tin.it
authors.forename: V
authors.initials: V
authors.lastname: Toschi
authors.forename: A
authors.initials: A
authors.lastname: Motta
authors.forename: C
authors.initials: C
authors.lastname: Castelli
authors.forename: M L
authors.initials: ML
authors.lastname: Paracchini
authors.forename: D
authors.initials: D
authors.lastname: Zerbi
authors.forename: A
authors.initials: A
authors.lastname: Gibelli
mesh_terms: D000328:Adult; D000367:Age Factors; D017152:Antibodies, Antiphospholipid / Q000097:blood*; D002545:Brain Ischemia / Q000453:epidemiology / Q000209:etiology / Q000276:immunology*; D000939:Epitopes / Q000276:immunology; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008297:Male; D008875:Middle Aged; D010716:Phosphatidylinositols / Q000276:immunology*; D015995:Prevalence
chemical_list: D017152:Antibodies, Antiphospholipid; D000939:Epitopes; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D010716:Phosphatidylinositols