title: Lupus anticoagulant and protein S deficiency in children with postvaricella purpura fulminans or thrombosis.
abstract: OBJECTIVE
  The objective of this study was to determine the cause of purpura fulminans, disseminated intravascular coagulation, or thrombosis in seven children with varicella. All children were found to have a lupus anticoagulant and acquired protein S deficiency. Thrombosis in five children was associated with presumed or documented infection with streptococcus.
  
  
  METHODS
  Coagulation tests included determinations of the activated partial thromboplastin time, the prothrombin time, the dilute Russell viper venom time, the prothrombin F 1 + 2 fragment, the C4b-binding protein (C4b), total and free protein S antigen, and clotting activities of factors II, V, VII, and X and of protein C and protein S. Autoantibodies to phospholipids, cardiolipin, and protein S were determined in enzyme-linked immunosorbent assays.
  
  
  RESULTS
  All children had a lupus anticoagulant and acquired protein S deficiency. Thrombosis in five children was associated with presumed or documented infection with streptococcus. All children transiently expressed free protein S deficiency, elevated levels of IgG, IgM, or both binding to protein S, the lupus anticoagulant, and increased concentration of the F 1+2 fragment. Four children also had antiphospholipid or anticardiolipin antibodies. In one child a purified IgG fraction cross-reacted with both protein S and a specific varicella antigen.
  
  
  CONCLUSIONS
  A subset of children with varicella infection, some of whom are coinfected with streptococcus, are prone to development of a lupus anticoagulant and an autoantibody to protein S, which results in acquired free protein S deficiency. Such children are at risk of having life-threatening thrombotic events.
authors.affiliation: Department of Pediatrics, University of Colorado Health Sciences Center, Denver 80262, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Manco-Johnson
authors.forename: R
authors.initials: R
authors.lastname: Nuss
authors.forename: N
authors.initials: N
authors.lastname: Key
authors.forename: C
authors.initials: C
authors.lastname: Moertel
authors.forename: L
authors.initials: L
authors.lastname: Jacobson
authors.forename: S
authors.initials: S
authors.lastname: Meech
authors.forename: A
authors.initials: A
authors.lastname: Weinberg
authors.forename: J
authors.initials: J
authors.lastname: Lefkowitz
mesh_terms: D017152:Antibodies, Antiphospholipid / Q000032:analysis; D001780:Blood Coagulation Tests; D016022:Case-Control Studies; D002644:Chickenpox / Q000150:complications*; D002648:Child; D002675:Child, Preschool; D004211:Disseminated Intravascular Coagulation / Q000209:etiology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D011695:IgA Vasculitis / Q000209:etiology*; D007223:Infant; D016682:Lupus Coagulation Inhibitor / Q000032:analysis*; D008297:Male; D018455:Protein S Deficiency / Q000209:etiology*; D012307:Risk Factors; D013290:Streptococcal Infections / Q000150:complications; D013297:Streptococcus pyogenes; D013927:Thrombosis / Q000209:etiology*
chemical_list: D017152:Antibodies, Antiphospholipid; D016682:Lupus Coagulation Inhibitor