LUPUS ANTICOAGULANT AND PROTEIN-S DEFICIENCY IN CHILDREN WITH POSTVARICELLA PURPURA FULMINANS OR THROMBOSIS

Objective: The objective of this study was to determine the cause of p urpura fulminans; disseminated intravascular coagulation, or thrombosi s in seven children with varicella, All children were found to have a lupus anticoagulant and acquired protein S deficiency, Thrombosis in f ive children was associated with presumed or documented infection with streptococcus. Study design: Coagulation tests included determination s of the activated partial thromboplastin time, the prothrombin time, the dilute Russell viper venom time, the prothrombin F 1+2 fragment, t he C4b-binding protein (C4b), total and free protein S antigen, and cl otting activities of factors II, V, VII, and X and of protein C and pr otein S. Autoantibodies to phospholipids, cardiolipin, and protein S w ere determined in enzyme-linked immunosorbent assays. Results: All chi ldren had a lupus anticoagulant and acquired protein S deficiency, Thr ombosis in five children was associated with presumed or documented in fection with streptococcus. All children transiently expressed free pr otein S deficiency, elevated levels of IgG, IgM, or both binding to pr otein S, the lupus anticoagulant, and increased concentration of the F 1+2 fragment, Four children also had antiphospholipid or anticardioli pin antibodies. In one child a purified IgG fraction cross-reacted wit h both protein S and a specific varicella antigen. Conclusions: A subs et of children with varicella infection, some of whom are coinfected w ith streptococcus, are prone to development of a lupus, anticoagulant and an autoantibody to protein S, which results in acquired free prote in S deficiency, Such children are at risk of having life-threatening thrombotic events.