[Nine-year's follow up on the appearance of autoantibodies in a child with idiopathic thrombocytopenic purpura subsequently developing lupus with central nervous system manifestations].

We describe a 23-year-old female who developed SLE 9 years after asymptomatic idiopathic thrombocytopenic purpura (ITP) with positive antinuclear antibody (ANA). Although the platelet count was normal before the onset of SLE, the titer of ANA was gradually increased and also autoantibodies, including antibodies to SS-A/Ro, single-stranded DNA (ss-DNA) and nuclear ribonucleoprotein (RNP) changed to positive. At 23 years of age, the patient was admitted to our hospital because of fever, butterfly rash and polyarthritis. Anti double-strand DNA (ds-DNA) antibody and anti Smith antigen (Sm) antibody were positive and the platelet count and titer of complements were decreased. The patient was diagnosed as SLE and treated with 60 mg/day of prednisolone. Despite steroid therapy, psychiatric symptoms appeared. Additional treatments with steroid pulse therapy and double filtration plasmaphresis resulted in the improvement of SLE including the central nervous system manifestations. This case suggested that increased titer of ANA and the appearance of antibodies to SS-A, ss-DNA, RNP, ds-DNA and Sm in ITP patients predict the development of SLE. Routine checkup of autoantibodies is needed to manage ITP with positive ANA.