Effectiveness of dapsone on refractory immune thrombocytopenia in a patient with systemic lupus erythematosus associated with sarcoidosis

: A 57-year-old man was admitted with massive nasal bleeding and blurred vision in January, 1991. Laboratory examination showed a prominent decrease of platelet number (1,000/microliters) and a marked elevation of PAIgG (4,025 ng/10(7) cells). Serological test revealed positive antinuclear factor, low concentration of C3 and C4, high level of immune complex and polyclonal hypergammaglobulinemia. The patient had uveitis and bilateral hilar lymphadenopathy with a high level of serum lysozyme and negative PPD skin test. The diagnosis of SLE complicated with thrombocytopenia and sarcoidosis was made. In spite of the various trials of treatment, such as oral prednisolone (PSL), methyl-PSL pulse therapy, plasma exchange, high-dose intravenous gammaglobulin, cyclophosphamide, azathioprine, vincristine, colchicine, cyclosporine-A, mizoribine, danazol, ascorbic acid and interferon alpha 2b, the platelet number could not be raised enough to keep more than 10,000/microliters, though the level of PAIgG decreased to 200 ng/10(7) cells. Finally, the administration of 75 mg/day of dapsone brought about a significant rise in platelet number within 2 weeks. The maximum number of 6.2 x 10(4)/microliters was obtained after 2 months. Then the patient stopped himself to take the drug, but the platelet number remained around 4-5 x 10(4)/microliters. Same dose of the drug was again prescribed to confirm the effect of dapsone. The platelet number increased to 7.9 x 10(4)/microliters in 2 weeks, and gradually returned to 5 x 10(4)/microliters after cessation of the drug. Thus being certainly effective against thrombocytopenia, dapsone should be considered as one of the therapeutic choice for refractory autoimmune thrombocytopenia.