Two Cases of Refractory Thrombocytopenia in Systemic Lupus Erythematosus that Responded to Intravenous Low-Dose Cyclophosphamide
A 47-yr-old woman was admitted for 2-month recurrent oral ulcer, anemia, and skin lesions, including purpura and petechiae, on August 14, 2010. On admission, laboratory results showed WBC and platelet counts of 3,700/µL (neutrophils, 55.6%; lymphocytes, 34.5%) and 5,000/µL, respectively. The hemoglobin concentration was 7.4 g/dL; the corrected reticulocyte percentage was 1.15%; the ESR was 33 mm/hr; and the CRP concentration was < 0.1 mg/L. Levels of ferritin and LDH were not elevated, to 4.2 ng/mL (normal: 11-306 ng/mL) and 223 IU/L (normal: 119-247 IU/L), respectively. Neither proteinuria nor hematuria was observed. ANA was detected at a titer of 1:640, but antids DNA was negative. Complements 3 and 4 were 78.7 and 11.5 mg/dL, respectively. She was diagnosed with SLE according to the presence of ANA and lupus anticoagulant, the recurrent oral ulcer, and thrombocytopenia. Abdominal ultrasonography showed no splenomegaly. And a bone marrow biopsy showed 50%-60% cellularity and abundant megakaryocytes, suggesting peripheral thrombocytopenia. She received intravenous dexamethasone (20 mg/day) and immunoglobulin (5 g/day) for 5 days, and then was maintained on a moderate dose of prednisolone (30 mg/day). However, 1 month later, her platelet count had decreased to 9,000/µL. She received pulsed intravenous methylprednisolone (1,000 mg/day) for 3 days and immunoglobulin (5 g/day) for 5 days, followed by oral prednisolone (1 mg/kg/day). However, this combination treatment showed no efficacy. She started low-dose IV CYC (500 mg/day, biweekly) on September 16 and achieved induction of remission after three cycles of CYC. After she finished six cycles of low-dose IV CYC therapy in the outpatient clinic, started AZA (50 mg/day) with reducing the dose of prednisolone to 15 mg/day. However, she switched from AZA to MMF (500 mg/day) because her platelet count was decreased to 41,000/µL when she was maintained on AZA. After maintenance on MMF, she showed a stable platelet count without relapse into thrombocytopenia or complications due to the medication after 24 months ().