[Severe corticoid-refractory autoimmune thrombocytopenia associated with mixed connective tissue disease (Sharp's syndrome). Treatment with rituximab].

HISTORY AND CLINICAL FINDINGS: An 18-year-old woman with mixed connective tissue disease (Sharp's syndrome), diagnosed two years earlier, was admitted because of severe thrombocytopenia. At that time the only symptom typical for collagen disease was Raynaud;s syndrome. The patient was in good general condition, the clinical examination revealed no signs of bleeding or of splenomegaly.

INVESTIGATIONS: Imaging procedures showed no abnormality. The platelets were decreased to 5 Gpt/l (normal range 150 - 400 Gpt/l). The bone marrow biopsy showed a secondary immunological thrombocytopenia with an increased number of megakaryocytes.

TREATMENT AND CLINICAL COURSE: Treatment with prednisolone, 100 mg/day, had no significant effect. As the patient refused splenectomy, treatment with rituximab 500 mg (375 mg/m2) per week was given over a period of four weeks, followed by azathioprine 2 x 50 mg/d. All tests demonstrated continuing increase of the platelet count up to 70 Gpt/l (normal range 150 - 400 Gpt/l). The signs of Raynaud;s syndrome also regressed.

CONCLUSION

Immunologic thrombocytopenia is a potentially life-threatening hematological manifestation of mixed connective tissue disease. If high-dosage prednisolone brings no response, a splenectomy is an efficacious treatment. B-cell depletion with rituximab offers another safe and adequate option.