Successful treatment of amegakaryocytic thrombocytopenia with anti-CD20 antibody (rituximab) in a patient with systemic lupus erythematosus.
Amegakaryocytic thrombocytopenia is an extremely rare disorder in systemic lupus erythematosus, and its mechanism and treatment are still largely unknown. We describe a 42-year-old woman with systemic lupus erythematosus who presented various clinical manifestations of life-threatening amegakaryocytic thrombocytopenia (10,000 platelets/mm3 with a marked decrease of megakaryocytes in the bone marrow), proteinuria, psychosis, refractory chylothorax, ascites, and type II diabetes caused by the anti-insulin receptor autoantibody. She was initially treated with prednisolone (25-50 mg/day) and cyclosporine A (200 mg/day) without any improvement in severe thrombocytopenia. However, her clinical symptoms, including platelet counts, dramatically improved, with a concurrent decrease in the anti-c-Mpl antibody, an autoantibody against the thrombopoietin receptor, after a subsequent treatment with rituximab (375 mg/m2 intravenously, weekly, for two consecutive weeks). Our case suggested that amegakaryocytic thrombocytopenia in patients with systemic lupus erythematosus might be mediated by the anti-c-Mpl antibody and could be treated with rituximab through elimination of pathogenic B cells producing autoimmune antibodies.
Fukushima
T
T
Division of Hematology and Immunology, Department of Internal Medicine, Kanazawa Medical University, Kahoku-gun, Ishikawa, Japan. tfukus@kanazawa-med.ac.jp
Dong
L
L
Sakai
T
T
Sawaki
T
T
Miki
M
M
Tanaka
M
M
Masaki
Y
Y
Hirose
Y
Y
Kuwana
M
M
Umehara
H
H
D000328:Adult; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D058846:Antibodies, Monoclonal, Murine-Derived; D018951:Antigens, CD20 / Q000276:immunology; D001323:Autoantibodies / Q000097:blood; D001792:Blood Platelets / Q000276:immunology; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000150:complications* / Q000276:immunology; D008533:Megakaryocytes / Q000473:pathology*; D053628:Receptors, Thrombopoietin / Q000276:immunology; D000069283:Rituximab; D013921:Thrombocytopenia / Q000188:drug therapy* / Q000209:etiology
D000911:Antibodies, Monoclonal; D058846:Antibodies, Monoclonal, Murine-Derived; D018951:Antigens, CD20; D001323:Autoantibodies; D053628:Receptors, Thrombopoietin; C082218:MPL protein, human; D000069283:Rituximab