title: Identification of anti-thrombopoietin receptor antibody in prolonged thrombocytopenia after allogeneic hematopoietic stem cell transplantation treated successfully with eltrombopag.
abstract: A 55-year-old female with stage IVA follicular lymphoma in third complete remission underwent allogeneic peripheral blood stem cell transplantation. Neutrophil engraftment was achieved on day +18; however, platelet counts remained below 10 × 10(3)/µL, necessitating transfusions twice a week for more than 3 months. Bone marrow showed a decreased number of megakaryocytes with hypolobulated nuclei. No graft versus host disease, viral infection, or disease relapse was observed. Furthermore, severe thrombocytopenia below 5.0 × 10(3)/µL refractory to transfusion appeared on day +240 after influenza virus infection. Treatments with intravenous immunoglobulin, romiplostim, and rituximab were administered without any recovery. Subsequently, eltrombopag was initiated on day +443, after which platelet counts rose gradually and continued to rise above 20 × 10(3)/µL after 10 weeks of administration. The serum thrombopoietin (TPO) level was markedly elevated, and anti-TPO receptor (TPOR) antibody was detected in the patient's serum. Anti-TPOR antibody may play an important role in some cases of prolonged thrombocytopenia after allogeneic hematopoietic stem cell transplantation with unknown etiology, and eltrombopag could be a novel therapeutic option for such cases.
authors.affiliation: Department of Hematology and Oncology, Oji General Hospital, 3-4-8 Wakakusa-cho, Tomakomai City, 053-8506, Japan. akihito.fujimi@ojihosp.or.jp.
authors.forename: Akihito
authors.initials: A
authors.lastname: Fujimi
authors.affiliation: Department of Hematology and Oncology, Oji General Hospital, 3-4-8 Wakakusa-cho, Tomakomai City, 053-8506, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kamihara
authors.affiliation: Department of Hematology and Oncology, Oji General Hospital, 3-4-8 Wakakusa-cho, Tomakomai City, 053-8506, Japan.
authors.forename: Akari
authors.initials: A
authors.lastname: Hashimoto
authors.affiliation: Department of Hematology and Oncology, Oji General Hospital, 3-4-8 Wakakusa-cho, Tomakomai City, 053-8506, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kanisawa
authors.affiliation: Department of Gastroenterology, Oji General Hospital, Tomakomai, Japan.
authors.forename: Chisa
authors.initials: C
authors.lastname: Nakajima
authors.affiliation: Department of Gastroenterology, Oji General Hospital, Tomakomai, Japan.
authors.forename: Naotaka
authors.initials: N
authors.lastname: Hayasaka
authors.affiliation: Department of Gastroenterology, Oji General Hospital, Tomakomai, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Yamada
authors.affiliation: Department of Gastroenterology, Oji General Hospital, Tomakomai, Japan.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Okuda
authors.affiliation: Department of Gastroenterology, Oji General Hospital, Tomakomai, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Minami
authors.affiliation: Department of Medical Oncology and Hematology, Sapporo Medical University, Sapporo, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Ono
authors.affiliation: Department of Medical Oncology and Hematology, Sapporo Medical University, Sapporo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Iyama
authors.affiliation: Department of Medical Oncology and Hematology, Sapporo Medical University, Sapporo, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Kato
mesh_terms: D064591:Allografts; D001323:Autoantibodies / Q000097:blood*; D001565:Benzoates / Q000008:administration & dosage*; D005260:Female; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D006834:Hydrazines / Q000008:administration & dosage*; D008224:Lymphoma, Follicular / Q000097:blood / Q000628:therapy; D008875:Middle Aged; D011720:Pyrazoles / Q000008:administration & dosage*; D053628:Receptors, Thrombopoietin; D013921:Thrombocytopenia / Q000097:blood / Q000188:drug therapy
chemical_list: D001323:Autoantibodies; D001565:Benzoates; D006834:Hydrazines; D011720:Pyrazoles; D053628:Receptors, Thrombopoietin; C082218:MPL protein, human; C520809:eltrombopag
keywords: Allogeneic hematopoietic stem cell transplantation; Anti-thrombopoietin receptor antibody; Eltrombopag; Prolonged thrombocytopenia