Third Department of Internal Medicine, Yamaguchi University School of Medicine, Ube, Yamaguchi, Japan.
Tohoku J Exp Med. 2010 Feb;220(2):121-6. doi: 10.1620/tjem.220.121.
The treatment of isolated extramedullary relapse (IEMR) after allogeneic hematopoietic stem-cell transplantation (allo-HSCT) poses a challenge for which no standard approach exists. Gemtuzumab ozogamicin (GO) is a recombinant humanized monoclonal antibody, conjugated to calicheamicin, which targets the CD33 antigen that is expressed in acute myelogenous leukemia (AML) blasts. The selectivity of GO for CD33-positive leukemic cells makes it an attractive agent for use in patients with multiple sites of IEMR after allo-HSCT, because GO does not suppress cells responsible for the putative graft-versus-leukemia (GVL) effect. Herein, we describe a 54-year-old male patient who developed AML with multiple sites of extramedullary (EM) relapse after allo-HSCT, and who exhibited apparent donor-derived hematopoiesis in the bone marrow. At approximately 120 days after allo-HSCT, the patient complained of severe lumbago. T2-weighted magnetic resonance images and fluorodeoxyglucose-positron emission tomography showed multiple mass lesions in soft tissue and bone. A biopsy specimen from a lumbar soft tissue mass confirmed EM relapse, and revealed that donor T lymphocytes were present in the relapse site and that leukemic cells expressed CD33. Therefore, to maintain the GVL effect of donor T lymphocytes, the patient was treated with GO as a single agent. He achieved complete hematological remission, and has remained in remission, with only mild liver injury, for more than 10 months since GO treatment. GO can be an effective therapy for IEMR after allo-HSCT, especially when cytotoxic T lymphocytes react to leukemic cells at the site of EM relapse.
异基因造血干细胞移植（allo-HSCT）后孤立性髓外复发（IEMR）的治疗是一个挑战，目前尚无标准方法。吉妥珠单抗奥佐米星（GO）是一种重组人源化单克隆抗体，与加利车霉素偶联，靶向急性髓系白血病（AML）细胞中的 CD33 抗原。GO 对 CD33 阳性白血病细胞的选择性使其成为 allo-HSCT 后发生多处 IEMR 患者的一种有吸引力的药物，因为 GO 不会抑制负责移植物抗白血病（GVL）效应的细胞。在此，我们描述了一位 54 岁男性患者，在 allo-HSCT 后发生 AML 伴多处髓外（EM）复发，并在骨髓中表现出明显的供体来源造血。在 allo-HSCT 后约 120 天，患者出现严重腰痛。T2 加权磁共振成像和氟脱氧葡萄糖正电子发射断层扫描显示软组织和骨骼多处肿块病变。腰椎软组织肿块的活检标本证实为 EM 复发，并显示供体 T 淋巴细胞存在于复发部位，白血病细胞表达 CD33。因此，为了维持供体 T 淋巴细胞的 GVL 效应，该患者接受 GO 作为单一药物治疗。他实现了完全血液学缓解，并且在 GO 治疗后 10 多个月内，仅出现轻微肝损伤，一直处于缓解状态。GO 可作为 allo-HSCT 后 IEMR 的有效治疗方法，尤其是当细胞毒性 T 淋巴细胞在 EM 复发部位对白血病细胞产生反应时。
