Department of Hematology, Saitama Medical University Hospital, 38 Morohongo, Moroyama-Machi, Iruma-Gun, Saitama, 350-0495, Japan.
Int J Hematol. 2023 Apr;117(4):613-617. doi: 10.1007/s12185-022-03492-9. Epub 2022 Nov 14.
Immune thrombocytopenia (ITP) and chronic myeloid leukemia (CML) are rarely observed concurrently. Here we report the case of a patient with ITP who developed CML that has been well controlled with tyrosine kinase inhibitor (TKI) therapy. A 55-year-old man was diagnosed with ITP. No cytogenetic abnormalities were found at the time of initial diagnosis. Four years later, he began corticosteroid therapy for progression of thrombocytopenia. At that time, the Philadelphia (Ph) chromosome was observed in 7 of 20 bone marrow (BM) cells, suggesting concurrent CML in the subclinical stage. Prednisolone resulted in a partial response. Seven months after starting prednisolone, he exhibited hematological features of CML with an increase in Ph-positive cells. TKI therapy with imatinib mesylate was started to treat CML and maintained at a daily dose of 400 mg. The patient achieved and sustained a major molecular response. His platelet count also increased, enabling discontinuation of corticosteroid therapy. TKIs have been reported to show various immunological off-target effects. In this case, off-target effects of TKI might have improved ITP by suppressing the autoimmune response. Alternatively, reconstitution of immune systems by Ph-negative cells or cancellation of immunoreaction against CML could have exerted favorable effects on ITP.
免疫性血小板减少症（ITP）和慢性髓性白血病（CML）很少同时发生。我们在此报告 1 例 ITP 患者并发 CML 的病例，该患者经酪氨酸激酶抑制剂（TKI）治疗后得到很好的控制。1 名 55 岁男性被诊断为 ITP。初次诊断时未发现细胞遗传学异常。4 年后，他因血小板减少症进展开始接受皮质类固醇治疗。当时，在 20 个骨髓（BM）细胞中有 7 个观察到费城（Ph）染色体，提示亚临床阶段同时发生 CML。泼尼松龙导致部分缓解。开始泼尼松龙治疗 7 个月后，他出现 CML 的血液学特征，Ph 阳性细胞增加。开始用甲磺酸伊马替尼进行 TKI 治疗以治疗 CML，并维持每日 400mg 的剂量。患者达到并维持主要分子缓解。他的血小板计数也增加，从而能够停止皮质类固醇治疗。已有报道称 TKI 具有各种免疫非靶点作用。在这种情况下，TKI 的非靶点作用可能通过抑制自身免疫反应来改善 ITP。或者，Ph 阴性细胞的重建或对 CML 的免疫反应的取消可能对 ITP 产生有利影响。
