Department of Geriatric Medicine, Ohio University College of Osteopathic Medicine, Athens, OH, USA.
J Hematol Oncol. 2008 Dec 18;1:26. doi: 10.1186/1756-8722-1-26.
Concurrent hemolysis in patients with vitamin B12 deficiency is a well-recognized phenomenon and has been attributed to intramedullary destruction of erythrocytes (ineffective erythropoiesis). Recent studies revealed that homocysteine increased the risk of hemolysis in vitamin B12 deficiency in vitro and there is a high frequency (30%) of vitamin B12 deficiency in asymptomatic patients with homozygous methylene tetrahydrofolate reductase (MTHFR) C677T mutation, a known cause of hyperhomocysteinemia. Here we report three patients with MTHFR mutations and vitamin B12 deficiency presenting with hemolytic anemia and severely elevated homocysteine levels. Patients demonstrated complete resolution of hemolysis with simultaneous normalization of serum homocysteine levels after vitamin B12 treatments. We reviewed pertinent literature, and hypothesized that hemolytic anemia may be more prevalent in patients who have a coexisting MTHFR gene mutation and vitamin B12 deficiency possibly related to severely elevated homocysteine levels. The hemolysis in these cases occurred predominantly in peripheral blood likely due to the combined effects of structurally defective erythrocytes and homocysteine-induced endothelial damage with microangiopathy.
维生素 B12 缺乏症患者同时发生溶血是一种公认的现象，其原因被认为是骨髓内红细胞破坏（无效性红细胞生成）。最近的研究表明，同型半胱氨酸增加了维生素 B12 缺乏症患者体外溶血的风险，并且在同型半胱氨酸水平升高的纯合子亚甲基四氢叶酸还原酶（MTHFR）C677T 突变无症状患者中，维生素 B12 缺乏症的频率很高（30%），MTHFR C677T 突变是高同型半胱氨酸血症的已知原因。在此，我们报告了 3 例 MTHFR 突变和维生素 B12 缺乏症患者，这些患者表现为溶血性贫血和同型半胱氨酸水平显著升高。在接受维生素 B12 治疗后，患者的溶血完全缓解，同时血清同型半胱氨酸水平恢复正常。我们回顾了相关文献，并假设在同时存在 MTHFR 基因突变和维生素 B12 缺乏症的患者中，溶血性贫血可能更为常见，这可能与同型半胱氨酸水平显著升高有关。这些病例中的溶血主要发生在外周血中，可能是由于结构缺陷的红细胞和同型半胱氨酸诱导的内皮损伤与微血管病的共同作用所致。
