Kelton J G
N Engl J Med. 1985 Sep 5;313(10):596-600. doi: 10.1056/NEJM198509053131002.
In about 20 per cent of patients taking the antihypertensive agent methyldopa, IgG autoantibodies form against red cells, but most such patients do not have hemolysis. The reason for this is uncertain; it does not appear to be explained by known characteristics of the autoantibody. Since antibody-dependent reticuloendothelial function is an important determinant of cell clearance, we measured reticuloendothelial function in nine patients taking methyldopa. We did this by measuring the rate of clearance of radiolabeled autologous red cells sensitized with anti-D alloantibody. Five patients had a positive direct antiglobulin test, and four did not. Only one patient had laboratory evidence of hemolysis. The patients without hemolysis had significantly impaired reticuloendothelial clearance. In contrast, the patient with hemolysis did not have impaired reticuloendothelial function. This study suggests that in patients taking methyldopa who have a positive direct antiglobulin test the absence of hemolysis may be caused by an impairment in reticuloendothelial function. That the drug itself may be responsible for the impairment is suggested by the occurrence of abnormal reticuloendothelial function in patients taking the drug who have a negative direct antiglobulin test.
在服用抗高血压药物甲基多巴的患者中，约20%会产生针对红细胞的IgG自身抗体，但大多数此类患者并无溶血现象。其原因尚不确定；已知的自身抗体特性似乎无法解释这一现象。由于抗体依赖的网状内皮系统功能是细胞清除的重要决定因素，我们对9名服用甲基多巴的患者的网状内皮系统功能进行了测量。我们通过检测用抗-D同种异体抗体致敏的放射性标记自体红细胞的清除率来进行此项测量。5名患者直接抗球蛋白试验呈阳性，4名呈阴性。只有1名患者有溶血的实验室证据。未发生溶血的患者网状内皮系统清除功能明显受损。相比之下，发生溶血的患者网状内皮系统功能并未受损。这项研究表明，在直接抗球蛋白试验呈阳性的服用甲基多巴的患者中，未发生溶血可能是由于网状内皮系统功能受损所致。服用该药物且直接抗球蛋白试验呈阴性的患者出现异常网状内皮系统功能，这表明药物本身可能是造成这种损害的原因。
