Jackson C G, Ochs H D, Wedgwood R J
N Engl J Med. 1979 May 17;300(20):1124-9. doi: 10.1056/NEJM197905173002002.
The clinical details of a five-year-old boy with systemic lupus erythematosus and an inherited deficiency of the fourth component of complement (C4) have been reported elsewhere. In this study of his immune responses, immunization with bacteriophage phi X 174 demonstrated diminished antibody formation, abnormal immunologic memory and failure to switch from IgM to IgG during secondary response. We also noted persistent lymphopenia and reductions in peripheral-blood T lymphocytes, lymphocyte responses to mitogens and allogeneic cells and granulocyte chemotaxis. Kinetic studies revealed that delayed activation of the alternative pathway was corrected by purified C4 only if the classical pathway was not blocked. This finding is consistent with the concept that minute amounts of C3b provided through the classical pathway are necessary to prime the properdin system. Inability to activate the classical complement pathway, abnormal kinetics of alternative-pathway activation and depressed antibody responses to a T-cell-dependent antigen may predispose C4-deficient patients to viral infection or immune-complex formation.
一名患有系统性红斑狼疮且遗传性缺乏补体第四成分（C4）的五岁男孩的临床细节已在其他地方报道过。在对其免疫反应的这项研究中，用噬菌体φX 174进行免疫显示抗体形成减少、免疫记忆异常以及二次反应期间无法从IgM转换为IgG。我们还注意到持续性淋巴细胞减少以及外周血T淋巴细胞、淋巴细胞对有丝分裂原和同种异体细胞的反应以及粒细胞趋化性降低。动力学研究表明，仅当经典途径未被阻断时，纯化的C4才能纠正替代途径的延迟激活。这一发现与以下概念一致，即通过经典途径提供的微量C3b对于启动备解素系统是必要的。无法激活经典补体途径、替代途径激活的异常动力学以及对T细胞依赖性抗原的抗体反应降低可能使C4缺乏患者易患病毒感染或免疫复合物形成。
