Laurell A B, Sjöholm A G
Department of Clinical Immunology, University of Lund, Sweden.
Behring Inst Mitt. 1993 Dec(93):292-8.
C1 subcomponents form a variety of complexes that can be detected in normal and pathological sera. Since aberrations of C1 subcomponents in disease could reflect in vivo interactions with influence on complement function, studies of C1 subcomponent complexes might provide insight into pathogenetic mechanisms. C1 inhibitor (C1Inh)-dependent dissociation of the C1q(C1r-C1s)2 complex gives rise to C1Inh-C1r-C1s or C1Inh-C1r-C1s-C1Inh complexes. Increased concentrations of C1Inh-C1r-C1s probably signify prevention of C1 activation, while C1Inh-C1r-C1s-C1Inh appears to be a clinically useful marker of efficient classical pathway activation. "Free" C1q as found in some pathological sera, and in joint fluids of patients with rheumatoid arthritis could be a result of C1Inh-dependent dissociation of C1q(C1r-C1s)2. The presence in serum of zymogen (C1r-C1s)2 is an expected finding in various conditions with low C1q concentrations without evidence of C1 activation. It is not excluded that circulating (C1r-C1s)2 might sometimes be acquired due to factors capable of interacting with the collagenous part of the C1q molecule.
C1亚成分形成多种复合物，可在正常和病理血清中检测到。由于疾病中C1亚成分的异常可能反映体内相互作用并影响补体功能，对C1亚成分复合物的研究可能有助于深入了解发病机制。C1抑制剂（C1Inh）依赖的C1q（C1r - C1s）2复合物解离产生C1Inh - C1r - C1s或C1Inh - C1r - C1s - C1Inh复合物。C1Inh - C1r - C1s浓度升高可能意味着C1激活受到抑制，而C1Inh - C1r - C1s - C1Inh似乎是经典途径有效激活的一个临床有用标志物。在某些病理血清以及类风湿性关节炎患者的关节液中发现的“游离”C1q可能是C1Inh依赖的C1q（C1r - C1s）2解离的结果。在各种C1q浓度低且无C1激活证据的情况下，血清中存在酶原（C1r - C1s）2是预期的发现。不排除循环中的（C1r - C1s）2有时可能是由于能够与C1q分子的胶原部分相互作用的因素而获得的。
