Berkel A I
Department of Pediatrics, Hacettepe University Faculty of Medicine, Ankara.
Turk J Pediatr. 1993 Jul-Sep;35(3):221-6.
Immune response in a six-year-old girl with a rare complement defect, namely selective complete C1q deficiency, was studied. Her cell-mediated immune response (delayed hypersensitivity skin tests, E, EAC rosettes, in vitro lymphocyte transformation with phytohemagglutinin), isohemagglutinin titers, serum immunoglobulin levels, antibody titers to tetanus, Epstein-Barr virus, keyhole limpet hemocyanin, pneumococcus and bacteriophage 0 x 174 were all normal. However, she had abnormal kinetics of the antibody response to bacteriophage following primary and secondary immunizations. Her antibody titers reached a peak four weeks after primary immunization and three weeks after secondary immunization, while the titers of controls peaked at two weeks and one week, respectively. In this study we could not prove the hypothesis that defective antibody response caused recurrent infections in this patient. An alternative hypothesis is the possible role of defective clearance of immune complexes in the development of severe infections. Patients with selective complete C1q deficiency form immune complexes with bacterial or viral antigens, thus activating the classical complement pathway. As a result, very low C1q levels decrease even further, leading to a severe immunodeficiency and recurrent infections. Future studies in this area may help to explain the mechanism(s) responsible for infections in this rare type of complement defect.
对一名患有罕见补体缺陷（即选择性完全C1q缺乏症）的6岁女孩的免疫反应进行了研究。她的细胞介导免疫反应（迟发型超敏皮肤试验、E花环试验、EAC花环试验、用植物血凝素进行的体外淋巴细胞转化）、同种血凝素滴度、血清免疫球蛋白水平、针对破伤风、爱泼斯坦-巴尔病毒、钥孔戚血蓝蛋白、肺炎球菌和噬菌体0 x 174的抗体滴度均正常。然而，她在初次和二次免疫后对噬菌体的抗体反应动力学异常。她的抗体滴度在初次免疫后4周和二次免疫后3周达到峰值，而对照组的滴度分别在2周和1周达到峰值。在本研究中，我们无法证实抗体反应缺陷导致该患者反复感染这一假说。另一种假说是免疫复合物清除缺陷在严重感染发生过程中可能发挥的作用。选择性完全C1q缺乏症患者会与细菌或病毒抗原形成免疫复合物，从而激活经典补体途径。结果，极低的C1q水平进一步降低，导致严重免疫缺陷和反复感染。该领域未来的研究可能有助于解释这种罕见类型补体缺陷中感染的发生机制。
