Gupta Sudhir, Gupta Ankmalika
Program in Primary Immunodeficiency and Aging, Division of Basic and Clinical Immunology, University of California at Irvine, Irvine, CA, United States.
Front Immunol. 2017 Sep 5;8:1056. doi: 10.3389/fimmu.2017.01056. eCollection 2017.
Although selective IgM deficiency (SIGMD) was described almost five decades ago, it was largely ignored as a primary immunodeficiency. SIGMD is defined as serum IgM levels below two SD of mean with normal serum IgG and IgA. It appears to be more common than originally realized. SIGMD is observed in both children and adults. Patients with SIGMD may be asymptomatic; however, approximately 80% of patients with SIGMD present with infections with bacteria, viruses, fungi, and protozoa. There is an increased frequency of allergic and autoimmune diseases in SIGMD. A number of B cell subset abnormalities have been reported and impaired specific antibodies to responses are observed in more than 45% of cases. Innate immunity, T cells, T cell subsets, and T cell functions are essentially normal. The pathogenesis of SIGMD remains unclear. Mice selectively deficient in secreted IgM are also unable to control infections from bacterial, viral, and fungal pathogens, and develop autoimmunity. Immunological and clinical similarities and differences between mouse models of deficiency of secreted IgM and humans with SIGMD have been discussed. Patients with SIGMD presenting with recurrent infections and specific antibody deficiency responses appear to improve clinically on immunoglobulin therapy.
尽管选择性IgM缺乏症(SIGMD)在近五十年前就已被描述,但它在很大程度上被忽视作为一种原发性免疫缺陷病。SIGMD被定义为血清IgM水平低于均值的两个标准差,而血清IgG和IgA正常。它似乎比最初认为的更为常见。SIGMD在儿童和成人中均有观察到。SIGMD患者可能无症状;然而,大约80%的SIGMD患者会出现细菌、病毒、真菌和原生动物感染。SIGMD中过敏性和自身免疫性疾病的发生率增加。已经报道了一些B细胞亚群异常,并且在超过45%的病例中观察到针对特定抗体反应的受损。固有免疫、T细胞、T细胞亚群和T细胞功能基本正常。SIGMD的发病机制仍不清楚。选择性缺乏分泌型IgM的小鼠也无法控制来自细菌、病毒和真菌病原体的感染,并发展出自身免疫性。已经讨论了分泌型IgM缺乏小鼠模型与患有SIGMD的人类之间的免疫学和临床异同。表现为反复感染和特异性抗体缺乏反应的SIGMD患者在接受免疫球蛋白治疗后临床症状似乎有所改善。