Laboratório de Investigação em Dermatologia e Imunodeficiências, LIM 56, Faculdade de Medicina da USP, Instituto de Medicina Tropical de São Paulo, São Paulo, Brazil.
J Clin Immunol. 2010 Nov;30(6):872-80. doi: 10.1007/s10875-010-9453-y. Epub 2010 Aug 25.
Immunoglobulin A deficiency (IgAD) is considered the most common form of primary immunodeficiency. The majority of IgA-deficient individuals are considered asymptomatic, even though IgAD has been associated with an increased frequency of recurrent infections, allergy, and autoimmune diseases. In this study we evaluate the Natural autoantibodies (NatAbs) reactivity to phosphorylcholine (PC) and to some pro-inflammatory molecules in IgAD with or without autoimmune disorders. We observed that in the absence of IgA there is an enhancement of IgG subclasses functioning as NatAbs against PC. Immunoglobulin G (IgG) against lipopolysaccharide, C-reactive protein, and IgA was found in IgAD, regardless of the autoimmune manifestations. Nonetheless, IgAD patients with autoimmune disease showed significantly higher IgG reactivity against pro-inflammatory molecules, such as cardiolipin, oxidized low-density lipoproteins, and phosphatidylserine, with positive correlation between them. In conclusion, the IgG NatAbs against PC may represent a compensatory defense mechanism against infections and control excess of inflammation, explaining the asymptomatic status in the IgA deficiency.
免疫球蛋白 A 缺乏症（IgAD）被认为是最常见的原发性免疫缺陷。尽管 IgAD 与复发性感染、过敏和自身免疫性疾病的频率增加有关，但大多数 IgA 缺乏的个体被认为是无症状的。在这项研究中，我们评估了 IgAD 中天然自身抗体（NatAbs）对磷酸胆碱（PC）和一些促炎分子的反应性，无论是否存在自身免疫性疾病。我们观察到，在没有 IgA 的情况下，IgG 亚类作为针对 PC 的 NatAbs 的功能得到增强。在 IgAD 中发现了针对脂多糖、C 反应蛋白和 IgA 的 IgG，无论是否有自身免疫表现。然而，患有自身免疫性疾病的 IgAD 患者对促炎分子（如心磷脂、氧化低密度脂蛋白和磷脂酰丝氨酸）的 IgG 反应性显著升高，它们之间呈正相关。总之，针对 PC 的 IgG NatAbs 可能代表一种针对感染的补偿性防御机制，并控制炎症的过度，这解释了 IgA 缺乏症的无症状状态。
