Overexpression of IgG2 in patients resembling IgG4-related disease with normal IgG4
Overexpression of IgG2 in patients resembling IgG4-related disease with normal IgG4
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DOI：
10.1111/sji.13126
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发表时间：
2021-12-14
影响因子：
3.7
通讯作者：
Coppo, Paul
中科院分区：
文献类型：
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作者：
Lecuit, Mathilde;Aucouturier, Pierre;Coppo, Paul
IgG4 相关疾病 (IgG4-RD) 是由表达 IgG4 的浆细胞和淋巴细胞组织浸润引起的，导致纤维化和器官肿大。根据受累器官的不同，临床表现差异很大，而高 IgG4 血清浓度最初被认为是 IgG4-RD 的诊断标志，但现在往往会被放弃作为其诊断不可或缺的标准；某些患者确实可能不存在这种免疫缺陷，这凸显了这种免疫失调疾病表现的多样性。尽管如此，在提示性环境中 IgG4 血清浓度升高仍然是支持 IgG4-RD 的一个论据，虽然其他 IgG 亚类可以升高，但这种生物学特征缺乏任何诊断价值。我们回顾性研究了 9 名患者（5 名女性，4 名男性，31-81 岁），根据临床、影像学或组织学标准，考虑诊断为 IgG4-RD，但似乎表现出异常高的血清 IgG2，而 IgG4 水平正常。还注意到一例血清 IgG1 升高，另一例血清 IgG3 升高。可以对 2 名患者的组织淋巴结活检进行细胞内免疫球蛋白的免疫组织化学分析，结果显示表达 IgG2 的浆细胞强烈浸润。因此，IgG2 亚类的过度表达可能会突出类似于 IgG4-RD 的免疫失调性疾病的病例，尽管疾病的触发因素可能不同，尤其是传染性的。我们建议测量具有 IgG4-RD 特征的患者的所有血清 IgG 亚类水平。
IgG4-Related Disease (IgG4-RD) results from tissue infiltration by IgG4-expressing plasma cells and lymphocytes, leading to fibrosis and organomegaly. Clinical presentation is remarkably variable according to organ involvement, and high IgG4 serum concentration, initially considered a diagnostic hallmark of IgG4-RD, tends to be forgone as an indispensable criterion for its diagnosis; it can indeed be absent in some patients, highlighting the diversity of presentation of this dysimmune condition. Nevertheless, elevation of IgG4 serum concentration in suggestive settings remains an argument in favour of IgG4-RD, and while other IgG subclasses can be elevated, this biological feature lacks any diagnostic value. We retrospectively studied 9 patients (5 females, 4 males, 31-81 years old) for whom a diagnosis of IgG4-RD had been considered, based on clinical, imaging or histological criteria, but appeared to display abnormally high serum IgG2 while IgG4 levels were normal. Increased serum IgG1 in one case and increased IgG3 in another one were also noticed. Immunohistochemical analyses of intracellular immunoglobulins could be performed on tissue lymph node biopsies from 2 patients, which demonstrated strong infiltration with IgG2-expressing plasma cells. Thus, overexpression of IgG2 subclass may highlight cases of dysimmune disorders resembling IgG4-RD, although the disease trigger might be different, notably infectious. We suggest measuring all serum IgG subclass levels in patients with features consistent with IgG4-RD.