First Department of Internal Medicine, University of Occupational and Environmental Health, Japan, Kitakyushu, Fukuoka, Japan.
Department of Pathology and Oncology, University of Occupational and Environmental Health, Japan, Kitakyushu, Fukuoka, Japan.
RMD Open. 2022 Mar;8(1). doi: 10.1136/rmdopen-2021-002086.
To study the pathophysiological differences of EGPA and IgG-related disease (RD) by clarifying their clinical, pathological and immunological features.
Clinical and pathological findings were compared in patients with EGPA and IgG-RD. Peripheral blood mononuclear cells were used for comprehensive flow cytometric analysis.
An elevation of the IgG4 level was found in all EGPA cases, with the accompanying pathological findings of lymphocytic infiltration and fibrosis observed in 30.8% patients, and the elevation of IgG/IgG ratio in 61.5% patients. However, actual IgG levels, as well as the degree of the infiltration of IgG-positive plasma cells, were still higher in patients with IgG-RD than patients with EGPA. Examination by ACR/EULAR classification criteria showed only 13.6% of the EGPA patients met entry criteria, while all of them met the exclusion criteria. In regard to the immunophenotyping, EGPA patients had increases in activated CD4 and CD8 T cells compared with the healthy controls. However, no such similar changes occurred in IgG-RD patients. On the other hand, both the EGPA and IgG-RD patient groups had correlated increased plasmablasts and Tfh. These results indicate the presence of two axes: namely, the activation of T cells and that of B cells. Both axes are present in EGPA, but the T cell activation axis was not observed in IgG-RD.
The elevation of serum IgG as well as pathological IgG infiltration are not specific. Meanwhile, EGPA and IgG4-RD differ in immunological phenotypes, indicating the possible importance of the predominant activation of T cells in the development of vasculitis.
通过阐明 EGPA 和 IgG 相关疾病（RD）的临床、病理和免疫学特征，研究其病理生理学差异。
比较 EGPA 和 IgG-RD 患者的临床和病理发现。使用外周血单核细胞进行综合流式细胞术分析。
所有 EGPA 病例均发现 IgG4 水平升高，伴有 30.8%患者淋巴细胞浸润和纤维化的病理发现，以及 61.5%患者 IgG/IgG 比值升高。然而，实际 IgG 水平以及 IgG 阳性浆细胞浸润程度仍高于 IgG-RD 患者。根据 ACR/EULAR 分类标准检查，只有 13.6%的 EGPA 患者符合纳入标准，而所有患者均符合排除标准。在免疫表型方面，与健康对照组相比，EGPA 患者的活化 CD4 和 CD8 T 细胞增加。然而，在 IgG-RD 患者中未发生类似变化。另一方面，EGPA 和 IgG-RD 患者组均有相关的浆母细胞和 Tfh 增加。这些结果表明存在两个轴：即 T 细胞激活和 B 细胞激活。两个轴均存在于 EGPA 中，但在 IgG-RD 中未观察到 T 细胞激活轴。
血清 IgG 升高以及病理 IgG 浸润并不具有特异性。同时，EGPA 和 IgG4-RD 在免疫表型上存在差异，表明 T 细胞激活在血管炎发展中的重要性。
