Department of Traditional Chinese Medicine, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China.
Department of Rheumatology and Clinical Immunology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China.
Clin Exp Rheumatol. 2020 Jan-Feb;38(1):35-41. Epub 2019 Apr 16.
SAPHO syndrome is a rare inflammatory disorder with multiple phenotypes, including synovitis, acne, pustulosis, hyperostosis, and osteitis. IgG4 is a subclass of immunoglobulin G, and the elevation of IgG4 has been found in different autoimmune diseases. In the present study, we explored the clinical significance of serum IgG4 levels in patients with SAPHO syndrome.
Fifty-two patients who met the classification criteria of SAPHO syndrome were included in this study. Clinical data and disease activity markers were collected including erythrocyte sedimentation rate (ESR), high sensitivity C-reactive protein (hsCRP), pain visual analogue scale (VAS), Bath Ankylosing Spondylitis Metrology Index (BASMI), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI) and Ankylosing Spondylitis Disease Activity Score (ASDAS). Serum immunoglobin (IgA, IgM, and IgG) and IgG subclass (IgG1, IgG2, IgG3, and IgG4) levels were determined using the immunonephelometric assay.
Raised serum IgG4 levels (>1400 mg/dL) were detected in 23% (12/52) of patients. Patients with elevated sIgG4 levels had significantly higher pain VAS (5.42±2.76 vs. 3.08±1.78, p=0.02), BASMI (1.80±1.64 vs. 0.38±0.94, p=0.03) and ASDAS (3.20±0.65 vs. 1.74±0.58, p<0.001) levels compared with patients with normal sIgG4 levels. This difference was also observed for ESR (38.2 vs. 22.2 mm/h, p=0.01) and serum CRP (21.0 vs. 2.2 mg/L, p=0.04) levels, which also positively correlated with sIgG4 levels. We also included 4 patients whose IgG4 levels decreased and correlated with the decrease in hsCRP and ESR levels after treatment.
Elevated sIgG4 levels are common in patients with SAPHO syndrome and are associated with high disease activity. Further investigations are needed for this phenomenon.
SAPHO 综合征是一种罕见的多表型炎症性疾病，包括滑膜炎、痤疮、脓疱病、骨肥厚和骨炎。免疫球蛋白 G4（IgG4）是免疫球蛋白 G 的一个亚类，在不同的自身免疫性疾病中发现 IgG4 升高。在本研究中，我们探讨了 SAPHO 综合征患者血清 IgG4 水平的临床意义。
本研究纳入了 52 名符合 SAPHO 综合征分类标准的患者。收集了临床数据和疾病活动标志物，包括红细胞沉降率（ESR）、高敏 C 反应蛋白（hsCRP）、疼痛视觉模拟评分（VAS）、Bath 强直性脊柱炎计量指数（BASMI）、Bath 强直性脊柱炎疾病活动指数（BASDAI）、Bath 强直性脊柱炎功能指数（BASFI）和强直性脊柱炎疾病活动评分（ASDAS）。采用免疫比浊法测定血清免疫球蛋白（IgA、IgM 和 IgG）和 IgG 亚类（IgG1、IgG2、IgG3 和 IgG4）水平。
在 52 名患者中，23%（12/52）的患者血清 IgG4 水平升高（>1400mg/dL）。与 IgG4 水平正常的患者相比，血清 IgG4 水平升高的患者疼痛 VAS（5.42±2.76 vs. 3.08±1.78，p=0.02）、BASMI（1.80±1.64 vs. 0.38±0.94，p=0.03）和 ASDAS（3.20±0.65 vs. 1.74±0.58，p<0.001）水平显著更高。ESR（38.2 vs. 22.2mm/h，p=0.01）和血清 CRP（21.0 vs. 2.2mg/L，p=0.04）水平也有类似的差异，这些指标也与 sIgG4 水平呈正相关。我们还纳入了 4 名患者，他们的 IgG4 水平下降，与治疗后 hsCRP 和 ESR 水平下降相关。
SAPHO 综合征患者常出现血清 IgG4 水平升高，与疾病活动度高相关。对此现象还需要进一步研究。
