Kawa Shigeyuki, Skold Markus, Ramsden David B, Parker Antony, Harding Stephen J
Clin Lab. 2017 Sep 1;63(9):1323-1337. doi: 10.7754/Clin.Lab.2017.170403.
IgG4-related disease (IgG4-RD) is an immune-mediated and chronic fibroinflammatory condition that affects almost any organ and often involves multiple organs in the same patient. In this review article, we address the clinical utility of measuring serum immunoglobulin G subclass 4 concentration ([IgG4]) in IgG4-RD diagnosis and in disease monitoring.
We discuss the latest literature on the relevance of [IgG4] to the investigation and management of IgG4RDs. In addition, we discuss the potential role of serum [IgG4] measurements in other inflammatory conditions and cancers.
Increasing awareness of IgG4-RD among clinicians has led to a growing list of organ systems that can be affected by this chronic condition and the development of new organ-specific diagnostic guidelines. Diagnosis of IgG4-RD depends on multiple clinical and laboratory tests, including serology. Quantification of serum [IgG4] is included in all IgG4-RD diagnostic guidelines available to-date. The scientific literature supports the idea that elevated serum [IgG4], typically > 135 mg/dL, identifies patients with a more active form of the disease, which correlates with increased concentrations of inflammatory serum biomarkers and hypocomplementemia, increased number of organs affected by the disease, and more extensive organ involvement. These patients seem more resistant to treatment and experience a shorter time to disease relapse compared to IgG4-RD patients with normal serum [IgG4] at the time of diagnosis.
Despite better understanding of how to diagnose IgG4-RD, monitoring for accurate prediction of disease relapse, which may involve organs not affected at the time of presentation, is poorly understood. Timely diagnosis and early detection of disease relapse is important to avoid delayed treatment and potential organ damage.
IgG4相关疾病（IgG4-RD）是一种免疫介导的慢性纤维炎症性疾病，几乎可累及任何器官，且同一患者常多个器官受累。在这篇综述文章中，我们探讨了检测血清免疫球蛋白G4亚类浓度（[IgG4]）在IgG4-RD诊断及疾病监测中的临床应用价值。
我们讨论了关于[IgG4]与IgG4-RD的检查和管理相关性的最新文献。此外，我们还讨论了血清[IgG4]检测在其他炎症性疾病和癌症中的潜在作用。
临床医生对IgG4-RD的认识不断提高，导致受这种慢性病影响的器官系统越来越多，同时也催生了新的器官特异性诊断指南。IgG4-RD的诊断依赖于多项临床和实验室检查，包括血清学检查。目前所有可用的IgG4-RD诊断指南均包含血清[IgG4]的定量检测。科学文献支持这样的观点，即血清[IgG4]升高（通常>135mg/dL）可识别出疾病更活跃形式的患者，这与炎症血清生物标志物浓度升高、补体血症、受累器官数量增加以及器官受累范围更广相关。与诊断时血清[IgG4]正常的IgG4-RD患者相比，这些患者似乎对治疗的反应较差，疾病复发时间更短。
尽管对如何诊断IgG4-RD有了更好的理解，但对于准确预测疾病复发的监测（这可能涉及就诊时未受累的器官）仍知之甚少。及时诊断和早期发现疾病复发对于避免延迟治疗和潜在的器官损害很重要。
