高血清免疫球蛋白G4濃度與間質性肺病：是敵是友？

High Serum IgG4 and Various Pulmonary Disease: Friend or Foe?

目的：免疫球蛋白G4（IgG4）抗體可以導致各種自體免疫疾病，除了已知的IgG4相關疾病外，IgG4抗體本身就可導致天皰瘡、重症肌無力、甚至是癌症。然而針對高血清IgG4濃度是否會導致間質性肺病目前並沒有定論。這篇回朔性研究的目的就在於研究高血清IgG4與間質性肺病之間的關係。研究方法：從2002年1月到2020年5月回朔臺北榮民總醫院的病人，共有845位患者血清IgG4濃度異常升高，其中267位符合IgG4相關性疾病的全面性準則（Comprehensive diagnostic criteria），其他578位不符合此準則但IgG4濃度升高的的患者被納入探討與整體肺部疾病、支氣管擴張／支氣管發炎、慢性阻塞性肺病以及間質性肺病的皮爾森積動差相關係數。結果：578位高IgG4血清濃度患者皮爾森積動差相關係數：整體肺部疾病（支氣管擴張/支氣管發炎、慢性阻塞性肺病以及間質性肺病）為-0.03，慢性阻塞性肺病為0.07，支氣管擴張／支氣管發炎為-0.026，間質性肺病為0.014。結論：此歷經18年、單一醫學中心，共收錄578名患者的回朔性研究指出，非IgG4相關性疾病但IgG4血清濃度高的患者與支氣管擴張／支氣管發炎、慢性阻塞性肺病以及間質性肺病並無相關性。

Objective: Antibodies of Immunoglobulin G4 (IgG4) class participate in many kinds of immune mediated inflammatory diseases including allergy, infections and neoplasms and can cause various autoimmune disorders, apart from the recently recognized IgG4-related disease (IgG4-RD), IgG4 itself is associated with pemphigus, myasthenia gravis and even malignancies. However, there is no consensus whether high serum IgG4 will lead to interstitial lung disease (ILD). The present retrospective study aimed to clarify the relationship between high serum IgG4 and ILD and other possible clinical relevance. Methods: 845 patients with high serum IgG4 were retrospectively reviewed from January 2002 to May 2020 in Taipei Veteran General Hospital. 267 of them fulfilled the criteria of IgG4-RD. Other 578 patients that failed to meet the standard criteria with high serum IgG4 level were assessed for their correlation with interstitial lung disease (ILD), bronchiectasis, and chronic obstruction pulmonary disease (COPD) by Spearman correlation method..Results: The correlation coefficient of 578 patients with high IgG4 and lung disease (combined COPD, bronchiectasis and ILD) was 0.055 whereas the coefficients between high IgG4 and COPD, bronchiectasis or ILD were 0.011, -0.003, and 0.067 respectively.Conclusion: Individuals with high IgG4-RD but not fulfilling IgG4-RD were not prone to getting ILD, COPD or bronchiectasis in our retrospective cohort (578 patients) during an 18-year follow-up in a single center.