Ngwa Taiwo N, Law Ryan, Murray David, Chari Suresh T
From the Divisions of *Internal Medicine, †Gastroenterology and Hepatology, and ‡Laboratory Medicine, Mayo Clinic, Rochester, MN.
Pancreas. 2014 Jul;43(5):704-7. doi: 10.1097/MPA.0000000000000118.
Immunoglobulin G4-related disease (IgG4-RD) is characterized by elevation in serum IgG4 levels, typical multiorgan involvement and dramatic response to steroid therapy. We determined the predictive value of an elevated serum IgG4 for the diagnosis of IgG4-RD. We also sought to identify novel conditions, which have characteristic features of IgG4-RD.
We identified all Mayo Clinic Rochester patients with serum IgG4 levels measured between January 2008 and December 2011 (n = 6014). Those with elevated serum IgG4 levels (reference range, 121-140 mg/dL) were included in the analysis and were classified as "definite," "probable," or "no" IgG4-RD.
Serum IgG4 levels were elevated in 390 subjects (6.5%) of whom only 39 (10%) had IgG4-RD (29 "definite," 10 "probable"). The positive predictive value of an elevated serum IgG4 for IgG4-RD was poor (10%). Subjects with IgG4-RD differed from those without IgG4-RD in mean age (59.6 ± 15.2 vs 54.4 ± 18.3 years, P < 0.05), % males (90% vs 58%, P < 0.05), mean serum IgG4 level (437 ± 471 vs 223 ± 194 mg/dL, P < 0.05), and presence of chronic rhinosinusitis (7/39 vs 29/351, P = 0.05).
Elevated serum IgG4 levels are not specific for IgG4-RD and are likely to be a false-positive. Chronic rhinosinusitis is likely an as yet underrecognized manifestation of IgG4-RD.
免疫球蛋白G4相关性疾病（IgG4-RD）的特征为血清IgG4水平升高、典型的多器官受累以及对类固醇治疗有显著反应。我们确定了血清IgG4升高对IgG4-RD诊断的预测价值。我们还试图识别具有IgG4-RD特征的新情况。
我们确定了2008年1月至2011年12月期间在梅奥诊所罗切斯特分院测量血清IgG4水平的所有患者（n = 6014）。血清IgG4水平升高（参考范围为121 - 140 mg/dL）的患者被纳入分析，并分为“确诊”、“可能”或“无”IgG4-RD。
390名受试者（6.5%）的血清IgG4水平升高，其中只有39名（10%）患有IgG4-RD（29名“确诊”，10名“可能”）。血清IgG4升高对IgG4-RD的阳性预测值较低（10%）。患有IgG4-RD的受试者与未患有IgG4-RD的受试者在平均年龄（59.6 ± 15.2岁对54.4 ± 18.3岁，P < 0.05）、男性比例（90%对58%，P < 0.05）、平均血清IgG4水平（437 ± 471 mg/dL对223 ± 194 mg/dL，P < 0.05）以及慢性鼻窦炎的存在情况（7/39对29/351，P = 0.用）方面存在差异。
血清IgG4水平升高对IgG4-RD不具有特异性，很可能出现假阳性。慢性鼻窦炎可能是IgG4-RD一种尚未得到充分认识的表现。
