Abstract:

Objective  To evaluate the value of serum IgG4 level for the differential diagnosis of IgG4-related disease (IgG4-RD) and investigate the ocular manifestations of IgG4-RD. Methods  A total of 29 patients with IgG4-RD, 161 patients with other diseases and elevated serum IgG4 levels (among them, 47 patients with autoimmune liver disease, 15 patients with acute pancreatitis, 61 patients with primary glomerulopathy and renal insufficiency, and 38 patients with inflammatory bowel disease), and 190 normal controls were enrolled. Serum IgG4 and IgG levels were measured by immunonephelometry and results of groups were compared. The receiver operating characteristic (ROC) curve was drawn based on the serum IgG4 levels of patients. The diagnostic value of serum IgG4 level was evaluated and the optimal cutoff value of serum IgG4 level for diagnosing IgG4-RD was determined. Patients with IgG4-RD underwent ophthalmologic tests and their ocular manifestations were evaluated. Results  The differences of serum IgG4 level between IgG4-RD group and primary glomerulopathy and renal insufficiency group, inflammatory bowel disease group, autoimmune liver disease group and acute pancreatitis group were statistically significant (P<0.01). According to the analysis of ROC curve, the Youden index reached the biggest when the IgG4 level was 2.37 g/L. The sensitivity and specificity of this cutoff value for the diagnosis of IgG4-RD were 93.1% and 84.3% and the area under the curve was 0.939. Among 29 patients with IgG4-RD, two of them had orbital occupying lesion and others had no special ocular manifestations. Conclusion  The sensitivity and specificity of serum IgG4 level for the diagnosis of IgG4-RD are high and can be regarded as one of evidences for the diagnosis of IgG4-RD. The serum IgG4 level indicates the possibility of IgG4-RD. Patients with IgG4-RD have no special ocular manifestations.

Key words: serum IgG4, diagnostic value, ocular manifestations