The clinical significance of serum IgG4 in the diagnosis of IgG4-related diseases

Abstract

Objective To evaluate the clinical applications of serum IgG4 for the diagnosis of IgG4-related disease (IgG4-RD). Methods In this retrospective study, 160 adult patients with IgG4-RD who in their first time visit in Peiking Union Medical College Hospital between 2011 to 2013 were reviewed. All patients had detailed clinical reference and final clear diagnosis. Meantime we selected 126 patients with other non- IgG4-related immune disease and 125 healthy subjects as controls from Peiking Union Medical College Hospital physical checkup center, IgG4 was detected by nephelometry, takeing the first testing result for analysis. Statistical analysis was performed using SPSS13.0 software. Results Serum IgG4 levels higher than 1 350 mg/L were seen in 82.5% of the patients (132/160) with IgG4-RD and 20.6% of the patients（26/126）with other diseases respectively. The serum concentrations of IgG4 in IgG4-RD group were significantly higher than other disease group and healthy control group(χ2 =110.8，158.6, P 0.05). The optimal diagnostic cut-off values for IgG4-RD was 1575mg / L . Conclusion The best diagnostic cut valuse of serum IgG4 for Chinese IgG4-RD is different from the current international standard, and realize that to establish reference vange of Chinese for diagnosis of IgG4-RD has very important significance.（Chin J Lab Med,2014,37:593-596） Key words: Autoimmune diseases; Immunoglobulin G; Reference values; Nephelometry and turbidimetry