Диагностическое значение определения IgG4 сыворотки в дифференциальной диагностике склерозирующих холангитов

Abstract

The aim: to determine the cut-off levels of serum IgG. IgG4 and IgG4/IgG ratio for the differential diagnosis of IgG4-sclerosing cholangitis and primary sclerosing cholangitis. Material and methods. We conducted a single-center study of 32 and 67 patients with IgG4-sclerosing cholangitis and primary sclerosing cholangitis. which were verified according to HISORt and EASL criteria. respectively. Patients underwent determination of total IgG and IgG4 in serum by enzyme immunoassay. and the IgG4/IgG ratio was calculated before the initiation of glucocorticoid therapy. The reference values for IgG were 7–16 g/L and for IgG4 ≤ 1.35 g/L. ROC-analysis was used to determine the cut-off values of serum IgG. IgG4. IgG4/IgG ratio for differential diagnosis between primary sclerosing cholangitis and IgG4-sclerosing cholangitis. Results. The mean age at diagnosis of IgG4-sclerosing cholangitis was 59 ± 13 years and primary sclerosing cholangitis was 41 ± 20 years (p < 0.001). IgG4-sclerosing cholangitis was initially misdiagnosed as primary sclerosing cholangitis in 41.2% of patients (95% CI 24.6–59.3). The median time before diagnosis of IgG4-sclerosing cholangitis was 10.5 months. The median serum IgG4 level was 2.7 g/L [1.92; 6.48] in patients with IgG4-sclerosing cholangitis and 0.6 g/L [0.60; 1.45] in patients with primary sclerosing cholangitis. 33% of patients with primary sclerosing cholangitis had blood IgG4 levels exceeded 1.35 g/L. Whereas among patients with IgG4-sclerosing cholangitis. 19.4% had normal values of this parameter. The cut-off values of serum IgG and IgG4 and IgG4/IgG ratios for distinguishing primary sclerosing cholangitis from IgG4-sclerosing cholangitis were 17.1 g/L (sensitivity 75.0% and specificity 72.4%). 1.99 g/L (sensitivity 92.3% and specificity 74.2%). and 0.11 (sensitivity 84.2% and specificity 64.3%). respectively. Conclusions. The cut-off values of IgG. IgG4 concentration and IgG4/IgG ratio in serum can be used for differential diagnosis of primary sclerosing cholangitis and IgG4-sclerosing cholangitis.