[Serum IgG subtypes features and differential diagnosis of autoimmunepancreatitis patients]

To investigate clinical value of serum IgG subclass distribution in differential diagnosis of autoimmune pancreatitis.

Inpatients were enrolled as follow, autoimmune pancreatitis (AIP, n=28), acute and chronic pancreatitis (ACP, n=112), pancreatic cancer (PC, n=15), cholangiocarcinoma (CC, n=9), retroperitoneal fibrosis (RPF, n=37), together with healthy controls (n=52). IgG subtypes, amylase, lipase, glucose and CA19-9 were tested.For patients with autoimmune pancreatitis and pancreatic cancer, radiographic CT of abdomen and pathological staining were included for comparison.

IgG4 subtype distributed in a wide range as 7.6(1.7-13.8) g/L in AIP, 0.4(0.2-0.7) g/L in ACP, 0.7(0.2-0.9) g/L in PC, 0.5(0.4-6.5) g/L in CC and 0.4(0.2-0.7) g/L in control group, the difference was significant (H=40.536, P<0.001). There were no significant differences of IgG1, IgG3 level in AIP, RPC and control group (all P>0.05). While IgG4 level was 7.6(1.7-13.8), 1.3(0.5-2.6), 0.4(0.2-0.7) g/L in AIP, RPC and control group, respectively. The difference was significant (H=36.833, P<0.001). IgG4 level in RPC group was lower than that in AIP group (P<0.05). And it was meaningful in the differential diagnosis.

Serum IgG4 subtype plays an important role in differentiation of autoimmune pancreatitis from associated diseases.