Parameter
| Biomarker | IgG4 | Full name | Immunoglobulin G4 | Molecular Type | Immunoglobulin (Antibody subtype) |
|---|---|---|---|---|---|
| Molecular Formula | Human IgG4: C₆₃₂H₉８₄N₁₆₄O₁₉６S₈ | Molecular Weight | ~150 kDa | Core Functional Dimensions | Assessment of immune imbalance |
| Disease | Inflammatory Bowel Disease (IBD) | Disease Subtypes | / | ||
| Organ | Intestine | Test Sample / Technology Platform | Serum/intestinal mucosal biopsy (ELISA, immunohistochemistry, flow cytometry, immunoblotting) | ||
| Pathobiological Mechanisms | 1. Abnormal activation of B cells inhibits complement activation and regulates Treg/Th17 balance by cross-reacting with intestinal mucosal antigens; (2) The serum IgG4 level of UC patients with PSC was significantly increased (≥175mg/dL), which indicated that the bile duct - intestinal immune cross-reaction was positively correlated with the degree of bile duct fibrosis (r=0.76). When intestinal mucosal IgG4 + plasma cell infiltration (> 50 / HPF), the risk of non-response to glucocorticoid in UC patients increased 3.1-fold | ||||
| Clinical Availability Status | Application in special clinical scenarios | ||||
| Notes and Dynamics | 1. IgG4 > 175mg/dL is a potential early warning indicator of cholangiocarcinoma in UC patients with PSC (Hepatology study 2025); 2. Rituximab (anti-CD20) can reduce the level of IgG4 in patients with UC-PSC, and preliminary clinical trials show that the remission rate of cholangitis is increased by 25% | ||||