IgG4-related disease (IgG4-RD), formerly known as IgG4-related systemic disease, is a chronic inflammatory condition characterized by tissue infiltration with lymphocytes and IgG4-secreting plasma cells, various degrees of fibrosis (scarring) and a usually prompt response to oral steroids.

Mar 31, 2025 · Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory condition that is capable of affecting multiple organs [1-3]. Organs affected by IgG4-RD share pathologic, serologic, and clinical features.

Immunoglobulin G4 (IgG4) represents the less abundant of the four IgG subclasses in human serum accounting for 3 to 6% of the total IgG [1]. IgG4 has been associated with several pathological conditions.

Great mimickers of IgG4-RD including pancreatic adenocarcinoma, lymphoma, and ANCA associated vasculitis can present with elevated serum IgG4 levels while biopsy confirmed IgG4-RD patients can have normal IgG4 concentrations.

Serum IgG4 levels are elevated in multiple non-IgG4-RD inflammatory and malignant conditions, with less than one-quarter of those with an elevated IgG4 meeting IgG4-RD diagnostic criteria. A serum IgG4 of ≥2.8 g l(-1) is useful in distinguishing between IgG4-RD and non-IgG4-RD diagnoses, predicting …

Aug 8, 2023 · The pathological hallmark of this disease is dense lymphoplasmacytic infiltrate with IgG4 positive plasma cells, storiform fibrosis, obliterative phlebitis, and a variable amount of eosinophils. Elevated levels of serum IgG4 is frequent. The pathology is very specific and looks similar in all organs.

Serum IgG4 level is often but not always elevated. Symptoms depend on which organs are affected. Diagnosis generally requires biopsy. Treatment is with corticosteroids and sometimes a B-cell–depleting medication. IgG4 is the least common of the 4 subtypes of IgG.

IgG4-related disease (IgG4-RD) is a newly classified, immunological condition. It involves potentially multi-organ inflammation and fibrosis, characterized (in most cases) by elevated serum IgG4 levels and presenting as tissue edema with fibrosis and marked inflammatory infiltration of IgG4-positive plasma cells.

When IgG4-related disease is suspected, serum protein electrophoresis and IgG subclasses are helpful as initial tests but a firm histological diagnosis is essential both to confirm the diagnosis and to rule out mimickers.

Dec 6, 2024 · IgG4 is the least naturally abundant IgG subclass, and the hallmark feature of IgG4-RD is markedly increased IgG4-positive plasma cells (with an IgG4 to IgG ratio >40%) in affected tissue, along with elevated polyclonal serum IgG and IgG4 in most patients.