IgG4 Autoimmune diseases
A brief introduction into IgG4-AID
IgG4 Autoimmune diseases
IgG4 autoimmune diseases (IgG4-AID) are a group of severe autoimmunopathies that are characterized by pathogenic IgG4 autoantibodies (abs) against defined target antigens (some examples shown in Table 1). IgG4-AID may affect different organs, with the largest number of diseases affecting the peripheral and central nervous systems(1). Interestingly, they share common mechanistic and therapeutic properties, but due to their diverse clinical involvements, their relation has not been recognized until recently. IgG4-AID are rare disorders, but their cumulative prevalence adds up to 11 patients per 10,000, thus >490,000 patients in the EU. IgG4-AID are clinically severe, difficult to diagnose and challenging to treat.
More information on each one of the diseases:
MuSK Myasthenia Gravis
LGI1 autoimmune encephalitis
Autoimmune nodopathies and paranodopathies
Caspr2 autoimmune encephalitis
Anti-IgLON5 disease
More information on IgG4 autoimmune diseases.
There is a group of conditions known as IgG4-related diseases (IgG4-RD), which are distinct from IgG4 autoimmune diseases.
IgG4 Related diseases
IgG4-RD includes conditions such as autoimmune pancreatitis, IgG4-related sclerosing cholangitis, Mikulicz's disease or IgG4-related tubulointerstitial nephritis, and can affect multiple organs throughout the body. Because of this, symptoms vary widely depending on which organs are involved. Common symptoms may include fatigue, unintentional weight loss, swollen glands, tumor-like masses, or reduced function of affected organs.
Some patients may notice a reference to "elevated IgG4 levels" in their diagnostic reports.
Current research indicates that IgG4-related diseases are biologically different from IgG4 autoimmune diseases and are therefore not the focus of this consortium's work.
If you have been diagnosed with IgG4-related disease, we recommend contacting specialized clinicians or patient organizations for further guidance and support. The following resources may be helpful:
IgG4-AID x IgG4-RD
