[Immunoglobulin G (IgG) 4-related diseases]

Immunoglobulin G (IgG) 4‑related diseases are fibrosing inflammatory systemic diseases that can affect almost every organ system. Typical disease manifestations include autoimmune pancreatitis, lymphadenopathy, retroperitoneal fibrosis, inflammatory orbitopathy and involvement of the salivary and lacrimal glands. Organ involvements can occur either isolated or in combination with other disease manifestations. Before diagnosing IgG4-related diseases, malignancies and other inflammatory diseases have to be excluded. The diagnosis requires a combination of laboratory findings, histological and radiological results. Typically, IgG4-related diseases respond well to glucocorticosteroids. In cases of relapse or severe organ involvement a longer term immunosuppression is often required, whereas watch and wait can also be sufficient in milder cases.