IgG4each

IgG4-related disease (IgG4-RD) is a rare, systemic, inflammatory condition characterized by the accumulation of IgG4-positive plasma cells and fibrosis in various organs. The disease was first described in 2003 by Japanese researchers who observed a distinct pattern of inflammation in patients with autoimmune pancreatitis (AIP). Since then, IgG4-RD has been recognized as a systemic disorder affecting multiple organs, including the pancreas, salivary glands, lacrimal glands, lymph nodes, kidneys, lungs, and blood vessels.

The exact cause of IgG4-RD remains unclear, but it is believed to involve an abnormal immune response, possibly triggered by environmental factors or genetic predisposition. Elevated levels of IgG4 antibodies are a hallmark of the disease, though not all patients with high IgG4 levels develop symptoms. Diagnosis typically relies on a combination of clinical presentation, imaging studies, laboratory findings, and histopathological examination, which reveals dense lymphoplasmacytic infiltrates with storiform fibrosis and obliterative phlebitis.

IgG4-RD often presents with mass-forming lesions that can mimic malignancies, such as lymphoma or cancer, leading to misdiagnosis. Common symptoms vary depending on the affected organ but may include swelling, pain, or dysfunction. For example, autoimmune pancreatitis may cause abdominal pain and jaundice, while involvement of the salivary glands can lead to dry mouth or facial swelling. Treatment primarily involves corticosteroids, which can induce remission in most cases. Long-term management may require steroid-sparing agents, such as rituximab or azathioprine, to prevent relapses.

Prognosis for IgG4-RD is generally favorable with appropriate treatment, though some patients may experience chronic or recurrent disease. Early recognition and diagnosis are crucial to avoid unnecessary invasive procedures and to initiate timely therapy. Research continues to improve understanding of the disease mechanisms and optimize treatment strategies for affected individuals.