La maladie associée aux immunoglobulines G4

Immunoglobulin G4- related disease (IgG4-RD) is a recent entity. It is characterized clinically, by involvement of one or more organs with tumor-like lesions and lymphoplasmablast infiltrate associated with fibrosis on biopsies. Elevated serum IgG4 concentration is found in many but not all patients. The main organs affected are the pancreas (type 1 autoimmune pancreatitis), bile ducts, salivary and lacrimal glands, retro-peritoneum, but all organs can be affected. The IgG4-RD pathophysiology remains incompletely understood and involves many mechanisms of innate and acquired immunity. The current diagnosis is based on knowledge of the main organs affected, serum IgG4 concentration and a rigorous histological analysis. Quantification of circulating plasmablasts looks promising especially in patients with normal IgG4 concentration in serum. IgG4-RD is a steroid-sensitive disease, Others immunosuppressive treatments, as rituximab, could also be proposed.