[Clinical importance of the IgG4 related disease].

IgG4 related disease is a chronic immunopathological disorder, proposed as a new diagnostic entity, and characterized as follows: 1. background is in multiorgan lymphoplasmocellular infiltration associated with presence of large number of polyclonal IgG4+ plasma cells, and fibrosclerosis; 2. structural damage of the affected organs is frequently associated with pseudotumorous enlargement and/or other morphological changes; for example aortitis with aneurysmatic dilatation, sclerosing pancreatitis, retroperitoneal fibrosis ect.; 3. serum concentration of IgG4 is usually significantly elevated; 4. responsivity to glucocorticoids is a hallmark of the disease: in rare cases of glucocorticoid-resistance a response to rituximab was observed. At presence the disease related to IgG4 is considered as a rare disorder. Presented knowledge may be useful for better elucidation of its importance in clinical specialities.