Comments on the European Guideline on IgG4-related Digestive Disease

Abstract

The main aim of the comments is to point out the most significant aspects of diagnosis and treatment of immunoglobulin G4 (IgG4)-related gastrointestinal diseases (IgG4-AGD), as described in European guidelines. According to the guidelines, measuring the amount of IgG4 in the serum cannot be used to confirm a diagnosis of IgG4-AGD on its own. The diagnosis of this pathology is based on a comprehensive assessment of serological and imaging studies, histological and immunohistochemical studies, the assessment of other organs’ damage, and the effectiveness of systemic glucocorticoids. Oral glucocorticoids are administered for symptomatic patients (obstructive jaundice, abdominal pain, pancreatic pain, liver, bile duct, esophagus, stomach, small and large intestine lesions), as well as asymptomatic patients with persistent cholestasis against the background of IgG4-related cholangitis and the presence of a mass lesion according to imaging studies to exclude malignant neoplasia. A typical starting dose of glucocorticoids is 0.6–0.8 mg/kg/day, or 30–40 mg/day of prednisolone equivalent. This dose of steroid should be administered orally for one month to induce remission. Subsequently, a gradual decrease in the dose of glucocorticoids begins over 3–6 months. Evaluation of the effectiveness of initial therapy with glucocorticoids is carried out after 2–4 weeks of taking steroids based on a comprehensive analysis of physical data and the results of biochemical, instrumental, and histological studies. The systemic course of the disease, with multiple organ damage or relapses, suggests the use of glucocorticoid maintenance doses. If there are no changes in the course of the disease after three months of treatment, even if the dose of glucocorticoids is reduced or the drug is withdrawn, immunosuppressive drugs (rituximab) are prescribed to keep the disease in remission.