Thoracic Involvement in IgG4-Related Disease.

Area of Science:

• Rheumatology
• Immunology
• Pathology

Background:

• Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibroinflammatory disorder with tumefactive lesions.
• Initially described as autoimmune pancreatitis (AIP), IgG4-RD is now recognized worldwide, affecting various organs, particularly in middle-aged to older men.
• Its pathogenesis is unclear, with suspected roles for genetic factors, microorganisms, and autoimmunity.

Purpose of the Study:

• To summarize the current understanding of Immunoglobulin G4-related disease (IgG4-RD).
• To highlight the diverse intrathoracic manifestations of IgG4-RD.
• To outline diagnostic criteria and therapeutic approaches for IgG4-RD.

Main Methods:

• Review of existing literature on IgG4-RD, focusing on its systemic and thoracic manifestations.
• Analysis of diagnostic criteria, including clinical, laboratory, imaging, and histopathologic features.
• Evaluation of current and emerging therapeutic strategies, including glucocorticoids and B cell depletion.

Main Results:

• IgG4-RD involves virtually any organ, often presenting as tumefactive lesions.
• Thoracic involvement is diverse, including parenchymal, pleural, airway, vascular, and mediastinal lesions, often found incidentally.
• Elevated serum IgG4 is common but nonspecific; characteristic histopathology includes lymphoplasmacytic infiltrate, fibrosis, and obliterative phlebitis.

Conclusions:

• Diagnosis of IgG4-RD necessitates a comprehensive correlation of clinical, laboratory, imaging, and histopathologic findings.
• Glucocorticoids are the primary treatment, leading to improvement in most patients.
• Ongoing research explores alternative therapies like B cell depletion for IgG4-RD management.