A clinical overview of IgG4-related systemic disease.
OBJECTIVE
To summarize the existing knowledge of various clinical presentations of IgG4-related systemic disease (IgG4-RSD) and to review the evolving list of organs affected by IgG4-RSD.


RESULTS
The term IgG4-RSD encompasses a variety of clinical entities once regarded as being entirely separate diseases. The list of organs associated with this condition is growing steadily. Tissue biopsies reveal striking histopathological similarity, regardless of which organ is involved, although subtle differences across organs exist. Diffuse lymphoplasmacytic infiltrates, presence of abundant IgG4-positive plasma cells and extensive fibrosis are the hallmark pathology findings. Tumorous swelling, eosinophilia, and obliterative phlebitis are other frequently observed features. Polyclonal elevations of serum IgG4 are found in most but not all patients.


CONCLUSIONS
IgG4-RSD is an underrecognized condition about which knowledge is now growing rapidly. Yet there remain many unknowns with regard to its cause, pathogenesis, various clinical presentations, approach to treatment, disease monitoring, and long-term outcomes. A wide variety of organs can be involved in IgG4-RSD. Clinicians should be aware of this entity and consider the diagnosis in the appropriate settings.
Rheumatology Unit, Massachusetts General Hospital, Boston, MA 02114, USA. akhosroshahi@partners.org
Arezou
A
Khosroshahi
John H
JH
Stone
D001327:Autoimmune Diseases / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology*; D002761:Cholangitis / Q000276:immunology; D005260:Female; D005767:Gastrointestinal Diseases / Q000276:immunology; D005938:Glucocorticoids / Q000627:therapeutic use; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism*; D008107:Liver Diseases / Q000276:immunology; D008297:Male; D009916:Orbital Diseases / Q000276:immunology; D010195:Pancreatitis / Q000276:immunology*; D012185:Retroperitoneal Fibrosis / Q000276:immunology; D012793:Sialadenitis / Q000276:immunology
D005938:Glucocorticoids; D007074:Immunoglobulin G