Which of the following are the most characteristic factors in IgG4-related disease?

Question:

	1. Increased IgG4+ plasma cells in involved tissues
	2. Predominantly affects young females
	3. High serum IgG4 level
	4. Well described etiology of an infectious nature
	5. Response to corticosteroids

Answer:

The correct answers for the question "Which of the following are the most characteristic factors in IgG4-related disease?" are:

1. Increased IgG4+ plasma cells in involved tissues

3. High serum IgG4 level

5. Response to corticosteroids

Explanation
1. Increased IgG4+ plasma cells in involved tissues are an important factor as identified by a recent consensus statement on the histopathologic findings [The most characteristic factor of this disease is an increased amount of IgG4+ plasma cells in the involved tissues or a high serum IgG4 level [11]. Recently, a consensus statement has been issued defining the histopathologic characteristics seen in IgG4-related disease, taking into account IgG4 counts, IgG4-to-IgG ratio, and histologic findings of dense lymphoplasmacytic infiltrate, storiform fibrosis, and obliterative phlebitis [2].]
2. This disease is thought to primarily affect older males, with head and neck lesions affecting males and females in a fairly even distribution. [In groups with manifestations other than those involving the head and neck, men are the primary group affected, making up 75-86% of the described cases in one study. On the other hand, in cases involving the head and neck, both genders appear to be equally affected with a male predilection of 48% [23].]
3. High serum IgG4 level is one of the most common characteristics of IgG4-related disease. [The most characteristic factor of this disease is an increased amount of IgG4+ plasma cells in the involved tissues or a high serum IgG4 level [11]]
4. The etiology of IgG4-related disease is unknown, but it is thought to be autoimmune rather than infectious. [While this disease is of uncertain etiology, it is thought to be an autoimmune entity based on the presence of antibodies such as antinuclear antigen and rheumatoid factor as well as its responsiveness to steroid administration [22].]
5. Corticosteroids are the 1st line treatment for IgG4-related disease and a rapid clinical response has been described as a striking feature of this disease helping to differentiate it from malignant and infectious disorders. [While this disease is of uncertain etiology, it is thought to be an autoimmune entity based on the presence of antibodies such as antinuclear antigen and rheumatoid factor as well as its responsiveness to steroid administration [22].]

From the manuscript:
IgG4-Related Disease Presenting as a Solitary Neck Mass
Radiology Case. 2015 Feb; 9(2):1-8

This article belongs to the Neuro section.

From the manuscript

IgG4-Related Disease Presenting as a Solitary Neck Mass

Free full text article: IgG4-Related Disease Presenting as a Solitary Neck Mass

Abstract
IgG4-related disease is a newly recognized entity associated with autoimmune conditions involving almost every organ system. It is characterized by elevated serum IgG4 as well as mass like tissue infiltration by IgG4-positive plasma cells. Imaging findings are nonspecific, vary depending on the site of disease, and include mass like enlargement of the salivary or lacrimal glands and enlarged lymph nodes. Radiographic findings often mimic malignancy, necessitating tissue sampling to confirm the diagnosis. Distinguishing IgG4-related disease from malignancy is important as IgG4 responds well to steroids and conservative management.

References

1. Kamisawa T, Okamoto A. Autoimmune pancreatitis: proposal of IgG4-related sclerosing disease. J Gastroenterol 2006 Jul; 41(7):613-625