IgG4 (M)

Product Description

The Biocare IgG4 [HP6025] antibody detects human IgG4, a subclass of immunoglobulin G, and specifically recognizes the Fc region. Mouse monoclonal IgG4 [HP6025] is highly specific and may be useful in the diagnosis of IgG4-related systemic disease (IgG4-RSD), also known as IgG4-related sclerosing disease, which can affect multiple organs and is characterized by lymphoplasmacytic infiltration, mass formation, sclerosis, obliterative phlebitis, and increased IgG4+ plasma cells, typically with an IgG4+/IgG+ ratio >30%.^15-18

IgG4 is overexpressed in inflammatory pseudotumor (IPT) and underexpressed in inflammatory myofibroblastic tumor (IMT), making it a useful differential marker in panels with IgG (higher IgG4+/IgG+ ratio in IPT) and ALK (positive in IMT).^18,19 In pulmonary nodular lymphoid hyperplasia (PNLH), increased IgG4+ plasma cells and a higher IgG4+/IgG+ ratio may help distinguish PNLH from low-grade B-cell lymphoma of the bronchus-associated lymphoid tissue (BALT).²⁰

Elevated IgG4 expression has also been reported in 39% of primary cutaneous marginal zone lymphomas, suggesting localized IgG4-mediated involvement at early stages, and in autoimmune pancreatitis (AIP), aiding differentiation from other pancreatic mass-forming lesions, including invasive ductal carcinoma.^21,22

Historically, immunofluorescence was used to detect IgG subclasses on paraffin-embedded tissues, but immunohistochemical (IHC) methods are increasingly employed for routine detection.^15-22

Specifications

1. Khosroshahi A, et al. A clinical overview of IgG4-related systemic disease. Curr Opin Rheumatol. 2011 Jan; 23(1):57-66.
2. Divatia M, Kim S, Ro J. IgG4-related sclerosing disease, an emerging entity: a review of a multi-system disease. Yonsei Med J. 2012 Jan; 53(1):15-34.
3. Sato Y, et al. Clinicopathologic analysis of IgG4-related skin disease. Mod Pathol. 2013 Apr; 26(4):523-32.
4. Saab ST, et al. IgG4 plasma cells in inflammatory myofibroblastic tumor: inflammatory marker or pathogenic link? Mod Pathol. 2011 Apr; 24(4):606-12.
5. Bhagat P, et al. Pulmonary inflammatory myofibroblastic tumor and IgG4-related inflammatory pseudotumor: a diagnostic dilemma. Virchows Arch. 2013 Dec; 463 (6):743-7.
6. Guinee DG Jr, et al. Pulmonary nodular lymphoid hyperplasia (pulmonary pseudolymphoma): the significance of increased numbers of IgG4-positive plasma cells. Am J Surg Pathol. 2010 Dec; 34(12):1812-9.
7. Brenner I, et al. Primary cutaneous marginal zone lymphomas with plasmacytic differentiation show frequent IgG4 expression. Mod Pathol. 2013 Dec; 26(12):1568-76. 8. Sepehr A, et al. IgG4+ to IgG+ plasma cells ratio of ampulla can help differentiate autoimmune pancreatitis from other “mass forming” pancreatic lesions. Am J Surg Pathol. 2008 Dec; 32(12):1770-9.
9. Hamilton RG, et al. Epitope mapping of human immunoglobulin-specific murine monoclonal antibodies with domain-switched, deleted and point-mutated chimeric antibodies. J Immunol Methods. 1993 Jan 14; 158(1):107-22.
10. Center for Disease Control Manual. Guide: Safety Management, NO. CDC-22, Atlanta, GA. April 30, 1976 “Decontamination of Laboratory Sink Drains to Remove Azide Salts.”
11. Clinical and Laboratory Standards Institute (CLSI). Protection of Laboratory Workers from Occupationally Acquired Infections; Approved guideline-Fourth Edition CLSI document M29-A4 Wayne, PA 2014.