Biomarkers of Immunity: An Immunoglobulin Overview

Immunoglobulins are gamma globulin proteins referred to as antibodies. They are produced by “activated” B lymphocytes (adaptive immunity) in response to various pathogens (e.g., bacteria, viruses, parasites, fungi), cellular antigens, chemicals, and even synthetic substances.

Optimal Takeaways

In general, immunoglobulins activate the complement system, tag microorganisms for elimination, interfere with the binding of microbes to tissue, and neutralize viruses and toxins.

Immunoglobulins may be used therapeutically in immunodeficiency, multiple sclerosis, lupus, myasthenia gravis, organ transplant, and Kawasaki disease (Justiz 2021). The complement system, activated by immunoglobulins, generates an inflammatory and aggressive response against pathogens and antigens. It bridges innate and adaptive immune responses (Dunkelberger 2010).

Serum immunoglobulins may be monitored in chronic infections, hypersensitivity disorders, autoimmune diseases, and immune deficiency. Levels in general can decrease in acquired and congenital immune deficiency and hypoproteinemia. Levels can increase in acute and chronic infections, connective tissue diseases, hepatic disease, and monoclonal gammopathies such as multiple myeloma. Medications that increase immunoglobulins include gamma globulin, hydralazine, isoniazid, phenytoin, tetanus toxoid/antitoxin, and procainamide (Pagana 2021).

Hypogammaglobulinemia increases an individual’s susceptibility to infection, allergy, cancer, and autoimmunity. Primary hypogammaglobulinemia is genetic while secondary hypogammaglobulinemia may be caused by steroid or immunosuppressant drugs, chemotherapy, infection, cancer, malnutrition, metabolic disease, nephrotic syndrome, and environmental factors. Immunity against infection is regulated by IgA, IgG, and IgM while the IgE antibodies regulate allergic reactions. These antibodies can be measured separately in the blood (Huq 2021). 

References

Agarwal, Shradha, and Charlotte Cunningham-Rundles. “Assessment and clinical interpretation of reduced IgG values.” Annals of allergy, asthma & immunology : official publication of the American College of Allergy, Asthma, & Immunology vol. 99,3 (2007): 281-3. doi:10.1016/S1081-1206(10)60665-5

Dunkelberger, Jason R., and Wen-Chao Song. "Complement and its role in innate and adaptive immune responses." Cell research 20.1 (2010): 34-50.

Huq, Madiha, et al. “Hypogammaglobulinemia.” StatPearls, StatPearls Publishing, 9 October 2021.

Justiz Vaillant, Angel A., et al. “Immunoglobulin.” StatPearls, StatPearls Publishing, 12 October 2021.

Pagana, Kathleen Deska, et al. Mosby's Diagnostic and Laboratory Test Reference. 15th ed., Mosby, 2021.