Diagnoses & Conditions

IgG Subclass Deficiency

Understanding IgG Subclass Deficiency

Immunoglobulin type G (IgG) subclass deficiency (IgG subclass deficiency) is an immune deficiency disorder and is characterized by low blood levels of one or more of the four antibodies (immunoglobulins), specifically immunoglobulin G subclasses (IgG1, IgG2, IgG3 and IgG4), which may result in an increased susceptibility to infections. With subclass deficiency, total immunoglobulin type G (IgG), immunoglobulin type M (IgM) and other components of the immune system are normal.

Symptoms of IgG Subclass Deficiency

As with other primary immune deficiencies, common symptoms include frequent infections requiring treatment with antibiotics.

Diagnosing IgG Subclass Deficiency

Both males and females can be affected and there has been no pattern of inheritance observed in the IgG subclass deficiencies. An IgG subclass deficiency discovery should prompt evaluations over a period of months before determining whether a patient is truly immunodeficient. IgG subclass deficiencies need to be carefully interpreted considering the clinical status of the patient and their ability to produce certain antibodies in response to vaccines. Diagnosis includes serial testing of total IgG and IgG subclasses and testing of immune response to vaccines.

Treating IgG Subclass Deficiency

The use of antibiotics to treat and prevent infections is standard treatment for patients with IgG subclass deficiency, as well as additional immunization with pneumococcal vaccines to assist with immunity. Immune globulin replacement therapy is a recommended for patients that have persistent IgG subclass deficiencies, poor responses to polysaccharide vaccines and fail prophylactic antibiotic therapy. Immune globulin is extracted from a large pool of human plasma and contains all the important antibodies present in the normal population. Immune globulin therapy can be administered into the blood stream intravenously (IVIG) or under the skin subcutaneously (SCIG).


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