From the Guidelines
Elevated Immunoglobulin A (IgA) levels indicate an immune system response to infection, inflammation, or certain diseases, such as IgA nephropathy, rheumatoid arthritis, lupus, liver diseases, inflammatory bowel diseases, and certain cancers like multiple myeloma and IgA monoclonal gammopathy. IgA is an antibody that plays a crucial role in mucosal immunity, protecting body surfaces exposed to external environments like the respiratory and gastrointestinal tracts. High IgA levels commonly occur in chronic infections, autoimmune disorders, and certain cancers. The elevation reflects increased production of these antibodies as the body responds to perceived threats.
Key Points to Consider
- The specific cause of elevated IgA requires further investigation through additional tests, medical history review, and physical examination 1.
- The degree of elevation and accompanying symptoms help determine the underlying condition, with very high levels (particularly if they show a monoclonal pattern) potentially indicating more serious conditions like IgA myeloma that require prompt evaluation by specialists.
- Elevated IgA levels can be associated with various conditions, including autoimmune hepatitis, where selectively elevated IgG in the absence of IgA and IgM elevation is particularly suggestive of AIH 1.
- In the context of autoimmune hepatitis, the presence of elevated IgG levels, especially in the absence of cirrhosis, is a distinctive feature of AIH, but IgA levels are usually normal 1.
Diagnostic Approach
- A quantitative serum IgA level should be obtained at the time of celiac disease screening to rule out IgA deficiency, which can lead to falsely low levels of IgA tissue transglutaminase (tTG) or endomysial autoantibody (EMA) assays 1.
- The diagnosis of atopic dermatitis remains clinical, and while elevated total and/or allergen-specific serum IgE levels are commonly associated with the disease, they are not present in about 20% of affected individuals, and IgA levels are not typically used as a biomarker for this condition 1.
Management and Prognosis
- The management of conditions associated with elevated IgA levels depends on the underlying cause and may involve treatment of the underlying infection, inflammation, or disease.
- In cases of autoimmune hepatitis, treatment with immunosuppressive medications and, in some cases, liver transplantation may be necessary 1.
From the Research
Elevated Immunoglobulin A (IgA) Levels
Elevated IgA levels can indicate various conditions and diseases. Some of the key points to consider include:
- Elevated IgA levels are found in certain autoimmune and inflammatory diseases, such as chronic active hepatitis and primary biliary cirrhosis 2.
- In inflammatory bowel diseases, such as Crohn's disease and ulcerative colitis, IgA subclass levels can provide a differential diagnostic tool 2.
- High levels of IgA are associated with certain clinical and biological characteristics in patients with rheumatoid arthritis, including microscopic haematuria, unilateral sacroiliitis, and arthritis of the distal interphalangeal joints 3.
- Elevated IgA levels can also be found in other conditions, such as coeliac disease and autoimmune diseases 4.
Conditions Associated with Elevated IgA
Some of the conditions associated with elevated IgA levels include:
- Chronic active hepatitis
- Primary biliary cirrhosis
- Coeliac disease
- Crohn's disease
- Ulcerative colitis
- Rheumatoid arthritis
- Autoimmune diseases, such as systemic lupus erythematosus and juvenile rheumatoid arthritis 2, 4, 3, 5.
Diagnostic Considerations
Elevated IgA levels can be detected through quantitative serum immunoglobulin tests, which are used to diagnose various conditions and diseases that affect the levels of one or more of the major immunoglobulin classes 6.