Immunoglobulin A, or IgA, is a type of antibody produced by the immune system. Antibodies are specialized proteins that identify and neutralize foreign invaders like bacteria and viruses, forming a key part of the body’s defense. Elevated IgA levels in a blood test are not a diagnosis on their own, but indicate a potential underlying health issue. Interpreting elevated IgA levels requires careful consideration by a healthcare professional, as it can point to a variety of conditions.
Understanding Immunoglobulin A (IgA)
IgA protects the body’s mucosal surfaces, the moist linings of various body systems. These surfaces include the respiratory tract, the gastrointestinal tract, and the urogenital tract. It is also found in external secretions like tears, saliva, and breast milk, providing a first line of defense against pathogens.
This antibody prevents microorganisms from adhering to and penetrating mucosal linings, neutralizing threats at their entry points. There are two main forms of IgA: serum IgA, which circulates in the bloodstream, and secretory IgA (sIgA), which is the predominant form found in mucosal secretions. Secretory IgA has a unique structure that makes it more resistant to degradation in harsh environments, like the digestive tract, maintaining its protective function.
Conditions Linked to Elevated IgA Levels
Elevated IgA levels associate with various medical conditions, reflecting the immune system’s response. Chronic infections, such as chronic hepatitis or tuberculosis, can continuously stimulate IgA production as the body attempts to clear the infection, leading to higher circulating levels.
Autoimmune disorders frequently present with elevated IgA, as the immune system mistakenly targets the body’s own tissues. IgA nephropathy, often called Berger’s disease, is a prime example where IgA deposits accumulate in the kidneys, potentially impairing kidney function. Celiac disease, an autoimmune condition triggered by gluten, also shows elevated IgA due to chronic inflammation in the small intestine. Other autoimmune conditions like rheumatoid arthritis and systemic lupus erythematosus can also link to increased IgA levels, reflecting a heightened immune response.
Liver diseases often lead to elevated IgA because the liver clears immune complexes, including those containing IgA, from the bloodstream. Conditions like alcoholic liver disease, cirrhosis, or chronic viral hepatitis can impair this clearance, resulting in an accumulation of IgA in the blood.
Inflammatory bowel diseases, including Crohn’s disease and ulcerative colitis, involve chronic inflammation of the digestive tract. Ongoing inflammatory processes can stimulate local IgA production in the gut, contributing to elevated bloodstream levels. Other inflammatory conditions can also cause a transient rise in IgA as part of the body’s inflammatory response.
Certain cancers, particularly those involving plasma cells, can also cause significantly elevated IgA levels. IgA multiple myeloma, a blood cancer, is characterized by uncontrolled proliferation of a plasma cell clone that produces excessive IgA. Lymphoma, another type of blood cancer, can also sometimes be associated with elevated IgA, though this is less common than in multiple myeloma.
Investigating Elevated IgA Levels
When elevated IgA is detected, further investigation determines the underlying cause. A healthcare provider begins by taking a detailed medical history, asking about symptoms, past illnesses, and family medical history. A thorough physical examination also looks for signs or symptoms pointing to a specific condition.
Following initial assessment, additional diagnostic tests are ordered to narrow possibilities. These may include liver function tests to assess liver health, kidney function tests to check for kidney impairment, and inflammatory markers such as C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR), which indicate general inflammation. Specific autoantibody tests may be performed if an autoimmune condition is suspected. In some cases, more invasive procedures like a kidney biopsy for suspected IgA nephropathy or a small bowel biopsy for celiac disease are required to confirm a diagnosis.
Managing Elevated IgA Levels
There is no direct treatment for elevated IgA levels themselves. Instead, management focuses on identifying and addressing the underlying condition responsible for the increase. Once the root cause is diagnosed, a targeted treatment plan can be implemented.
For instance, if a chronic infection is identified, antibiotics or antiviral medications would be prescribed to eliminate the pathogen. In cases of autoimmune diseases, treatment often involves immunosuppressant medications to modulate immune system activity and reduce inflammation. For liver diseases, management includes lifestyle modifications, such as avoiding alcohol, and specific medications to support liver function or treat the underlying cause of liver damage. If celiac disease is diagnosed, a strict gluten-free diet is the primary management strategy.