Immunoglobulins are immune system proteins that identify and neutralize foreign objects. Immunoglobulin A (IgA) is a specific antibody crucial for defense. Elevated IgA levels often signal an active immune response to a perceived threat or imbalance.
Understanding Immunoglobulin A
IgA primarily functions in “mucosal immunity,” forming a protective barrier on surfaces interacting with the external environment. It is abundant in secretions like tears, saliva, mucus (respiratory and gastrointestinal tracts), and breast milk, intercepting pathogens before they enter the body.
IgA has two main forms: secretory IgA (sIgA) and serum IgA. Secretory IgA is predominant in mucosal secretions, existing as a polymeric structure that withstands harsh conditions. Serum IgA circulates in the bloodstream, primarily in a monomeric form, with its precise functions still under investigation.
Why IgA Levels Rise
Elevated IgA levels indicate an active immune system defense. This physiological increase reflects the body’s ramped-up antibody production. Heightened IgA can stem from various categories of immune activation.
Increased IgA often results from the body fighting infections (bacterial, viral, parasitic). When pathogens invade, especially via mucosal surfaces, the immune system produces more IgA to neutralize them. Chronic inflammation, regardless of cause, can also lead to persistently elevated IgA, signaling an ongoing immune alert. An overactive immune system, mistakenly targeting its own tissues, can also result in higher IgA as part of its misguided response.
Conditions Linked to High IgA
Elevated IgA levels can manifest in several conditions and diseases, often involving the immune system’s active engagement.
Chronic or recurrent infections, especially those affecting the respiratory tract (e.g., bronchitis, sinusitis) or gastrointestinal tract (e.g., giardiasis, H. pylori), frequently lead to sustained high IgA. Liver diseases, including alcoholic cirrhosis and other chronic liver damage, are also associated with increased IgA, though mechanisms can involve impaired clearance of immune complexes.
Autoimmune diseases, where the immune system mistakenly attacks healthy tissues, can also cause IgA to rise. Examples include rheumatoid arthritis, systemic lupus erythematosus, and inflammatory bowel diseases (Crohn’s disease, ulcerative colitis). IgA may be part of the broader inflammatory response. IgA nephropathy (Berger’s disease), a specific kidney condition, is characterized by IgA immune complex accumulation in the kidney’s filtering units, leading to inflammation and damage.
Celiac disease, an autoimmune disorder triggered by gluten, results in an immune response with elevated IgA antibodies against gluten components and intestinal tissues. Less commonly, certain cancers like multiple myeloma (a plasma cell cancer) can lead to very high, often monoclonal, IgA levels due to uncontrolled proliferation of antibody-producing cells.
Interpreting Results and Next Steps
An elevated IgA level is a laboratory finding, not a definitive diagnosis. It indicates immune system activation but does not specify the underlying cause. Therefore, consulting a healthcare professional for comprehensive evaluation and proper interpretation is important.
A doctor will consider IgA levels with a person’s symptoms, medical history, and other diagnostic tests. Additional investigations are often necessary to pinpoint the reason for high IgA. These might include specific antibody panels for autoimmune markers, biopsies of affected tissues (e.g., kidney or intestinal), or imaging studies like ultrasounds or CT scans to assess organ health.
Treatment for elevated IgA levels focuses on addressing the underlying condition causing immune system overactivity. For example, identified infections may require antibiotics or antiviral medications. Autoimmune diseases might be treated with immunosuppressive therapies to modulate the immune response. Only a qualified healthcare professional can provide an accurate diagnosis and develop an appropriate treatment plan based on the full clinical picture.