Immunoglobulin A (IgA)

What it is

Immunoglobulin A, often shortened to IgA, is a type of protein made by your immune system. Think of it as one of your body's specialised defenders. Antibodies are like tiny soldiers that circulate in your blood and other body fluids, looking for and neutralising foreign invaders like bacteria and viruses.

IgA is a particularly important antibody because it's the main type found in your body's secretions – the sticky fluids that line your mucosal surfaces. These include things like your saliva, tears, mucus in your nose and lungs, and the fluid in your digestive system. There are two main forms of IgA: secretory IgA (sIgA), which is found in these secretions, and serum IgA, which is found in your blood. Secretory IgA acts as a first line of defence, helping to prevent germs from entering your body through these vulnerable entry points.

Why it matters

The level of IgA in your blood can give your doctor clues about what's happening within your immune system and your body. Measuring IgA is particularly useful when investigating certain types of infections, inflammatory conditions, and some autoimmune diseases.

High levels of IgA might suggest your body is actively fighting off an infection or dealing with chronic inflammation. Conversely, low levels could indicate that your immune system isn't producing enough antibodies, which might make you more susceptible to infections, particularly those affecting the respiratory and digestive systems. In some cases, very low IgA can be a sign of a genetic condition that affects immune function.

What can cause it to be high or low

Higher than normal IgA levels can be associated with a variety of situations. These might include:

• Infections: Your body may produce more IgA to fight off bacterial or viral infections. Chronic infections can sometimes lead to persistently elevated IgA.
• Inflammatory conditions: Certain long-term inflammatory diseases, such as rheumatoid arthritis or inflammatory bowel disease (like Crohn's disease or ulcerative colitis), can be associated with increased IgA.
• Liver disease: Some types of liver conditions can affect IgA levels.
• Certain cancers: In some rare instances, specific types of cancer, particularly those affecting the immune system or plasma cells (which produce antibodies), can lead to high IgA.
• Autoimmune conditions: When the immune system mistakenly attacks the body's own tissues, IgA levels can sometimes rise.

Lower than normal IgA levels can also be associated with several factors:

• Genetic conditions: Some people are born with conditions that affect their immune system's ability to produce antibodies. Selective IgA deficiency is the most common primary immunodeficiency, where the body produces very little or no IgA, though other antibody types are usually normal.
• Certain medications: Some drugs used to treat conditions like cancer or autoimmune diseases can suppress the immune system and lower antibody levels.
• Chronic infections: While some infections raise IgA, certain long-term or severe infections can sometimes deplete the immune system, leading to lower levels.
• Gastrointestinal issues: Conditions affecting the gut lining can sometimes be linked to lower IgA production.

It's important to remember that these are just potential associations, and a single blood test result needs to be interpreted within the context of your overall health and medical history.

Lifestyle factors that may help

While IgA levels are largely determined by your immune system's natural function and any underlying medical conditions, certain lifestyle choices can support overall immune health. Discussing these with your GP is always a good idea:

• Balanced diet: Eating a diet rich in fruits, vegetables, lean proteins, and whole grains provides the nutrients your immune system needs to function effectively.
• Regular exercise: Moderate physical activity can contribute to a healthy immune response.
• Adequate sleep: Getting enough quality sleep is crucial for immune system recovery and function.
• Stress management: Chronic stress can impact immune function. Finding healthy ways to manage stress, such as mindfulness or hobbies, may be beneficial.
• Avoiding smoking: Smoking can negatively affect immune responses and overall health.

Questions to discuss with your GP

If your IgA levels have been discussed with you, or if you have concerns about your immune health, here are some questions you might consider asking your GP:

• What does my specific IgA level mean in the context of my overall health?
• Are my IgA levels considered high, low, or within the normal range for me?
• Could my IgA level be related to any of my current symptoms or medical conditions?
• Are there any further tests you would recommend based on my IgA result?
• What are the potential implications of my IgA level for my long-term health?
• Are there any lifestyle changes you would suggest to support my immune system?