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Secretory IgA and Autoimmune Disease

What Is Secretory IgA

IgA stands for Immunoglobulin A. Our bodies contain 5 different types of immunoglobins; IgG, IgA, IgM, IgE, IgD. We have many different types of immune cells, and these are a few of them. They each have unique roles to play.

IgA is the most abundant immunoglobulin in the human body. In fact, more IgA is made per day than the other 4 immunoglobulins combined. It specializes in mucosal immunity, development of tolerance and protection against infection and is key in respiratory and gastrointestinal tracts [1] as well as the saliva, tears, breastmilk, urogenital mucus [2].

IgA is found on the mucosa, the inner-most parts of our digestive tract (and other organ system)
IgA is found on the mucosa, the inner-most parts of our digestive tract (and other organ system)

Where Does IgA Come From

IgA is made by special white blood cells and transported into fluids and released by mucosal cells.

 

What Does It Do?

  • First line of defense against harmful microbes [2]
  • Neutralizes toxins [2]
  • Kills viruses [2]
  • IgA helps limit adhesion of antigen to the epithelium. [3]
  • It shapes the composition of the gut microbiota [2]

What Findings Do We See with Low IgA?

  • Increased systemic and gut-localized inflammation [3]
  • Enhanced intestinal permeability and disruption of functional integrity of the gut (leaky gut) [3]
  • Increased gut-immune activation (food sensitivities and chemical sensitivities) [3]
  • Dybiosis (poor gut bacteria balance)
  • Significant association between IgA Deficiency and Autoimmune disease [3]

 

Autoimmune Disease

Autoimmune Disease has multiple proposed mechanisms, many of which are directly affected by IgA and the rest of the immune system.

Although we don’t know the exact mechanisms of why someone may be IgA deficient, there is a strong relationship between IgA deficiency and autoimmune disease. It is proposed there is some involvement with another type of immune cell called B-cells [1].

 

Trends Seen with Autoimmune Disease and IgA Deficiency

  • Celiac Disease: 10-20x higher risk [4]
  • Type 1 Diabetes: 10x higher risk[5] [6]
  • Lupus: 10x higher risk [5][6]
  • Juvenile Idiopathic Arthritis: 10x higher risk [5][6]
  • IBD (Crohn’s and ulcerative colitis): 10x higher risk[5] [6].
  • Rheumatoid Arthritis: 10x higher risk[5] [6]
  • Thyroid disorders (Hashimoto’s and Graves Disease): 10x higher risk[5] [6]
  • Increased inflammation systemically and locally can also drive autoimmune disease [7]

 

Testing IgA

IgA can be tested through stool analysis as well as blood tests. The various testing options are best determined by your health care professional.

 

Factors that Lower IgA

  • Acute Stress [3], [8]
  • Chronic stress [3]
  • Prolonged exercise [9], [10][11]
  • REM sleep deprivation; as little as 4 nights per week[12]
  • Tobacco Smoking[13]
  • Sexual activity in women: during ovulation, immunity decreases to prevent immune interference with possible conception [14][15]
  • Certain medications
    • Anti-seizures meds, anti-rheumatic meds,  and those used for treating IBD [16]
    • Phenytoin [16]
    • Anti-TNF-α drugs [17]

Factors that increase IgA

  • Probiotics
    • reuteri increased IgA levels [18]
    • Lactobacillus helveticus Lafti L10 helps increase IgA in athletes [19]
    • Mothers supplementing a multi-strain probiotic affects breast milk antibody content favourably, increasing IgA production in their children/newborns [20]
    • Formula fed children given prebiotics and probiotics promotes gut health and increases IgA levels [21]
    • Healthy adults consuming Lactobacillus casei Shirota [22]
  • L-glutamine
    • Works through multiple mechanisms to increase IgA including: production of IgA, intestinal microbiota, induction pathways (T cells), plasma cells and transport of IgA [23]
  • Short moderate exercise [24]
  • Intermittent fasting [25]
  • Bright light [26]
  • Vitamin A
    • Need for transport and release of secretary IGA across the mucosa [27][28]
  • Chlorella
    • 4 weeks supplementation shown to increase IgA in men [29]
  • Estrogen
    • Estrogens increase IgA transport into the mucus, decreasing bacterial invasion [30]

Summary and Take-Home Message

IgA is one of many immune cells our body has. It plays a vital role in the immune system at our mucosal levels – the areas very vulnerable to infection and external pathogenic disease. IgA deficiency can present in many ways, but one strong connection is Autoimmune disease. Several autoimmune diseases are known to be associated with low IgA and furthermore low IgA can drive existing autoimmune disease.

Anyone with autoimmune disease should be aware of these relationships and learn from their Naturopath if and when testing would be helpful.

References

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