2023-04-18 20:00:02
Immunoglobulins A, often abbreviated as IgA, are part of the antibodies. They are produced by the immune system of the mucous membranes. Immunoglobulins A allow it to fight once morest infectious agents and toxins with which the body is confronted.
Definition: what is immunoglobulin A?
Immunoglobulin A (IgA) is a class of antibodies present in the human immune system. “IgAs are mainly found in mucous membranes and in secretions, such as saliva, tears, respiratory mucus, intestinal secretions and breast milk“, explains Dr. Zoé Thibaud, medical biologist. “They work by preventing bacteria, viruses and other pathogens from adhering to cell surfaces in these mucous areas, helping to prevent infections“. IgAs are produced by the plasma cells, specialized cells of the immune system, in response to infection or antigenic stimulation. “High levels of IgA in mucous secretions are often associated with good immune health.e”. IgA can also be transferred from mother to child during breastfeedingproviding temporary protection once morest infections.
What are the dosage indications?
“The immunoglobulin A (IgA) assay is prescribed primarily in the as part of a review of chronic infections or one of a balance sheet of suspicion of immune defines“, continues the doctor. It will also help diagnose or monitor certain diseases or conditions that affect the immune system“. Among the other indications for an IgA assay:
► Diagnosis of the celiac disease : “but it is the anti-transglutaminase IgA or the anti-endomysial IgA that are involved in the diagnosis of celiac disease and not the total IgA assay”.
► Monitoring of inflammatory bowel disease (IBD) : “anti-saccharomyces cerevisiae (ASCA) IgA levels can be used to monitor the progression of IBD”.
► “Finally, the IgA assay is part of the assessment of repeated infections because an IgA deficiency is a form of immune deficiency favoring certain respiratory ENT infections (for example, recurrent otitis)”.
What is the normal level of immunoglobulin A?
“The dosage of IgA in the blood only reflects the IgA which is produced by the bone marrow and which passes through the serum, says our interlocutor We do not measure the IgA of the mucous membranes and secretions, specific to local immune reactions“. The normal level of immunoglobulin A (IgA) may vary slightly depending on the lab performing the test, but in generalit is regarding 0.7 to 4.0 g/L in blood for adults. “However, it is important to note that IgA levels can vary greatly from person to person depending on age, gender, ethnicity, and other factors. IgA levels can also fluctuate in response to infections, autoimmune diseases, or other medical conditions“.
Elevated immunoglobulin A: why?
There are several factors that can explain a high level of immunoglobulin A (IgA). “Globally all chronic infections and especially those located at the level respiratory, digestive or cutaneousanswers the biologist. THE viral hepatitis can also cause a sharp increase in all immunoglobulins“. Autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus (SLE), or multiple sclerosis can also lead to increased production of IgA. “liver cirrhosis is a chronic disease that causes scarring of liver tissue. Patients with cirrhosis may have elevated levels of IgA. Like those affected by Shepherd’s disease (IgA nephropathy), a rare autoimmune disease that affects the kidneys“. Finally, a rare cause, myeloma-like blood cancer to IgA can cause an elevated level of immunoglobulin A.
Immunoglobulin A low: why?
Similarly, a low level of immunoglobulin A (IgA) can be caused by several factors. There are also certain factors that simultaneously generate a high level of immunoglobulin A, such as certain autoimmune diseases such as lupus erythematosus systemic (LES) or crohn’s disease or some types of blood cancer, such as multiple myeloma. “A low immunoglobulin level can be linked to an IgA deficiency, completes Dr. Thibaud. This is a rare genetic condition in which the body does not produce enough IgA. Patients with kidney failure may also have low IgA levels“. Note that some drugs used to suppress the immune system, such as corticosteroids, can reduce IgA levels. “One can also cite the viral infections, such as CMV (cytomegalovirus) or EBV (Epstein-Barr). The deficit is then short-lived and self-limiting“. In many cases, the immune system can compensate for the decrease in IgA levels by producing more other types of antibodies.”However, people with IgA deficiency may be more susceptible to respiratory, gastrointestinal, and genitourinary infections.“.
Thanks to Dr Zoé Thibaud, biologist at SYNLAB Hauts-de-France.
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