Immunoglobulin IgA

Immunoglobulin A (IgA): role, symptoms of deficiency and excess, blood standards

1. The role of IgA in the body

Immunoglobulin A (IgA) is an antibody that plays a key role in local mucosal immunity.

Main functions:
✔ Mucosal protection – IgA is present in:

Saliva, tear fluid, breast milk.
Mucous membranes of the respiratory tract, gastrointestinal tract, and genitourinary system.
✔ Neutralization of pathogens -binds viruses, bacteria, and toxins, preventing them from entering the body.
Suppressing inflammation -regulates the immune response, preventing overreactions.

Two forms of IgA:

Serum IgA (circulates in the blood, 10-15% of all antibodies).
Secretory IgA (sIgA) is the main defender of mucous membranes.

2. Symptoms of IgA deficiency

Reasons:

Selective IgA deficiency (most common immunodeficiency, 1 in 500 people).
Congenital immunodeficiency (for example, general variable immune deficiency).
Acquired conditions (chronic kidney disease, taking immunosuppressants).

Symptoms:

Frequent infections of ENT organs (otitis media, sinusitis, bronchitis).
Intestinal infections and diarrhea.
Autoimmune diseases (celiac disease, rheumatoid arthritis).
Allergies (due to an imbalance of the immune system).

Important: In some people, IgA deficiency is asymptomatic.

3. Symptoms of excess IgA

Reasons:

Chronic infections (HIV, tuberculosis).
Autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis).
Multiple myeloma of the IgA type (malignant disease of plasma cells).
Liver diseases (cirrhosis).

Symptoms:

For myeloma: bone pain, anemia, kidney failure.
In autoimmune processes: damage to the joints, skin, and kidneys.
Hyperviscosity of the blood (headaches, visual disturbances).

4. IgA standards in the blood test

Group	Reference values (g/L)
Adults	0.7–4.0
Children:
0–1 year	0.1–0.9
1–5 years	0.2–1.5
6–10 years	0.3–2.1
11–16 years	0.5–2.5

Notes:

The level of IgA in children reaches adult values by 12-16 years.
To assess secretory IgA , saliva, tear fluid, or feces are examined.

5. When is the test scheduled?

Recurrent infections of the respiratory tract or intestines.
Suspected immunodeficiency or autoimmune disease.
Diagnosis of myeloma (in combination with protein electrophoresis).
Control of chronic inflammatory diseases.

Important: If IgA is deficient , false negative results of antibody tests are possible (for example, in celiac disease).

6. What should I do in case of deviations?

IgA Deficiency:
Prevention of infections (vaccination, hygiene).
Treatment is only symptomatic (substitution therapy is not used).
Excess IgA:
For myeloma – chemotherapy.
In autoimmune processes- immunosuppressants.