also known as IgA deficiency: is the most common immunoglobulin
deficiency. The major immunoglobulin in human saliva, nasal and bronchial
fluids, and intestinal secretions, IgA guards against bacterial and viral
reinfections. Ultimately, IgA deficiency leads to chronic sinopulmonary
(related to the paranasal sinuses and the airway of the lungs) infections,
GI diseases, and other disorders.
Causes: IgA deficiency seems to be linked to autosomal
dominant or recessive inheritance. The presence of normal numbers
of peripheral blood lymphocytes carrying IgA receptors and of normal amounts
of other immunoglobulins suggests that B cells may not be secreting IgA.
In an occasional patient, T-suppressor cells appear to inhibit IgA.
IgA deficiency is also link to autoimmune disorders, since many patients
with rheumatoid arthritis or SLE ( systemic lupus erythematosus) are also
IgA deficient. Some medications, such as anticonvulsants, may cause
transient IgA deficiency.
Symptoms:
May have the following signs and symptoms-
Chronic sinopulmonary
Respiratory allergy (often triggered by infection
GI tract diseases, such as celiac disease, ulcerative colitis, and regional
enteritis
Autoimmune diseases, such as rheumatoid arthritis, SLE, hemolytic anemia,
and chronic hepatitis
Malignant tumors, such as squamous cell carcinoma of the lungs, reticulum
cell sarcoma, and thymoma
Some IgA deficient patients have no symptoms, possibly because they
have extra amounts of low-molecular-weight IgM, which takes over IgA function
and helps maintain immunologic defenses.
Diagnostic test:
Immunologic analyses of IgA deficient patients show serum IgA levels
below 5 mg/dl. Although IgA is usually absent from secretions in
IgA deficient patients, levels may be normal in rare cases.
Test may also indicate auto antibodies and antibodies against IgG (rheumatoid
factor).
Treatment:
Selective IgA deficiency has no known cure. Treatment aims to
control symptoms of associated diseases.