a selective lack of immunoglobulin A (IgA). The most common type of immunoglobulin deficiency, it occurs in about 1 in 400 individuals. IgA is a major antibody in the saliva and in the mucous membranes of the intestines and the bronchi. It protects against bacterial and viral infections. IgA deficiency is inheritied as an autosomal-dominant or autosomal-recessive trait and is associated with autoimmune abnormalities. It is common in patients with rheumatoid arthritis and in those with systemic lupus erythematosus. Many individuals with this deficiency have normal numbers of peripheral blood lymphocytes with IgA receptors and normal amounts of other immunoglobulins. Normality accompanied by IgA deficiency suggests that the B lymphocytes of the patient may not secrete IgA. In some patients with this deficiency, T cells seem to depress the synthesis of IgA.
observations Common symptoms are respiratory allergies associated with chronic sinopulmonary infection; GI diseases, such as celiac disease and regional enteritis; autoimmune diseases, such as rheumatoid arthritis, systemic lupus erythematosus, and chronic hepatitis; and malignant tumors, such as squamous cell carcinoma of the lungs, reticulum cell sarcoma, and thymoma. However, symptoms of IgA deficiency are often lacking in patients whose immune system may compensate for low IgA levels with extra amounts of IgM. The age of onset varies. Some children with IgA deficiency may begin to synthesize IgA spontaneously when a recurrent infection wanes and their condition improves. Diagnoses of IgA-deficient patients depend on the results of tests that commonly show normal IgE and IgM levels while IgA levels are below 5 mg/dL in serum. The cell-mediated immune response and circulating B cell levels often appear normal, although tests may indicate autoantibodies and antibodies against IgG, IgM, and cow's milk. T cell interferon production may be decreased in some patients with IgA deficiency, increasing the chances of infection.
interventions There is no known cure for selective IgA deficiency. Treatment usually involves efforts to control associated diseases, such as respiratory and GI infections.
nursing considerations The patient with IgA deficiency should not receive gamma globulin because associated sensitization may cause anaphylaxis during administration of blood products. If the patient requires a blood transfusion, the risk of any harmful reaction can be reduced by using washed red blood cells. Using the crossmatched blood of an IgA-deficient donor in such a transfusion is considered safer because it completely eliminates the risk of an adverse reaction. IgA deficiency is a lifelong condition, and patients with this disorder are commonly instructed to identify its symptoms and to seek treatment promptly when the symptoms appear.