What Is an Immunoglobulin Deficiency?

Pediatric selective immunoglobulin A (IgA) deficiency (SIgAD) is the most common primary immunodeficiency disease. This disease can be autosomal recessive or autosomal dominant, or sporadic. It is caused by A set of syndromes caused by multiple causes, in addition to genetic factors, environmental factors are also important. The mildest clinical manifestations of the disease can be asymptomatic for a long time. Many children only show mild upper respiratory tract infections, and some children have various concomitant diseases, especially autoimmune diseases, allergic diseases and repeated infections.

Basic Information

Visiting department: Pediatrics
Multiple groups: Children

Common causes: Autosomal recessive or autosomal dominant
Common symptoms: Mild upper respiratory tract infection

Causes of pediatric selective immunoglobulin A deficiency

The etiology is not clear. Most believe that the disease is a group of syndromes caused by multiple causes. In addition to genetic factors, environmental factors are also important.

Clinical manifestations of pediatric selective immunoglobulin A deficiency

The lightest can have no symptoms for a long time. Many children only show mild upper respiratory tract infections, and some children develop various concomitant diseases, especially autoimmune diseases and repeated infections of allergic diseases. Some cases have gastrointestinal symptoms such as diarrhea and malabsorption. May be accompanied by ulcerative colitis, segmental enteritis, atrophic gastritis, gastric ulcer, intestinal lymphangiectasis, Giardia infection, pancreatitis and hepatitis. Small bowel biopsy revealed that almost all of the lamina propria were immunoglobulin M (IgM) plasma cells, but lacked IgA plasma cells.

Some cases are accompanied by autoimmune diseases, chronic active hepatitis, systemic lupus erythematosus, dermatomyositis, rheumatoid arthritis, nodular periarteritis, chronic thyroiditis, mixed connective tissue disease, idiopathic adrenal function Hypotension, autoimmune hemolytic anemia, and idiopathic thrombocytopenic purpura. Common autoimmune phenomena (autoantibodies only, asymptomatic), including anti-IgA antibodies, anti-immunoglobulin G (IgG) antibodies, IgM antibodies, anti-thyroglobulin antibodies, rheumatoid factor, anti-nuclear antibodies, anti-deoxygenation Nucleoprotein antibodies, anti-smooth muscle antibodies, anti-mitochondrial antibodies, anti-basement membrane antibodies, anti-parietal cell antibodies, etc. May also be accompanied by asthma or urticaria.

Infusion of IgA-containing plasma, whole blood, or IVIG (intravenous immunoglobulin) (containing trace amounts of IgA) can sensitize the sick child to produce high concentrations of anti-IgA antibodies. When IgA-containing blood products are reinfused, severe allergic reactions can occur, including anaphylactic shock. Allergic reactions may also occur in patients with no previous infusion history, which may be related to maternal and child placental infusion and / or milk sensitization to IgA.

Children with selective IgA deficiency are sometimes associated with malignancies. Such as lung cancer, gastric cancer, colon cancer, rectal cancer, breast cancer, ovarian cancer, uterine cancer, thymoma, leukemia and lymphoma.

Pediatric selective immunoglobulin A deficiency test

Children's serum IgA levels are often lower than 0.05g / L, and they are not even detectable at all. Secreted IgA was not detected in the saliva of critically ill children, and urine levels were very low. IgG and IgM levels are normal or elevated, and can even be twice as high. About 40% of children can detect autoantibodies.

Diagnosis of selective immunoglobulin A deficiency in children

Stiehm's diagnostic criteria were used for the diagnosis: serum IgA content <50mg / L; serum IgG and IgM levels were normal or elevated; cellular immune function was normal or decreased; exclude other causes of serum IgA low. However, it should be noted that the phylogeny of IgA is closely related to age during diagnosis. Serum IgA is deficient in infants within 1 year, especially infants younger than 6 months, and SIgAD has a natural tendency to recover. Therefore, the diagnosis of SIgAD should be cautious. In addition, the general amount of serum IgA can indirectly reflect the state of SIgA, but individual children have normal serum IgA, but there is a lack of secreted components. Therefore, children suspected of SIgAD should be tested for SIgA in saliva to exclude the lack of secreted components.

Complications of Pediatric Selective Immunoglobulin A Deficiency

Often accompanied by autoimmune diseases such as lupus erythematosus, dermatomyositis, rheumatoid arthritis, nodular periarteritis, chronic thyroiditis, mixed connective tissue disease, autoimmune hemolytic anemia, and idiopathic thrombocytopenic purpura May be accompanied by allergic diseases, repeated infections, etc .; Absorption disorders, may be nutritional diseases, may be accompanied by ulcerative colitis, segmental enteritis, atrophic gastritis, gastric ulcer, pancreatitis and hepatitis; May have low intelligence, epilepsy, may be accompanied by asthma or urticaria, infusion of blood containing IgA to sensitize the sick child, severe allergic reactions may occur; may be associated with malignant tumors.

Treatment of pediatric selective immunoglobulin A deficiency

No satisfactory treatment. Although some children can spontaneously recover IgA synthesis, the defects are usually persistent. The main treatment of various concomitant diseases, such as with systemic lupus erythematosus, the application of immunosuppressants. If infection occurs, the antibiotics or Chinese medicines are used to actively fight the infection. For children with diarrhea, consider human colostrum that is rich in secreted Ig.

Infusion of fresh blood and immunoglobulin preparations containing IgA is contraindicated. When a child needs blood transfusion, the donor of blood should also be a child with selective IgA deficiency or transfused to washed red blood cells.

Prognosis of pediatric selective immunoglobulin A deficiency

The clinical course of this disease is relatively mild, and some patients hardly find abnormal manifestations or only mild recurrent respiratory infections by the age of 50-60. A considerable number of infants can recover naturally without treatment, and often reach IgA levels within 5 years of age. Since the prognosis of this disease mainly depends on the accompanying disease, it should be carefully checked for the accompanying disease for early treatment.