Summary Statement : Disease Description Selective IgA Deficiency is the most common of the primary imunodeficiencies.

Details : Selective IgA Deficiency

Disease Description Selective IgA Deficiency is the most common of the primary imunodeficiencies. It is defined as the total absence
or severe deficiency of IgA. Blood serum levels for IgA deficient
persons are usually found to be 7 mg/dl or less, while serum IgA in
normal adults ranges from 90 to 450 mg/dl.


IgA is deficient in these individuals because their B-lymphocytes,
cells which normally produce IgA, are unable to mature into IgA-
producing plasma cells. IgA deficient persons appear to have IgA-
bearing B-cells that are arrested at an immature stage of
development.

The disorder is termed "selective" because other serum
immunoglobulins, such as IgM and IgG, are present at normal or
increased levels. Additionally, IgA deficient persons have normal or
near normal T-cell, phagocytic cell and complement system function

The IgA class of immunoglobulins has the specific function of
protecting the body's mucosal surfaces (eyes, mouth, throat, lungs,
gastrointestinal, and genitourinary tract) from infection. While IgA
is aided in this role to some degree by other classes of
immunoglobulins, the lack or severe deficiency of IgA at these body
sites makes one or more prone to recurrent infection, allergies,
chronic diarrhea, or autoimmune diseases. In autoimmune diseases,
the immune system mistakenly attacks the body's own tissues.

Medical research has not yet determined the exact cause or causes of
Selective IgA Deficiency. In some families, there is evidence of
familial occurrence, suggesting both autosomal dominant (only one
abnormal gene is required which dominates the other) and recessive
modes (two abnormal genes, one from each parent, are required) of
transmission. Selective IgA Deficiency also occurs frequently in
immediate relatives of persons with Common Variable
Immunodeficiency, suggesting similarity in causes of the two
disorders.

Clinical Signs and Symptoms

Clinical presentation of IgA deficient persons may range from
healthy and symptom free to significant illness. However, most
people with this defect are healthy and symptom free. No one knows
why the course of Selective IgA Deficiency is so varied. However,
some IgA deficient persons with significant illness may also be
missing a fraction of their IgG (IgG2), a class of immunoglobulin
that offers protection against some kinds of bacterial infections.

Thus, some IgA deficient persons may be totally unaware of their
antibody deficiency with no more than the usual number of upper
respiratory infections and/or occasional diarrhea.

For those IgA deficient patients with a history of recurrent
infections, the most common presentation is ear infections,
sinusitis, and/or pneumonia Other infection sites can be the throat,
the gastrointestinal tract or the eyes. These infections may become
chronic and may not completely clear up with a course of
antibiotics, necessitating prolonged antibiotic therapy.

Allergies are another common presentation of Selective IgA
Deficiency, and also may be quite varied, ranging from mild to
sever. Common allergic reactions include asthma and food allergies.
Asthma in some IgA deficient patients may be severe and less
responsive to drug therapy. Food allergies may result in symptoms
such as diarrhea or abdominal cramps. A link between Selective IgA
Deficiency and allergic rhinitis or eczema is uncertain.

Autoimmune diseases (immune system mistakenly attacks the body's own
tissues) comprise the third common clinical presentation of persons
with Selective IgA Deficiency. Autoimmune diseases occur in
Selective IgA Deficiency when patients produce antibodies to their
own tissues, damaging some of their organs or tissues. Autoimmune
diseases most frequently associated with Selective IgA Deficiency
include rheumatoid arthritis, systemic lupus erythematosus and
Sj?gren's Syndrome (a syndrome more common in women, characterized
by decreased lacrimal and salivary gland secretion). These diseases
may present as sore and swollen joints of the hands or knees, a
facial rash, anemia (decreased red blood cells or hemoglobin), or
abnormally low platelet count.

Other autoimmune diseases associated with Selective IgA Deficiency
affect the endocrine system, blood forming organs, or the
gastrointestinal system. These include thyroiditis (inflammation of
the thyroid gland), hemolytic anemia (anemia caused by increased red
blood cell destruction), and chronic active hepatitis (chronic
inflammation of the liver).

Diseases and genetic disorders reported to be associated with
Selective IgA Deficiency include:

Allergic disorders
Recurrent infections
Asthma
Food Allergies
Crohn's Disease
Relation to patient with hypogammaglobulinemia
Celiac disease (an intestinal malabsorption syndrome characterized
by diarrhea, malnutrition, and low calcium levels)
Chromosomal abnormality
Possible malignancy
Endocrinopathy (any disease caused by disorder of the endocrine
glands)
Hyersplenism (an increased spleen activity causing anemia, increased
red blood cell destruction, and spleen enlargement) and
thrombocytopenia (abnormally low platelet count)
Intestinal nodular hyperplasia (excessive formation of intestinal
nodes)
Recurrent giardiasis (protozoan infection)
Pulmonary hemosiderosis (deposits of iron-containing pigment from
hemoglobin in lungs due to red blood cell destruction)
Autoimmune diseases associated with Selective IgA Deficiency
include:

Rheumatoid arthritis (chronic inflammatory disease causing joint
changes and deformities)
Juvenile rheumatoid arthritis (rheumatoid arthritis affecting
juveniles with onset before 16; remission occurs in 75% of patients)
Systemic lupus erythematosus (chronic inflammation of connective
tissues affecting skin, joints, kidneys, and nervous system)
Thyroiditis (inflammation of the thyroid gland)
Transfusion reaction
Pernicious anemia (anemia due to low intestinal absorption of
vitamin B12)
Dermatomyositis (connective tissue disease with edema, dermtitis,
and muscle inflammation)
Coomb's positive hemolytic anemia (positive for antibodies to part
of red blood cell causing anemia due to red blood cell destruction)
Idiopathic Addison's disease (deficiency of secretions of
adrenocortical hormones from the adrenal gland which affects almost
all body systems)
Sj?gren's Syndrome (syndrome more common in women characterized by
decreased lacrimal and salivary gland secretion)
Cerebral vasculitis (inflammation of blood or lymph vessels of the
brain?cerebrum)
Idiopathic thrombocytopenic purpura (hemorrhagic disorder with
severe decrease of circulation platelets due to clumping of
platelets)
Treatment There is no treatment for Selective IgA Deficiency.
Instead, treatment should be directed toward the specific disease
associated with Selectuive IgA Deficiency, if any.

For example, steroids or immunosuppressive treatment may be needed
in patients with systemic lupus erythematosus (chronic inflammation
of connective tissue, affecting skin, joints, kidneys and the
nervous system), autoimmune diseases (immune system mistakenly
attacks body's own tissues), or antibiotics for infections.

Gammaglobulin treatment is not used in IgA Deficiency unless IgG2
Subclass Deficiency and/or antibody deficiency is also present.
Commercial gammaglobulin preparations do not contain much IgA, and
even if IgA-rich preparations were produced, the infused IgA appears
not to go to the mucous membranes where this protein is needed. If
anti-IgA antibodies are known to be present, IgA depleted
intravenous immunoglobulin are available and safe (brand name:
Gammagard SD and Polygam SD).



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