Cause
Selective IgA deficiency is inherited and has been associated with differences in chromosomes 18, 14 and 6. Selective IgA deficiency is often inherited, but has been associated with some congenital intrauterine infections. Pathophysiology
Pathogenesis of IgA Deficiency
‘In IgA-deficient patients, the common finding is a maturation defect in B cells to produce IgA’. ‘In IgA deficiency, B cells express IgA; however, they are of immature phenotype with the coexpression of IgM and IgD, and they cannot fully develop into IgA-secreting plasma cells’. There is an inherited inability to produce immunoglobulin A (IgA), a part of the bodys defenses against infection at the bodys surfaces (mainly the surfaces of the respiratory and digestive systems). As a result, bacteria at these locations are somewhat more able to cause disease.Types include:

Diagnosis
When suspected, the diagnosis can be confirmed by laboratory measurement of IgA level in the blood. SIgAD is an IgA level < 7 mg/dL with normal IgG and IgM levels (reference range 70–400 mg/dL for adults; children somewhat less). Treatment
The treatment consists of identification of co-morbid conditions, preventive measures to reduce the risk of infection, and prompt and effective treatment of infections. Infections in an IgA-deficient person are treated as usual (i.e., with antibiotics). There is no treatment for the underlying disorder. Use of IVIG as treatment
There is a historical popularity in using intravenous immunoglobulin (IVIG) to treat SIgAD, but the consensus is that there is no evidence that IVIG treats this condition.
In cases where a patient presents SIgAD and another condition which is treatable with IVIG, then a physician may treat the other condition with IVIG. The use of IVIG to treat SIgAD without first demonstrating an impairment of specific antibody formation is not recommended. Prognosis
Prognosis is excellent, although there is an association with autoimmune disease. Of note, selective IgA deficiency can complicate the diagnosis of one such condition, celiac disease, as the deficiency masks the high levels of certain IgA antibodies usually seen in celiac disease.As opposed to the related condition CVID, selective IgA deficiency is not associated with an increased risk of cancer.Patients with Selective IgA deficiency rarely have severe reactions to blood transfusions. Although Selective IgA deficiency is common, severe reactions to blood transfusions are very rare. People with selective IgA deficiency do not require special blood products unless they have a history of a severe allergic reaction to a blood transfusion. Epidemiology
Prevalence varies by population, but is on the order of 1 in 100 to 1 in 1000 people, making it relatively common for a genetic disease. SIgAD occurs in 1 in 39 to 1 in 57 people with celiac disease. This is much higher than the prevalence of selective IgA deficiency in the general population. It is also significantly more common in those with type 1 diabetes.It is more common in males than in females. See also
B cell deficiency

References


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