Selective IgA Deficiency

Selective IgA Deficiency is a condition where the body does not produce enough immunoglobulin A (IgA), an important antibody that helps protect the body's mucous membranes. These membranes line areas such as the respiratory and digestive tracts, which are common entry points for germs. Because of low IgA levels, people with this condition may experience more frequent infections, especially in the sinuses, lungs, and intestines. It can also lead to increased risk of allergies and autoimmune diseases. Despite these challenges, many individuals with Selective IgA Deficiency have no symptoms and live normal lives.

Selective IgA Deficiency is the most common primary immunodeficiency characterized by a marked decrease or absence of serum and secretory immunoglobulin A (IgA) with normal levels of other immunoglobulin isotypes. The underlying mechanism involves a failure in B-cell differentiation into IgA-secreting plasma cells, often due to genetic factors affecting immune regulation. This deficiency impairs mucosal immunity, leading to increased susceptibility to recurrent sinopulmonary infections, gastrointestinal infections, and a higher prevalence of autoimmune disorders and allergic diseases. The condition is often asymptomatic but can present with chronic infections or complications such as giardiasis or celiac disease. Diagnosis requires exclusion of other causes of hypogammaglobulinemia and is clinically significant due to potential complications and transfusion-related anaphylaxis risk.