What is the most common complication associated with selective IgA deficiency?

Selective IgA deficiency is characterized by an absence or very low levels of immunoglobulin A (IgA), which plays a critical role in mucosal immunity. Given that IgA is predominantly found in mucosal areas such as the respiratory and gastrointestinal tracts, individuals with this deficiency are often more susceptible to infections in these regions. Hence, the most common complication associated with selective IgA deficiency is an increased risk of respiratory infections.

While some individuals may experience autoimmune diseases or other complications, the prominent clinical feature leading to morbidity in those with selective IgA deficiency is indeed the recurrent infections. Additionally, while the risk of severe transfusion reactions is notable, it is more specific to cases where IgA deficiency is associated with IgA antibodies; however, this is not the most common complication experienced in a general context of IgA deficiency.

Understanding the role of IgA in immune defense underscores the connection between this deficiency and increased susceptibility to infections, particularly respiratory ones.