American Board of Internal Medicine (ABIM) Certification Practice Exam

Which infections are commonly repeated in patients with selective IgA deficiency?

1. Cardiovascular infections

2. Recurrent sinopulmonary and gastrointestinal infections

3. Neurological infections

4. Urinary tract infections

The correct answer is: Recurrent sinopulmonary and gastrointestinal infections

Selective IgA deficiency is the most common primary immunodeficiency and is characterized by a significant lack of immunoglobulin A (IgA) while maintaining normal levels of other immunoglobulin classes. IgA plays a crucial role in mucosal immunity, particularly in protecting mucosal surfaces from infections. This deficiency leads to an increased susceptibility to infections, particularly in mucosal areas. Recurrent sinopulmonary infections, such as sinusitis, bronchitis, and pneumonia, are common in these patients due to the lack of IgA, which normally helps to neutralize pathogens entering through the respiratory tract. Similarly, gastrointestinal infections are also frequent because IgA is essential for maintaining gut barrier function and controlling intestinal flora. Without adequate IgA, patients are more prone to infections from common pathogens in the respiratory and gastrointestinal tracts. In contrast, other types of infections, such as neurological or cardiovascular infections, are not typically associated with selective IgA deficiency. Neurological infections are more often linked to other underlying immune deficiencies or specific pathogens, and cardiovascular infections generally involve systemic pathogens that do not specifically relate to IgA function. Urinary tract infections, while they can occur, are not as prominently observed in patients with selective IgA deficiency as the recurrent sinopul