🚨 Quick Immunology Check – Don’t Miss This One Most common primary immunodeficiency? 👉 Selective IgA deficiency — simple to remember, commonly tested, often missed clinically. Key points to lock in 👇 * Recurrent respiratory and GI infections due to loss of mucosal immunity * Strong association with celiac disease * Standard blood products can trigger severe anaphylaxis because of anti-IgA antibodies * Safer option: Washed RBCs * Labs show low IgA with normal IgG and IgM Now the exam-level que