CD79A and infection: Selective IgA deficiency, defined as level of serum IgA (<7 mg/dL) accompanied by normal levels of other immunoglobulins, is the most common primary immunodeficiency.[1] Selective IgA deficiency has been associated with higher risk for respiratory infections in the general population.[2] Subnormal serum IgA levels (IgA serum level of ≤70 mg/dL) have also been associated with higher risk of infection in the general population.