It results from the inability of IgA B cells to mature to plasma cells. Other immunoglobulins are normal.
Most often, the disorder is asymptomatic, but it may be characterized by occasional anaphylactic reactions to transfused blood products; this can be prevented by “washing” of the products to remove immunoglobulins prior to transfusion.
It may also be associated with infections, especially those involving mucosal surfaces, and manifest as recurrent upper respiratory tract infections and frequent episodes of diarrhea.