IgA deficiency may be primary ,sporadic, or familial. Both serum and secretory IgA are lacking in most patients and, rarely, one or the other.
Although certain studies have reported recurrent infections in as many as 50% of IgA-deficient patients, most of these individuals are healthy. Some patients develop symptoms after an uneventful childhood and early adulthood.
Recurrent or chronic upper and lower respiratory tract infections may result in bronchiectasis or cor pulmonale in insufficiently treated patients. G lamblia infection of the GI tract is common. Other GI diseases, such as spruelike syndrome, ulcerative colitis, and Crohn disease, have been reported.