The four most common pediatric immunodeficiencies.

The four most common immunodeficiencies in pediatric patients are transient hypogamma-globulinemia of infancy, IgG subclass deficiency, impaired polysaccharide responsiveness (partial antibody deficiency) and selective IgA deficiency. Most of these patients have normal cellular immune systems, phagocyte function and complement levels. All four illnesses are characterized by recurrent bacterial respiratory infections such as purulent rhinitis, sinusitis, otitis and bronchitis. Except for some IgA-deficient patients, the molecular basis for these illnesses is not known, and indeed each syndrome is heterogeneous, with multiple causes, including genetic factors, drug/environmental toxicant exposure, and/or prenatal physiological events. This paper describes the clinical and laboratory features, postulated causes, current management and prognosis. Only a few of these cases require the use of intravenous IgG (IVIG) and the outlook for long life is excellent.