Clinical manifestations of IgE hypogammaglobulinemia.

BACKGROUND: Although IgE has been shown to play a role in the expulsion of intestinal parasites in experimental animals, its overall contribution to host defense in humans remains a subject of controversy. In order to clarify the potential role of IgE in host defense, we have studied the clinical characteristics of patient with serum IgE levels of < 2.5 IU/mL, using patients with normal or elevated IgE levels as controls.

OBJECTIVE: To determine the clinical characteristics of IgE deficiency.

METHODS: Serum IgE levels were measured in 420 adult patients seen in our Allergy-Immunology Clinic over a period extending from January, 1990 to March, 1996. All subjects were examined by one of the authors (JKS or GHK) using a standardized history and physical examination form. Patients with IgE levels of < 2.5 IU/mL also had measurements of serum IgG, IgG subclasses, IgA and IgM. All IgE-deficient patients and 73% of those with normal to elevated IgE levels underwent RAST and/or skin testing for Type I hypersensitivity, and, where clinically indicated, had serum drawn for autoimmune serologic profiles. Infectious complications were documented by culture. The American Rheumatology Association criteria were used to establish a diagnosis of autoimmune disease.

RESULTS: Forty-four patients were found to have IgE levels of < 2.5 IU/mL; 57% of these had depressed serum levels of other immunoglobulins, and 43% had isolated IgE deficiencies. Respiratory symptoms were equally common in IgE-deficient patients and in patients with normal to elevated IgE levels. IgE-deficient patients, however, were more likely to complain of arthralgias (P < .0001), chronic fatigue (P < .0001), and symptoms suggestive of airway infection (P = .0119). Compared with controls, patients with IgE deficiency had a higher prevalence of autoimmune disease (46% versus 15%) (P < .0001) and nonallergic reactive airway disease (73% versus 20%) (P < .0001). There was no difference in the prevalence of these disease in patients with selective IgE deficiency as compared with those with IgE deficiency complicated by deficits in other immunoglobulin classes. IgE-deficient patients with multiple immunoglobulin deficiencies, however, were more likely to have serious infection involving both the upper and lower respiratory tract than those with isolated IgE deficiency.

CONCLUSIONS: IgE-deficient patients have an increased prevalence of multiple immunoglobulin deficits, autoimmune disease, and nonallergic reactive airway disease when compared with a clinic population of patients with normal to elevated IgE levels.