CLINICAL MANIFESTATIONS OF IGE HYPOGAMMAGLOBULINEMIA

Background: Although IgE has been shown to play a role in the expulsio n of intestinal parasites in experimental animals, its overall contrib ution to host defense in humans remains a subject of controversy. In o rder to clarify the potential role of IgE in host defense, we have stu died the clinical characteristics of patients with serum IgE levels of <2.5 IU/mL, using patients with normal or elevated IgE levels as cont rols. Objective: To determine the clinical characteristics of IgE defi ciency. Methods: Serum IgE levels were measured in 420 adult patients seen in our Allergy-Immunology Clinic over a period extending from Jan uary, 1990 to March, 1996. All subjects were examined by one of the au thors (JKS or GHK) using a standardized history and physical examinati on 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 in dicated, had serum drawn for autoimmune serologic profiles. Infectious complications were documented by culture. The American Rheumatology A ssociation criteria were used to establish a diagnosis of autoimmune d isease. Results: Forty-four patients were found to have IgE levels of <2.5 IU/mL; 57% of these had depressed serum levels of other immunoglo bulins, and 43% had isolated IgE deficiencies. Respiratory symptoms we re equally common in IgE-deficient patients and in patients with norma l to elevated IgE levels. IgE-deficient patients, however, were more l ikely to complain of arthralgias (P < .0001), chronic fatigue (P < .00 01), and symptoms suggestive of airway infection (P = .0119). Compared with controls, patients with IgE deficiency had a higher prevalence o f autoimmune disease (46% versus 15%) (P < .0001) and nonallergic reac tive airway disease (73% versus 20%) (P < .0001). There was no differe nce in the prevalence of these diseases 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 hav e serious infection involving both the upper and lower respiratory tra ct than those with isolated IgE deficiency. Conclusions: IEE-deficient patients have an increased prevalence of multiple immunoglobulin defi cits, autoimmune disease, and nonallergic reactive airway disease when compared with a clinic population of patients with normal to elevated IgE levels.