The IgE synthesis is tightly controlled by a complex network of T and B cells. Because human immunodeficiency virus (HIV) disease associates T cell activation and depletion, polyclonal B cell activation, atopic symptoms, drug hypersensitivity, and autoimmune activity, we have evaluated IgE, as well as IgA, IgG, and IgM, in 315 HIV-seropositive individuals with or without acquired immunodeficiency syndrome (AIDS) and compared the results to those of 100 HIV-seronegative subjects. IgE levels were higher in HIV-infected subjects as a whole, compared to levels in seronegative control subjects (p less than 0.05). This difference was particularly marked between patients with AIDS and control subjects (p less than 0.005). A strong relationship appeared between IgE and the immune status as assessed by CD4 cell counts (p less than 0.001 between IgE values in patients with CD4 less than 300 or greater than 300/microliters). In addition, we assessed the predictive value of IgE elevation over disease progression: in subjects with a CD4 count less than 300/microliters, the survival analysis disclosed a 24-month occurrence rate of AIDS of 83% in individuals with IgE greater than 150 KIU/L versus 44% in individuals with IgE less than 150 (p = 0.016). In subjects with an AIDS-related complex, IgE greater than 150 indicated a 100% rate of AIDS versus 9% in individuals with IgE less than 150 (p = 0.003). Thus, IgE levels appear to be a very discriminative marker between patients in late stages of HIV infection.(ABSTRACT TRUNCATED AT 250 WORDS)