Undetectable interferon-alpha serum levels in a patient with atopic dermatitis

A 3-year-old boy [corrected] was evaluated for the possible diagnosis of hyperimmunoglobulin E syndrome (HIES). From the age of 4 months he developed significant atopy and was subsequently diagnosed with severe atopic dermatitis, asthma, and allergic rhinitis, with moderately high total serum IgE levels. Because IgE production has been shown to be regulated by cytokines produced by the CD4+ helper T lymphocyte subsets, we measured the circulating levels of cytokines representative of these cellular subsets in this patient. We therefore measured serum levels of interleukin-4 (IL-4), the Th2 subset-derived cytokine that upregulates IgE synthesis, as well as the levels of interferon-gamma and interferon-alpha (IFN-gamma/alpha), cytokines produced by the Th1 subset that inhibit IL-4-mediated IgE upregulation. We found that in this patient, IL-4 levels were normal, indicating normal Th2 activity. The levels of IFN-gamma were higher than normal, but the serum IFN-alpha levels in this patient were undetectable and were actually below the normal range. Thus, even though both IFN-gamma and IFN-alpha have been shown to be necessary for controlling IL-4 actions, the selective absence of IFN-alpha, even in the presence of normal or increased amounts of IFN-gamma, could permit IL-4 induced IgE production. Lack of IFN-alpha may explain this patient's recurrent infections, as well as IgE-induced atopic conditions. Our data in this study with the patient showing selective deficiency of IFN-alpha but not of IFN-gamma provide support for the role of IFN-alpha in the pathogenesis of atopic dermatitis. The findings in this patient clearly warrant further studies of IFN-alpha in patients with atopic disorders.