Total serum IgE levels and atopic status in patients with sarcoidosis.

To date, two studies have reported lower total serum immunoglobulin E (IgE) levels and lower prevalence of atopy in patients with sarcoidosis compared with healthy subjects. However, those reports did not consider age or gender differences between cases and controls. In addition, the association between total serum IgE levels and clinical manifestations of sarcoidosis has not been clarified. This study assessed total serum IgE levels and prevalence of atopy in patients with sarcoidosis after taking age and sex differences into account and evaluated associations between total serum IgE levels and clinical manifestations of sarcoidosis. Total serum IgE levels and prevalence of atopy on initial visits were compared between 189 patients with sarcoidosis and 378 age- and sex-matched controls. Associations between total serum IgE levels and involvement of each affected organ were evaluated. Changes in total serum IgE levels during the clinical course of sarcoidosis were also evaluated. Total serum IgE levels were significantly lower in patients with sarcoidosis than in controls, independent of atopic status (atopic subjects, p = 0.025; nonatopic subjects, p < 0.001). Total serum IgE levels did not differ according to the involvement of different organs. Total serum IgE levels decreased further, albeit only slightly, after disease remission (p < 0.001). Increased susceptibility to sarcoidosis may be attributable to several underlying genetic or environmental factors that result in lower total serum IgE levels.