The role of atopy in the clinical course of pulmonary sarcoidosis in the Japanese population

Sarcoidosis is a multisystem disorder characterized by a T-helper 1 (Th1)-mediated immune response. Conversely, atopy characterized by the presence of a specific immunoglobulin E (IgE) E response in association with a Th2-type immune response. Several epidemiological studies have shown that atopic status influences disease activity and clinical course for several Th1-mediated diseases. The aim of this study was to evaluate associations between atopic status and clinical findings sarcoidosis. We further evaluated the impact of atopic status on the clinical course of pulmonary sarcoidosis. We defined atopy as a positive specific IgE response to at least one common inhaled allergen (multiple antigen simultaneous test scores, lumicount of >1.01). Subjects comprised 134 patients given a diagnosis of sarcoidosis between 2000 and 2006, divided into atopic and nonatopic groups. Several clinical findings were compared between the two groups. Furthermore, 100 subjects observed 2 years after diagnosis were divided into resolving and persistent clinical course groups according to chest radiography and associations with atopic status were evaluated. Atopy was more prevalent among men than women (p = 0.009) and subjects with atopy were younger (p = 0.002) and showed less frequent lung parenchymal lesions (stages II and III; p = 0.018) compared with subjects without atopy. The prevalence of atopy was higher in the resolving clinical course group than in the persistent clinical course group (p = 0.002) and this association was independent of sex, age, presence of lung parenchymal lesions, and presence extrapulmonary lesions (p = 0.037). Classification of sarcoidosis based on atopic status might be useful for predicting the clinical course of pulmonary sarcoidosis.