Increased levels of serum interferon-gamma in pulmonary sarcoidosis and relationship with response to corticosteroid therapy.

The aim of this study was to evaluate serum levels of the lymphokine interferon-gamma (IFNg) in patients with chronic pulmonary sarcoidosis, and to investigate its value as a predictive marker of clinical response to corticosteroid therapy. Twenty-five patients and 28 age-matched control subjects were studied. All the patients had parenchymal shadows (Stage II or Stage III) and none had clinical evidence of extrathoracic disease. Before therapy, serum IFNg levels were significantly higher in the patient group (p < 0.001), and 20 (80%) had values above the normal range. After oral treatment with corticosteroids for a median 13 months (range, 3 to 49 months) the levels decreased significantly (p < 0.01). However, the falls were less pronounced in patients who had a better outcome in terms of achieving complete radiographic resolution and in those who improved in forced vital capacity by ⩾ 10%. The prognostic value of the pretreatment serum IFNg was explored, and a significant relationship was found between ...