ADA and sarcoidosis: The aims of this study were to describe the clinical, radiological and immunological features of a population of sarcoidosis patients and to analyse chitinase-3-like protein 1 (YKL-40), soluble interleukin-2 receptor (sIL-2R), neopterin concentrations and adenosine deaminase (ADA) activity in serum of these patients in order to understand their potential as disease markers.