Serum Concentration of Soluble lnterleukin-2 Receptor as a Sensitive Parameter of Disease Activity in Sarcoidosis (1)
Although sarcoidosis is self-limited in most cases, some instances of the disease are progressive and occasionally fatal. Therefore, monitoring disease activity is of great importance in the management of this disease.
Disease activity of sarcoidosis currently has been assessed by clinical status, chest x-ray film findings, pulmonary function tests, gallium 67 scans, BAL findings or serum ACE levels, Chest roentgenogram and BAL findings may reflect the grade of pulmonary involvement of this disease, but they may not reflect the total amount of granulomatous changes of sarcoidosis. Furthermore, difficulty in repetitive performance of BAL or gallium 67 scanning militates against its use in monitoring the disease activity of sarcoidosis. Serum activity of ACE, which can be obtained easily and is considered to reflect the total amount of sarcoid granulomata, has been used as a good marker of the disease, but the overlap of the enzyme level between some patients with sarcoidosis and healthy controls limits its value in regard to its sensitivity.
Immunopathologically, sarcoidosis is a chronic granulomatous disease characterized by local accumulation of activated T-helper/inducer cells. In this context, it is reasonable that parameters indicating T-cell activation may reflect disease activity of sarcoidosis. Recently, it has been reported that the serum concentration of soluble IL-2R is elevated in patients with diseases known to be associated with T-cell activation, such as T-cell leukemia, autoimmune disease, tuberculosis and leprosy.