Serum level of soluble tumour necrosis factor receptor II (75 kDa) indicates inflammatory activity of sarcoidosis

Objectives. Tumour necrosis factor alpha (TNF alpha) is a key cytokine invo lved in granuloma formation of sarcoidosis. Since soluble TNF receptors (sT NF-R) are known to inhibit TNF effects, we were interested in whether they are elevated in the serum of sarcoidosis patients. Methods. We determined serum levels of sTNF-R I (55 kDa) and sTNF-R II (75 kDa) in 49 patients with sarcoidosis and 22 controls. The clinical course o f the disease was re-evaluated in a follow-up after (mean +/- SE) 6.8 +/- 6 .6 months. Results. sTNF-R I (3.1 +/- 1.1 ng mL(-1), P < 0.05) and sTNF-R II (5.5 +/- 2.7 ng mL(-1), P < 0.0005) were significantly elevated in sarcoidosis compa red with controls (2.4 +/- 0.7 and 3.0 +/- 1.3 ng mL(-1), respectively). In terestingly, both sTNF receptors were significantly higher in the serum of patients with active compared with inactive sarcoidosis (P < 0.005 and P < 0.0005, respectively). Furthermore, serum sTNF-R II levels were significant ly higher in sarcoidosis patients with advanced radiological types II and I II. In 10 patients, serum sTNF-R levels were obtained before and after syst emic corticosteroid therapy and we observed a significant decrease of sTNF- R II (P < 0.02), whereas sTNF-R I levels were not reduced significantly. Conclusions. Both types of sTNF receptors are elevated in the serum of sarc oidosis patients with active disease, but only the sTNF-R II seems to be us eful for monitoring the inflammatory activity of the disease.