SYSTEMIC LEVELS OF THE T-CELL REGULATORY CYTOKINES IL-10 AND IL-12 INBEHCETS-DISEASE - SOLUBLE TNFR-75 AS A BIOLOGICAL MARKER OF DISEASE-ACTIVITY

Objective. To analyze the levels of the T cell regulatory cytokines in terleukin 10 (IL-10) and IL-12. in plasma of patients with Behcet's di sease (BD), and to assess the value of cytokines and cytokine antagoni sts as biological markers of disease activity. Methods. Sera/plasma of 66 consecutive outpatients with established diagnosis of BD were anal yzed for the presence of IL-2R, IL-6, tumor necrosis factor-alpha (TNF -alpha), soluble (s) TNF receptor (R)-55, sTNFR-75, IL-10, and IL-12 u sing immunological methods. Additional laboratory measurements include d erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). D ata from the history and clinical examination were recorded to correla te cytokine levels with clinical markers of disease activity. Results, 18 patients had inactive (Group I), 36 had mildly active (Group II), and 12 patients had active BD (Group III). IL-10 was elevated in 42 pl asma samples (64%). The percentage of samples containing IL-10 and the median levels of IL-10 of the 3 patient groups did not differ signifi cantly. IL-12 was detectable in plasma of 9 patients: One from Group I (5%). 3 from Group II (8%), and 5 from Group III (41%). IL-12 correla ted with disease activity (difference between Groups I and III, p = 0. 02, between Groups II and III, p = 0.008). ESR In patients with active disease and mildly active disease was significantly higher than value s in patients with inactive disease (p = 0.03, p = 0.02, respectively) , while median CRP levels were significantly different between Group I and Group III only (p = 0.006). sTNFR-75 levels were significantly di fferent between Groups II and III (p = 0.003) and between Groups I and III (p = 0.008). Conclusion, The elevation of plasma IL-10 in the maj ority of patients and the correlation of IL-l:! plasma levels with dis ease activity suggest a pathogenic role of a TH1-type immune response in active disease. In addition, the correlation of sTNFR-75 levels wit h disease activity indicates that sTNFR-75 may serve al a biological m arker of disease activity in BD.