Serum interleukin-8 level is a more sensitive marker than serum interleukin-6 or tumor necrosis factor-α level in monitoring the disease activity of mucocutaneous type of Behcet's disease
The purposes of this study were to investigate whether the serum interleukin (IL)-6, IL-8 or tumor necrosis factor (TNF)-α level was a sensitive marker in monitoring the disease activity of mucocutaneous type of Behcet’s disease (MCBD) and to assess whether IL-6, IL-8 or TNF-α was a useful serum marker in evaluating the therapeutic effects of levamisole plus colchicine on MCBD patients. We used a solid phase, two-site sequential chemiluminescent immunometric assay to determine the baseline serum levels of IL-6, IL-8 and TNF-α in 64 patients with MCBD, 9 patients with traumatic oral ulcers (TOU), and 54 normal control subjects. All MCBD patients with serum IL-6, IL-8 or TNF-α levels higher than the upper normal limits were treated with levamisole plus colchicine and their serum IL-6, IL-8 and TNF-α levels were measured after treatment. We found that 67﹪(43/64), 83﹪(53/64) or 67﹪(43/64) of MCBD patients had a serum IL-6, IL-8 or TNF-α level greater than the upper normal limit of 4.7, 8.7 or 7.4 pg/ml, respectively. The mean serum level of IL-6 (9.9±2.4 pg/ml, P < 0.005), IL-8 (107.5±21.4 pg/ml, P < 0.001) or TNF-α (22.5±4.1 pg/ml, P < 0.001) in 64 MCBD patients was significantly higher than that (2.1±0.2, 5.7±0.2 or 3.8±0.2 pg/ml for IL-6, IL-8 or TNF-α level, respectively) in normal control subjects. In 46 MCBD patients with the serum IL-6, IL-8 or TNF-α level higher than the upper normal limit, treatment with levamisole plus colchicine for a period of 0.5-11.5 months could significantly reduce the mean serum IL-6, IL-8 and TNF-α levels from 9.0±1.7 to 1.6±0.2 pg/ml (P < 0.001), from 134.6±28.2 to 6.0±0.4 pg/ml (P < 0.001), and from 25.7±5.6 to 3.5±0.4 pg/ml (P < 0.001), respectively. We conclude that serum IL-8 level is a more sensitive marker than serum IL-6 or TNF-α level in monitoring the disease activity of MCBD. Either IL-6, IL-8 or TNF-α is a useful serum marker in evaluating the therapeutic effects of levamisole plus colchicine on MCBD patients.