Serum IL-31 levels are increased in patients with cutaneous T-cell lymphoma.

RESULTS As previously reported (4), serum IL-31 levels were significantly higher in patients with AD (2.13 ± 0.26 pg/ ml) than those of healthy controls (0.94 ± 0.28 pg/ml; p < 0.01; Fig. 1a). In addition, serum IL-31 levels were significantly higher in patients with CTCL (3.19 ± 0.74 pg/ml) than those of healthy controls (p < 0.05; Fig. 1a). We subsequently examined serum IL-31 levels in CTCL patients with different types of skin lesions. Serum IL31 levels in patients with patch and plaque, tumour and erythroderma were 1.05 ± 0.30 pg/ml, 6.25 ± 2.11 pg/ml and 5.00 ± 1.46 pg/ml, respectively (Fig. 1b). Serum IL-31 levels in patients with tumour were extremely high, which were significantly higher than those with healthy controls (p < 0.01) and patients with patch and plaque (p < 0.05). Serum IL-31 levels in patients with erythroderma were also significantly higher than those in healthy controls (p < 0.01). Serum IL-31 levels in patients with stage I, stage II, stage III and stage IV were 0.95 ± 29 pg/ml, 3.97 ± 1.43 pg/ml, 2.07 ± 0.00 pg/ ml and 7.98 ± 2.56 pg/ml, respectively (Fig. 1c). Serum IL-31 levels in patients with stage IV were significantly higher than those with healthy controls and patients with stage I (p < 0.05). Serum IL-31 levels in patients with stage II were significantly higher than those with healthy controls (p < 0.05). We also found that serum IL-31 levels correlated significantly with serum sIL-2R and LDH levels (r = 0.43, p < 0.05 and r = 0.34, p < 0.05, respectively; Fig. 1d, e), which have been reported to reflect disease activity of CTCL (8, 9). Thus, serum IL31 levels correlate with disease activity of CTCL.