Objective: To evaluate serum levels of CXCL10 and CCL2 in a large series of PsA patients, and to relate chemokines levels to the clinical phenotype of these patients.
Methods: Serum levels of CXCL10 and CCL2 were measured in 68 PsA patients, and in gender- and age-matched (1:1) controls drawn from the general population.
Results: PsA patients showed significantly (p<0.001) higher mean CXCL10 serum levels than controls (p<0.0001), (269+/-234 vs. 92+/-53 pg/ml; respectively). By defining a high CXCL10 level as a value at least 2 SD above the mean value of the control group (>198 pg/ml), 49% of patients with PsA and 5% of the control subjects had high CXCL10 (p<0.0001; chi-square). A significant inverse correlation was observed between CXCL10 serum levels and disease duration (r= 0.374, p=0.002).Patients with PsA showed significantly higher mean CCL2 serum levels than controls (p<0.001), (512+/-309 vs. 386+/-172, pg/ml; respectively). By defining a high CCL2 level as a value at least 2 SD above the mean value of the control group (>730 pg/ml), 19% of patients with PsA, 2% of the control subjects had high CCL2 (p<0.001; chi-square=22.02).
Conclusion: In conclusion, high circulating levels of CXCL10 and CCL2 have been found in PsA patients, with a Th1 immune predominance in the early phase of the disease. A decline of CXCL10 levels has been observed in long lasting PsA, with a significant increase of the CCL2/CXCL10 ratio, suggesting a shift from Th1 to Th2 immune response in long duration PsA.