Background: Interleukin-19 (IL-19), a cytokine from the IL-10 family, has been recently involved in the pathogenesis of Rheumatoid Arthritis (RA). It has been detected in RA synovial tissue where it seems to promote joint inflammation and decrease synovial cell apoptosis. IL-19 is also expressed in psoriatic skin lesion, where it exerts a pro-inflammatory role and induces hyperplasia of epidermal keratinocytes. No studies investigated IL-19 expression in Psoriatic Arthritis (PsA) patients. Objectives: Aim of this study is to analyze IL-19 levels in synovial fluid (SF) and serum from PsA patients and compare them with those found in RA and osteoarthritis (OA) patients. Methods: We enrolled consecutive patients with PsA, RA, and OA classified according to standard criteria and presenting a knee effusion. Paired SF and serum samples were stored at -20°C until IL-19 levels were analyzed by ELISA. In all patients we evaluated the clinical and inflammatory laboratory parameters and performed analysis of SF. IL-19 levels were also investigated in the serum of 20 healthy controls. Results: We enrolled 72 patients: 23 with PsA (M/F=16/7; mean age=47 years, range=16-74; mean disease duration=99 months, range 1-492), 30 with RA (M/F=7/23; mean age=53 years, range=26-67; mean disease duration=109 months, range 6-588), 19 with OA (M/F=12/7; mean age=59 years, range=45-78; mean disease duration=86 months, range 12-240), and 20 healthy subjects (M/F=12/8; mean age=51 years, range 30-68). IL-19 levels (pg/ml; median/25th-75th percentile) in the SF of PsA patients (484.9/389.8-558.5) were significantly higher than those in RA (335.1/304.3-407.3; p<0.0001) and OA patients (286.7/260.5-310.7; p<0.0001). On the contrary, IL-19 serum levels were significantly lower in PsA patients (159.3/116.7-255.7) compared with OA patients (381.2/314.2-428.4; p=0.0001) and healthy donors (377.2/335.8-471.7; p<0.0001). OA and healthy subjects showed comparable IL-19 serum levels. Similarly, IL-19 levels in the SF from RA patients were significantly higher than those in OA patients (p=0.0005), while serum levels were lower in RA (165.2/155.5-275.4) compared with OA patients (p=0.0001) and healthy donors (p<0.0001). The ratio between serum and SF IL-19 levels was higher in RA and OA patients compared with PsA patients (p=0.002, p<0.0001, respectively). Moreover, the ratio between serum and SF was higher in OA patients than in RA patients (p<0.0001). Conclusions: IL-19 is expressed in different local sites of inflammation where may modulate the inflammatory response. IL-19 is also known to induce in vitro IL-6 and TNF production in monocyte and synovial tissue cell. In this study we demonstrated elevated levels of IL-19 in the joints of PsA patients compared to those found in the peripheral blood. We speculate that IL-19 in PsA, together with the other immune mediators, could induce locally the tissue damage regulating the inflammatory response, synovial hyperplasia and apoptosis, hallmarks of the disease.
Elevated levels of IL-19 in the joints of patients with psoriatic arthritis
Perrotta FM;
2011-01-01
Abstract
Background: Interleukin-19 (IL-19), a cytokine from the IL-10 family, has been recently involved in the pathogenesis of Rheumatoid Arthritis (RA). It has been detected in RA synovial tissue where it seems to promote joint inflammation and decrease synovial cell apoptosis. IL-19 is also expressed in psoriatic skin lesion, where it exerts a pro-inflammatory role and induces hyperplasia of epidermal keratinocytes. No studies investigated IL-19 expression in Psoriatic Arthritis (PsA) patients. Objectives: Aim of this study is to analyze IL-19 levels in synovial fluid (SF) and serum from PsA patients and compare them with those found in RA and osteoarthritis (OA) patients. Methods: We enrolled consecutive patients with PsA, RA, and OA classified according to standard criteria and presenting a knee effusion. Paired SF and serum samples were stored at -20°C until IL-19 levels were analyzed by ELISA. In all patients we evaluated the clinical and inflammatory laboratory parameters and performed analysis of SF. IL-19 levels were also investigated in the serum of 20 healthy controls. Results: We enrolled 72 patients: 23 with PsA (M/F=16/7; mean age=47 years, range=16-74; mean disease duration=99 months, range 1-492), 30 with RA (M/F=7/23; mean age=53 years, range=26-67; mean disease duration=109 months, range 6-588), 19 with OA (M/F=12/7; mean age=59 years, range=45-78; mean disease duration=86 months, range 12-240), and 20 healthy subjects (M/F=12/8; mean age=51 years, range 30-68). IL-19 levels (pg/ml; median/25th-75th percentile) in the SF of PsA patients (484.9/389.8-558.5) were significantly higher than those in RA (335.1/304.3-407.3; p<0.0001) and OA patients (286.7/260.5-310.7; p<0.0001). On the contrary, IL-19 serum levels were significantly lower in PsA patients (159.3/116.7-255.7) compared with OA patients (381.2/314.2-428.4; p=0.0001) and healthy donors (377.2/335.8-471.7; p<0.0001). OA and healthy subjects showed comparable IL-19 serum levels. Similarly, IL-19 levels in the SF from RA patients were significantly higher than those in OA patients (p=0.0005), while serum levels were lower in RA (165.2/155.5-275.4) compared with OA patients (p=0.0001) and healthy donors (p<0.0001). The ratio between serum and SF IL-19 levels was higher in RA and OA patients compared with PsA patients (p=0.002, p<0.0001, respectively). Moreover, the ratio between serum and SF was higher in OA patients than in RA patients (p<0.0001). Conclusions: IL-19 is expressed in different local sites of inflammation where may modulate the inflammatory response. IL-19 is also known to induce in vitro IL-6 and TNF production in monocyte and synovial tissue cell. In this study we demonstrated elevated levels of IL-19 in the joints of PsA patients compared to those found in the peripheral blood. We speculate that IL-19 in PsA, together with the other immune mediators, could induce locally the tissue damage regulating the inflammatory response, synovial hyperplasia and apoptosis, hallmarks of the disease.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
