AB0983 PENTRAXIN 3 AS A MARKER OF DISEASE ACTIVITY IN JUVENILE IDIOPATHIC ARTHRITIS PATIENTS

Abstract

Background: Pentraxin-3 (PTX3) is a secretory acute phase protein which is produced and expressed in many immune cells especially macrophages, fibroblasts and endothelial cells at different inflammatory sites [1]. PTX3 is known to have an interesting role in regulation of innate immunity and it is a key player in regulation of many inflammatory reactions [2]. Objectives: This study aimed to measure serum and synovial fluid (SF) levels of PTX3 in juvenile idiopathic arthritis (JIA) patients and to correlate them with different clinical, laboratory and musculoskeletal ultrasound parameters of disease activity. Methods: We measured PTX3 in the serum (n=57) and SF samples (n=18) from 57 JIA patients and in the serum from twenty healthy control. Disease activity was calculated using the Juvenile Arthritis Disease Activity Score in 27 joints (JDAS27) and musculoskeletal ultrasound examination (MSUS) was performed using grey scale (GS) and power Doppler (PD) 10-joint score (bilateral knee, ankle, wrist, elbow and the 2nd metacarpophalangeal (MCP) joints) [3]; Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) levels, serum ferritin, rheumatoid factor (RF) titre were measured and the Juvenile arthritis multidimensional assessment report (JAMAR) was documented. Results: Serum PTX3 level was significantly higher in JIA patients (3.59± 2.38 ng/mL) compared to serum level in the healthy controls (1.5 ± 0.9 ng/mL) (p<0.001). There was no significant difference between SF PTX3 level (4.73 ± 2.62 ng/mL) and its level in paired serum samples(4.23± 2.93 ng/mL) (p=0.59). JIA patients with systemic onset subtype (n=13) had higher PTX3 serum levels (5.57± 2.52 ng/mL) compared to serum level in the oligoartiular (n=25) and polyarticular (n=19) subtypes (2.88± 2.13 ng/mL and 3.18 ±11.92 ng/mL respectively) (p=0.001 and 0.005 respectively). In JIA patients, serum PTX3 level significantly correlated with JDAS27 (r=0.52, p<0.05), CRP titres (r=0.46, p<0.05) and serum ferritin (r=0.48, p<0.05). Both serum and SF PTX3 levels significantly correlated with PD score (r=0.51 and 0.48 respectively, p<0.05). SF PTX3 (p =0.001) was shown to be superior to serum PTX3(p =0.02), ESR (p =0.07) and comparable to CRP (p =0.001) at predicting PD synovitis score. Conclusion: JIA patients have significantly increased serum and synovial fluid levels of Pentraxin 3 that remarkably correlated with the JDAS27 and MSUS parameters of inflammations suggesting that it could be a useful marker to reflect JIA disease activity.