15A122

Myeloid related Proteins 8 and 14 (MRP 8/14) – Biomarkers of Arthritis in Children with Trisomy 21 (T21)?

Author(s)

C Foley, EJ MacDermott, D Veale, OG Killeen

Department(s)/Institutions

NCPR OLCHC; SVUH

Introduction

MRP8/14 are calcium-binding proteins secreted by infiltrating phagocytes in synovial inflammation. Studies suggest their concentration in serum/synovial fluid (SF) represent useful markers of inflammation in JIA. MRP8/14 have never been studied in DA.

Aims/Background

Determine the accuracy of standard (CRP & ESR) and novel (MRP 8/14) inflammatory markers, as biomarkers of disease in DA, compared with JIA.

Method

Over 12 months, new cases of JIA and DA attending the NCPR had blood drawn to measure CRP, ESR and MRP 8/14 levels. Corresponding AJC was documented. Paired SFsamples were taken for analysis from children requiring steroidJIs.

Results

MRP8/14, ESR and CRP were measured in serum of DA (n=34) and JIA (n=50) patients. In a subgroup, MRP8/14 levels were also quantified in pairedSF; DA (n=3), JIA (n=21). At diagnosis, ESR and CRP levels were raised in a lower percentage of DA cases compared with our JIA cohort, even though on average, a higher AJC was observed in the DA cohort. In JIA, ESR was raised in almost 75% at diagnosis, suggesting that it is a more useful marker of inflammation in this patient group (p<0.05). SerumMRP 8/14 levels were also significantly higher in JIA compared to DA, levels of which correlated with ESR(r=0.312, p < 0.05). No correlation between serumMRP 8/14 and CRP/ESR was observed for DA.

Conclusions

Preliminary data has shown SFMRP 8/14 levels are higher than their paired serum levels in DA, and correlate with AJC. Our observations in DA may suggest that there is dissociation between systemic and local inflammation in this patient group. Further studies are planned.