Background Predicting prognosis in patients with early RA remains a challenge. There is currently limited data from early arthritis cohorts examining the relationship between synovial pathotype, clinical phenotype and clinical outcome, including tissue obtained from small joints biopsy.
Objectives The aim of this study was to evaluate in an early RA cohort the association between baseline synovial pathotype -including synovial tissue from small joints- clinical phenotype and clinical response to DMARD therapy.
Methods A cohort of 67 DMARD naïve patients with early (<12 months duration) RA according to 1987 ACR criteria was recruited at Barts and The London Hospital. Baseline disease characteristics assessed included erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level, rheumatoid factor (RF), anti-cyclic-citrullinated peptide (CCP) and 28 joints-disease activity score (DAS28), semiquantitative (0-3 scale) ultrasound score for synovial thickening (ST) and power doppler (PD) of 10 metacarpophalangeal joints (MCPs) and wrists' midline, radial and ulnar longitudinal views. All patients underwent a baseline ultrasound-guided synovial biopsy prior to commencing DMARD combination therapy (+/- oral steroids). In 80% of cases the biopsied joint was a small joint. DAS28 was assessed at 6 month follow up in order to determine response to treatment. Sections of paraffin embedded RA synovial tissue were stained with standard Haematoxylin and Eosin (H&E) and sections graded as either aggregate or diffuse according to the presence or absence of grade 2/3 lymphocytic aggregates respectively [Manzo, A. et al; European Journal of Immunology 2005].
Results Characteristics of patients at baseline and comparison between ELN- and ELN+ groups are shown in the table (Chi sqare or Mann Whitney test, as appropriate).
The presence of ELN is associated with higher ESR (p=0.01), RF (p=0.01) and CCP (p=0.03) seropositivity and higher DAS28 (p=0.05);
The presence of ELN is associated with higher median DAS28 change at 6mo (p=0.02);
Logistic regression analysis performed by entering several baseline variables (gender, age, disease duration, use of steroids, RF and CCP status, DAS28, HAQ, presence of ELN, MCPs and wrists ST and PD score, shows that presence of ELN is an independent predictor of good/moderate EULAR clinical response at 6 months (OR=5.9, 95% CI =1.0-33.0, p=0.04).
Conclusions Presence of synovial lymphocyte aggregates is associated with a more severe clinical phenotype at baseline, including antibody status, and is a predictor of good/moderate EULAR clinical response to DMARD therapy in early RA. Further studies are needed in order to establish to what extent the presence of lymphocyte aggregates could be used in the future as a prognostic tool to guide clinical strategies.
Disclosure of Interest None declared