AB0555 Correlations between RF and ACPA dynamics and achievement of response in active rheumatoid arthritis patients treated with rituximab

Background Rheumatoid arthritis (RA) is a chronic inflammatory joint disease with a prevalence ranging from 0,5-1% in the general population, associated with premature mortality, disability and compromised quality of life. The classification criteria for RA (American College of Rheumatology/European League Against Rheumatism classification criteria for rheumatoid arthritis – the 2010 ACR/EULAR classification criteria for RA) was introduced in 2010 as a tool with high sensitivity and specificity for diagnosing RA, including anti-cyclic citrullinated peptide antibodies (ACPA) and rheumatoid factor (RF). Rituximab (RTX) has been shown to be an effective RA treatment for use in anti tumor necrosis alpha (TNF-alpha) refractory disease. Objectives The aim of the study is to establish the dynamic correlation of ACPA and RF patterns with Disease Activity Score 28 – C reactive protein (DAS28-CRP), after the third completed cure. Methods The study included 45 active RA (DAS28 >5,1) subjects with a mean age of 48 years, 88,8% were women with mean disease duration of 7,1 years; all subjects had failed to at least one anti-TNF-alpha regimen and were RTX naive. All the patients were RF-positive, 91,1% were ACPA positive at the inclusion testing and DAS28 was determined each time one day prior the RTX cure. A moderate response was considered as a decrease of DAS28 of at least 1.2 from the prior value. Results Moderate response to RTX was observed in 41 cases (91,1%). 33 subjects from responders (80,5%) showed also a significant decrease (more than 50% from initial testing levels) of both RF and ACPA. The number of previous anti-TNF agents (p=0.003), RF positivity (p