Systemic inflammation and antibodies to citrullinated peptides in hand osteoarthritis

To investigate systemic inflammation and autoimmune response to citrullinated peptides in patients with erosive and non erosive 'lone' hand osteoarthritis (HOA) with no hip/knee involvement and their relationship with radiographic structural damage.

Sera were obtained from a total of 99 patients with HOA (52 patients with erosive HOA and 47 patients with non-erosive HOA) and from 50 control subjects (NC). Hand radiographs were obtained from all patients and scored for joint damage according to the Kellgren-Lawrence and the Kallman scores. Serum levels of high-sensitivity CRP (hsCRP), IL-6, pentraxin-3 (PTX-3), anti-CCP and anti-modified citrullinated vimentin (MCV) antibodies were evaluated by a sandwich ELISA.

Circulating levels of inflammatory biomarkers hsCRP, IL-6 and PTX3 were not significantly different in the two groups of patients with erosive and non-erosive HOA compared to NC and no significant difference was seen between non-erosive and erosive HOA. Anti-CCP positivity was detected respectively in 1 patient (2.1%) with non-erosive HOA and 1 patient (1.9%) with erosive HOA. Anti-MCV antibodies were present in 4 patients (8.5%) with non-erosive HOA, and 4 patients (7.7%) with erosive HOA. In the control group, one subject (2%) was positive for anti-CCP and 2 subjects (4%) had anti-MCV antibodies. Significant correlation was obtained only between body mass index and hsCRP concentration (r=0.4071; p<0.0001). No correlation between inflammation markers/autoantibodies and disease duration and radiological scores was found.

Our study underlines the lack of systemic inflammation and autoimmunity in 'lone' HOA and confirms the association between BMI and CRP levels.