The journal of BMC Musculoskeletal Disorders presents a study according to which patients with hand OA, particularly with erosive type exhibited a considerably lower CLU levels as compared to healthy patients. Also, an inverse relationship between pain and CLU levels was observed. 

The CLU is an apolipoprotein J protein, involved in various biological activities like apoptosis and inflammation. Tereza Kropáčková and colleagues conducted the analysis to compare CLU serum levels among healthy and hand OA patients and erosive and non-erosive disease condition. The relationship of CLU concentrations with laboratory and clinical parameters was also assessed.

The analysis comprised 135 hand OA patients and 53 healthy people. Out of 135 hands OA patients, 81 suffered from erosive and 54 from non-erosive disease condition. All healthy and OA individuals went through hand joint ultrasound and clinical examination. The pain was determined via visual analogue scale (VAS), algofunctional index and Australian/Canadian hand osteoarthritis index (AUSCAN). ELISA (enzyme-linked immunosorbent assay) was used to measure CLU serum levels.

The hand OA patients and patients with erosive form exhibited considerably lower CLU levels as compared to healthy (p < 0.0001) and non-erosive patients group (p = 0.044) respectively. The VAS and AUSCAN scores showed a negative association with CLU levels (p = 0.049; 0.013, respectively).