Serum human cartilage glycoprotein‑39 levels in patients with systemic lupus erythematosus

INTRODUCTION: Human cartilage glycoprotein‑39 (HC gp‑39) is a protein secreted by various cells including chondrocytes. Serum HC gp‑39 has been suggested to be a marker of cartilage damage. However, inflammation involving other sites than the joints is an additional factor that increases the serum level of HC gp‑39. OBJECTIVES: The aim of the study was to evaluate the usefulness of HC gp‑39 determination in serum of patients with systemic lupus erythematosus (SLE) as a marker of joint involvement. PATIENTS AND METHODS: Serum HC gp‑39 levels were measured in 25 patients with SLE and 22 healthy controls. SLE activity was assessed by the Systemic Lupus Erythematosus Disease Activity Index, and articular involvement by calculating the number of swollen and tender joints. The markers of inflammation (erythrocyte sedimentation rate, C‑reactive protein) were determined. RESULTS: We observed an increase in HC gp‑39 in SLE patients. However, there was no correlation of this parameter with disease activity, inflammatory markers (except serum γ globulin levels), and articular involvement. CONCLUSIONS: The study suggests that increased HC gp‑39 in SLE patients results mainly from inflammation and is not useful as a marker of joint involvement.