Serum cartilage oligomer proteins in psoriatic arthritis

Background

In the cartilage of the joint, the matrix proteins are very pronounced in relation to the scattered chondrocytes in the tissue. In recent years, many different small molecules have been described with close relation to the collagen fibers and with activities that could be important in protecting the collagen fiber structure. One of these proteins is cartilage oligometric protein (COMP).

Objective

The aim of our study was to investigate the serum level of COMP in psoriatic arthritis, to determine whether cartilage destruction is taking place.

Methods

Thirty-six psoriatic arthritis patients (22 women, 14 men), with an avarage disease duration of 7 years, were examined. For every patient, the disease activity on a visual analogue scale, the number of painful and swollen joints and the Ritchie index were recorded, as well as the sedimenation rate and CRP. The level of COMP was measured. Correlations between the activity parameters and the level of COMP were evaluated.

Results

A good correlation was found between the Ritchie index and the serum level of COMP (r = 0.4). Low correlation was seen between the level of COMP and the number of painful joints (r = 0.1). No correlation was found between COMP and any of CRP, sedimentation rate or number of swollen joints.

Conclusion

The serum level of COMP can be used as one of the activity indicators of arthritis activity, though the correlation with other activity parameters in PsA is not so strong as in rheumatoid arthritis. The reasons for this difference may lie in the additional activity of the skin disease.