Serum and synovial fluid concentrations of soluble granzyme b in early rheumatoid arthritis

Abstract EN

Background : cytotoxic cells possess specialized granules which contain performing and a group of serine proteinases termed grazes.

Granzyme B is a serine protease that have been identified in synovial fluid and tissue of rheumatoid arthritis (RA) patients, where they may play an important role as mediators of granule-mediated apoptosis, extracellular proteolysis, and cytokine induction.

Objective : to assess plasma and synovial fluid soluble granzyme B concentrations in early RA patients and its association to seropositivity, ESR, C-reactive protein (CRP), disease activity and the rate of radiological progression.

This was in an attempt to throw light on its possible role as predictive factor for disease severity and joint outcome.

Methods : this study included 80 early RA patients presenting with knee effusion and 30 matched osteoarthritis (OA) patients presenting with traumatic non-hemorrhagic knee synovial effusion as a control group.

Serum and synovial fluid granzyme B concentrations were determined with ELISA.

Assessment of disease activity.

Rheumatoid factor (RF), CRP and ESR were measured.

Radiographs of the hands, wrists and forefeet were taken for all RA patients at baseline and after one year.

Radio graphical damage and scoring were evaluated.

Results : there was a highly significant increase in serum and synovial fluid concentrations of soluble granzyme B in RA patients as compared to OA control group.

Also, there was a highly significant increase in synovial fluid concentrations of granzyme B as compared to serum concentrations in RA patients.

There was a highly significant increase in serum and synovial fluid concentrations of granzyme B in seropositive RA patients as compared to seronegative patients.

There were highly significant elevations in the mean serum and SF granzyme B concentrations at the entry of the study in patients showing radiological progression than non-progressive group.

There was a statistically significant positive correlation between serum granzyme B concentration and CRP and a highly significant positive correlation as compared with disease duration, number of swollen joints, Ritchie articular index (RAI), general health status, ESR, disease activity score, RF, radiological progression or granzyme B synovial fluid concentration.

Conclusions : high soluble granzyme B concentrations are found in early rheumatoid arthritis patients.

Increase in serum concentrations of granzyme B in seropositive RA patients as compared to seronegative patients and increased concentrations associated with the development of radiographic erosions in those patients raise the attention to the importance of granzyme B as a marker for prediction of radiographic joint damage.

So granzyme B concentration can be considered as a useful prognostic marker in early rheumatoid arthritis patients.