A pilot study of CXCL8 levels in crystal proven gout patients during allopurinol treatment and their association with cardiovascular disease

OBJECTIVES: Gout is associated with cardiovascular diseases, and systemic inflammation has a role in this. CXCL8 (interleukin-8) levels were increased in synovial fluid of gout patients, and in serum in gout patients irrespective of their disease activity. We hypothesized that the well-known cardiovascular protective effects of allopurinol could be related to effects of this drug on CXCL8 levels.

METHODS: Patients with a crystal proven gout diagnosis, who newly started allopurinol treatment, were included in this prospective cohort study. After evaluation at baseline for cardiovascular diseases, tophi, uric acid, CRP and CXCL8 serum levels, patients were followed for changes in uric acid and CXCL8 levels. A subgroup analysis was performed in 10 patients with the longest follow-up period and at least 4 assessments of serum uric acid and CXCL8.

RESULTS: Sixty patients were included, and patients known with cardiovascular diseases at baseline had significantly higher CXCL8 and uric acid levels (P<0.01). In the whole group, median CXCL8 levels had not decreased after a median (IQR) follow-up of 27 (12-44) weeks (P=0.66). In the subgroup analysis in 9 out of 10 patients, CXCL8 levels showed a slight decrease, sometimes after an initial increase after a median (IQR) follow-up of 51 (45-60) weeks.

CONCLUSIONS: This pilot study indicates that higher CXCL8 levels were associated cardiovascular diseases in gout patients. Short-term use of allopurinol does not decrease CXCL8 levels in gout patients, but longer use possibly does. Further studies are warranted to establish the potential mechanisms of treatment and effects on CXCL8 levels.