Objective: The aim of the present study was to evaluate serum soluble interleukin-1 receptor antagonist (sIL-1RA) concentration and its relationship with the degree of cigarette smoking in patients with Graves' ophthalmopathy (GO).
Design and subjects: Twenty-two consecutive GO patients (20 women, two men; age range 25-68 years, mean 48 years; 12 smokers, 10 non-smokers) submitted to IV glucocorticoid pulses over a 3-month period.
Measurements: sIL-1RA levels were measured by an immunoenzymatic assay (sensitivity, 4 ng/l; normal range, 50-290 ng/l) before glucocorticoid treatment, after two months of therapy, and 3 months after drug withdrawal.
Results: Thirteen patients responded to treatment (59%; five smokers and eight non-smokers), nine were non-responders (41%; seven smokers and two non-smokers). Baseline median sIL-1RA concentration did not differ in smokers and non-smokers (222 and 173 ng/l, respectively; P = 0.69). Likewise, no significant differences were found between the two groups during treatment (537 and 389 ng/l, respectively; P = 0.28); sIL-1RA concentration after treatment was higher in smokers (258 vs. 94 ng/l; P = 0.02). There was no correlation between basal sIL-1RA levels and the degree of cigarette smoking. Likewise, there was no difference in sIL-1RA levels in responders and non-responders, either at baseline (186 vs. 216 ng/l; P = 0.83), during or after treatment.
Conclusion: Our study suggests that circulating soluble interleukin-1 receptor antagonist levels, both at baseline and during glucocorticoid treatment, are neither influenced by cigarette smoking nor predictive of subsequent response to glucocorticoid treatment.