Interleukin-6 (IL-6), the major proinflammatory cytokine, has been described to be associated with the hypertensive and atherosclerotic states. We aimed to explore whether the concentration of circulating IL-6 and adhesion molecules could be modified by decreasing blood pressure in hypertensive subjects. A total of 30 subjects (18 men), aged 34-48 years, were enrolled in this study, 17 hypertensive never-treated patients (HTA) and 13 normotensive subjects (C). HTA subjects were treated with irbesartan, 150-300 mg/day for 3 months, and serum IL-6, vascular cell adhesion molecule-1, intercellular adhesion molecule-1, sP-selectin, sE-selectin and monocyte chemoattractant protein-1 were measured at 0 and 12 weeks. The two study groups were similar in age, body mass index (BMI) and gender. At baseline, circulating IL-6 levels, but not adhesion molecules, were significantly associated with systolic blood pressure (r=0.41; P=0.03) and BMI (r=0.53; P=0.005). Systolic and diastolic blood pressure decreased significantly (P<0.01) in parallel to serum IL-6 levels (from 3.72+/-0.82 to 3.23+/-0.19 pg/ml, P=0.02) reaching a similar concentration to normotensive patients (3.33+/-0.3 pg/ml) after treatment with irbesartan. No significant changes were observed in any other of the tested parameters. In conclusion, the treatment of high blood pressure lowers circulating IL-6 in young hypertensive patients.