White blood cells may have a role in the aetiopathogenesis of atherosclerosis disease in patients with risk factors for this disease. We examined the white blood cell count in a group of 331 patients and controls of the same age group (139 women and 192 men), the numbers of individuals with no, one, two or more atherosclerotic risk factors being 29, 47, 35 and 28 for women and 50, 45, 68 and 29 for men, respectively. The risk factors included were hypertension, hyperlipidaemia, current smoking and diabetes mellitus. A stepwise increment in the white blood cell count was found in both women and men, the respective values for no, one, two or more risk factors being 6.3 +/- 1.5, 7.6 +/- 1.9, 7.5 +/- 1.8, 7.3 +/- 1.4 and 6.6 +/- 1.6, 6.9 +/- 1.9, 7.4 +/- 2.1, 8.1 +/- 2.6 (absolute number of cells per cm x 103). The one-way analysis variance was found to be significant for both women (P=0.01) and men (P=0.01), as well as the entire cohort (P=0.03). We conclude that the multiplicity of risk factors for atherosclerosis is associated with the appearance of an increased number of white blood cells in the peripheral blood. These findings might represent an enhanced inflammatory response in these individuals and at the same time reveal a potential harmful role of the cells in the aetiopathogenesis of the disease.