Elevated Plasma Osteopontin Levels Were Associated With Osteopontin Expression of CD4⁺ T Cells in Patients With Unstable Angina

Abstract

Background Plaque instability in patients with unstable angina (UA) is associated with stimulated CD4⁺ T cells, so the present study investigated whether there is a relationship among plaque instability, osteopontin and CD4⁺ T cells. Methods and Results Peripheral blood mononuclear cells were collected from 51 consecutive patients with UA, 60 patients with stable angina (SA), and 39 patients with chest pain syndrome (CPS). Osteopontin-producing CD4⁺ T cells were quantified by flow cytometry. Plasma osteopontin levels (ng/ml) were measured by ELISA and were higher in patients with UA (792.0±316.7) than in those with SA (626.0±195.0, p<0.005) or CPS (594.7±239.4, p<0.005). The frequency (%) of osteopontin-producing CD4⁺ T cells was higher in patients with UA (26.7±13.3) than in those with SA (19.5±11.1, p<0.05) or CPS (16.6±9.0, p<0.005). Furthermore, the plasma osteopontin level correlated with the frequency of osteopontin-producing CD4⁺ T cells (r=0.327, p=0.0004), as did the high-sensitivity C-reactive protein level (r=0.360, p=0.0002). Conclusions The plasma osteopontin levels are elevated in patients with UA, accompanied by an increase in the number of osteopontin-production of circulating CD4⁺ T cells. Circulating CD4⁺ T cells may play a role through osteopontin in the pathophysiology of UA. (Circ J 2006; 70: 851 - 856)