Enhanced plasma soluble CD40 ligand levels in essential hypertensive patients with blunted nocturnal blood pressure decrease

Background: Hypertensives with a blunted nocturnal blood pressure (BP) decrease have increased risk of developing atherosclerotic disease. Soluble CD40 ligand (sCD40L) is involved in the pathogenesis of risk factor-related vascular damage. Therefore, we evaluated the relationship between circulating sCD40L levels, circadian BP profile, and early carotid atherosclerosis in essential hypertensives. Methods: Plasma sCD40L concentrations were assessed in two groups of 25 never-treated hypertensives, without additional cardiovascular risk factors, differentiated on the basis of a nocturnal decrease of BP either of > 10% (dippers) or < 10% (nondippers) of daytime values, and in 25 matched normotensives. Carotid intima-media thickness (IMT) was also measured in all participants. Results: Plasma sCD40L concentrations were higher in nondippers (4.9 +/- 1.2 ng/mL) than in dippers (3.7 +/- 0.7, P = .0005) and controls (1.6 +/- 0.6, P < .0001). These latter had lower sCD40L concentrations than dippers (P < .0001). The IMT was higher in both hypertensive groups than in normotensives (P < .0001). In the entire hypertensive population IMT directly correlated with circulating levels of sCD40L (r = 0.365, P = .01) and inversely correlated with nocturnal systolic BP decreases (r = -0.286, P = .043). In a multivariate regression analysis sCD40L was the main determinant of IMT (r(2) = 0.157, P = .004). Conclusions: Nondippers have enhanced plasma sCD40L levels, which may contribute to their increased susceptibility to develop vascular damage.