The magnitude of FMD change for the vaccine group was significantly different MDV3100 from that for the sham procedure group at both 8 and 48 h (P=0.04 and 0.03, respectively). The magnitude of change for FMD is depicted in Figure 1. The white blood cell count increased at 8 h post vaccination and remained elevated at 48 h. The sham procedure resulted in a significant drop in white blood cell count at 48 h (Table 2). The magnitude of the change in white blood cell count at 8 and 48 h did not differ across groups (Fig. 2). sICAM-1 levels decreased following vaccination, with the lowest values noted at 48 h. Conversely, no time interaction for sICAM-1 was noted during the sham

procedure (Table 2). The magnitude of the change in sICAM-1 for the vaccine group at 8 h differed significantly (P=0.01) from that of the sham procedure group; a comparison of the change in sICAM-1 between groups at 48 h yielded a marginal P value (P=0.07) (Fig. 2). Following vaccination, CRP levels across time-points did not differ significantly; nevertheless, a P value of 0.08 for repeated measures anova suggests that further research is needed. No time interaction across study groups was noted for IL-6 and ADMA levels, indicating that the concentration of these compounds remained stable for both groups across time (Table 2). To the best of our knowledge, this is the first study to explore the effect of vaccination against the influenza A/H1N1 virus on endothelial

function in HIV-infected patients. see more There are two novel aspects to this study. First, the effect on endothelial function of the vaccine against the pandemic influenza A/H1N1 virus has not been studied to date in any population, and this also applies to vaccines that contain an adjuvant as a booster for the immune system. Secondly, the effects on endothelial function of any vaccine have not previously been investigated in an HIV-positive group. Previous studies have used vaccines as a model of the impact of a transient inflammatory stimulus on endothelial and arterial function. Acute systemic inflammation and endothelial dysfunction 3-mercaptopyruvate sulfurtransferase ensue from

vaccination against Salmonella typhi [5]. Our group has reported a short-lived, yet significant impairment of arterial elastic properties following administration of a vaccine in healthy individuals, with a concomitant increase in inflammatory markers [6]. In a concordant fashion, vaccination against influenza provoked an inflammatory and oxidative response. Interestingly, endothelial dysfunction persisted for 14 days following vaccination [7]. Endothelial function has been advocated as a surrogate marker of subclinical atherosclerosis, and a dysfunctioning endothelial layer has been linked to worse outcomes [16]. In addition to classical risk factors, it is influenced by a multitude of factors, including HIV infection [17,18], pharmacological agents [19,20] and lifestyle modifications [21].