Systemic inflammation and residual viraemia in HIV-positive adults on protease inhibitor monotherapy: a cross-sectional study

BACKGROUND: Increased levels of markers of systemic inflammation have been associated with serious non-AIDS events even in patients on fully suppressive antiretroviral therapy. We explored residual viremia and systemic inflammation markers in patients effectively treated with ritonavir-boosted protease inhibitor monotherapy (PImono). METHODS: HIV-infected adults with persistent HIV-RNA <50 copies/ml and treated with either a) PImono or b) standard triple-drug cART were recruited for this cross-sectional, exploratory study. Plasma samples were tested for high-sensitivity CRP (hsCRP), Serum Amyloid A (SAA), soluble CD14, IL-6, IL-8 and Cytochrome C. HIV-RNA was measured by real-time PCR (detection limit of 10 copies/ml). RESULTS: 81 patients were recruited (31% on PImono). Two out of 25 (8%) and 3 of 56 (5.4%) patients from the PImono and cART groups respectively had detectable HIV-RNA. Significant correlation between SAA and hsCRP was observed (0.804). No difference between groups was found on prevalence of hsCRP >3 mg/l (21% vs 20% in the PImono and cART groups respectively; p = 0.577) or SAA >6.4 mg/l (38% vs 22% in the PImono and cART groups respectively; P = 0.172). In a univariate analysis IL6 and IL8 levels were associated with SAA >6.4 mg/l (OR = 1.74 and 1.46; 95% CI = 1.00 – 3.03 and 1.06 – 2.01; p = 0.051 and 0.02 respectively) and hsCRP >3 mg/l in (OR = 2.00 and 1.37; 95% CI = 1.09 – 3.69 and 1.02 – 1.85; p = 0.026 and 0.039 respectively). CONCLUSIONS: We found no evidence of increased levels of inflammatory biomarkers or higher prevalence of residual viraemia in patients effectively suppressed on PImono as compared with patients on standard cART.