A pilot study to assess inflammatory biomarker changes when raltegravir is added to a virologically suppressive HAART regimen in HIV-1-infected patients with limited immunological responses.

BACKGROUND: Despite successful suppression of HIV-1 with HAART, some patients do not have robust immunological recovery. Chronic inflammation from persistent immune activation could contribute to this poor response, resulting in HIV-1 disease progression and the development of some non-HIV-1 comorbidities. METHODS: We conducted a pilot study of 30 HIV-1-infected patients with undetectable viral loads and poor CD4(+) T-cell responses on long-term stable HAART to assess whether the addition of raltegravir would have an effect on biomarkers of chronic inflammation. A total of 26 patients were followed for 1 year on the intensified regimen. In addition to T-cell responses, we evaluated changes in activated CD4(+) and CD8(+) T-cells, several pro-inflammatory cytokines and chemokines and memory cell responses to HIV-1-associated peptides. RESULTS: Although there was no improvement in CD4(+) T-cell counts, the percentage change in CD4(+)%, CD4(+)/CD8(+) ratios and RANTES (regulated on activation normal T-cells expressed and secreted) increased significantly while the percentage change in CD8(+) T-cell counts and CD8(+)%, activated CD4(+) T-cells and several pro-inflammatory chemokines and cytokines decreased significantly. The percentage change in HIV-1-specific nef, pol set 1, gag and env memory T-cells also declined. CONCLUSIONS: The addition of raltegravir to a virologically suppressive HAART regimen in patients with poor immunological responses resulted in the reduction of several pro-inflammatory biomarkers; increases were seen in RANTES levels and CD4(+)/CD8(+) T-cell ratios. The clinical relevance of these observations is beyond the scope of this study.

Toll-like receptor 2 down-regulation in established mouse allergic lungs contributes to decreased mycoplasma clearance.

RATIONALE: Respiratory Mycoplasma pneumoniae (Mp) infection is involved in asthma pathobiology, but whether the established allergic airway inflammation compromises lung innate immunity and subsequently predisposes patients with asthma to Mp infection remains unknown. OBJECTIVES: To test whether the established allergic airway inflammation compromises host innate immunity (e.g., Toll-like receptor 2 [TLR2]) to hinder the elimination of Mp from the lungs. METHODS: We used mouse models of ovalbumin (OVA)-induced allergic airway inflammation with an ensuing Mp infection, and cultures of mouse primary lung dendritic cells (DCs) and bone marrow-derived DCs. MEASUREMENTS AND MAIN RESULTS: Lung Mp clearance in allergic mice and TLR2 and IL-6 levels in lung cells, including DCs as well as cultured primary lung DCs and bone marrow-derived DCs, were assessed. The established OVA-induced allergic airway inflammation, or the prominent Th2 cytokines IL-4 and IL-13, inhibited TLR2 expression and IL-6 production in lung cells, including lung DCs, and eventually led to impaired host defense against Mp. Studies in IL-6 knockout mice indicated that IL-6 directly promoted Mp clearance from the lungs. IL-4- and IL-13-induced suppression of TLR2 was mediated by inhibiting nuclear factor-kappaB activation through signal transducer and activator of transcription 6 (STAT6) signaling pathway. CONCLUSIONS: The established OVA-induced allergic airway inflammation impairs TLR2 expression and host defense cytokine (e.g., IL-6) production, and subsequently delays lung bacterial clearance. This could offer novel therapeutic strategies to reinstate TLR2 activation by using TLR2 ligands and/or blocking IL-4 and IL-13 to ameliorate persisting respiratory bacterial infections in allergic lungs.