A cluster of rapid disease progressors upon primary HIV-1 infection shared a novel variant with mutations in the p6gag/pol and pol/vif genes

Clinical characteristics of HIV-1-infected patients with high levels of plasma interferon-γ: a multicenter observational study

Background

Circulating interferon-γ (IFN-γ) concentration may be sustained at a high level regardless of the initiation of antiretroviral therapy (ART) in some patients with HIV-1 infection. In the present study, we examined the clinical characteristics of HIV-1-infected patients with high levels of plasma IFN-γ.

Methods

The study subjects were patients infected with HIV-1 who were either naïve to ART with CD4⁺ cell count > 200 cells/μL (n = 12), or had achieved viral suppression after ART for over a year (n = 188). The levels of plasma IFN-γ and interleukin-6 (IL-6) were measured by the enzyme-linked immunosorbent assay. Patients were divided into high IFN-γ and low IFN-γ groups based on a cutoff level of 5 pg/mL.

Results

The high IFN-γ group included 41 patients (21%). Compared to the patients on ART with low IFN-γ levels, those on ART in the high IFN-γ group were more likely to be younger than 50 years of age (P = 0.0051) and less likely to have dyslipidemia (P = 0.0476) or to be on a protease inhibitor (P = 0.0449). There was no significant difference between groups in the median increase of CD4⁺ cell counts from the initiation of ART for up to 3 years. However, after 4 years, the increase in CD4⁺ cell counts was significantly lower in the high IFN-γ group compared with that in the low IFN-γ group. There were no such significant differences between patients with low and high (> 2 pg/mL) levels of plasma IL-6.

Conclusion

We concluded that HIV-1-infected patients with high levels of circulating IFN-γ did not have a higher rate of comorbidities related to immune activation. However, they exhibited lower CD4⁺ cell count recovery after 4 years of being on ART. This deficit could be a consequence of persistent immune activation.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3643-2) contains supplementary material, which is available to authorized users.

Inhibition of the precursor and mature forms of HIV-1 protease as a tool for drug evaluation

HIV-1 protease (PR) is a homodimeric enzyme that is autocatalytically cleaved from the Gag-Pol precursor. Known PR inhibitors bind the mature enzyme several orders of magnitude more strongly than the PR precursor. Inhibition of PR at the precursor level, however, may stop the process at its rate-limiting step before the proteolytic cascade is initiated. Due to its structural heterogeneity, limited solubility and autoprocessing, the PR precursor is difficult to access by classical methods, and limited knowledge regarding precursor inhibition is available. Here, we describe a cell-based assay addressing precursor inhibition. We used a reporter molecule containing the transframe (TFP) and p6* peptides, PR, and N-terminal fragment of reverse transcriptase flanked by the fluorescent proteins mCherry and EGFP on its N- and C- termini, respectively. The level of FRET between EGFP and mCherry indicates the amount of unprocessed reporter, allowing specific monitoring of precursor inhibition. The inhibition can be quantified by flow cytometry. Additionally, two microscopy techniques confirmed that the reporter remains unprocessed within individual cells upon inhibition. We tested darunavir, atazanavir and nelfinavir and their combinations against wild-type PR. Shedding light on an inhibitor’s ability to act on non-mature forms of PR may aid novel strategies for next-generation drug design.