Differences in T cell distribution and CCR5 expression in HIV-positive and HIV-exposed seronegative persons who inject drugs

Getting to the point: Methamphetamine injection is associated with biomarkers relevant to HIV pathogenesis

BACKGROUND

People living with HIV who use stimulants, such as methamphetamine, display greater immune dysregulation and experience faster clinical HIV progression. However, it remains unclear if the extent of immune dysregulation differs between methamphetamine users who engage in injection drug use (Meth IDU) and methamphetamine users who do not.

METHODS

This cross-sectional study enrolled 86 sexual minority men living with HIV who had an undetectable viral load (< 40 copies/mL) and recent, biologically confirmed methamphetamine use. Meth IDU participants were compared to methamphetamine users who did not report IDU with respect to microbial translocation, immune activation, and inflammation plasma biomarkers. Multiple linear regression models were adjusted for age, antiretroviral therapy regimen, CD4 + T-cell count, and reactive urine toxicology results (Tox+) for stimulants.

RESULTS

The Meth IDU participants were significantly more likely to be homeless and Tox + for stimulants. In adjusted analyses, those reporting Meth IDU displayed elevated plasma levels of lipopolysaccharide binding protein (LBP), soluble CD163 (sCD163), interleukin-6 (IL-6), and soluble tumor necrosis factor - alpha receptor I (sTNF-αRI).

DISCUSSION

Even among methamphetamine users with treated HIV, those who engage in Meth IDU display exacerbations in key pathophysiologic processes that are linked to faster clinical HIV progression. These findings highlight the importance of screening for Meth IDU, discussing safer injection practices, and providing linkages to needle exchanges to reduce the harms of Meth IDU. Those who are not ready, willing, or able to abstain from methamphetamine use could also derive important health benefits from avoiding Meth IDU.

Enhanced Signaling Through the TLR9 Pathway Is Associated With Resistance to HIV-1 Infection in Chinese HIV-1-Exposed Seronegative Individuals

Innate immunity is the first line of defense against invading pathogens and may mediate HIV-1 resistance in HIV-1–exposed seronegative (HESN) individuals. This study aims to identify components of innate immunity that confer natural HIV-1 resistance in Chinese HESN individuals. Specifically, we compared the expression levels of Toll-like receptors (TLRs) and associated pathway molecules in peripheral blood mononuclear cells (PBMCs), monocytes/macrophages, and plasma obtained from HESN and control individuals. HESN individuals had higher expression of TLR9, IRF7, IFN-α/β, RANTES, and MIP-1α/1β in PBMCs and plasma than control subjects. Upon TLR9 stimulation, significantly higher expression of TLR9 and IRF7, as well as higher production of IFN-α/β, RANTES, and MIP-1α/1β, was observed in PBMCs and monocytes/macrophages from HESN individuals than in the corresponding cells from control individuals. More importantly, both with and without TLR9 stimulation, the levels of HIV-1 replication in monocyte-derived macrophages (MDMs) from HESN individuals were significantly lower than those in MDMs from control individuals. These data suggest that increased TLR9 activity and subsequent release of antiviral factors contribute to protection against HIV-1 in HESN individuals.

Influence of Injection Drug Use-Related HIV Acquisition on CD4 Response to First Antiretroviral Therapy Regimen Among Virally Suppressed Individuals

BACKGROUND

The inflammatory effects of injection drug use (IDU) may result in an impaired immune response to antiretroviral therapy (ART). We examined CD4 response to first ART regimen among individuals in routine HIV care, stratified by IDU-related HIV acquisition.

SETTING

Cohort study including patients who initiated ART between 2000 and 2015 in the Johns Hopkins HIV Clinic.

METHODS

We followed individuals from ART initiation until death, loss to follow-up, loss of viral load suppression (<500 copies/mL), or administrative censoring. We described CD4 trajectories after ART initiation using inverse probability weighted quantile regression models with restricted cubic splines for time. Weights accounted for differences in baseline characteristics of persons comparing those with IDU-related HIV acquisition to those with other HIV acquisition risks (non-IDU) and possible nondifferential censoring due to death, loss to follow-up, or loss of viral load suppression. We also examined CD4 response by strata of CD4 at ART initiation (≤200, 201-350, >350).

RESULTS

Of 1244 patients initiating ART, 30.4% were IDU. Absolute CD4 cell difference at the 50th percentile comparing IDU with non-IDU was -25 cells [95% confidence interval (CI): -63 to 35], -66 cells (95% CI: -141 to 16), and -91 cells (95% CI: -190 to -5) at 2, 4, and 6 years after ART initiation, respectively. Results were similar (non-IDU with slightly higher CD4 count, but not statistically significant differences) at other percentiles and stratified by baseline CD4.

CONCLUSIONS

CD4 recovery after ART initiation was similar for IDU and non-IDU, conditional on consistent viral load suppression.

Brief Report: The Relationship Between Injection Drug Use Risk Behaviors and Markers of Immune Activation

High levels of immune activation are reported for people who inject drugs. Studies of the relationship between injection behaviors and immune activation have yielded mixed results, in part due to lack of control for hepatitis C virus in analyses. This study, of 48 HIV-seronegative people who inject drugs, examines this relationship controlling for hepatitis C virus viremia. Frequency of injection was positively related to markers of immune activation (soluble CD14, %CD8CD38HLADR T cells), as was duration of injection (high-specificity C-reactive protein and D-dimer). Sharing injection equipment was not related to markers studied. Findings suggest that efforts to encourage injection cessation or reduction in frequency can have positive health benefits through reducing immune activation.

T Cell Distribution in Relation to HIV/HBV/HCV Coinfections and Intravenous Drug Use

Intravenous drug use (IDU) is one of the most important transmission routes for blood borne viruses, including human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV). These infections alter the subset distributions of T cells; however, knowledge of such effects during HIV, HBV, and or HCV coinfection is limited. Therefore, we aimed to evaluate any associations between T cell distribution and the presence of HIV, HBV, and HCV coinfections among persons who inject drugs (PWID). Blood samples from 88 Caucasian PWID (mean age 30; 82% male) and 47 age-matched subjects negative for all three infections (mean age of 29; 83% male) were analyzed. The T cell markers CD3, CD4, CD8, CD45RA, CCR7, HLA-DR, and CCR5 were assessed using flow cytometry. Of the PWID, 40% were HIV+HBV+HCV+, 20% HBV+HCV+, 19% HCV+, and 13% negative for all three infections. The HIV+HBV+HCV+ PWID had lower percentages of CD4⁺ and higher percentages of CD8⁺ cells compared to triple negative PWID (p < 0.001 in all cases). The only difference between HBV+HCV+ with triple negative PWID was the lower CD4⁺ cell percentages among the former (52.1% and 58.6%, p = 0.021). Triple negative PWID had higher immune activation and number of CCR5⁺ cells compared to the controls. We suggest that the altered T cell subset distribution among PWID is mainly triggered by HIV infection and or IDU, while HBV and or HCV seropositivity has minimal additional effects on CD4⁺ cell distribution.