Behavioural, Mucosal and Systemic Immune Parameters in HIV-infected and Uninfected Injection Drug Users

Injection Drug Use Alters Plasma Regulation of the B Cell Response

The opioid epidemic continues to be a major public health issue that includes millions of people who inject drugs (PWID). PWID have increased incidence of serious infections, including HIV as well as metabolic and inflammatory sequelae. We sought to discern the extent of systemic alterations in humoral immunity associated with injection drug use, including alterations in the plasma proteome and its regulation of B cell responsiveness. Comprehensive plasma proteomics analysis of HIV negative/hepatitis C negative individuals with a history of recent injection heroin use was performed using mass spectrometry and ELISA. The effects of plasma from PWID and healthy controls on the in vitro proliferation and transcriptional profile of B cell responses to stimulation were determined by flow cytometry and RNA-Seq. The plasma proteome of PWID was distinct from healthy control individuals, with numerous immune-related analytes significantly altered in PWID, including complement (C3, C5, C9), immunoglobulin (IgD, IgM, kappa light chain), and other inflammatory mediators (CXCL4, LPS binding protein, C-reactive protein). The plasma of PWID suppressed the in vitro proliferation of B cells. Transcriptome analysis indicated that PWID plasma treatment increased B cell receptor and CD40 signaling and shifted B cell differentiation from plasma cell-like toward germinal center B cell-like transcriptional profiles. These results indicate that the systemic inflammatory milieu is substantially altered in PWID and may impact their B cell responses.

Injecting drug use and hepatitis C virus infection independently increase biomarkers of inflammatory disease risk which are incompletely restored by curative direct-acting antiviral therapy

Background

Hepatitis C virus (HCV) infections are more prevalent in people who inject drugs (PWID) who often experience additional health risks. HCV induces inflammation and immune alterations that contribute to hepatic and non-hepatic morbidities. It remains unclear whether curative direct acting antiviral (DAA) therapy completely reverses immune alterations in PWID.

Methods

Plasma biomarkers of immune activation associated with chronic disease risk were measured in HCV-seronegative (n=24) and HCV RNA+ (n=32) PWID at baseline and longitudinally after DAA therapy. Adjusted generalised estimating equations were used to assess longitudinal changes in biomarker levels. Comparisons between community controls (n=29) and HCV-seronegative PWID were made using adjusted multiple regression modelling.

Results

HCV-seronegative PWID exhibited significantly increased levels of inflammatory biomarkers including soluble (s) TNF-RII, IL-6, sCD14 and sCD163 and the diabetes index HbA1c as compared to community controls. CXCL10, sTNF-RII, vascular cell adhesion molecule-1 and lipopolysaccharide binding protein (LBP) were additionally elevated in PWID with viremic HCV infection as compared to HCV- PWID. Whilst curative DAA therapy reversed some biomarkers, others including LBP and sTNF-RII remained elevated 48 weeks after HCV cure.

Conclusion

Elevated levels of inflammatory and chronic disease biomarkers in PWID suggest an increased risk of chronic morbidities such as diabetes and cardiovascular disease. HCV infection in PWID poses an additional disease burden, amplified by the incomplete reversal of immune dysfunction following DAA therapy. These findings highlight the need for heightened clinical surveillance of PWID for chronic inflammatory diseases, particularly those with a history of HCV infection.

Methadone use is associated with increased levels of sCD14, immune activation, and inflammation during suppressed HIV infection

Opioid use has negative effects on immune responses and may impair immune reconstitution in persons living with HIV (PLWH) infection undergoing antiretroviral treatment (ART). The effects of treatment with μ opioid receptor (MOR) agonists (e.g., methadone, MET) and antagonists (e.g., naltrexone, NTX) on immune reconstitution and immune activation in ART-suppressed PLWH have not been assessed in-depth. We studied the effects of methadone or naltrexone on measures of immune reconstitution and immune activation in a cross-sectional community cohort of 30 HIV-infected individuals receiving suppressive ART and medications for opioid use disorder (MOUD) (12 MET, 8 NTX and 10 controls). Plasma markers of inflammation and immune activation were measured using ELISA, Luminex, or Simoa. Plasma IgG glycosylation was assessed using capillary electrophoresis. Cell subsets and activation were studied using whole blood flow cytometry. Individuals in the MET group, but no in the NTX group, had higher plasma levels of inflammation and immune activation markers than controls. These markers include soluble CD14 (an independent predictor of morbidity and mortality during HIV infection), proinflammatory cytokines, and proinflammatory IgG glycans. This effect was independent of time on treatment. Our results indicate that methadone-based MOUD regimens may sustain immune activation and inflammation in ART-treated HIV-infected individuals. Our pilot study provides the foundation and rationale for future longitudinal functional studies of the impact of MOUD regimens on immune reconstitution and residual activation after ART-mediated suppression.

Impact of Heroin and HIV on Gut Integrity and Immune Activation

BACKGROUND

Altered gut integrity is central to HIV-related immune activation. Opioids may promote similar changes in gut permeability and/or increase systemic inflammation, potentially augmenting processes already occurring in people with HIV (PWH).

SETTING

Urban hospital systems in Cleveland, Ohio, and surrounding communities.

METHODS

This is a prospectively enrolled, cross-sectional study including people with and without HIV using heroin and people with and without HIV who have never used heroin, matched by age, sex, and CD4+ T-cell count (PWH only) to compare markers of gut integrity, microbial translocation, systemic inflammation, and immune activation.

RESULTS

A total of 100 participants were enrolled. Active heroin use was associated with higher concentrations of lipopolysaccharide-binding protein (LBP), beta-D-glucan (BDG), high-sensitivity C-reactive protein (hsCRP), soluble tumor necrosis factor-α-receptors I and II, soluble CD163, inflammatory monocytes, and activated CD4+ lymphocytes in adjusted models. HIV status tended to modify the effect between heroin use and LBP, BDG, hsCRP, patrolling monocytes, and activated CD4+ lymphocytes (P < 0.15 for interactions); however, it was not as expected. The effect of heroin on these markers (except patrolling monocytes) was greatest among those without HIV rather than among those with HIV.

CONCLUSIONS

Heroin use is associated with heightened microbial translocation, systemic inflammation, and immune activation. Concurrent HIV infection in virologically suppressed individuals does not seem to substantially worsen the effects heroin has on these markers.

Influence of HIV-1 V2 sequence variability on bacterial translocation in antiretroviral naïve HIV-1 infected patients

HIV-1 V2 domain binds α4β7, which assists lymphocyte homing to gut-associated lymphoid tissue. This triggers bacterial translocation, thus contributing to immune activation. We investigated whether variability of V2 179-181 binding site could influence plasma levels of lipopolysaccharide (LPS) and soluble cluster of differentiation 14 (sCD14), markers of microbial translocation/immune activation. HIV gp120 sequences from antiretroviral naïve patients were analyzed for V2 tripeptide composition, length, net charge, and potential N-linked-glycosylation sites. LPS and sCD14 plasma levels were quantified. Clinical/immuno-virologic data were retrieved. Overall, 174 subjects were enrolled, 8% with acute infection, 71% harboring a subtype B. LDV179-181 was detected in 41% and LDI in 27%. No difference was observed between levels of LPS or sCD14 according to different mimotopes or according to other sequence characteristics. By multivariable analysis, only acute infection was significantly associated with higher sCD14 levels. In conclusion, no association was observed between V2 tripeptide composition and extent of bacterial translocation/immune activation.

Effect of Opioid Use on Immune Activation and HIV Persistence on ART

While there is an emerging consensus that engagement of the Mu opioid receptor by opioids may modulate various stages the HIV life cycle (e.g.: increasing cell susceptibility to infection, promoting viral transcription, and depressing immune responses to virally-infected cells), the overall effect on latency and viral reservoirs remains unclear. Importantly, the hypothesis that the increase in immune activation observed in chronic opioid users by direct or indirect mechanisms (i.e., microbial translocation) would lead to a larger HIV reservoir after ART-suppression has not been supported to date. The potential for a subsequent decrease in reservoirs after ART-suppression has been postulated and is supported by early reports of opioid users having lower latent HIV burden. Here, we review experimental data supporting the link between opioid use and HIV modulation, as well as the scientific premise for expecting differential changes in immune activation and HIV reservoir between different medications for opioid use disorder. A better understanding of potential changes in HIV reservoirs relative to the engagement of the Mu opioid receptor and ART-mediated immune reconstitution will help guide future cure-directed studies in persons living with HIV and opioid use disorder. Graphical Abstract Review. HIV replication, immune activation and dysbiosis: opioids may affect immune reconstitution outcomes despite viral suppression.

The Opioid Epidemic: Impact on Inflammation and Cardiovascular Disease Risk in HIV

PURPOSE OF REVIEW

People infected with HIV through injection drug use are more likely to experience progression to AIDS, death due to AIDS, and all-cause mortality even when controlling for access to care and antiretroviral therapy. While high-risk behavior and concurrent infections most certainly are contributors, chronic immune activation, downstream metabolic comorbidities may play an important role.

RECENT FINDINGS

Altered intestinal integrity plays a major role in HIV-related immune activation and microbial translocation markers are heightened in active heroin users. Additionally, greater injection frequency drives systemic inflammation and is associated with HIV viral rebound. Finally, important systemic inflammation markers have been linked with frailty and mortality in people who inject drugs with and without concurrent HIV infection. Heroin use may work synergistically with HIV infection to cause greater immune activation than either factor alone. Further research is needed to understand the impact on downstream metabolic comorbidities including cardiovascular disease. Medication-assisted treatment for opioid use disorder with methadone or buprenorphine may ameliorate some of this risk; however, there is presently limited research in humans, including in non-HIV populations, describing changes in immune activation on these treatments which is of paramount importance for those with HIV infection.

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.

DNA methylation signatures of illicit drug injection and hepatitis C are associated with HIV frailty

Intravenous illicit drug use (IDU) and hepatitis C infection (HCV) commonly co-occur among HIV-infected individuals. These co-occurring conditions may produce interacting epigenetic effects in white blood cells that influence immune function and health outcomes. Here, we report an epigenome-wide association analysis comparing IDU+/ HCV+ and IDU-/HCV- in 386 HIV-infected individuals as a discovery sample and in 412 individuals as a replication sample. We observe 6 significant CpGs in the promoters of 4 genes, NLRC5, TRIM69, CX3CR1, and BCL9, in the discovery sample and in meta-analysis. We identify 19 differentially methylated regions on chromosome 6 harboring MHC gene clusters. Importantly, a panel of IDU+/HCV+-associated CpGs discriminated HIV frailty based upon a validated index with an area under the curve of 79.3% for high frailty and 82.3% for low frailty. These findings suggest that IDU and HCV involve epigenetic programming and that their associated methylation signatures discriminate HIV pathophysiologic frailty.

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.

Chronic Hepatitis C Virus Infection and the Proinflammatory Effects of Injection Drug Use

BACKGROUND

 Chronic inflammation, as defined by persistent immune activation, is associated with adverse clinical outcomes. People who inject drugs (PWID) have evidence of persistent immune activation. Here, in a cohort of PWID with or without hepatitis C virus (HCV) infection, we sought to dissect out the contribution of chronic HCV infection (common in PWID) from the effects of injection drug use itself.

METHODS

 Four groups of study volunteers were recruited: group 1 comprised active PWID; group 2, individuals who ceased injecting drugs 1-2 months before recruitment; group 3, individuals who ceased injecting drugs 3-4 months before recruitment; and group 4, healthy volunteers. Soluble and cell-associated markers of immune activation were quantified.

RESULTS

 HCV-viremic PWID have elevated levels of immune activation when compared to healthy volunteers. Cessation of injection drug use results in a decline in immune activation in the absence of HCV viremia, while HCV-viremic individuals who previously were PWID continue to harbor elevated levels of immune activation, as defined by increased levels of soluble CD14 and tumor necrosis factor α and by the presence of CD38⁺HLA-DR⁺ CD4⁺ and CD8⁺ T cells.

CONCLUSIONS

 Immune activation, a well-defined surrogate of poor clinical outcome that is elevated in PWID, can regress to normal levels in former injection drug users who are HCV aviremic. Therefore, enhanced harm-reduction efforts should incorporate aggressive treatment of HCV infection.

CLINICAL TRIALS REGISTRATION

 NCT01831284.