Systemic cytokine levels show limited correlation with risk of HIV-1 acquisition

Concomitant Imbalances of Systemic and Mucosal Immunity Increase HIV Acquisition Risk

BACKGROUND

We previously reported association of increased cervical RANTES and decreased secretory leukocyte protease inhibitor (SLPI) with higher risk of HIV acquisition in reproductive-age women. We now examine the interaction of concomitantly altered systemic and cervical immunity on such risk.

METHODS

We measured immune biomarkers in 4390 cervical and 2390 paired serum specimens at quarterly visits in 218 HIV seroconverters and 784 seronegative women. We assessed proinflammatory (IL-1β, IL-6, IL-8, MIP-3α, and RANTES), anti-inflammatory (IL-1RA and SLPI), vascular activation (vascular endothelial growth factor and Intercellular Adhesion Molecule-1) and defensin (BD2) cervical biomarkers and systemic (peripheral blood) C reactive protein (CRP), IL-6, IL-7, and sCD14 as indicators of immune dysregulation. Biomarker levels were Box-Cox transformed and odds ratios for HIV acquisition calculated based on top quartile or higher/lower than median levels for all HIV-negative visits.

RESULTS

Subsequent HIV acquisition was associated with 5 of 14 individual biomarkers: low systemic CRP [odds ratio (OR) = 1.49, 1.21-1.83] and IL-6 (OR = 1.23, 1.00-1.51), high cervical BD-2 (OR = 1.33, 1.11-1.58) and RANTES (OR = 1.20, 1.01-1.43), and low cervical IL-1RA (OR = 0.65, 0.48-0.86). Low systemic CRP concomitant with altered cervical immunity, especially high BD2, conveyed highest HIV risk (1.63, 1.29-2.05). Additional markers of increased risk emerged when low systemic CRP coincided with: low systemic IL-6 and IL-7 (OR = 1.53, 1.18-1.97); high cervical IL-8 and MIP-3α (OR = 1.40, 1.07-1.83); high cervical IL-1β and IL-6 (OR = 1.43, 1.09-1.86); or low cervical SLPI (OR = 1.36, 1.08-1.71).

CONCLUSIONS

Changes in both peripheral and mucosal immunity may precede and predispose women to HIV infection. Suppressed systemic immunity (ie, low CRP) alone or in combination with imbalanced cervical innate immunity (high proinflammatory and low anti-inflammatory mediators) indicated increased vulnerability to infection. Understanding these combined effects on HIV susceptibility is essential to preventing new infections.

Genital-Systemic Chemokine Gradients and the Risk of HIV Acquisition in Women

Supplemental Digital Content is Available in the Text.

Background:

Mucosal and systemic immune mediators have been independently associated with HIV acquisition risk, but the relationship between compartments remains unclear.

Methods:

To address this, the concentrations of 12 cytokines were compared in matched plasma and cervicovaginal lavages (CVLs) from 57 HIV-positive women before their acquisition of HIV (cases) and 50 women who remained uninfected (controls) during the CAPRISA 004 trial.

Results:

Although genital IP-10 concentrations were significantly higher in cases, plasma IP-10 concentrations were inversely associated with HIV risk. Comparing differences in mucosal and systemic cytokine concentrations between cases and controls, mucosa-biased gradients indicating higher cervicovaginal lavage relative to plasma concentrations were observed for all 5 chemokines in the panel. Four were significantly associated with HIV acquisition, including IP-10 (odds ratio [OR] 1.73, 95% confidence interval [CI]: 1.27 to 2.36), macrophage inflammatory protein–1β (OR 1.72, 95% CI: 1.23 to 2.40), interleukin (IL)-8 (OR 1.50, 95% CI: 1.09 to 2.05), and monocyte chemotactic protein-1 (OR 1.36, 95% CI: 1.01 to 1.83). None of the other 7 cytokines tested predicted HIV risk. Decision tree analyses confirmed this association, with gradients of IP-10, IL-8, and granulocyte-macrophage colony-stimulating factor concentrations correctly classifying 77% of HIV outcomes.

Conclusions:

Our findings suggest that mucosa-biased gradients of IP-10, macrophage inflammatory protein–1β, IL-8, and monocyte chemotactic protein-1 are associated with an increased risk of HIV infection.

The Effects of Hormones and Vaginal Microflora on the Glycome of the Female Genital Tract: Cervical-Vaginal Fluid

In this study, we characterized the glycome of cervical-vaginal fluid, collected with a Catamenial cup. We quantified: glycosidase levels; sialic acid and high mannose specific lectin binding; mucins, MUC1, MUC4, MUC5AC, MUC7; and albumin in the samples collected. These data were analyzed in the context of hormonal status (day of menstrual cycle, hormonal contraception use) and role, if any, of the type of the vaginal microflora present. When the Nugent score was used to stratify the subjects by microflora as normal, intermediate, or bacterial vaginosis, several important differences were observed. The activities of four of six glycosidases in the samples from women with bacterial vaginosis were significantly increased when compared to normal or intermediate women: sialidase, P = <0.001; α-galactosidase, P = 0.006; β-galactosidase, P = 0.005; α-glucosidase, P = 0.056. Sialic acid binding sites as measured by two lectins, Maackia amurensis and Sambucus nigra binding, were significantly lower in women with BV compared to women with normal and intermediate scores (P = <0.0001 and 0.008 respectively). High mannose binding sites, a measure of innate immunity were also significantly lower in women with BV (P = <0.001). Additionally, we observed significant increases in MUC1, MUC4, MUC5AC, and MUC7 concentrations in women with BV (P = <0.001, 0.001, <0.001, 0.02 respectively). Among normal women we found that the membrane bound mucin MUC4 and the secreted MUC5AC were decreased in postmenopausal women (P = 0.02 and 0.07 respectively), while MUC7 (secreted) was decreased in women using levonorgestrel-containing IUDs (P = 0.02). The number of sialic acid binding sites was lower in the postmenopausal group (P = 0.04), but the number of high mannose binding sites, measured with Griffithsin, was not significantly different among the 6 hormonal groups. The glycosidase levels in the cervical-vaginal mucus were rather low in the groups, with exception of α-glucosidase activity that was much lower in the postmenopausal group (P<0.001). These studies present compelling evidence that the vaginal ecosystem responds to the presence of different vaginal microorganisms. These effects were so influential that it required us to remove subjects with BV for data interpretation of the impact of hormones. We also suggest that certain changes occurring in vaginal/cervical proteins are due to bacteria or their products. Therefore, the quantitation of vaginal mucins and lectin binding offers a new method to monitor bacteria-host interactions in the female reproductive tract. The data suggest that some of the changes in these components are the result of host processing, such as the increases in mucin content, while the microflora is responsible for the increases in glycosidases and the decreases in lectin binding. The methods should be considered a valid marker for insult to the female genital tract.

Innate activation of MDC and NK cells in high-risk HIV-1-exposed seronegative IV-drug users who share needles when compared with low-risk nonsharing IV-drug user controls

BACKGROUND

Previous studies have described increased innate immune activation in HIV-1-exposed seronegative intravenous drug users (HESN-IDU), but have not addressed the independent role of injected drugs and/or repeated injections in driving immune activation.

METHODS

In this study, we investigated innate [natural killer (NK) cells and dendritic cells] and adaptive (HIV-specific antibody and CD8 T cell) immune parameters among a high-risk cohort of needle-sharing HESN-IDU subjects and compared them with low-risk nonsharing IDU subjects (NS-IDU) and non-drug-user controls.

RESULTS

We observed that HIV-specific antibody and CD8 T-cell responses were not detected in HESN-IDU subjects, yet innate immune cell activation was found to be significantly increased on NK cells (CD69 and CD107a upregulation) and myeloid dendritic cells (CD40 and CD83 upregulation) when compared with NS-IDU subjects or non-drug-user controls (P < 0.01 and P < 0.05, respectively). HESN-IDU subjects maintained strong NK-cell CD107a degranulation and cytokine (IFN-gamma, TNF-alpha, and MIP-1 beta) production after target cell incubation suggesting that constitutive innate activation does not induce functional exhaustion of innate cells in HESN-IDU subjects. NK activation in HESN-IDU subjects was independent of drug use patterns but was durable over time and correlated with plasma levels of IP-10 by Luminex analysis (ρ = 0.5073, P = 0.0059, n = 28).

CONCLUSIONS

Our results indicate that heightened innate immune cell activation in HESN-IDU subjects is not the result of the IV drugs and repeated injection practice itself, but to repeated exposure to factors intrinsic to sharing needles (ie, exposure to pathogens or heterologous cells among donor blood).