Effect of Household Air Pollution Exposures on Respiratory Symptoms and Systemic Immunoregulatory Cytokines in HIV-Positive Individuals

Abstract

SESSION TITLE: Environmental and Occupational Health SESSION TYPE: Original Investigation Poster PRESENTED ON: Wednesday, November 1, 2017 at 01:30 PM - 02:30 PM PURPOSE: Household air pollution (HAP), an independent risk factor for chronic obstructive pulmonary disease (COPD), is currently a major global health concern. HAP is especially relevant in Sub-Saharan Africa, where solid biomass use for cooking is widespread. This region also has a large burden of HIV/AIDS, which has emerged as a risk factor for the development of COPD, in particular emphysema. Our overarching hypothesis is that the combination of HAP and HIV exposure will lead to earlier onset and/or to more severe COPD. We studied individuals in Malawi, a country that has among the highest prevalence of HIV/AIDS in the world (10.6% of age 15-49) and documented HAP exposures at levels far greater than WHO’s recommendations (Fullerton et al 2009). We investigated if habitually exposed to HAP (HAP+) and infected with HIV (HIV+), when compared to individuals who are HIV negative (HIV-) and lack habitual exposure to HAP (HAP-), have higher prevalence of respiratory symptoms and if they exhibit alterations in levels of circulating immunomodulatory cytokines. METHODS: Fifty subjects from Malawi with known HIV status were given a survey that recorded their demographics, HAP exposure, and respiratory symptoms/diagnoses. In addition, serum was collected and levels of 41 serum markers were measured using MSD® Multi-Spot assay. RESULTS: Survey analyses showed 46% of subjects reported respiratory diagnoses and/or respiratory symptoms. Most common symptoms were breathlessness and cough, followed by wheezing. Increased sputum production was the lest common symptom--reported by <5% of subjects. We noted a higher prevalence of respiratory diagnoses and/or symptoms in HIV+ subjects (n=20) or those with HAP exposures (n=28), reported by more than 50% of individuals in each group, compared to 14% of those in the HIV− or HAP- groups. Among subjects with HAP+ exposure, HIV+ subjects were more likely to carry a respiratory diagnosis than HIV− subjects (50% vs. 28%). Individuals with dual HIV+ and HAP+ exposures exhibited significant decreases in serum IL-16 levels, which were 44% (p=0.03) lower than those in the HIV- and HAP- group. We also noted a significant decrease in serum IL-2 by 31% (p=0.02) and a trend for decrease in serum IL-10 levels by 42% (p=0.10) in HIV+ subjects with persistent respiratory symptoms compared to all other subjects. CONCLUSIONS: HIV+ or HAP+ exposures, and especially their combination, tend to be associated with higher prevalence of respiratory diagnoses and symptoms such as breathlessness and cough. Those with HAP+ and HIV+ exposures have lower circulating IL-16, a cytokine that inhibits HIV replication and is essential for the immune system homeostasis. Circulating IL-2, which promotes CD4+ cells’ proliferation and survival, and IL-10, an immunoregulatory cytokine that enhances HIV viral clearance were also particularly decreased in HIV+ subjects with respiratory symptoms. CLINICAL IMPLICATIONS: As low IL-2 or IL-16 levels were found to correlate with worsening COPD (Bowler et al 2013 & D'Armiento et al 2009) and low IL-10 levels correlated with COPD and cigarette smoke-exposed subjects (Zhu et al 2009), future studies should investigate if these cytokines can be utilized as biomarkers for COPD development in this susceptible population. DISCLOSURE: The following authors have nothing to disclose: Charles Kim, Hannah Jary, Kelly Schweitzer, Doug Curran-Everett, Stephen Gordon, Kevin Mortimer, Irina Petrache No Product/Research Disclosure Information