Effects of Tobacco Products on Live Attenuated Influenza Virus (LAIV) Infections in Human Volunteers

Overview

Chronic exposure to (cigarette smoke) CS causes biological changes, including airway remodeling and changes in baseline gene expression profiles at the level of the epithelium. Our own data indicate that chronic exposure to CS suppresses the ability of epithelial cells to enhance antiviral gene expression in response to influenza infection and activate host defense responses. While there is a large body of evidence supporting the notion that exposure to CS causes significant changes in host defense responses, which may be linked to permanent changes in epithelial cells at the genomic level, it is not known whether new and emerging tobacco products have similar or distinct effects. Using live attenuated influenza virus (LAIV) inoculation in human volunteers, this study will compare influenza-induced responses in non-smokers (NS), cigarette smokers (CS), e-cigarette smokers (EC), hookah smokers (HS), and Little Cigar smokers (LCS) in vivo. This will be done by analyzing nasal viral titers, antiviral defense responses, inflammatory mediator production, and markers of immune responses for LAIV-induced responses between the different groups of volunteers.

Cigarette smoke (CS), e-cigarette smoke (EC), hookah smoke (HS), and Little Cigar smoke (LCS)-exposed populations will be stratified based on their responses to a smoking diary, protocol questionnaire, as well as urine cotinine levels (which should be present in all three groups). We are aware that many current smokers are poly-tobacco product users (i.e. smoke cigarettes in addition to non-cigarette products), which could be confounding our observations. This will be controlled for by having potential volunteers complete a smoking diary and provide daily urine samples for 1 week prior to enrolling in the study. Based on this diary, subjects will be grouped as CS (cigarettes only), EC (e-cigarette smokers and smoking less than ½ pack of cigarettes per week), HS (hookah smokers and smoking less than ½ pack of cigarettes per week), and LCS (little cigar smokers and smoking less than ½ pack of cigarettes per week). Individuals with mixed exposures that exceed those described above (i.e. smoking more than ½ pack of cigarettes per week in addition to smoking hookah, e-cigarettes, or Little Cigars) will be excluded from the studies. Potential subjects will then complete a questionnaire regarding their smoking history, and will undergo urine collection for measurement of cotinine for 7 consecutive days. Subjects will be assigned to the different groups as followed: Group NS (no routine exposure to tobacco smoke, and average log10 urine cotinine/creatinine ratio \< 1.0), Group CS (active cigarette smoker and log10 urine cotinine/creatinine ratio \> 4), Group EC (active e-cigarette smokers and average log10 urine cotinine/creatinine ratio 1-4), Group HS (active routine hookah smokers and average log10 urine cotinine/creatinine ratio 1-4), or Group LCS (active routine Little Cigars smoker and average log10 urine cotinine/creatinine ratio 1-4). Study protocol outline: Screening visit (2-4 weeks prior to Day 0): Obtain informed consent, history (including smoke exposure questionnaire), physical examination, vital signs (VS), blood draw (for anti-influenza antibody titer, HIV and T cell stimulation with flu antigen), urine (for cotinine), nasal lavage (NL, for differential cell count, viral culture and antigen detection, cytokine panel), nasal epithelial lining fluid (ELF, collected with filter paper for cytokine analysis), nasal epithelial biopsy (NB) #1, pregnancy test for females of child bearing potential. In addition, smokers will undergo spirometry. Subjects will return to the research lab daily the for the week prior to D0 to provide a urine sample for cotinine. Subjects will given a daily smoking/exposure diary during this time to continue throughout the study. Day 0 (Monday): Obtain VS, NL, ELF, urine. Administer FluMist. Day 1 (Tuesday): Obtain VS, NL, ELF, urine, NB #2 Day 2 (Wednesday): Obtain VS, NL, ELF, urine Day 8 +/- 1 day (Monday-Wednesday): Obtain VS, NL, ELF, urine, NB #3 Day 21 +/- 7 days: Obtain VS, blood draw, collect completed smoking/exposure diary