Lifetime Exposure to Cigarette Smoke, B-Cell Tumor Immune Infiltration, and Immunoglobulin Abundance in Ovarian Tumors.

BACKGROUND: Cigarette smoke exposure has been linked to systemic immune dysfunction, including for B-cell and immunoglobulin (Ig) production, and poor outcomes in patients with ovarian cancer. No study has evaluated the impact of smoke exposure across the life-course on B-cell infiltration and Ig abundance in ovarian tumors. METHODS: We measured markers of B and plasma cells and Ig isotypes using multiplex immunofluorescence on 395 ovarian cancer tumors in the Nurses' Health Study (NHS)/NHSII. We conducted beta-binomial analyses evaluating odds ratios (OR) and 95% confidence intervals (CI) for positivity of immune markers by cigarette exposure among cases and Cox proportional hazards models to evaluate hazard ratios (HR) and 95% CI for developing tumors with low (

IL-27 mediates anti-inflammatory effect in cigarette smoke induced emphysema by negatively regulating IFN-γ producing cytotoxic CD8+ T cells in mice.

Chronic airway inflammation mediated by CD8+ T lymphocytes contributes to the pathogenesis of Chronic obstructive pulmonary disease (COPD). Deciphering the fingerprint of the chronic inflammation orchestrated by CD8+ T cells may allow the development of novel approaches to COPD management. Here, the expression of IL-27 and IFN-γ+ CD8+ Tc1 cells were evaluated in patients with COPD and in cigarette smoke-exposed mice. The production of IL-27 by marrow-derived dendritic cells (mDCs) in response to cigarette smoke extract (CSE) was assessed. The role of IL-27 in IFN-γ+ CD8+ Tc1 cells was explored. We demonstrated that elevated IL-27 was accompanied by an exaggerated IFN-γ+ CD8+ Tc1 response in a smoking mouse model of emphysema. We noted that lung dendritic cells were one of the main sources of IL-27 during chronic cigarette smoke exposure. Moreover, CSE directly induced the production of IL-27 by mDCs in vitro. IL-27 negatively regulated the differentiation of IFN-γ+ CD8+ Tc1 cells isolated from cigarette smoke-exposed mice in a STAT1- and STAT3-independent manner. Systemic administration of recombinant IL-27 attenuated IFN-γ+ CD8+ Tc1 response in the late phase of cigarette smoke exposure. Our results uncovered that IL-27 negatively regulates IFN-γ+ CD8+ Tc1 response in the late stage of chronic cigarette smoke exposure, which may provide a new strategy for the anti-inflammatory treatment of smoking-related COPD/emphysema.

Cigarette smoking and risk of palindromic rheumatism: A propensity score matching analysis.

Present study was conducted to investigate smoking status in palindromic rheumatism (PR) patients compared to healthy individuals as well as to assess the effect of smoking on clinical features and outcomes of PR. One hundred and forty-six patients with diagnosis of PR and 346 healthy controls were included in this study. Demographic, clinical, and laboratory characteristics and the smoking history of PR patients at the cohort entry were obtained from patients' records. Demographic and smoking history of the control group were obtained by direct interview. In order to reduce heterogeneity between the studied groups, propensity score matching (PSM) analyses was performed. Matching was achieved by considering age, gender, educational status, and marital status. After PSM, we carried out a multivariate analysis with PR as the main outcome variable, ever smoking as the main predictor variable and age, gender, educational status, and marital status as covariates. PSM resulted in 123 PR patients and 246 matched controls. Multivariate analysis did not show a significant increase in the risk of PR in ever smokers. Seventy-six patients were anti-citrullinated protein/peptide antibody positive (ACPA-positive). Multivariate logistic regression showed a significant increase in the risk of PR in ACPA-positive ever smokers. Except lower sustained remission rate in ever smokers, no significant differences were observed in clinical manifestations and outcomes of PR between ever and never smokers. In conclusion, smoking is a risk factor for ACPA-positive PR.

Rosiglitazone ameliorated airway inflammation induced by cigarette smoke via inhibiting the M1 macrophage polarization by activating PPARγ and RXRα.

BACKGROUND: Rosiglitazone, an exogenous ligand of PPARγ, plays an important anti-inflammatory role during the inflammation caused by cigarette smoke (CS). CS exposure induces pulmonary inflammation via activating macrophage polarization. However, the effects of rosiglitazone on macrophage polarization induced by CS are unclear. METHODS: 36 male Wistar rats were randomly divided into 3 groups: control, CS and ROSI. In the CS group, rats were passively exposed to cigarette smoke for consecutive 3 months. In the ROSI group, rats were treated with rosiglitazone (3 mg/kg/day, ip) during CS exposure period. Alveolar macrophages of rats were isolated and cultured with CSE. The slices of lung tissues were stained with hematoxylin and eosin. The histomorphology was observed to evaluate emphysema and the pulmonary function was detected. Cells in bronchoalveolar lavage fluid (BALF) were examined and the expression of cytokines TNF-α and IL-1ß was detected by ELISA and qPCR. The alveolar macrophage polarization was evaluated by immunohistochemistry and flow cytometry assay in vivo and by qPCR in vitro. The protein level of PPARγ and RXRα was measured by Western blot. RESULTS: CS exposure induced significant emphysema, diminished FEV0.2/FVC, elevated PEF, and higher level of total cells, neutrophils and cytokines (TNF-α and IL-1ß) in BALF compared with control group, whereas rosiglitazone partly ameliorated above disorders. CS exposure activated M1 and M2 macrophage polarization in vivo and in vitro, whereas rosiglitazone inhibited CS induced M1 macrophage polarization and decreased the ratio of M1/M2. The effects of rosiglitazone on macrophage polarization were partly blocked after AMs treated with the antagonists of PPARγ and RXRα, and were synergistically enhanced by the agonist of RXRα. CS exposure decreased the expression of PPARγ and RXRα in lung tissues and AMs, and rosiglitazone partly reversed CS-mediated suppression of PPARγ and RXRα. CONCLUSION: Rosiglitazone ameliorated the emphysema and inflammation in lung tissues induced by CS exposure via inhibiting the M1 macrophage polarization through activating PPARγ and RXRα.

Dual interleukin-17A/F deficiency protects against acute and chronic response to cigarette smoke exposure in mice.

IL-17A and IL-17F are both involved in the pathogenesis of neutrophilic inflammation observed in COPD and severe asthma. To explore this, mice deficient in both Il17a and Il17f and wild type (WT) mice were exposed to cigarette smoke or environmental air for 5 to 28 days and changes in inflammatory cells in bronchoalveolar lavage (BAL) fluid were determined. We also measured the mRNA expression of keratinocyte derived chemokine (Kc), macrophage inflammatory protein-2 (Mip2), granulocyte-macrophage colony stimulating factor (Gmcsf) and matrix metalloproteinase-9 (Mmp9 ) in lung tissue after 8 days, and lung morphometric changes after 24 weeks of exposure to cigarette smoke compared to air-exposed control animals. Macrophage counts in BAL fluid initially peaked at day 8 and again on day 28, while neutrophil counts peaked between day 8 and 12 in WT mice. Mice dual deficient with Il17a and 1l17f showed similar kinetics with macrophages and neutrophils, but cell numbers at day 8 and mRNA expression of Kc, Gmcsf and Mmp9 were significantly reduced. Furthermore, airspaces in WT mice became larger after cigarette smoke exposure for 24 weeks, whereas this was not seen dual Il17a and 1l17f deficient mice. Combined Il17a and Il17f deficiency resulted in significant attenuation of neutrophilic inflammatory response and protection against structural lung changes after long term cigarette smoke exposure compared with WT mice. Dual IL-17A/F signalling plays an important role in pro-inflammatory responses associated with histological changes induced by cigarette smoke exposure.

Epithelium-derived IL17A Promotes Cigarette Smoke-induced Inflammation and Mucus Hyperproduction.

The airway epithelium is a central modulator of innate and adaptive immunity in the lung. IL17A expression was found to be increased in the airway epithelium; however, the role of epithelium-derived IL17A in chronic obstructive pulmonary disease (COPD) remains unclear. In this study, we aimed to determine whether epithelium-derived IL17A regulates inflammation and mucus hyperproduction in COPD by using a cultured human bronchial epithelial (HBE) cell line in vitro and an airway epithelium IL17A-specific knockout mouse in vivo. Increased IL17A expression was observed in the mouse airway epithelium upon cigarette smoke (CS) exposure or in a mouse model of COPD that was induced by using CS and Eln (elastin). CS extract (CSE) also triggered IL17A expression in HBE cells. Blocking IL17A or IL17RA (IL17 receptor A) effectively attenuated CSE-induced MUC5AC and the inflammatory cytokines IL6, TNF-α, and IL1ß in HBE cells, suggesting that IL17A mediates CSE-induced inflammation and mucin production in an autocrine manner. CSE activated p-JUN (phospho-JUN) and p-JNK (phospho-c-Jun N-terminal kinase), which were also reduced by IL17RA siRNA, and JUN siRNA attenuated CSE-induced IL6 and MUC5AC. In vivo, selective knockout of IL17A in the airway epithelium markedly reduced the neutrophilic infiltration in BAL fluid, peribronchial inflammation, proinflammatory mediators (CXCL1 [CXC ligand 1] and CXCL2), and mucus production in a COPD mouse model. We showed a novel function of airway epithelium-derived IL17A, which can act locally in an autocrine manner to amplify inflammation and increase mucus production in COPD pathogenesis.

Biomarkers of Potential Harm among Adult Cigarette and Smokeless Tobacco Users in the PATH Study Wave 1 (2013-2014): A Cross-sectional Analysis.

BACKGROUND: While smokeless tobacco (ST) causes oral cancer and is associated with cardiovascular diseases, less is known about how its effects differ from other tobacco use. Biomarkers of potential harm (BOPH) can measure short-term health effects such as inflammation and oxidative stress. METHODS: We compared BOPH concentrations [IL6, high-sensitivity C-reactive protein, fibrinogen, soluble intercellular adhesion molecule-1 (sICAM-1), and F2-isoprostane] across 3,460 adults in wave 1 of the Population Assessment of Tobacco and Health study (2013-2014) by tobacco use groups: primary ST users (current exclusive ST use among never smokers), secondary ST users (current exclusive ST use among former smokers), exclusive cigarette smokers, dual users of ST and cigarettes, former smokers, and never tobacco users. We estimated geometric mean ratios using never tobacco users, cigarette smokers, and former smokers as referents, adjusting for demographic and health conditions, creatinine (for F2-isoprostane), and pack-years in smoker referent models. RESULTS: BOPH levels among primary ST users were similar to both never tobacco users and former smokers. Most BOPH levels were lower among ST users compared with current smokers. Compared with never tobacco users, dual users had significantly higher sICAM-1, IL6, and F2-isoprostane. However, compared with smokers, dual users had similar biomarker levels. Former smokers and secondary ST users had similar levels of all five biomarkers. CONCLUSIONS: ST users have lower levels of inflammatory and oxidative stress biomarkers than smokers. IMPACT: ST use alone and in combination with smoking may result in different levels of inflammatory and oxidative stress levels.

Does smoking affect level of seropositivity in RA? A post-HOC global and inter-country analysis of COMORA cohort.

To study the association of smoking status and the level of seropositivity in RA patients from COMORA Cohort. A post hoc analysis of COMORA database included 3439 RA patients was performed. Current smokers or recently quitted (< 3 years) were initially compared to those who never smoked or stopped > 3 years (Group I vs. II) regarding their seropositivity status (high positive, low positive and negative) for Rheumatoid Factor (RF) or Anti-citrullinated antibodies (ACPA). A further comparison was made between current smokers (Group III) and never smoked patients (Group IV). Analysis was also done on the individual country level for the 17 countries included in the COMORA study. Out of 3439 RA patients, 705 (20.5%) were smokers (group I), and 2734 (79.5%) were non-smokers (group II). Significantly more patients in group I, 442 (62.7%), had high levels of seropositivity than those in group II, 1556 (56.9%), [P = 0.006, OR 1.27 (95% CI, 1.07-1.5)]. More current smoker patients (group III-286 out of 456 "62.7%") had high levels of seropositivity than never smoked patients (group IV-1236 out of 2191 "56.4%"), with significant difference [P = 0.013, OR 1.3 (95% CI, 1.06-1.6)]. In 11 countries, higher proportions of patients with high level of seropositivity in group I was found, with statistical significance in four countries. Smoking was associated with higher level of seropositivity in patients with RA in this post hoc analysis, both on a global level and in certain individual countries. As smoking is a modifiable risk factor, studying the effects of quitting smoking on level of seropositivity and other disease parameters is warranted.

Effects of cigarette smoking and human T-cell leukaemia virus type 1 infection on anti-citrullinated peptide antibody production in Japanese community-dwelling adults: the Nagasaki Islands Study.

Objectives: We investigated whether the positivity of anti-citrullinated peptide antibody (ACPA) is associated with cigarette-smoking status and human T-cell leukaemia virus type 1 (HTLV-1) infection in a general population in Nagasaki, Japan, which is an ageing and HTLV-1-endemic area.Method: Baseline data from community-dwelling people in the Nagasaki Islands Study (NaIS) were included in this cross-sectional analysis. ACPA and HTLV-1 were measured in 3887 subjects without a history of treatment for rheumatoid arthritis. A logistic regression analysis was performed to assess the relationship between ACPA positivity and candidates of correlation with ACPA, i.e. the cigarette-smoking status quantified by Brinkman's index (BI) and HTLV-1 positivity.Results: Fifty-one subjects (1.3%) showed ACPA positivity, and 650 subjects (16.6%) were HTLV-1 carriers. In an age- and gender-adjusted logistic regression analysis, the BI [odds ratio (OR) 1.09, 95% confidence interval (CI)1.02-1.14, p = 0.0031] and a BI value > 500 (OR 3.92, 95% CI 1.72-9.22, p = 0.0014) were each significantly associated with ACPA positivity. HTLV-1 positivity did not show any association with ACPA positivity.Conclusion: A significant effect of cigarette-smoking status on ACPA production was revealed, whereas HTLV-1 positivity was not associated with ACPA production in this general population.

Cigarette Smoke Underlies the Pathogenesis of Palmoplantar Pustulosis via an IL-17A-Induced Production of IL-36γ in Tonsillar Epithelial Cells.

Palmoplantar pustulosis (PPP) is characterized by sterile pustules on the palms and soles. A strong association between PPP and tobacco smoking has been reported, and it has been speculated that the IL-17A pathway may play an important role in PPP. Recent studies have suggested that IL-36 plays a pivotal role in the pathogenesis of psoriasis and its subtypes. The relationships among IL-36, smoking, and PPP have not been examined. Here, we investigated the relationships among the smoking index, severity of the clinical condition of PPP, and in vitro dynamics of IL-36 in human tonsillar epithelial cells under the condition of exposure to a cigarette smoke extract. The results demonstrated that the Palmoplantar Pustulosis Area and Severity Index was strongly and positively correlated with the smoking index in female patients. Immunohistochemical examinations showed that IL-36γ was highly expressed in tonsillar epithelial cells from patients with PPP but not in those from patients with recurrent tonsillitis without PPP. The in vitro study revealed that IL-17A synergistically induced a release of IL-36γ under cigarette smoke extract exposure. These results suggest that local production of IL-36γ by epithelial cells induced by cigarette smoke exposure plays an important role in the pathogenesis of PPP.

Single-cell analyses identify dysfunctional CD16+ CD8 T cells in smokers.

Tobacco smoke exposure contributes to the global burden of communicable and chronic diseases. To identify immune cells affected by smoking, we use single-cell RNA sequencing on peripheral blood from smokers and nonsmokers. Transcriptomes reveal a subpopulation of FCGR3A (CD16)-expressing Natural Killer (NK)-like CD8 T lymphocytes that increase in smokers. Mass cytometry confirms elevated CD16+ CD8 T cells in smokers. Inferred as highly differentiated by pseudotime analysis, NK-like CD8 T cells express markers characteristic of effector memory re-expressing CD45RA T (TEMRA) cells. Indicative of immune aging, smokers' CD8 T cells are biased toward differentiated cells and smokers have fewer naïve cells than nonsmokers. DNA methylation-based models show that smoking dose is associated with accelerated aging and decreased telomere length, a biomarker of T cell senescence. Immune aging accompanies T cell senescence, which can ultimately lead to impaired immune function. This suggests a role for smoking-induced, senescence-associated immune dysregulation in smoking-mediated pathologies.

Activation of NLRP3 inflammasome assembly is associated with smoking status of patients with coronary artery disease.

OBJECTIVE: Cigarette smoke is considered as a sterile inflammatory stimulus which triggers an innate immune response, accountable for vascular events. Previously, we reported smoking-induced NLRP3 inflammasome activation in the pathogenesis of atherosclerosis through caspase-1 activation and secretion of pro-cytokines (interleukin (IL)-1ß and IL-18) in vitro and in vivo. Therefore, the present study aimed to reconnoitre the association of cigarette smoking and NLRP3 inflammasome activation ex vivo in human subjects with coronary atherosclerosis. METHODS AND RESULTS: In order to establish and validate the association between smoking status and NLRP3 inflammasome ex vivo, mononuclear cells were isolated from smokers with angiographically-proven coronary artery disease (CAD); non-smokers with CAD; smokers without CAD, and healthy non-smokers (controls) (n = 20 each). The transcriptional and translational expression of NLRP3 inflammasome markers i.e. NLRP3, pro-caspase-1, caspase-1, pro-IL-1ß, IL-1ß, pro-IL-18 and IL-18 was significantly increased (2 to 7-fold) in smokers with CAD vs non-smokers with CAD; and smokers without CAD vs non-smoker controls. In addition, the oxidative stress, an upstream mediator of NLRP3 inflammasome was evaluated and found to be significantly augmented in smokers vs non-smokers (with and without CAD respectively). Further, the levels of serum cotinine, oxidative stress markers (8-isoprostane and 8-oxo-2́'-deoxyguanosine), caspase-1 and pro-cytokines (IL-1ß and IL-18) were also higher in smokers vs non-smokers. Moreover, the levels of pro-cytokines were positively correlated with caspase-1 and serum cotinine, corroborating the secretion of cytokines in a caspase-1-dependent manner. CONCLUSION: Our data may imply NLRP3 inflammasome as a mediator of the pro-atherosclerotic property of cigarette smoking in atherosclerotic patients.

Role of Regulatory T Cells in Disturbed Immune Homeostasis in Patients With Chronic Obstructive Pulmonary Disease.

Chronic obstructive pulmonary disease (COPD) is a complex chronic disease in which T cell-mediated pulmonary inflammation has been shown to play a key role. Accumulating evidence shows that COPD has many of the characteristics of an autoimmune response. An adaptive immune response directed against lung self-antigens, which are released during the initial innate inflammatory response and are triggered by constant exposure to cigarette smoke and epithelial injury, drives the persistent inflammatory response found in smokers. The development and severity of adaptive inflammation depend on the level of tolerance to self-antigens. For these reasons, the effect of regulatory T (Treg) cells on adaptive immunity in COPD patients is of particular interest and could be targeted therapeutically. The disturbance in immune homeostasis caused by changes in the number or function of Treg cells, which is related to cigarette smoke exposure, may be of importance in understanding the development and progression of COPD.

Cigarette smoking induces human CCR6+Th17 lymphocytes senescence and VEGF-A secretion.

Chronic exposure to environmental pollutants is often associated with systemic inflammation. As such, cigarette smoking contributes to inflammation and lung diseases by inducing senescence of pulmonary cells such as pneumocytes, fibroblasts, and endothelial cells. Yet, how smoking worsens evolution of chronic inflammatory disorders associated with Th17 lymphocytes, such as rheumatoid arthritis, psoriasis, Crohn's disease, and multiple sclerosis, is largely unknown. Results from human studies show an increase in inflammatory CD4+ Th17 lymphocytes at blood- and pulmonary level in smokers. The aim of the study was to evaluate the sensitivity of CD4+ Th17 lymphocytes to cigarette smoke-induced senescence. Mucosa-homing CCR6+ Th17- were compared to CCR6neg -and regulatory T peripheral lymphocytes after exposure to cigarette smoke extract (CSE). Senescence sensitivity of CSE-exposed cells was assessed by determination of various senescence biomarkers (ß-galactosidase activity, p16Ink4a- and p21 expression) and cytokines production. CCR6+ Th17 cells showed a higher sensitivity to CSE-induced senescence compared to controls, which is associated to oxidative stress and higher VEGFα secretion. Pharmacological targeting of ROS- and ERK1/2 signalling pathways prevented CSE-induced senescence of CCR6+Th17 lymphocytes as well as VEGFα secretion. Altogether, these results identify mechanisms by which pro-oxidant environmental pollutants contribute to pro-angiogenic and pathogenic CCR6+Th17 cells, therefore potential targets for therapeutic purposes.

The Impact of Cigarette Smoking on Risk of Rheumatoid Arthritis: A Narrative Review.

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation and subsequent proliferation of synovial tissues, which eventually leads to cartilage and bone destruction without effective treatments. Anti-citrullinated cyclic peptide/protein antibody (ACPA) and rheumatoid factor (RF) are two main characteristic autoantibodies found in RA patients and are associated with unfavorable disease outcomes. Although etiologies and causes of the disease have not been fully clarified yet, it is likely that interactive contributions of genetic and environmental factors play a main role in RA pathology. Previous works have demonstrated several genetic and environmental factors as risks of RA development and/or autoantibody productions. Among these, cigarette smoking and HLA-DRB1 are the well-established environmental and genetic risks, respectively. In this narrative review, we provide a recent update on genetic contributions to RA and the environmental risks of RA with a special focus on cigarette smoking and its impacts on RA pathology. We also describe gene-environmental interaction in RA pathogenesis with an emphasis on cigarette smoking and HLA-DRB1.

Relationships between the Nicotine Metabolite Ratio and a Panel of Exposure and Effect Biomarkers: Findings from Two Studies of U.S. Commercial Cigarette Smokers.

BACKGROUND: We examined the nicotine metabolite ratio's (NMR) relationship with smoking intensity, nicotine dependence, and a broad array of biomarkers of exposure and biological effect in commercial cigarette smokers. METHODS: Secondary analysis was conducted on two cross-sectional samples of adult, daily smokers from Wave 1 (2013-2014) of the Population Assessment of Tobacco Use and Health (PATH) Study and baseline data from a 2014-2017 randomized clinical trial. Data were restricted to participants of non-Hispanic, white race. The lowest quartile of NMR (<0.26) in the nationally representative PATH Study was used to distinguish slow from normal/fast nicotine metabolizers. NMR was modeled continuously in secondary analysis. RESULTS: Compared with slow metabolizers, normal/fast metabolizers had greater cigarettes per day and higher levels of total nicotine equivalents, tobacco-specific nitrosamines, volatile organic componds, and polycyclic aromatic hydrocarbons. A novel finding was higher levels of inflammatory biomarkers among normal/fast metabolizers versus slow metabolizers. With NMR modeled as a continuous measure, the associations between NMR and biomarkers of inflammation were not significant. CONCLUSIONS: The results are suggestive that normal/fast nicotine metabolizers may be at increased risk for tobacco-related disease due to being heavier smokers, having higher exposure to numerous toxicants and carcinogens, and having higher levels of inflammation when compared with slow metabolizers. IMPACT: This is the first documentation that NMR is not only associated with smoking exposure but also biomarkers of biological effects that are integral in the development of tobacco-related disease. Results provide support for NMR as a biomarker for understanding a smoker's exposure and potential risk for tobacco-related disease.

Cigarette and Cannabis Smoking Effects on GPR15+ Helper T Cell Levels in Peripheral Blood: Relationships with Epigenetic Biomarkers.

Background: Smoking causes widespread epigenetic changes that have been linked with an increased risk of smoking-associated diseases and elevated mortality. Of particular interest are changes in the level of T cells expressing G-protein-coupled receptor 15 (GPR15), a chemokine receptor linked with multiple autoimmune diseases, including inflammatory bowel disease, multiple sclerosis and psoriasis. Accordingly, a better understanding of the mechanisms by which smoking influences variation in the GPR15+ helper T cell subpopulation is of potential interest. Methods: In the current study, we used flow cytometry and digital PCR assays to measure the GPR15+CD3+CD4+ populations in peripheral blood from a cohort of n = 62 primarily African American young adults (aged 27-35 years) with a high rate of tobacco and cannabis use. Results: We demonstrated that self-reported tobacco and cannabis smoking predict GPR15+CD3+CD4+ helper T cell levels using linear regression models. Further, we demonstrated that methylation of two candidate CpGs, cg19859270, located in GPR15, and cg05575921, located in the gene Aryl Hydrocarbon Receptor Repressor (AHRR), were both significant predictors of GPR15+CD3+CD4+ cell levels, mediating the relationship between smoking habits and increases in GPR15+CD3+CD4+ cells. As hypothesized, the interaction between cg05575921 and cg19859270 was also significant, indicating that low cg05575921 methylation was more strongly predictive of GPR15+CD3+CD4+ cell levels for those who also had lower cg19859270 methylation. Conclusions: Smoking leads changes in two CpGs, cg05575921 and cg19859270, that mediate 38.5% of the relationship between tobacco and cannabis smoking and increased GPR15+ Th levels in this sample. The impact of cg19859270 in amplifying the association between cg05575921 and increased GPR15+ Th levels is of potential theoretical interest given the possibility that it reflects a permissive interaction between different parts of the adaptive immune system.

Cigarette smoking increases the risk of nasopharyngeal carcinoma through the elevated level of IgA antibody against Epstein-Barr virus capsid antigen: A mediation analysis.

BACKGROUND: The study aims are to evaluate the associations between nasopharyngeal carcinoma (NPC) risk and cigarette smoking and to explore the effects of cigarette smoking on Epstein-Barr virus (EBV) infection for NPC risk. METHODS: 1235 male NPC cases and 1262 hospital-based male controls matched to cases were recruited across six collaborative hospitals between 2010 and 2014. Using a standardized questionnaire, information on cigarette smoking and other potential risk factors for NPC was obtained. Blood was collected and used for anti-EBV VCA IgA and anti-EBV EA-EBNA1 IgA testing using standard methods. Unconditional logistic regression analysis was used to estimate odds ratio (OR) with 95% confidence interval (CI) for each risk factor after adjusting for confounders. RESULTS: 63.6% of cases and 44.0% of controls reported ever smoking cigarettes. After full adjustment, current smokers had a significant 1.60-fold (95% CI = 1.30-1.97) and former smokers a borderline significant 1.27-fold (95% CI = 1.00-1.60) increased NPC risk compared to never smokers. NPC risk increased with increasing duration, intensity, and pack-years of cigarette smoking but not with age at smoking initiation. Among controls, anti-EBV VCA IgA seropositivity rate was higher in current smokers than never smokers (14.0% vs 8.4%; OR = 1.82; 95% CI = 1.19-2.79). Mediation analyses showed that more than 90% of the cigarette smoking effect on NPC risk is mediated through anti-EBV VCA IgA. CONCLUSION: This study confirms the association between long-term cigarette smoking and NPC and demonstrates that current smoking is associated with seropositivity of anti-EBV VCA IgA antibodies.