Background: Activated inflammatory cells are found in coronary plaques as well as peripheral circulation in patients with acute coronary syndrome. We explored the circulating T cell profile, their reactivity to self-antigens and plasma cytokine levels in Indian patients with Myocardial Infarction. Methods and Results: Intracellular expression of interferon-γ Interleukin (IL)-4, IL-17, IL-10 and Foxp3 were determined in CD4 + and CD8 + T cells using flow cytometry in patients with ST elevated myocardial infarction (STEMI) (N = 79) and controls (N = 80). Cytokines were measured using Milliplex kit and T cell reactivity was studied by CFSE dilution. Statistical analysis was performed using SPSS software. Patients with myocardial infarction showed higher proportion of IL-17 expressing CD4 + and CD8 + T cells (Th17 and Tc17) and elevated levels of IL-6 and IL-17 in plasma with significant reduction in circulating Tregs. Th1, Th2 and CD4 +CD28 null cells were not significantly different in patients compared to healthy individuals. The ratio of Th17 and Tc17 to Tregs showed an independent association with STEMI with an adjusted odds ratio of 2.92 (95% CI: 1.73 - 4.92), P < 0.001 and 2.22 (95% CI: 1.42 - 3.44), P < 0.001 respectively. Reactivity to HSP60 and oxidized LDL with expansion of IL-17 expression was higher in patients compared with control. Young patients (<45 years) with no apparent risk factor could be distinguished from healthy controls by the increase in Th17 and ratio of Th17 and Tc17 to Tregs in peripheral blood. Conclusion: Our results suggest that an imbalance in both CD4 + and CD8 + T cells secreting IL-17 and Tregs is associated with acute myocardial infarction. HSP60 and Ox-LDL may contribute to this response and pathogenesis of AMI in Indian population.
Coronary artery disease (CAD) is the most significant cause of global mortality despite advances in medicine and drug development [
Naturally occurring Treg cells, characterized by the intracellular expression of fox head transcription factor (CD4+CD25+Foxp3+), maintain the immune homeostasis and suppress the inflammatory immune response [
Earlier studies have shown increased frequency of circulating pro inflammatory T cells secreting IL-17 and IFN-γ and a reduction in the number of naturally occurring Tregs with compromised suppressive properties in MI patients [
Although several studies have shown differences in the circulating T cells in independent populations, the mechanism and the cause of skewed balance in T lymphocyte subsets in the peripheral circulation are not known. Asian Indian population belongs to a high risk group for developing atherothrombotic disease, which is not explained by the conventional risk factors alone [
The investigation conforms to the principles outlined in the Declaration of Helsinki and guidelines approved by Indian council of medical research (ICMR, India). The study was approved by the Institutional ethics committees of Thrombosis research Institute and Narayana Hrudayalaya hospital. An informed consent was taken from all the participants prior to enrolment. The study population included patients admitted to the Narayana Hrudayalaya hospital between October 2012 and April 2014, with no previous report of cardiac problem. Patients with acute myocardial infarction with elevation of ST segment and increase in cardiac troponin I were classified as STEMI. Samples were collected within 24 - 48 hrs from the onset of event. Age and gender matched healthy volunteers without any clinical symptoms of CAD, and with normal ECG were enrolled as controls for the study. Exclusion criteria included presence of any major illness as defined by world health organization (known primary myocardial disease, presence of congenital heart disease or contagious diseases. Individuals with family history of CAD were excluded from the study. A standardized questionnaire was used to record history of hypertension, diabetes mellitus, smoking, body mass index, waist hip ratio and medication. Resting blood pressure, fasting blood glucose levels, ECG and angiogram records (only for patients) were obtained for all the participants. Subjects were considered as active smokers if they were current smokers or had stopped smoking within a month before entry into the study. Subjects with high fasting blood sugar levels >7 mm/litre (125 mg/dL) were categorized as hyperglycemic.
Peripheral blood mononuclear cells (PBMCs) are isolated using Ficoll (Histopaque-Sigma Chemicals, USA) density gradient centrifugation from venous blood samples. PBMCs were activated for 4 hours with phormalmyristate acetate (10 ng/ml) and ionomycin (1 µg/ml) in the presence of 100 ng/ml Brefeldin (Sigma Chemicals, St. Louis, USA). Surface staining was performed by using anti CD3 and anti CD4 antibodies conjugated to Allophyocyanin H7 and Fluorescein isothiocyanate respectively for 20 minutes at room temperature. Intracellular staining was carried out with Peridinin chlorophyll Cy5.5 conjugated anti IL-4, Phycoerythrin conjugated anti IL-10, Allophyocyanin conjugated anti IL-17 and PE CY7conjugated anti IFN-γ. For regulatory T cell staining, Allophyocyanin conjugated CD25 and Phycoerythrin conjugated anti human FOX P3 were used in a separate tube along with CD3 and CD4 as mentioned earlier (Allantibodies were from BD Biosciences, CA, USA). Samples were acquired using FACS Canto II flow Cytometer using FACS Diva software (Becton Dickinson, NJ, USA). Fluorescence minus one and unstained control were used for setting the gates. FLOWJO Version 7.6.5 (Tree star Ltd., Oregon, USA) was used for data analysis and results were expressed as a percentage of CD4+ T cells by sequential gating on lymphocytes (
Cell proliferation experiments were performed in Rosewell Park Memorial Institute (RPMI) 1640 medium (Bio Whittaker, Walkersville, MD, USA) supplemented with 10% AB serum, 2 mM glutamine, 10 mM HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid), sodium pyruvate, and antibiotics. T cell proliferation was monitored by the reduction in 5, 6-carboxyfluorescein diacetate succinimidyl ester (CFSE) fluorescence in the CD3positive cells for 3 days [
Cytokines, interleukin (IL)-4, IL-5, IL-6, IL-10, IL-17, and interferon γ (IFN-γ), were measured using the
MILLIPLEX (MAP-plex) Cytokine Kit (Millipore, Billerica, MA) at the Millipore Service facility (Bangalore, India). Lipid concentrations were determined on the Cobas Fara II Clinical Chemistry auto analyzer (F. Hoffman La Roche Ltd., Basal, Switzerland), following the manufacturer’s instructions.
Quantitative data were tested for normality using Kolmogorov-Smirnov test and were transformed using natural logarithms wherever a deviation from normality was observed (lipids levels, BMI, WHR and cytokine levels). Percentage data was arcsine transformed for analysis [
Baseline demographic characteristics of STEMI patients compared to age and gender matched controls is given in
Variables | Control (N = 79) | STEMI (N = 80) |
---|---|---|
Age (years) | 46.79 (7.2) | 47.52 (7.0) |
Male (%) | 74 (92.5) | 75 (94.9) |
Diabetes N (%) | 7 (8.8%) | 29 (36.7%)*** |
Hyperglycaemia (%) | 25 (31.3%) | 54 (68.4%)*** |
Hypertension N (%) | 4 (5.0%) | 21 (26.6%)*** |
Current Smoking N (%) | 18 (22.5%) | 30 (38.0%)* |
BMI-Mean (SD) | 25.29 (3.45) | 25.38 (4.06) |
WHR-Mean (SD) | 0.92 (0.05) | 0.92 (0.04) |
TC-Mean (95% CI) | 4.64 (3.84 - 5.59) | 4.23 (3.33 - 5.38)* |
TG-Mean (95% CI) | 1.67 (0.91 - 3.05) | 1.55 (0.89 - 2.71) |
SBP-Mean (SD) | 128.90 (15.48) | 114.18 (15.82)*** |
DBP-Mean (SD) | 84.58 (11.28) | 75.14 (10.54)*** |
FBS-Mean (SD) | 6.45 (2.29) | 9.04 (4.42)*** |
LDL-Mean (95% CI) | 2.75 (1.97 - 3.84) | 2.54 (1.80 - 3.59) |
HDL-Mean (95% CI) | 0.88 (0.68 - 1.13) | 0.81 (0.59 - 1.08) |
Beta-blockers N (%) | NA | 54 (70.1%) |
ACE inhibitors N (%) | NA | 36 (46.8%) |
Statin N (%) | NA | 71 (92.2%) |
Aspirin N (%) | NA | 71 (92.2%) |
>1 Affected vessel N (%) % | NA | 17 (21.5%) |
Values are represented as percentage or as Mean (SD-standard deviation) and as Mean (95% CI) for variables which were log transformed for analysis. Lipid and sugar levels are expressed in mMol/L. BMI: Body mass index, WHR: Waist hip ratio, SBP: Systolic blood pressure, DBP: Diastolic blood pressure, TC: Total cholesterol, TG: Triglycerides, LDL: Low density lipoprotein, HDL: High density lipoprotein. *P < 0.01, ***P<0.001, ***P < 0.0001.
STEMI patients showed an increase in CD4+ and CD8+ cells expressing IL-17, (P < 0.001), and CD4+ cells double positive for IL-17 and IFN-γ (P = 0.048), while regulatory T cells of the phenotype CD4+ CD25+ Foxp3+ were significantly lower (P = 0.017) in patients compared to control. The ratio of Th17 cells to Treg (P < 0.001), Tc17 to Treg (P < 0.001), Th1 to Treg (P = 0.014) and that of Th17 to Th2 (p = 0.028) were significantly higher in patients. We did not observe any significant difference in the frequency of CD4+CD28− cells and Th1 cells between patient and controls (
Variable | Control (N = 79) | STEMI (N = 80) | P value Model 1 | P value Model 2 |
---|---|---|---|---|
CD4 | 37.13 (27.28 - 47.56) | 37.68 (27.47 - 48.48) | NS | NS |
CD8 | 34.99 (25.66 - 44.94) | 32.42 (23.48 - 42.07) | NS | NS |
CD4/CD8 | 1.13 (0.64 - 1.75) | 1.25 (0.65 - 2.04) | NS | NS |
CD4+IFNγ+ (Th1) | 3.87 (1.85 - 6.58) | 4.61 (2.83 - 6.79) | NS | NS |
CD4+IL-4+ (Th2) | 3.00 (1.93 - 4.32) | 3.45 (2.07 - 5.16) | 0.046 | NS |
CD4+IL-17+ (Th17) | 3.72 (2.34 - 5.41) | 5.07 (3.03 - 7.60) | <0.001 | <0.001 |
CD4+IL-10+ | 50.13 (28.94 - 71.30) | 54.39 (35.72 - 72.44) | NS | NS |
CD4+CD25+ | 5.47 (3.42 - 7.96) | 4.79 (3.00 - 6.98) | 0.043 | NS |
CD4+ 25+ Foxp3+ (Treg) | 3.78 (2.17 - 5.82) | 3.07 (1.78 - 4.69) | 0.006 | 0.017 |
CD4+CD28− | 3.13 (0.92 - 6.82) | 4.26 (0.55 - 6.80) | NS | NS |
CD4+IL-4+IL-10+ | 1.74 (0.71 - 3.21) | 2.13 (0.95 - 3.77) | NS | NS |
CD4+IL-17+IFNγ+ | 0.27 (0.06 - 0.64) | 0.41 (0.09 - 0.95) | 0.020 | 0.048 |
Th17/Treg | 1.11 (0.52 - 1.71) | 2.08 (0.51 - 3.65) | <0.001 | <0.001 |
Th1/Treg | 1.27 (0.34 - 2.19) | 1.88 (0.67 - 3.09) | 0.001 | 0.014 |
Th17/Th2 | 1.43 (0.661 - 2.26) | 1.82 (0.44 - 3.20) | 0.044 | 0.028 |
Th1/Th2 | 1.50 (0.41 - 2.60) | 1.55 (0.61 - 2.48) | NS | NS |
CD8+IFNG+ (Tc1) | 3.16 (1.25 - 5.89) | 3.36 (1.50 - 5.91) | NS | NS |
CD8+IL-4+ (Tc2) | 2.29 (0.92 - 4.26) | 2.75 (1.17 - 5.01) | NS | NS |
CD8+IL-17+ (Tc17) | 3.77 (2.03 - 6.01) | 4.95 (2.89 - 7.52) | 0.001 | 0.004 |
CD8+IL-10+ | 50.01 (28.88 - 71.15) | 51.03 (30.75 - 71.14) | NS | NS |
Tc17/Treg | 1.16 (0.51 - 1.80) | 2.11 (0.37 - 3.84) | <0.001 | <0.001 |
IFN-γ | 18.77 (11.87 - 29.69) | 19.18 (9.08 - 40.52) | NS | NS |
IL-4 | 47.06 (21.23 - 104.35) | 34.42 (13.92 - 85.11) | NS | NS |
IL-5 | 3.58 (1.65 - 7.76) | 3.78 (1.77 - 8.06) | NS | NS |
IL-17 | 10.86 (6.53 - 18.07) | 13.87 (6.97 - 27.61) | 0.097 | 0.027 |
IL-6 | 14.82 (8.31 - 26.42) | 22.30 (11.36 - 43.79) | 0.004 | <0.001 |
IL-10 | 9.50 (4.45 - 20.27) | 8.08 (3.36 - 19.41) | NS | NS |
Values are represented as Mean (95% CI). Multivariate analysis of covariance (MANCOVA) was used to compare the mean values. In Model 1 age and gender, were taken as covariates and in Model 2 age, gender, hypertension, diabetes and smoking were taken as covariates. Gating strategy used to identify the different population is given in
Gating strategy followed for Sequential analysis of Lymphocyte population by flow cytometry: Representative dot plot showing lymphocytes from peripheral blood mononuclear cells. PBMCs were gated on forward and side scatter to identify the lymphocyte population. The lymphocytes were further gated as CD3 and CD4 positive cells. Fluorescent minus control for each cytokine antibody was used to gate for the cytokine expression. Fluorescent minus control for CD25 was used to get the CD3+CD4+CD25+ positive cells. Intracellular expression of Foxp3 was determined in these cells. The numbers of CD4+CD25+Foxp3+ cells were calculated as percentage of CD4 positive cells.
B: Representative dot plots of distribution of T cell subsets across MI Patients and Control. The quantitative data is given in
Logistic regression analysis showed a significant association between Th17 (OR: 135, 95% CI: 1.14 - 1.61, P < 0.001) and Tc17 (OR: 1.20, 95% CI: 1.04 - 1.38, P = 0.009) cells in circulation with STEMI. The ratio of Th17 to Treg cells and that of Tc17 to Treg were also significantly associated with STEMI (OR: 2.92, 95% CI: 1.73 - 4.92, P < 0.001 and OR: 2.22, 95% CI: 1.42 - 3.94, P < 0.001) respectively. Th1/Treg ratio also showed a positive association with an odds ratio of 1.58, 95% CI: 1.10 - 2.29, P = 0.014). The frequency of Treg cells (CD4+Foxp3+) was a protective marker with a protective ratio of (OR: 0.83, 95% CI: 0.71 - 0.97, P = 0.026) (
To assess the sensitivity of the T cell markers in discriminating the patients from control population in the logistic regression models, we assessed the Area under the Receiver Operating Characteristic (ROC) curve (AUC or C statistics). Incorporation of T cell markers to classical risk factors (age, gender, BMI, WHR, Diabetes, hyperglycaemia, hypertension and current smoking) significantly increased the AUC values. The increase was highest for Th17/Treg ratio (0.049), but this change in area under the curve was not found to be significant (
Logistic regression analysis was carried out by taking the markers as continuous variable. Classical risk factors, (Age, gender, body mass index, waist hip ratio, hypertension, diabetes, hyperglycaemia, LDL and current smoking) were taken as covariates. The Receiver Operating Characteristic (AUC) analysis and C-Statistics were computed to understand the improvement in predictive probability of the T cell subsets in addition to classical risk factors in a multivariable model. The change in AUC and its significance was calculated using De long test. AUC: area under the curve, CI: confidence interval, OR: odds ratio. The ROC curves are represented in
The Receiver Operating Characteristic (AUC) analysis and C-Statistics were computed to understand the improvement in predictive probability of the T cell subsets in addition to classical risk factors in a multivariable model. The change in AUC and its significance was calculated using De long test. AUC: area under the curve, CI: confidence interval, OR: odds ratio.
Inflammatory immune response apolipoprotein B (ApoB) 100, heat shock protein (HSP) 60 and modified LDL are known to have a critical role in atherosclerosis. To understand the role of immune response to these antigens in inflammation associated with CAD, we compared the response of T cells from patient and control to these an- tigens to understand the differential immune response in these subjects. T cell proliferation as assessed by CFSE
Marker | OR (95% CI), p Value | AUC (95% CI), | Z Statistics | P value for change |
---|---|---|---|---|
Risk Factors | 0.787(0.715 - 0.849) | |||
Th17 | 1.35 (1.14 - 1.61), <0.001 | 0.817 (0.747 - 0.874) | 1.21 | 0.225 |
Tc17 | 1.20 (1.04 - 1.38), 0.009 | 0.804 (0.733 - 0.864) | 0.91 | 0.363 |
Treg | 0.83 (0.71 - 0.97), 0.026 | 0.800 (0.728 - 0.860) | 0.76 | 0.447 |
Th17/Treg | 2.92 (1.73 - 4.92), <0.001 | 0.836 (0.768 - 0.891) | 1.86 | 0.061 |
Tc17/Treg | 1.58 (1.10 - 2.29), 0.014 | 0.793 (0.720 - 0.854) | 0.30 | 0.761 |
Th1/Treg | 2.22 (1.42 - 3.44), <0.001 | 0.891 (0.749 - 0.877) | 1.54 | 0.121 |
dilution in CD3 positive cells was significantly higher in patients for oxidized LDL (1.27 ± 0.06 vs. 0.84 ± 0.11, P = 0.015) and HSP60 protein (1.62 ± 0.71 vs. 0.75 ± 0.21, P = 0.004) compared to healthy control (
Young Indians are known to have a higher susceptibility for acute MI. To understand if the immune markers can distinguish these susceptible individuals, we divided the study population into two groups of age group less than 45 years (N = 33) and more than 45 years (n = 46). In young STEMI patients ( mean age:40.6 ± 3.74 years), the classical risk factors including diabetes, hypertension, lipid levels, BMI and smoking were comparable with control, while in older patients( mean age: 52.43 ± 4.0 years), we observed a significant increase in occurrence of diabetes, hypertension and smoking. Hyperglycaemia was significantly higher in both young and older patients. Most of the young patients had a single vessel disease (93.94%) while multiple vessels were affected in 32.6% of older patients. Th17 (P < 0.001) cells and the ratio of Th17/Treg (P < 0.005) and Tc17/Treg (P < 0.01) were higher in both young and older patients compared to control. In the older patients Tc17 cells (P = 0.006) were also higher, which was not significant in young patients. The numbers of circulating Tregs were lower in patients but were not statistically significant. Plasma IL-6 levels were significantly higher in young patients (P = 0.01). No difference was observed in the concentration of other cytokines tested (
We then compared the risk association of classical risk factors and T cells with MI in young and older MI patients. Hypertension and Diabetes contributed to significant risk in older MI patients but was not a significant
factor in young patients. Hyperglycaemia contributed to significant risk association (OR: 5.87, 95% CI: 1.47 - 23.47, P = 0.012) in young MI patients but was not significant in older patients. Amongst the cellular markers, Th17 (OR: 1.38 95% CI: 1.03 - 1.84, P = 0.032), Th17/Treg (OR: 2.65, 95% CI: 1.23 - 5.73, P = 0.013) and Tc17/Treg (OR: 4.76, 95% CI: 1.05 - 21.27, P = 0.043) showed a significant association with MI in young patients. While for older patients the association for the markers were Th17 (OR: 1.44 95% CI: 1.11 - 1.89, P = 0.007), Tc17 (OR: 1.32, 95% CI: 1.05 - 1.66, P = 0.018), Th17/Treg (OR: 3.03, 95% CI: 1.38 - 6.60, P = 0.005) and Tc17/Treg (OR: 1.59, 95% CI: 1.14 - 2.22, P = 0.007) (
The role of adaptive immune response in the pathogenesis of myocardial infarction has been demonstrated by several studies [
Th17 cells are derived from naïve CD4+ cells and produce characteristic inflammatory cytokines like IL-17A,
Age < 45 years | Age > 45 years | |||
---|---|---|---|---|
Variables | Control (N = 36) | STEMI (N = 33) | Control (N = 44) | STEMI (N = 46) |
Age (years) | 39.85 (3.62) | 40.67 (3.74) | 52.57 (3.7) | 52.43 (4.0) |
Male-% | 35 (97.2) | 31 (93.9) | 39 (88.6) | 44 (95.4) |
Diabetes-% | 3 (8.3) | 9 (27.3) | 4 (9.1) | 20 (43.5)*** |
Hyperglycaemia-% | 7 (19.4) | 21 (63.6)*** | 18 (40.9) | 33 (71.7)*** |
Hypertension-% | 2 (5.6) | 6 (18.2) | 2 (4.5%) | 15 (32.6%)*** |
Current Smoking-% | 8 (22.2) | 11 (33.3) | 10 (34.5%) | 19 (41.3)* |
BMI | 25.44 (3.83) | 25.38 (3.90) | 25.02 (3.21) | 25.39 (4.21) |
WHR | 0.91 (0.05) | 0.91 (0.06) | 0.93 (0.05) | 0.94 (0.04) |
TC | 4.61 (3.75 - 5.65) | 4.25 (3.35 - 5.38) | 4.66 (3.91 - 5.55) | 3.77 (1.71 - 8.31) |
TG | 1.75 (0.88 - 3.5) | 1.51 (0.87 - 2.62) | 1.60 (0.94 - 2.73) | 1.59 (0.91 - 2.78) |
LDL | 2.59 (1.72 - 3.90) | 2.60 (1.84 - 3.66) | 2.89 (2.24 - 3.72) | 2.26 (1.06 - 4.84)* |
HDL | 0.89 (0.71 - 1.12) | 0.78 (0.56 - 1.09) | 0.87 (0.67 - 1.14) | 0.82 (0.61 - 1.08) |
>1 Affected vessel % | NA | 2 (6.06) | NA | 15 (32.6%) |
Th1 | 4.00 (2.55 - 3.77) | 4.44 (2.83 - 6.38) | 3.93 (1.73 - 6.98) | 4.78 (2.85 - 7.06) |
Th2 | 3.25 (1.97 - 4.83) | 3.67 (2.36 - 5.25) | 2.90 (1.93 - 4.06) | 3.27 (1.88 - 5.02) |
Th17 | 3.58 (2.41 - 4.97) | 5.21 (3.08 - 7.87)*** | 3.91 (2.64 - 5.42) | 5.03 (3.05 - 7.46)*** |
Treg | 3.72 (2.31 - 5.44) | 3.14 (1.90 - 4.67) | 3.94 (2.40 - 7.555) | 3.04 (1.73 - 6.87) |
Tc17 | 3.95 (2.84 - 5.22) | 5.02 (2.74 - 7.94)* | 3.79 (1.83 - 6.18) | 4.97 (3.08 - 7.30)** |
Th17/Treg | 1.11 (0.54 - 1.68) | 2.02 (0.68 - 3.38)*** | 1.12 (0.53 - 1.72) | 2.10 (0.41 - 3.81)** |
Th17/Th2 | 1.36 (0.38 - 2.35) | 1.76 (0.40 - 3.13) | 1.49 (0.82 - 2.16) | 1.89 (0.50 - 3.25)* |
Tc17/Treg | 1.07 (0.79 - 1.36) | 1.34 (0.85 - 1.84)** | 3.04 (1.66 - 4.44) | 5.32 (1.53 - 9.11)** |
IL-6 | 16.59 (6.87 - 40.05) | 26.66 (11.62 - 61.18)* | 14.16 (6.09 - 32.94) | 18.19 (6.61 - 50.06) |
Values are represented as percentage or as Mean (SD-standard deviation) for age, BMI and WHR and as Mean (95% CI) for variables which were log transformed for analysis. Lipid levels are expressed in mMol/L. Multivariate analysis was used to compare the cellular markers using age and gender, hypertension, diabetes, hyperglycaemia and smoking as covariates. Cytokine levels in serum were measured using Milliplex-Cytomax kit. BMI: Body mass index, DBP: Diastolic blood pressure, LDL: Low density lipoprotein, HDL: High density lipoprotein IL: Interleukin, IFN: Interferon, SBP: Systolic blood pressure, TC: Total cholesterol, TG: Triglycerides, WHR: Waist hip ratio. *P < 0.05, **P < 0.005, ***P < 0.0005.
Marker | Age > 45 years OR (95% CI), P Value | |
---|---|---|
Model 1 | Model 2 | |
Diabetes | 0.89 (0.13 - 5.8), NS | 5.43 (1.13 - 26.03), 034 |
Hyperglycemia | 5.87 (1.47 - 23.47), 0.012 | 1.99 (0.59 - 6.70), NS |
Hypertension | 2.07 (0.29 - 15.06), NS | 11.47 (1.80 - 73.15) 0.010 |
Smoking | 2.00 (0.28 - 15.06), NS | 2.63 (0.84 - 8.24), NS |
Th17 | 1.38 (1.03 - 1.84), 0.032 | 1.44 (1.11 - 1.89), 0.007 |
Tc17 | 1.20 (0.95 - 1.55), NS | 1.32 (1.05 - 1.66), 0.018 |
Th17/Treg | 2.65 (1.23 - 5.73), 0.013 | 3.03 (1.38 - 6.60), 0.005 |
Tc17/Treg | 4.76 (1.05 - 21.27), 0.043 | 1.59 (1.14 - 2.22), 0.007 |
Logistic regression analysis was carried out by taking the markers as continuous variable. Classical risk factors, (Age, gender, body mass index, waist hip ratio, hypertension, diabetes, hyperglycaemia, LDL and current smoking) were taken as covariates.
IL-22 and IL-23 which in turn can induce the expression of an array of pro inflammatory cytokines and chemokines (TNF-α, IL-1, IL-6 CXCL1, CXCL2, and CCL7) to intensify inflammation [
Although it is known that CD8 cells may also contribute to the pathogenesis of acute MI, changes in circulating CD8 cells have not been explored in detail [
Regulatory T cells (Tregs) limit inflammation and exert an immune regulatory function and are known to have an anti atherogenic effect [
Th1 cells (CD4+IFN-γ+) are known to play a major role in T cell-mediated injury in coronary atherosclerosis [
India is an epicenter for coronary artery disease accounting for 25% of all mortality [
Young patients (<45 years) with MI, without conventional risk factors showed an increase in circulating Th17 cells and an imbalance in the ratio of Th17 and Tc17 to Tregs compared to control. Th17/Treg ratio emerged as a significant risk association marker in the young patients. In older patients (>45 years), Diabetes and Hypertension emerged as significant risk factors apart from Th17, Tc17 and Th17/Treg ratio. Hyperglycemia was found to be highly prevalent in young patients, and was associated with considerable risk of MI. It is interesting to note that most of these hyperglycemic individuals were not diabetic. Association between Stress hyperglycemia and poor cardiac outcome has been reported in Mi patients [
Few limitations of the study need to be considered. This being a case control study, retrospective in nature, samples were collected after the event, which limits the causal relationship between the elevation in Th17 cells and occurrence of an AMI event. Although Th17 has been shown to exacerbate atherosclerosis and induce plaque disruption in mice model, causal role of these cells have not been studied in CAD patients. We propose to collect samples post MI from the same subjects and analyse the same markers to understand if the elevation of Th17 causes MI or it is a consequence of an acute event.
In conclusion, our results suggest an important role for Th17 and Tc17 cells in acute coronary disease in Indian population. HSP60 and Ox-LDL may contribute to this response and pathogenesis of AMI in Indian population. Young MI patients with no apparent risk factors could be distinguished by the increase in Th17 cells and Th17/Treg ratio in peripheral blood. The ratio of Th17 to Treg cells in the peripheral blood emerged as an independent marker showing significant association with acute myocardial infarction and could be developed as a potential new marker to differentiate individuals at a higher risk for developing an acute clinical event.
We gratefully acknowledge the support of the trustees of Thrombosis Research Institute, London and Bangalore and the Tata Social Welfare Trust, India (TSWT/IG/SNB/JP/Sdm). Support for the PhD program by Bharti Foundation is gratefully acknowledged.
The study was supported by the Indian Council for Medical Sciences (ICMR), Government of India (5/4/1- 4/11-NCD-II).
ThiruvelselvanPonnusamy,Komarlu VenkatachalaSrikanth,RamanjappaManjunatha,Vijay V.Kakkar,LakshmiMundkur, (2015) Circulating Th17 and Tc17 Cells and Their Imbalance with Regulatory T Cells Is Associated with Myocardial Infarction in Young Indian Patients. World Journal of Cardiovascular Diseases,05,373-387. doi: 10.4236/wjcd.2015.512043