Demographic characteristics A total of 150 participants were recruited: 90 COPD patients and 60 clinically healthy non-smokers for the control group. The COPD patients consisted of 50 patients with a history of smoking (COPD/tobacco) and 40 patients who previously had TB (COPD/post-TB) (table I). A significant difference was observed between COPD patients with a history of smoking and the patients with post-TB airflow obstruction with regards to sex and age, with p values of 0.0023 and 0.0002, respectively. A multivariate analyzes indicated that spirometric data were not influenced by the sex and age, with the following results: for the sex, odd ratio (IC 95%) = 2.0 (1.05 – 10.71) and p = 0.54; for the age, odd ratio = 2.74 (1.15 -109.3) and p value of 0.51.Spirometric characteristicsIn the COPD patients with a smoking history, FEV1 ranged from 20.3% to 64.6% and in the post-TB airflow obstruction patients, FEV1 ranged from 30.0% to 79.0%. In the control group, FEV/FVC ranged from 70.0% to 97%. The FEV/FVC ratio of COPD/tobacco patients ranged from 35.0% to 68.0% and in the post-TB airflow obstruction patients, it ranged from 35.0% to 74.4%. The FEV1 and FEV/FVC ratio was lower in the COPD patients with a history of tobacco than in the post-TB airflow obstruction patients with p-values of 0.014 and 0.033, respectively. As a result, the stage of COPD was more advanced in COPD patients with a smoking history compared to COPD patients with anterior TB with a p-value of 0.032 (Table I)
Concentrations of cytokines in participantsThe detected cytokines in the sputum were anti-cytokines (IL-1RA), pro-inflammatory cytokines (IL-1α, IL-1β, IL-6, IL-17 and TNF-α), chemokines (MCP-1, IL-8, MIP-1α, MIP-1β, GRO, IP-10 and sCD40L) and growth factors (VEGF, G-CSF and GM-CSF). Other cytokines such as IFN-α, IFN-γ, IL-10, IL-12, MDC, PDGF, IL-15, IL-2, IL-4, IL-7 and RANTES were not detected in the sputum of either the COPD patients or the control group.Table II shows the mean (± SD) concentrations of cytokines in sputum in the three groups: in patients with COPD, the levels of cytokines such as IL-1RA, IL-1α, IL-1β, MIP-1β, sCD40L and VEGF were statistically higher compared to the control group with p-values all lower at 0.05. IL-6 and TNF-α were higher in COPD patients with a history of tobacco compared to the post-TB airflow obstruction patients and to the control. GRO concentration was higher in COPD patients with anterior TB than in the control. There were no statistically significant differences in cytokine concentrations, such as IL-17, GM-CSF, G-CSF, MIP-1α and IP-10.Figure 1 show the variation of cytokines and the comparison of their concentration using the Student’s T-test or Mann-Whitney U test. When the two subgroups of COPD patients were compared with each other, the levels of IL-1α, IL-6, TNF-α and IL-8 were higher in the COPD patients with a tobacco history than in the patients with post-TB airflow obstruction with p-values of 0.031; 0.049; 0.021 and 0.016 respectively, with no significant differences on the other cytokines (figure 1). The comparison of COPD patients with the history of smoking to the control group indicated that in COPD/tobacco patients, the levels of cytokines, such as IL-1RA, IL-1α, IL-1β, IL-6, TNF-α, IL-17, IL -8 MIP-1β and VEGF, were statistically higher compared to the control group, with p-values of 0.014; 0.006; 0.025; 0.033; 0.048, 0.041; 0.009, 0.012 and 0.035 respectively (figure 1), without statistically significant differences in the concentrations of cytokines, such as IP-10, MCP-1, GRO, sCD40L, G-CSF and GM-CSF (figure 1) The comparison of COPD patients with the history of tuberculosis with the control group showed that the concentrations of six cytokines, IL-1RA, IL-1β, IL-1α, IL-17, GRO and sCD40L were higher in patients with the history of tuberculosis with p-values of 0.014; 0.048; 0.029; 0.045; 0.028 and 0.0013, respectively (figure 1), without statistically significant difference in the levels of the other cytokines, such as G-CSF, GM-CSF, MIP-1α, MIP-1β, MCP-1, IL-6, TNF-α, IP-10, IL-8, and VEGF between the control group and COPD with anterior TB (figure 1).
Correlation between clinical stage, cells and cytokine levels in sputum Figure 2 shows the significant correlations between cytokines and spirometric data or cells in the COPD patients with a history of smoking. The significant correlations were: The lower the FEV1 was, the higher the concentrations of sCD40L, IL-1α and IL-1β were (figure 2). The lower the FEV/FVC ratio was, the higher the concentrations of sCD40L, IL-1α and IL-1β were (figure 2). The more advanced the clinical stage was, the higher the IL-1α and IL-1β concentrations were, with correlation coefficients of 0.295 and 0.384 respectively and p-values below 0.05 (figure 2). Statistically significant positive correlations were found between neutrophils levels and cytokines IL-1β and sCD40L, between lymphocytes and IL-1α and between monocytes and sCD40L (figure 2). The non significant correlations were: There were negative non significant correlations between FEV1 and cytokines IL-17, IL-6, MIP-1α, MIP-1β and IL-8. There were negative non significant correlations between FEV/FVC ratio and cytokines IL-17, MIP-1α and IL-8. There were positive non significant correlations between clinical stage and cytokines GRO, sCD40L, IL-17, IL-6, MIP-1β and IL-8. The positive non significant correlations were found between neutrophils and IL-1α, between lymphocyte and cytokines such as sCD40L, IL-6, MIP-1β and TNF-α and between monocytes and cytokines such as IL-17, IL-1β, IL-1α and IL-8.
Figure 3 shows the significant correlations between cytokines and spirometric data or cells in the patients with post-TB airflow obstruction: The significant correlations were: The lower the FEV1 was, the higher the concentration of IL-1α was (figure 3). The lower the FEV/FVC ratio was, the higher the concentrations of IL-1α and TNF-α were (figure 3). The more advanced the clinical stage was, the higher the IL-17 and IL-6 concentrations were, with correlation coefficient of 0.489 and 0.401 with p-values of 0.013 and 0.047. Statistically significant positive correlation was found between lymphocytes levels and MIP-1α (figure 3: Fig 3g). The non significant correlations were: There were negative non significant correlations between FEV1 and cytokines such as IL-17, IL-1β, IL-6, MIP-1α, MIP-1β, TNF-α and IL-8. There were negative non significant correlations between FEV/FVC ratio and cytokines such as GRO, sCD40L, IL-1β, IL-6, MIP-1α MIP-1β and IL-8. There were positive non significant correlations between clinical stage and cytokines such as: GRO, sCD40L, IL-1β, IL-1α, MIP-1α, MIP-1β, TNF-α and IL-8. The positive non significant correlations were found: between neutrophils and cytokines sCD40L, IL-1β and MIP-1β, between lymphocyte and cytokines IL-17, IL-1α, IL-6, MIP-1α, MIP-1β, TNF-α and IL-8 and between monocytes and cytokines sCD40L, IL-1β, IL-1α, IL-6, TNF-α and IL-8.