reduced phagocytic capacity of blood monocyte/macrophages in tuberculosis patients is further reduced by smoking

tuberculosis (tb) and tobacco use are two major alarming global health issues posing immense threats to human populations. mycobacterium tuberculosis (mtb) by activation of macrophages could induce the sequences of cells activation and releases of inflammatory cytokines such as cxcl-8, il-12 and tnf-α which in turn induces the immune system network. however no information is available on other activity of cells by mtb and smoking. in the current study we aimed to investigate the serum levels tnf-a, cxcl-8 and phagocytosis capacity in tuberculosis patients with and without smoking. 103 subjects entered the study including 61 new diagnosed pulmonary tb patients (23 smokers and 38 nonsmokers) and 42 control healthy subjects. the phagocytosis of fluorescein isothiocyanate dextran (fitc-dextran) in blood monocytes/macrophages through flowcytometry was assessed. serum levels of tnf-a and cxcl-8 were analyzed by elisa methods. a lower percentage of cells from tb patients who smoked [50.29% (43.4-57.2), p <0.01] took up fitc-dextran after 2h compared to non-smoking tb subjects [71.62% (69.2-74.1)] and healthy cases [97.45% (95.9-99.1). phagocytic capacity was inversely correlated with cigarette smoking as measured by pack years (r=-0.73, p <0.001). the serum levels of tnf-a and cxcl-8 were significantly higher in the tb patients who smoked compared to the tb non-smoker group ( p <0.001, p <0.01 respectively). blood monocytes/macrophages from tb patients have reduced phagocytic capacity which is further reduced in tb patients who smoke. smoking enhanced serum levels of tnf-a and cxcl-8 suggesting a greater imbalance between the proinflammatory and anti-inflammatory factors in these patients.