Smoking is known to reduce phagocytic activity of phagocytes and production of IFNɣ from CD4+ T-lymphocytes in TB patients.[27] Thus, the elevation in monocytes, neutrophils and CD4+ T-lymphocytes in TB patients who are current smokers supports the understanding that smoking causes systemic inflammation as observed in the general population of smokers.[14,28]. The gene discussed is CD4; the disease is tuberculosis.