TOBACCO'S IMPACT ON THE IMMUNE SYSTEM

Edited by, SNEHA MAVIS

Smoking is one of the major causes of preventable deaths and illnesses in India, with over 926,000 people dying each year from smoking-related illnesses. Smoking not only raises the risk of cancer, but it also raises the risk of heart attack, stroke and impotence in males. Smoke inhalation can damage the lungs, resulting in COPD and pneumonia. Pre existing respiratory disorders, such as asthma, bronchitis and the common cold, can be exacerbated by smoking.

Nicotine is an immunosuppressive substance that can reduce neutrophil phagocytic activity, as well as influence chemotaxis and cell signaling, as well as prevent the release of reactive oxygen species(ROS), decreasing neutrophils' ability to kill pathogens. Tobacco use leads to activation of inflammatory chemicals in the lungs, causing macrophages to destroy tissue and release further inflammatory agents, resulting in a chronic inflammatory syndrome.

A study used neuroimaging to assess neuroimmune function in smokers compared to 19 non-smokers, with 8 smokers and 9 non-smokers subjected to a mild immune system activation by intravenous administration of 1 ng/kg lipopolysaccharide (LPS), an endotoxin. Three hours after LPS administration, PET imaging was done, and immune activity was measured in several brain areas using [11C]PBR28. Baseline measurements were taken, as well as alterations in metabolism.

There were no significant differences between smokers and non-smokers in baseline measures of immune activation(prior to LPS injection). However, when smokers were given LPS to stimulate an immune response, their neuroimmune response was much lower than that of non-smokers in the striatum and cortex.

The findings of this study show that the immune system within the brain is defective in certain critical areas associated with motivation, desire and executive control.