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more bad news for smokers. The cancer stick undermines the body's immune system, leaving it more susceptible to bacterial infections, shows new research. It is already known that

smokers are more prone to infections and inflammatory diseases due to the hundreds of toxic components in cigarettes. Now researchers have found that the nicotine in tobacco affects the

functioning of neutrophils--a type of white blood cells that are the body's natural defence against infections. Nicotine reduces these cells' ability to seek and destroy microbes.

Like all other white blood cells, neutrophils are generated by our bone marrow. They are usually the first responders to any microbial infection. Although nicotine has been known to affect

neutrophils, there has been no study until now of the mechanisms at work when nicotine is present during neutrophil differentiation. That is, when they are being formed from stem cells in

the marrow through the process of cell division and differentiation. David Scott of the Oral Health and Systemic Disease Research Group at the University of Louisville School of Dentistry,

Kentucky, usa, along with a colleagues from the uk and Canada, decided to investigate how nicotine presence influenced the differentiation process. Their findings were published in the April

15 issue of bmc _ Cell Biology_. The team used serum samples from a group of 20 smokers (with reported consumption of about 10 cigarettes a day) and 20 non-smokers. They modelled the

neutrophil differentiation process using promyelocytic cells--large mononuclear bone marrow cells that are still in an undifferentiated state--of the hl -60 cell line (a leukaemic human

tissue culture commonly used to study cell differentiation). Batches of these cells were put in a medium (dimethylsufoxide or dmso) that keeps the cells active. In some batches, nicotine was

added to the medium. The researchers found that once these cells differentiated into neutrophils, the ones treated with nicotine were less able to seek and destroy bacteria than

nicotine-free neutrophils. The nicotine suppressed the oxidative burst in hl -60 cells, a function that helps kill invading bacteria. The authors suggest the processes partially explain

tobacco users' increased susceptibility to bacterial infection and inflammatory diseases. A better understanding of this relationship could pave the way for specific therapeutic

strategies to treat tobacco-associated inflammatory diseases and conditions, they say. "It must be acknowledged that our study model, dmso -differentiated hl -60 cells, are not entirely

similar to normal neutrophils," says Scott. "This leukaemic human cell line permits the reproducible study of differentiation and retains many of the key functions of

neutrophils." Through their research "the authors have found another example of how nicotine concentrations acquired through tobacco smoking or smokeless products can be bad for

our health; in this case a detrimental effect on granulocyte function and how we fight infection", John Minna, director of the Hammon Center for Therapeutic Oncology Research in Dallas,

Texas, told _Down To Earth_. Minna has studied the effect of nicotine exposure in the pathogenesis of lung cancer. India critical These findings come at a time when researchers are

predicting that 2010 onwards, around one million people will die every year of smoking-related causes in India. A study by the University of Toronto's Centre for Global Health Research,

published in the _ New England Journal of Medicine _ in February, says India is in the midst of a "catastrophic epidemic of smoking deaths". It also says that most tobacco deaths

will occur in rural India and the risk of heart disease to passive smokers will increase by 60 per cent. The findings were based on the first nationally representative study of smoking in

India. Union health minister Anbumani Ramadoss has been spearheading a campaign against tobacco products. The centre is soon to come out with a national anti-tobacco campaign that will warn

youth against using such products. "If an individual is caught smoking then he will have to pay a fine of Rs 1,000 and if it takes place in an institution then a fine of Rs 5,000 would

be collected from the institution for each person caught," Ramdoss says. Industry sources say such measures will affect livelihood of millions. "In all, 35 million people are

dependent on tobacco cultivation, trading, processing and cigarette and bidi manufacturing.This amounts to 3.5 per cent of the country's population," says Bellam Kotaiah, president

of the Indian Tobacco Association.