Reacción a "Reactions: tobacco alters the immune response even in the long term"

The study is excellent, especially the selection of the cohort and that it adds to other national initiatives, as has been done in the UK and Iceland. In Spain we should take an example to be able to study our own health problems in depth. The article presents an excellent and ambitious experimental approach, but precisely the size of the cohort implies certain experimental limitations. The variables analysed, tobacco and body mass index, are very frequent, and CMV status [cytomegalovirus infection] is used as an additional control. 

The experiments are generally adequate, although further analyses will be needed to verify the conclusions. I am convinced that Dr Luis Quintana Murci's contributions are among the most relevant in the article, he is a great authority in his field. 

It fits very well with the epidemiological data that already told us that tobacco, in addition to a direct carcinogenic effect, had effects on the immune system. This has implications not only with regard to tobacco-associated cancers: lung, laryngeal, intestinal, etc. Dysregulation of the immune system is a key element in the generation and spread of neoplasms. It has also long been known that tobacco increases the incidence of autoimmune and inflammatory diseases, has perverse effects on the cardiovascular system or fertility, and many other negative effects. This article reveals that much of this effect is due to a long-lasting dysfunction of the adaptive immune system, while its effect is limited and reversible on the innate immune system, is much more long-lasting on lymphocytes and is closely related to the years smoked and the amount smoked. This deleterious effect takes a long time to disappear after quitting smoking. 

For me, the main limitation of the study is that the authors themselves comment that the findings have not been repeated in another cohort, although I would add something else: a more detailed study is needed with more variables, of course in a smaller group of smokers and controls, with other exposure times, response curves, etc.