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The human immune system changes with the seasons
Researchers have found in a large genetic analysis that the human immune system apparently adapts to the seasons. This could explain why people tend to stay healthy in the summer. The new findings could impact on the therapies of diseases.
Some diseases are more common in winter
The human immune system is likely to adapt to the seasons. According to a report by the news agency dpa, scientists came to this conclusion in a large genetic analysis. The researchers report in the journal "Nature Communications" that change the activity of almost a quarter of genes depending on the season. It is said that this may be a possible explanation that certain diseases occur more often or worse during the winter and that people tend to stay healthy during the summer months. It has long been known that cardiovascular and autoimmune diseases such as type 1 diabetes and multiple sclerosis vary seasonally. This also applies to certain mental illnesses. In addition, changes in the course of the year, the vitamin D budget. Now, the Cambridge University study suggests that all these changes could be related to a seasonal variable immune system.
The Imminsystem adjusts to the seasons. A quarter of genes more active in some seasons
Of the 22,822 genes studied, 5,136 are more active in summer or winter, the team around geneticist John Todd found. This seasonal dependency affects the cells that are responsible for the immune system and the composition of our blood and fatty tissue. Todd said in a statement to the study that the discovery may seem obvious at first sight, but it explains why so many physical and psychological problems worsen in the winter. "No one would have expected the extent to which the immune system changes." According to the results, the results could affect the therapies, for example, for the treatment of type 1 diabetes and also affect the planning of future studies.
Blood and fat tissue samples from several continents were examined
For the study, the scientists had examined blood and adipose tissue samples from more than 16,000 people from the United Kingdom, the United States, Iceland, Australia and the Gambia. They used a variety of methods to analyze the activity of selected genes in specific cells or tissues. The more than 5,000 genes, which function differently depending on the season, showed contrasting patterns, depending on whether they came from people from the southern or northern hemisphere. Gambia samples, for example, contained a particularly high number of immune cells in the blood when taken during the rainy season (June to October). In the African country, infectious diseases, especially those transmitted by mosquitoes, are very common at this time of year. The fact that there are differences between people in different climatic zones was also shown by US researchers in a study last year. They came to the conclusion that the human intestinal flora is different in the north than in the south. As a result, locals are more prone to obesity in colder regions than in warmer climes.
Vaccination programs in winter more effective
Of particular interest to the researchers was the gene ARNTL, which - at least in mice - suppresses inflammation in response to infections. In summer this was more active than in winter. Researchers conclude that if ARNTL works in a similar way in humans, targeted support for this genetic function in winter may help to treat various diseases more effectively. In addition, the scientists found that genes responsible for the individual response to vaccination are more active in winter than in summer. According to the experts, therefore, some vaccination programs in the winter would be more effective. Then the immune system is already "prepared" and react better.
Daylight and ambient temperature as possible factors
How this interaction of season and immune system works exactly is still unclear. The researchers suspect that daylight and ambient temperature could be crucial factors. In particular, one finding of relevance to British immunologist, Mike Turner, is that "one possible outcome is that treatment for certain diseases could become more effective if they were tuned to the seasons". Although the immune system is changing during the year according to new knowledge, each person can also help to strengthen it. Experts are advised to eat a balanced and healthy diet, to exercise regularly, to avoid stress as far as possible, or to practice relaxation exercises to reduce stress. All of this can help strengthen one's own immune system. (Ad)