Microorganisms living on the skin protect against the immunosuppressive effects of UV radiation. Disinfecting the skin can weaken the natural protective effect and increase the risk of skin cancer. Scientists at the Medical University of Graz in Austria have investigated the impact of UV radiation on the skin microbiome and the immune system. According to a study published in the online magazine iScience, the immunosuppressive effect of UV radiation weakens the skin’s immune system, which can lead to the development of skin cancer. However, the immunosuppressive effect is not the same in all cases and is influenced by the skin microbiome, which is the collection of all microorganisms living on the skin.
To investigate the extent of immune system suppression, the Austrian scientists analyzed two groups of laboratory mice, one of which was germ-free and had no skin microbiome, while the skin microbiome of the second group was intact. After treatment with UV radiation, there were significant differences in the immune response of the two groups, indicating that an intact skin microbiome can reduce the immunosuppressive effect of UV radiation. The increased release of cytokines, which create an immunosuppressive environment and suppress the protective function of the immune system, is responsible for the weakened immune system in a non-intact skin microbiome. The immunomodulatory cytokine Interleukin 10 is mainly responsible for this effect, which was released more strongly in the germ-free mice in the experiment.
Further studies will show whether the results obtained with laboratory mice can be transferred one-to-one to humans. Skin swabs will be used in the laboratory, which will be treated with UV radiation. In addition, further experiments will show which microorganisms influence the protective effect against UV radiation. From the current results, concrete recommendations for action can already be derived. This includes avoiding disinfectants before sunbathing, as they attack the skin microbiome and weaken the protective effect of the immune system.
