Health risk - sun: Aggressive UV radiation dampens our immune system

Enjoy the sun only in moderation: damage to health caused by UV radiation

It has gotten a bit cooler at the moment, but in a few days summer temperatures will prevail in some regions of Germany. Then it is important to protect yourself as well as possible from the aggressive sun rays. Because UV radiation can lead to serious damage to health.

Most important risk factor for skin cancer

Although the summer has just passed, an official warning about high UV intensity has recently been issued for large parts of Germany. In this context, it was pointed out to protect yourself as well as possible from the intense sun rays. After all, UV radiation is considered the most important risk factor for skin cancer. These rays also affect the immune system.

There is a risk of acute or chronic damage to health

Warm sun rays invite you to stay outdoors. But especially in midsummer it is important to enjoy the sun only in a protected manner and in moderation.

As the Medical University of Graz explains in a communication, ultraviolet radiation is contained in the short-wave portion of solar radiation and, among other things, fulfills important functions for the metabolism.

But the UV radiation also threatens acute or chronic health damage.

Researchers at the MedUni Graz have now investigated the influence of UV radiation on the interaction of the skin's microbiome and the immune system.

The study results published in the specialist magazine "iScience" show the role of the microbiome under the influence of UV radiation in the development of skin cancer.

It depends on the amount

UV rays have an important function for the metabolism, among other things, because they support the body in producing vitamin D.

This vitamin then provides, for example, for the bone structure, supplies the muscles with calcium or supports the immune system.

However, as is so often the case - it depends on the amount, because an overdose harms health and acute damage, such as sunburn, as well as chronic damage such as skin cancer can occur.

“UV radiation suppresses the skin's immune system and is therefore immunosuppressive. This creates a certain defense weakness, which plays an important role in the development of skin cancer, ”explains Univ.-Prof. Dr. Peter Wolf from the University Clinic for Dermatology and Venerology at the Medical University of Graz.

As the experts explain, the extent of the immune system suppression caused by UV radiation can be shown with a contact allergy model.

Vijaykumar Patra, PhD - member of Peter Wolf's research group - used the contact allergy model for his scientific work.

In cooperation with the Karolinka Institutet, Stockholm, the research group led by Peter Wolf was able to show the effects of UV rays on the microbiome of the skin and thus subsequently influence the immune system and possibly contribute to the development of skin cancer.

Influence of UV radiation on the microbiome of the skin

In their work, the scientists found that the microbiome of the skin - the entirety of the microorganisms that colonize the skin - protects against the immunosuppressive effects of UVB radiation.

"In the laboratory model, we were able to clearly determine that the immune response to UVB radiation from a model with an intact microbiome clearly differs from that of a model without a microbiome," explains Wolf.

Under the influence of UV radiation, the microbiome causes a condition on the skin that promotes inflammatory processes, while in the skin without a microbiome there is an increasingly immunosuppressive environment, so that the immune system no longer works to its full extent.

"This condition is mainly caused by the increased expression of interleukin 10, a messenger substance of the immune system," said Wolf.

For example, disinfecting the skin with an antiseptic leads to more immunosuppression after exposure to UV radiation. The skin can no longer adequately protect itself due to the microbiome which is no longer intact.

As stated in the communication, the research results clearly demonstrate the change in the effect of the microbiome on the immune system under the influence of UV radiation.

The research results are of far-reaching importance, especially since the influence of the microbiome by skin care products, disinfectants etc. could direct the immune response to UV radiation in one direction or the other, the experts write. (ad)

More interesting articles on this topic can be found here:

  • Sun protection: Important - protect babies and children from the aggressive sun rays!
  • Skin cancer wave: fashion trends of the 70s and 80s are now taking their toll
  • Sunscreen avoided: Man suffers severe burns from the sun's rays

Author and source information

This text corresponds to the specifications of the medical literature, medical guidelines and current studies and has been checked by medical doctors.


  • Medical University of Graz: Skin protection through the microbiome: Researchers show connection between UV radiation and immune system, (accessed: July 15, 2019), Medical University of Graz
  • Trade magazine "iScience": Skin Microbiome Modulates the Effect of Ultraviolet Radiation on Cellular Response and Immune Function, (access: July 15, 2019), iScience

Video: Why sunlight is critical for your mood and immune system (January 2022).