Swiss study shows effect of tattoo ink on mouse defence system

Tattoos influence the defence system of mice Keystone-SDA

A study on mice by Swiss researchers shows, tattoo ink influences the immune system by changing how the body reacts to vaccinations.

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For the study, the research team led by Santiago Gonzalez from the Università della Svizzera italiana (USI) gave around 40 mice foot tattoos in black, red or green colour.

They then used special microscopes to observe how the tattoo ink spread in the mice. They published the results in the scientific journal Pnas.

They showed that after tattooing, the ink is rapidly transported via the lymph channels of the mice and accumulates in large quantities in the lymph nodes within a few hours.

There it is absorbed by components of the immune system, the so-called macrophages. This uptake triggers an inflammatory reaction in two phases, as the USI explained in a press release on the study: an acute phase that lasts around two days after tattooing, followed by a chronic phase that can last for years.

According to the study, the macrophages are unable to break down the ink. The ink remains trapped in the lymph nodes, which leads to a continuous cycle of uptake and cell death and gradually impairs the immune system’s ability to defend itself.

Fewer antibodies

Tattoo ink also changes how the body reacts to vaccinations, as the researchers further demonstrated. In the experiments, tattooed mice that were vaccinated with an mRNA-based COVID-19 vaccine showed a reduced antibody response. According to the researchers, this indicates that the tattoo negatively affects the immune system’s ability to respond to the vaccine.

This effect is probably due to the reduced function of the immune cells that remain in contact with the tattoo ink over a longer period of time, the USI explained in the press release. Likewise, human immune cells that were previously exposed to the ink showed a weaker immune response after vaccination.

The researchers emphasise in the study that the results could be relevant not only for mice, but also for humans. However, they warn that the effects of tattoos on the immune system are not yet fully understood and that further research is needed to clarify long-term effects and possible risks.

Translated from German by DeepL/mga

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