Date: 11.12.2025
Tattoos Can Have Long-Term Effects on the Immune System
Did you know that when you get a tattoo, you leave a mark not only on your skin but also on your immune system? A groundbreaking international study, which also involved researchers from the Biology Centre of the Czech Academy of Sciences, shows that commonly used tattoo pigments influence immunity, trigger inflammation, and may reduce the effectiveness of certain vaccines. Immediately after application, the pigments rapidly spread through the lymphatic system and accumulate in lymph nodes, where they can persist for years. The research examined the toxicity of the three most commonly used colors—black, red, and green—and revealed that the pigments not only remain in the skin but also become permanently stored in immune cells.
The study involved twelve international research groups led by Prof. Santiago F. González from the Institute for Research in Biomedicine (IRB, Università della Svizzera italiana) in Switzerland. The scientists found that tattoo ink travels through lymphatic vessels within just a few hours after tattooing and accumulates in large quantities in lymph nodes, where it is actively engulfed by immune cells—macrophages. These cells, which normally clear foreign particles such as bacteria, viruses, or toxins, are unable to break down the pigment. This leads to cellular damage and cell death, most notably in response to black and red inks.
The tattooing process triggers an inflammatory reaction with two clearly distinguishable phases. First comes an acute inflammation that peaks within hours after tattooing and gradually subsides over the following days. This is followed by a longer-lasting phase in which inflammatory processes and activation of immune cells in the lymph nodes persist for at least two months. Scientists observed pigment in the lymph nodes not only of laboratory mice but also in samples taken from human lymph nodes—even many years after tattooing.
Image: Tattoo ink is transported by the lymphatic system and accumulates in the draining lymph node. Snapshots showing the tattooed area on the mouse footpad and the ink accumulation in the draining Lymph nodes at 2 monoths after tattooing with commercial True Black, Bright Red, or Pure Green inks. (pLN - Popliteal lymph node; ILN - iliac lymph node.
The study also examined whether tattooing could influence vaccine effectiveness, a topic that gained considerable attention during the COVID-19 pandemic. The results show that tattooed mice produced significantly fewer antibodies after receiving an mRNA vaccine. One possible reason is that some immune cells remain affected by pigment long-term, process antigens less efficiently, and provide weaker signals necessary for antibody production. Similarly, human immune cells exposed to tattoo ink responded to antigens less effectively. These findings raise new questions about the safety of tattooing and potential implications for people with extensive tattoos. “From an immunological perspective, tattoo ink is not neutral. It can alter the environment in lymph nodes over the long term, which may be important for responses to infections and vaccinations,” said Martin Palus from the Biology Centre of the Czech Academy of Sciences.
This study is far from the end of the research. Scientists will continue to investigate the relationship between tattoo pigments, the immune system, and disease in greater depth. Lead author Santiago F. González and Martin Palus have already jointly applied for a grant under the WEAVE – Lead Agency program, funded by the Swiss National Science Foundation and the Czech Science Foundation. Their goal is to gain deeper insight into how tattoo pigments affect immune responses in the context of infectious diseases.
The study, published in the prestigious scientific journal PNAS, underscores the need for further research into the safety of tattoo inks and the effects of their long-term presence in the body.
Original study:
Capucetti A., Falivene J., Pizzichetti C., Latino I., Mazzucchelli L., Schacht V., Hauri U., Raimondi A., Virgilio T., Pulfer A., Mosole S., Grau-Roma L., Baumler W., Palus M., Renner L., Ruzek D., Goldman Levy G., Foerster M., Chahine K., Gonzalez S. F. (2025) Tattoo ink induces inflammation in the draining lymph node and alters the immune response to vaccination, Proc Natl Acad Sci USA Vol.122. No 48 ppe2510392122
