Tattoo ink doesn't just inertly stay in the skin. A new study shows that "it quickly moves into the lymphatic system, where it can remain for months, kill immune cells, and even disrupt the body's response to vaccines," Bloomberg reports, writes UNN.
Details
Scientists in Switzerland used a mouse model to track what happens after tattooing. "Pigments entered nearby lymph nodes within minutes and continued to accumulate for two months, causing immune cell death and persistent inflammation," the report said.
"The ink also weakened the immune response to the Pfizer and BioNTech Covid vaccine when injected into tattooed skin. In contrast, the same inflammation appeared to enhance the response to an inactivated flu vaccine," the report noted.
The findings, published this week in the Proceedings of the National Academy of Sciences, highlight public health concerns as tattooing becomes mainstream, the publication notes. According to a 2023 Pew Research survey, 32% of US adults have at least one tattoo, and 22% have several.
Given that billions are spent on tattoos each year, the authors from the University of Italian Switzerland in Bellinzona argue that the results indicate the need for stricter toxicological testing and more rigorous oversight of tattoo ink ingredients, which face much less stringent regulation than medical devices.
"This work is the most extensive study to date on the effects of tattoo ink on immune response and raises serious health concerns associated with tattooing practices," the researchers said. "Our work highlights the need for further research to inform public health policy and regulatory frameworks regarding tattoo ink safety."
The study does not show whether similar immune effects occur in humans – this has not yet been tested. But it points to clear risks. Pigments have long been documented in human lymph nodes, and the results of mouse studies reflect what has been observed in both humans and primates, the publication writes.
A 2024 Swedish study involving nearly 12,000 people found that people with tattoos had a 21% higher risk of malignant lymphoma than those without tattoos, with the strongest association observed in the first two years after tattooing and again after more than ten years. The increased risk covered major types of lymphoma, both aggressive forms such as diffuse large B-cell lymphoma and slower-growing ones such as follicular lymphoma, the publication writes.
A Danish study published in January showed similar patterns. "Participants with tattoos had a higher risk of skin cancer, including melanoma and squamous cell carcinoma, as well as lymphoma, with risks increasing even further for tattoos larger than a palm. In one section of the study, large tattoos were associated with a 2.7 times higher risk of lymphoma and more than twice the risk of skin cancer," the report said.
Researchers in both countries say that the accumulated evidence warrants deeper investigation, especially given that pigments such as carbon black, polycyclic aromatic hydrocarbons, and azo dyes are known to migrate to lymph nodes and remain there for years.