The Impact of Tattoos on Immunity Revealed 0 5

Tattoo inks can remain not only in the skin: some of the pigment travels through lymphatic vessels and accumulates in nearby lymph nodes. This was shown in a study on mice, published in PNAS: in the nodes, pigments were captured by immune cells (mainly macrophages), some of these cells died, and the inflammatory response lasted for up to two months.

The authors traced the process in the first minutes and hours after the tattoo was applied: the inks quickly reached the lymph nodes and were retained in areas where lymph is typically filtered. Over time, the amount of pigment in the nodes did not decrease, and in some cases even increased, indicating a prolonged "leakage" of particles from the tattooed skin.

Separately, the researchers examined how tattoos affect vaccination when the injection is made in the tattooed area. In experiments, the response depended on the type of vaccine: after the mRNA vaccine against COVID-19, antibody production decreased, while after the UV-inactivated influenza vaccine, it could actually increase — likely due to differences in the mechanisms of how vaccines work and the role of local inflammation.

The authors emphasize that the results were obtained from animals and cannot be directly transferred to humans, but they show that a tattoo is not just a local procedure and can change the functioning of the immune system in lymph nodes. Therefore, the researchers advise against getting vaccinated directly in the tattoo area until the impact of the inks on the immune response is better understood.