Study Finds Tattoo Ink Affects Immune Cells and Vaccine Responses

A study published at the end of 2025 in the Proceedings of the National Academy of Sciences that investigated the effects of tattoo ink on the body has found that the ink travels through the lymphatic system and kills immune cells, as well as alters the effects of some vaccines.

In the study, the researchers characterized the transport and accumulation of different tattoo inks in the lymphatic system using a murine model. They observed that, upon quick lymphatic drainage, macrophages mainly capture the ink in the lymph node (LN), causing an initial inflammatory reaction at local and systemic levels. They also observed clear signs of inflammation in the draining LN two months following tattooing, meaning the inflammatory process is maintained over time. What’s more, the capture of ink by macrophages was associated with the induction of apoptosis (programmed cell death) in both human and murine models. 

In addition to its effect on the immune system, the ink accumulated in the LN altered the immune response against two different types of vaccines: a reduced antibody response following an mRNA-based SARS-CoV-2 vaccine, which was associated with a decreased expression of the spike protein in macrophages in the draining LN, as well as an enhanced response when vaccinated with influenza vaccine inactivated by ultraviolet radiation. 

According to the researchers, “Considering the unstoppable trend of tattooing in the population, our results are crucial in informing the toxicology programs, policymakers and the general public regarding the potential risk of the tattooing practice associated with an altered immune response.”