Tattoos and the Immune System

Lynn CD, Dominguez JT, DeCaro JA. Tattooing to "Toughen up": Tattoo experience and secretory immunoglobulin A. Am J Hum Biol. 2016 Sep 10;28(5):603-9. doi: 10.1002/ajhb.22847. Epub 2016 Mar 4. PMID: 26946186.

Tattoos have been a part of human culture for many years. The oldest record of a tattooed person dated back to 3250 BCE, where he was encapsulated in ice with around 60 tattoos covering his body. Oftentimes, tattoos are imprinted for cosmetic features, but some people have tattoos for religious purposes. For example, many Native American tribes have tattoos that signal the tribe that they belong to.

Tattoos are imprinted onto the skin by the injection of ink into the dermis, or the second layer of the skin. They are permanent as a result of immune cells within the dermis that ingest the ink. When those cells die, they imprint the ink further into the dermis, resulting in a lasting effect. 

Some scientific studies have reported that tattoos may be protective against certain health risks such as allergic reactions or bacterial transmissions. This may be a result of the immune system stimulation that occurs when one receives a tattoo. As immune cells ingest the ink, they become more protective, ensuring a greater protection against specific health risks. This is similar to vaccination, where receiving a vaccine makes you less susceptible to a disease in the future. 

There is a hypothesis that suggests undergoing the stress of getting a tattoo might result in the immune system becoming temporarily suppressed, and this effect could be less pronounced in individuals with more tattoo experience as they have become acclimated to the tattooing process. The group of researchers in this study planned to test this hypothesis by comparing the levels of two biomarkers before and after tattooing sessions in individuals with varying tattoo experience. These biomarkers can be sampled from saliva, a mucus that is part of the body’s immune system. Before experimentation, the researchers predicted that people with more tattoo experience will exhibit reduced immunosuppression as a result of the tattooing process, reflecting greater immunity to the stress.

The researchers had a group of 29 subjects receive tattoos and collected their saliva samples before and after the tattoo appointment. With these samples, the researchers began a series of procedures to analyze the data. They discovered positive correlations with tattoo body percentage covering post-tattoo and the biomarkers. However, there was an inverse correlation with other tattooing factors, such as the hours spent getting tattoos and total tattoo experience. Physical factors, such as weight, strength, and body density did not seem to have any effect on the biomarkers. 

The hypothesis, which stated that individuals with greater tattoo experience will exhibit a more pronounced immune response, was supported by the data collected. This idea also fits in with the context of history, as other societies have aligned tattoos with the idea of protective symbolism. Yet, tattoos are not the only thing capable of administering this protective effect via immune system biomarkers. Athletes have demonstrated immunosuppression post-exercise due to excitation of bodily processes. The scientists determined that those with greater tattoo experience experience feelings of joy rather than feelings of nervousness, possibly explaining the lack of immunosuppression that they face.