Metal particles from tattoo needles found in human lymph nodes
A few years ago, a team of European researchers discovered nanoparticles from tattoo pigments seem to be able to travel from a tattoo site into a body’s lymph nodes. A new follow-up study has now revealed chromium and nickel particles can break off the tattoo needle during a procedure and it is these molecules that may be responsible for some allergic reactions to tattoos.
A landmark 2017 study for the first time revealed how a number of tiny molecules can travel from a tattoo site through the human body, often aggregating in the lymph nodes. At the time the researchers assumed these particles came from tattoo ink but further work revealed not all of the compounds identified could be found in inks.
"We were following up on our previous study, by trying to find the link between iron, chromium and nickel and the coloring of the inks,” explains Ines Schreiver, from the Federal Institute for Risk Assessment in Germany, and corresponding author on the new study. “After studying several human tissue samples and finding metallic components, we realized that there must be something else. We also tested around 50 ink samples without finding such metal particles and made sure that we hadn't contaminated the samples during sample preparation. Then we thought of testing the needle and that was our 'eureka' moment.”
Tattoo needles commonly contain decent levels of nickel and chromium, but the researchers wondered how consistently could these needles be degrading and shedding metallic nanoparticles into a body?
Utilizing one of the world’s most powerful X-ray systems at the European Synchrotron Radiation Facility (ESRF), the researchers closely examined a tattoo needle before and after a single use. The tests revealed the needle did show abrasion following a single use but the abrasion was specifically related to certain ink pigments.
The abrasion was only seen when pigments incorporating titanium dioxide were used. Titanium dioxide is a commonly used white pigment in tattoo ink, and unlike its carbon-based black counterpart, it is known to be dense and highly abrasive.
"It is beyond doubt that the metal particles derive from the tattoo needle as a result of pure mechanical grinding,” says Bernhard Hesse, one of the scientists from ESRF working on the project.
Up until now researchers only suspected tattoo inks to be the source of the frequently identified nanoparticles seen to accumulate in a person’s body following a tattoo. It is unclear what the health implications are of these nanoparticles entering a human body, and the only directly hypothesized consequence cited by the researchers is the implication the study has on allergy research. It is well known these two metallic compounds cause allergic responses, and such reactions to tattoos are not uncommon.
"The fact that all pigments and wear particles are deposited in lymph nodes calls for special attention to be placed on allergy development,” says Schreiver. “Unfortunately, today, we can't determine the exact impact on human health and possible allergy development deriving from the tattoo needle wear. These are long-term effects which can only be assessed in long-term epidemiological studies that monitor the health of thousands of people over decades."
The new research was published in the journal Particle and Fibre Toxicology.