Immune cells pass pigment from one generation to the next
A. Baranska et al/J. Expt. Med. 2018
Tattoos may have staying power because of a hand off between generations of immune cells known as macrophages, say a group of French researchers.
If true, this would overturn notions that tattoo ink persists in connective tissue or in long-lasting macrophages.
Immunologist Sandrine Henri of the Immunology Center of Marseille-Luminy, in France, and colleagues tattooed mice tails with green ink to see how waste-disposing macrophages in the skin would respond.
“Macrophages will scavenge everything. That’s their job,” Henri says. “If they could do their job properly, tattoo ink would be removed rapidly.”
In the experiment, described March 6 in the Journal of Experimental Medicine, macrophages gobbled up the ink as expected, but did not digest and remove it. Instead, the cells held onto the ink until the researchers killed the cells. About 90 days later,