Tattoo Pigment Travels to Lymph Nodes, Prolonging Inflammation in Mice

A mouse study published in PNAS shows tattoo pigment quickly reaches draining lymph nodes within hours, is taken up by macrophages but not cleared, and sustains inflammatory signals for at least two months. When vaccines were administered into tattooed tissue, the mice exhibited a weaker antibody response, a pattern echoed in cultured human cells, though this is not a conclusion about humans and requires validation through trials.