Hidden Guests: Migrating Cells and How the New Science of Microchimerism is Redefining Human Identity is shortlisted for the 2026 Royal Society Science Book Prize, supported by the Trivedi Family Foundation.
About the book
Part mind-bending medical mystery, part cutting-edge science, Hidden Guests uncovers the astonishing phenomenon of microchimerism: the presence of foreign cells inside our own bodies. The incredible story of how those cells got there, and what they do once they arrive, might change everything we know about the immune system, lineage, and identity.
Barnéoud interviews doctors, researchers, and medical experts at the forefront of microchimerism research. She interweaves their fascinating discoveries with the shocking human stories of microchimerism, including the story of a woman whose children were nearly taken away after genetic testing showed she was not their mother, until she proved that their DNA came from a vanished twin whose cells she had absorbed in utero.
Hidden Guests traces the history of this still emerging science while asking philosophical and probing questions about immunity, biology, evolution, parental testing, criminal forensics, and the concept of individual identity. Barnéoud makes the case for expanding our notions of both self and immunity: as ever-changing collectives of cells in relation, we are not unlike ecosystems. And like ecosystems, perhaps, the greater our diversity, the greater our resilience.
About the author
Lise Barnéoud is a freelance science journalist who regularly contributes to Le Monde and Mediapart. In addition to Hidden Guests, she is the author of two books about vaccines, Immunisés? and Vaccins. She won the 2008 Fondation Varenne award for science journalism in a national daily newspaper and the Trophées Signatures Santé’s 2016 Grand Prix.
