One of the biggest challenges of transplants is the need to suppress the immune response - so the new organ is not rejected - while keeping it strong enough to be able to fight all kinds of disease. As the high numbers of rejected organs show, this is a tricky balance. But a discovery by Maria Monteiro and Luis Graça, two Portuguese scientists, could help solving the problem, at least in the liver. They have found a new type of white blood cell – baptised NKTreg (reg from regulatory) – that, remarkably, once activated, migrate into this organ where it suppress any immune response in its vicinity (but not elsewhere).

CDF and DZERO, the two experiments at the Fermillab Tevatron collider, have studied top quark production since their own discovery of the heavy particle in 1995 (see here, here, and here for a three-post history of the top quark quest).