Trillions of bacteria live in or on your body. There are actually as many bacteria in your body as cells in your body. Fortunately, for most of us, most bacteria that live within us are helpful, not harmful. We call these bacteria commensal bacteria. Dr. Martin Kriegel and his team have been studying these bacteria, and more specifically, a protein that humans and bacteria produce, called Ro60, that plays a role in the development of lupus.