Immune responses to gut bacteria may initiate systemic lupus erythematosus (lupus) in susceptible individuals. Individuals who go on to develop lupus have autoantibodies years before the onset of symptoms, and the earliest detectable antibodies are often those to the RNA-binding protein Ro60. Scientists from Yale University and the NIH investigated potential sources of Ro60 antigen, and they showed that several species of commensal bacteria express bacterial versions of Ro60.