Commensal orthologs of the human autoantigen Ro60 as triggers of autoimmunity in lupus

Lupus: No Longer a Lone Wolf. Lupus (represented by the wolf, Canis lupus) is a chronic autoimmune disorder that progresses over decades. Greiling et al. analyzed commensal bacteria in lupus patients and identified species with Ro60 proteins similar to human Ro60, an early autoantigen in lupus. Bacterial Ro60 could activate patient lymphocytes, and colonization of mice with the bacterium instigated lupus-like symptoms. These results suggest that immune recognition of a bacterial protein leads to cross-reactive immune cells targeting the human version, thereby initiating lupus.