Professor Carola Vinuesa has revealed how our immune system produces high quality, long lasting antibody responses. This has significance for understanding immune responses to pathogens and autoimmune diseases. Her team identified T-follicular helper (TFH) cells as an independent cell subset and demonstrated how failure to limit these cells causes rogue selection of B cells and diseases such as lupus and type-1 diabetes. Carola unearthed cells and molecules that control TFH cells, shedding light on pathways to autoimmunity, and providing a rationale for new approaches to treatment.