The CD40–soluble CD40 ligand signalling cascade may have a role in the development and progression of renal injury in patients with atherosclerotic renal artery stenosis, conclude the researchers of a new study. In a single-centre cohort of 60 patients with renal artery stenosis, Haller and colleagues found low baseline levels of circulating CD40 and baseline creatinine level to be associated with loss of kidney function at 1-year follow-up.