Abstract. Increased synthesis of hyaluronan (HA) in the renal corticointerstitium has been documented in renal injury, although the functional significance of this is unclear. The aim of the work presented in the current study was to examine the role of HA in monocyte binding by proximal tubular cells (PTC). Using the PTC line HK-2, the authors show that unstimulated cells formed pericellular HA cable-like structures that bound mononuclear leukocytes via their cell surface CD44. Stimulation with bone morphogenic protein-7 (BMP-7) led to increased formation of HA cable-like structures and also a dosedependent increase in CD44-dependent binding of radiolabeled