Increased hyaluronan in acutely rejecting human kidney grafts

The glycosaminoglycan hyaluronan is not only involved in cellular differentiation and migration but may also play a role in several inflammatory diseases. We have previously demonstrated an increased local production of hyaluronan in chronically rejected kidneys and the correspondingly affected renal vessels. In this report, we demonstrate the presence of hyaluronan in acutely rejecting kidneys. A total of 77 biopsies classified as either acute rejection or nonrejecting were analyzed using a biotin-labeled hyaluronan-binding protein in conjunction with an avidin-biotin peroxidase detection system and graded using an arbitrary scale from 0 to 3. Those biopsies classified as nonrejecting did not contain any peritubular hyaluronan in the cortex, with hyaluronan being localized only in the medulla. In contrast, those biopsies exhibiting acute rejection had an increase of hyaluronan both in the cortex and in the medulla. This increase was significantly different (P = 0.0001) and correlated with edema and interstitial inflammation. The detection of the local hyaluronan production may be a useful marker to measure acute rejection episodes.