BACKGROUND: Determining patterns of heat shock protein (Hsp) induction in normal kidneys and transplanted kidneys could provide insight into pathogenesis. The aim was to evaluate Hsp expression in normal kidneys, normal renal allografts and diseased renal allografts.

MATERIAL AND METHODS: Immunohistochemical staining for Hsp27, 60, 70i and 72/73 was performed on 11 morphologically normal human kidney nephrectomy specimens and needle biopsies of 32 human renal allografts.

RESULTS: Within the normal kidney, Hsp27 was detected in the endothelium, distal tubules and collecting ducts. Hsp60 was present within the distal convoluted tubules and ascending thick limb. Inducible Hsp70 (Hsp70i) was identified in the collecting ducts and ascending thick limb. Constitutively-expressed Hsp72/73 stained within podocytes and parietal epithelium. In renal allografts the low grade constitutive expression of Hsp in normal allografts became changed in disease. In acute cellular rejection and cyclophilin toxicity, distal tubules showed increased cytoplasmic immunopositivity for Hsp27, 60 and 70i. In chronic allograft nephropathy there was also induction of Hsp27, 60 and 70i in the distal tubules but this was less pronounced. Constitutively-expressed Hsp72/73 wasn’t significantly induced in any diseased grafts.

CONCLUSIONS: Multiple Hsps are induced in diseased renal allografts, particularly within the distal nephron and the induction profile differs between diseases.

Keywords: Diseased renal allografts, heat shock proteins