Background: Toll-like receptors (TLR) recognize a variety of ligands, including pathogen-associated molecular patterns and link innate and adaptive immunity. Individual receptors can be up-regulated during infection and inflammation. We examined the expression of selected TLRs at the protein level in various types of renal disease.
Methods: Frozen sections of renal biopsies were stained with monoclonal antibodies to TLR-2, -4 and -9.
Results: Up-regulation of the three TLRs studied was seen, although the extent was modest. TLR-2- and -4-positive cells belonged to the population of infiltrating inflammatory cells; only in the case of TLR-9 were intrinsic glomerular cells positive in polyoma virus infection and haemolytic uraemic syndrome (HUS).
Conclusions: Evidence for the involvement of the three TLRs tested in a variety of human renal diseases was found. These findings add to our understanding of the role of the innate immune system in kidney disease.