TLR4 and infection: Hsp70 is released by cell injury secondary to infections [7], and some authors have proposed that extracellular Hsp70 is a TLR2 and/or TLR4 agonist that induces the production of pro-inflammatory cytokines [22], while other authors argue that an LPS contamination of the Hsp70 used in these experiments is accountable for the inflammatory response [16,23].