TLR4 and periodontitis: Swaminathan et al. found that TLR2 and TLR4 mRNAs were up regulated in epithelial cells of unstimulated whole saliva from chronic periodontitis, while PGRP3 and PGRP4 mRNAs were reduced.96 In their further study, they confirmed that the TLR4 mRNA was significantly higher in the salivary epithelial cells of the gingivitis and the chronic periodontitis cohort as compared to that from the healthy saliva samples.