title: An immunohistochemical study of Toll-like receptors 2 and 4 in placenta with and without infection.
abstract: OBJECTIVE
  The placenta constitutes a physical and immunological barrier against infectious agents. Toll-like receptors (TLRs) are essential components for the induction of innate immunity responses in different human tissues including the placenta. We investigated the expressions of TLR2 and TLR4 in the decidua and amniotic cells in non-inflamed placenta and placenta with infection.
  
  
  METHODS
  There were a total 74 placentas (37 with infection and 37 without infection- 25 bacterial, 10 viral and 2 toxoplasma). TLR2 and TLR4 expressions were assessed using immunohistochemical technique. Positive cells were indicated by cytoplasmic staining and the percentage of positive in 100 cells was recorded and graded. The grades were 1+ (< 25%), 2+ (25-75%) and 3+ (> 75%).
  
  
  RESULTS
  We found significantly higher expression of TLR2 in the amniotic cells and decidua cells in infected placentas as compared to non-inflamed placentas among the preterm placenta. A higher number of cases have TLR4 expression in the amnion of preterm infected placenta than in term placenta. This, however, is not statistically significant.
  
  
  CONCLUSIONS
  Our findings suggest that TLR2 plays a role in the innate immunity in bacterial and viral infection in the placenta, however, their role in protection against toxoplasma may be limited. This study further supports the observations that TLR2 expression was higher in placenta with infection which strengthened the role of TLR2 in the protection of preterm placenta against infection.
authors.affiliation: Department of Pathology, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia.
authors.forename: Abdul Rahman
authors.initials: AR
authors.lastname: Hayati
authors.forename: Abdulwakil Elraied
authors.initials: AE
authors.lastname: Mohamed
authors.forename: Geok Chin
authors.initials: GC
authors.lastname: Tan
mesh_terms: D002821:Chorioamnionitis / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D010920:Placenta / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D011247:Pregnancy; D047928:Premature Birth / Q000276:immunology / Q000382:microbiology; D012189:Retrospective Studies; D051195:Toll-Like Receptor 2 / Q000096:biosynthesis* / Q000276:immunology; D051197:Toll-Like Receptor 4 / Q000096:biosynthesis* / Q000276:immunology
chemical_list: C495342:TLR2 protein, human; C495345:TLR4 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4