title: Altered Expression of Toll-like Receptors in Human Oral Epithelium in Oral Lichenoid Reactions.
abstract: Oral lichenoid reactions (OLRs) are chronic inflammatory lesions induced by contact with allergens. Toll-like receptors (TLRs) are members of pattern-recognition receptor superfamily. Once activated, TLRs induce production of cytokines and chemokines, thus leading to inflammatory reaction in host tissue. In the present study, we aimed to investigate the potential role of TLRs in the initiation and perpetuation of OLRs, in which TLRs induce innate immune responses mounted against allergens. TLRs, 1 through 10, were mapped in tissue samples obtained from healthy donors and OLR patients using real-time quantitative reverse transcription polymerase chain reaction, immunostaining, and image analyses. We found that the immunoreactivity for all TLRs was increased in OLRs, except for TLR5, which was noticeably reduced. Gene analysis revealed that TLR1, TLR2, TLR4, TLR7, TLR8, and TLR9 transcripts were upregulated in OLRs compared with controls. In contrast, expression of TLR3, TLR5, and TLR6 genes were negatively regulated in OLRs. TLR10 remained unchanged in both groups. In conclusion, TLRs expression is deranged in OLRs in which TLRs could be sensitized by allergens and haptens derived from dental restorations. TLR reactivity is further enhanced by recruitment of T lymphocytes forming a diffuse lymphocytic infiltrate and thus creating a proinflammatory loop cycle. These findings suggest that TLRs are involved in OLRs and pave the way for alternative cost-effective therapeutic intervention.
authors.affiliation: *Department of Clinical Medicine, Clinicum, University of Helsinki, Finland; †Department of Oral and Maxillofacial Diseases, Clinicum, University of Helsinki, Finland; ‡Orton Orthopedic Hospital and Research Institute, Invalid Foundation, Helsinki, Finland; §Department of Internal Medicine and Rehabilitation, Clinicum, University of Helsinki and Helsinki University Hospital, Finland; and ¶Department of Rheumatology, Clinicum, University of Helsinki and Helsinki University Hospital, Helsinki Finland.
authors.forename: Abdelhakim
authors.initials: A
authors.lastname: Salem
authors.forename: Rabeia
authors.initials: R
authors.lastname: Mustafa
authors.forename: Dyah
authors.initials: D
authors.lastname: Listyarifah
authors.forename: Ahmed
authors.initials: A
authors.lastname: Al-Samadi
authors.forename: Goncalo
authors.initials: G
authors.lastname: Barreto
authors.forename: Dan
authors.initials: D
authors.lastname: Nordström
authors.forename: Kari K
authors.initials: KK
authors.lastname: Eklund
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D007150:Immunohistochemistry; D017676:Lichen Planus, Oral / Q000235:genetics / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000276:immunology*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D051193:Toll-Like Receptors / Q000032:analysis* / Q000235:genetics; D055815:Young Adult
chemical_list: D012333:RNA, Messenger; D051193:Toll-Like Receptors