Expression of Toll-like receptors in healthy and allergic conjunctiva.
OBJECTIVE
To investigate the expression of toll-like receptors (TLRs) in healthy and active vernal keratoconjunctivitis (VKC) conjunctiva.


METHODS
Comparative nonrandomized interventional study.


METHODS
Nine patients with vernal keratoconjunctivitis and 10 healthy subjects.


METHODS
Normal and VKC conjunctiva were evaluated for TLR-2, TLR-4, and TLR-9 mRNA and proteins by relative real-time polymerase chain reaction and immunohistochemistry. Colocalization of TLRs was further evaluated by confocal microscopy and double-labeled immunofluorescence in T cells (CD4), mast cells (AA1), and eosinophils (EG2).


METHODS
Identification of TLRs at molecular and biochemical levels and identification of inflammatory cells that coexpress these receptors.


RESULTS
Toll-like receptor 2, TLR-4, and TLR-9 were expressed in normal and VKC conjunctival epithelium and stroma, both with a more intense immunoreactivity in the stroma. In VKC tissues, TLR-4 was upregulated, TLR-9 was downregulated, and TLR-2 was slightly decreased relative to normal tissues. Toll-like receptor 4 was localized on CD4+ lymphocytes, eosinophils, and mast cells, whereas lymphocytes and eosinophils, but not mast cells, expressed TLR-9.


CONCLUSIONS
Toll-like receptors are expressed in healthy and allergic conjunctiva. The upregulation or downregulation of these receptors and their presence on inflammatory cells suggest a role of TLRs in VKC.
Bonini
Stefano
S
CIR Laboratory of Ophthalmology, Campus Bio-Medico and G. B. Bietti Eye Foundation, Rome, Italy. s.bonini@unicampus.it
Micera
Alessandra
A
Iovieno
Alfonso
A
Lambiase
Alessandro
A
Bonini
Sergio
S
D000293:Adolescent; D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D003228:Conjunctiva / Q000378:metabolism*; D003233:Conjunctivitis, Allergic / Q000378:metabolism*; D004804:Eosinophils / Q000276:immunology; D004848:Epithelium / Q000378:metabolism; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008407:Mast Cells / Q000276:immunology; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D018613:Microscopy, Confocal; D012333:RNA, Messenger / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051217:Toll-Like Receptor 9; D051193:Toll-Like Receptors; D015854:Up-Regulation
D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; C495342:TLR2 protein, human; C495345:TLR4 protein, human; C495371:TLR9 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051217:Toll-Like Receptor 9; D051193:Toll-Like Receptors