Characterization of dendritic cell phenotype in allergic conjunctiva: increased expression of Fc(epsilon)RI, the high-affinity receptor for immunoglobulin E.
OBJECTIVE
Dendritic cells (DCs) express the high-affinity receptor for IgE (Fc(epsilon)RI) on their surface, which may enhance their ability to capture and internalize antigens for presentation to T-lymphocytes. The aim of this study was to determine if expression of Fc(epsilon)RI(+) DCs is increased in the conjunctivae of vernal keratoconjunctivitis (VKC) patients compared with those of normal controls.


METHODS
Conjunctival biopsies were obtained from non-atopic and VKC patients. Double immunohistochemical staining was carried out using antibodies against Fc(epsilon)RI and the CD1a antigen, a DC marker. The double-positive cells were counted in five representative fields of view for each conjunctival sample.


RESULTS
Fc(epsilon)RI(+) CD1a(+) cells were present in significantly higher numbers in VKC conjunctivae compared with normal controls (mean cell count of 21.3 in VKC vs5.0 in controls, P<0.005). In normal patients the Fc(epsilon)RI-expressing DCs tended to be confined to the epithelial layer or the superficial substantia propria, but in the VKC samples these Fc(epsilon)RI(+) cells were mainly concentrated in the deeper substantia propria.


CONCLUSIONS
Fc(epsilon)RI(+) DC numbers are elevated in the conjunctivae of VKC patients, a finding consistent with the results of other studies focusing on atopic conditions. Elevated expression of Fc(epsilon)RI on DCs would facilitate antigen presentation and enhance T-cell priming, thereby contributing to ocular symptoms.
Manzouri
B
B
UCL, Institute of Ophthalmology, London, UK. b.manzouri@ucl.ac.uk
Ohbayashi
M
M
Leonardi
A
A
Larkin
D F P
DF
Ono
S J
SJ
D003228:Conjunctiva / Q000378:metabolism; D003233:Conjunctivitis, Allergic / Q000378:metabolism*; D003713:Dendritic Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D010641:Phenotype; D017455:Receptors, IgE / Q000378:metabolism*
D017455:Receptors, IgE