Abstract
Purpose::
Dendritic cells (DCs) express the high affinity receptor for IgE (FcεRI) on their surface, which may enhance their ability to capture and internalize antigens for presentation to T-lymphocytes. It has been demonstrated that DCs in lesional skin of patients with active atopic dermatitis or in the bronchial tree of asthmatic patients show increased expression of this receptor. The aim of this study was to investigate the expression of the FcεRI receptor in the DCs of conjunctiva derived from non-atopic and vernal keratoconjunctivitis (VKC) patients to compare the differences in the expression of FcεRI on tissue DCs.
Methods::
Conjunctival biopsies were obtained from non-atopic patients at the time of cataract surgery and from VKC patients. Double immunohistochemical staining was performed using conjugated antibodies against the FcεRI receptor and the DC tissue marker CD1α. Double positive cells in each sample were counted in five representative fields to allow for statistical analysis.
Results::
Double positive cells were far fewer in the non-atopic samples than in the VKC samples (p<0.05). In normal patients these cells were confined to the epithelial layer or the superficial substantia propria but in the VKC samples the cells were mainly concentrated in the deeper substantia propria, although double positive cells were also seen in the epithelium and in the superficial substantia propria.
Conclusions::
This finding in VKC patients is consistent with other studies indicating that this DC phenotype is upregulated in allergic patients, thereby facilitating the role of DCs in the step of antigen presentation, allowing for an enhanced ability to prime T-cells. The FcεRI receptor may, therefore, be a potential target in therapeutic drug development to limit the damage caused by the immunological response to antigen in patients suffering from this potentially blinding condition.
Keywords: immunohistochemistry