Abstract
Abstract: :
Purpose: Ocular adnexal lymphoproliferative lesions present a continuum ranging from reactive lymphoid hyperplasia through atypical lymphoid hyperplasia to malignant B cell lymphoma. The homeostatic chemokine, B cell attracting chemokine 1 (BCA–1, CXCL13), which is constitutively expressed by follicular dendritic cells and vascular endothelium in secondary lymphoid organs, has been implicated in the pathogenesis of lymphocyte–mediated diseases. We investigated the cellular expression of BCA–1 in the spectrum of ocular adnexal lymphoproliferative lesions. Methods: Formalin–fixed, paraffin–embedded ocular adnexal biopsy specimens were obtained from 16 patients aged 10–82 years. Along with normal tonsil as positive control, specimens were sectioned at 5 microns thickness and immunostained with goat polyclonal anti–human BCA–1 antibody (R & D Systems) or goat IgG (2.5µg/mL); antigen retrieval was achieved by boiling the tissue sections for 10 minutes in a commercial retrieval solution (Dako: product number S1700) using a microwave. To confirm B cells as a source of BCA–1, double immunostaining was performed using mouse monoclonal anti–human CD20 antibody (Dako) along with the anti–BCA–1 antibody. Results: In 16 of 17 biopsy specimens, including reactive lymphoid hyperplasia (n = 7), atypical lymphoid hyperplasia (n = 3) and B cell lymphoma (n = 7), BCA–1 was detected. Based on nuclear and cytoplasmic morphology, the BCA–1–positive cells in the ocular adnexal lymphoproliferative lesions were identified as dendritic cells, endothelial cells and lymphocytes. BCA–1 expression by B cells, which under normal conditions are not a source of this chemokine, was confirmed by double immunostaining demonstrating co–localization of CD20 and BCA–1. Conclusions: B cells in ocular adnexal lymphoproliferative lesions demonstrate expression of BCA–1, a chemokine that may participate in tumor pathogenesis. This finding raises the possibility of treating these lesions with anti–BCA–1 neutralizing antibody or with a BCA–1 anti–sense oligonucleotide.
Keywords: tumors • conjunctiva • cytokines/chemokines