Study of the expression of CD30 in pterygia compared to healthy conjunctivas

PURPOSE The pterygium is characterized by a fibrovascular neoformation from the bulbar conjunctiva into the cornea. The recent discovery that abnormal markers associated with tumor diseases are identified in the pterygium strengthens the theory that the pterygium is a tumor-like disease rather than a degenerative disease. The CD30 molecule has been identified in neoplastic and normal epithelial proliferating cells. The aim of this study was to determine the expression of the CD30 molecule in the pterygium. METHODS Immunohistochemical staining using an antibody to CD30 and to the Ki-67 nuclear antigen was performed on 25 pterygial specimens and 10 healthy conjunctivas. RESULTS Strong immunostaining against CD30 was observed in all pterygium specimens, in contrast to the healthy conjunctivas that showed weak immono-positivity in only three cases. The staining was diffused, predominantly to the basal epithelium. The Ki-67 antigen was observed in the nucleus of the basal epithelium of the pterygial specimens, and no staining was observed in the healthy conjunctiva. When serial sections were stained with CD30 and Ki-67, the cells that expressed CD30 also expressed Ki-67. CONCLUSIONS The present study identified for the first time the existence of CD30 molecules in the basal epithelium of a pterygium. The fact that the positivity to Ki-67 in the basal epithelium of the pterygium correlated with the CD30 reactivity suggested that this protein could be associated with the uncontrolled cell proliferation of the epithelium in this pathology. The CD30 molecule could therefore be a suitable target to be inhibited using chimerical antibodies in pterygium diseases.