Feline leukemia virus detection in corneal tissues of cats by polymerase chain reaction and immunohistochemistry

Objectives To determine the presence of feline leukemia virus (FeLV) in the corneas of FeLV-infected cats. Animals studied Thirty-four random source cats. Procedures Seventeen cats were found positive for FeLV ser-um p27 antigen b y enzyme-linked immunosorbent assay (ELISA). Twelve ELISA positive cats wer e also positive on peripheral blood samples by immunofluorescent antibody ( IFA) testing. Seventeen ELISA negative cats served as negative controls. Fu ll thickness corneal specimens were collected from the left cornea of all c ats and analyzed for FeLV proviral DNA and gp70 antigen by polymerase chain reaction (PCR) and immunohistochemical (IHC) testing, respectively. Results Eleven (64.7%) positive corneal PCR results were obtained from 17 E LISA positive cats. Of 12 cats that were both ELISA and TEA positive on per ipheral blood, 10 (83.3%) had positive corneal PCR results. All corneal tis sues from ELISA negative cats were PCR negative. IHC staining of corneal se ctions revealed the presence of FeLV gp70 in corneal tissues of nine (52.9% ) ELISA positive cats. Of the 12 cats that were both ELISA and IFA positive on peripheral blood, eight (66.7%) had positive corneal IHC results. Posit ive IHC staining was localized to the corneal epithelium. Corneal tissues o f all ELISA negative cats and all IFA negative cats were negative on THC te sting. Conclusions FeLV antigens and proviral DNA are present in corneal tissues o f some FeLV-infected cats. Screening corneal donors for FeLV infection is w arranted.