CA 19-9 ELISA test: a new method for studying mucus changes in tears
- aDepartment of Ophthalmology, CHU Dijon, France, bDepartment of Ophthalmology, CHU Ambroise Paré, Paris, France, cINSERM U 55, Hôpital Saint-Antoine, Paris, France
- Catherine Garcher, Department of Ophthalmology, Hôpital Général, 3 rue du Faubourg Raines, 21000 Dijon, France.
- Accepted 13 August 1997
AIMS This study investigated mucus changes in the tears in various eye conditions using impression cytology. The quantity of mucins was measured by enzyme linked immunosorbent assay (ELISA) using the tumour marker CA 19-9. This assay quantifies the sialylated Lewisa structure mainly associated with ocular mucins.
METHODS Impression cytology was performed using a cellulose nitrate membrane, on 53 healthy patients, 50 glaucoma patients treated with β blockers, 24 patients suffering from dry eye syndrome, and 45 contact lens wearers. The tear film glycoproteins were eluted and CA 19-9 was measured.
RESULTS CA 19-9 content expressed as kilo units (kU) per μg of tears was significantly decreased in dry eye syndrome (25.8 kU (SD 17.3)/μg) (p<0.05), glaucoma patients over 60 years (28.9 (19.5) kU/μg) (p<0.05), and contact lens wearers (28.4 kU (18)/μg) (p<0.05), when compared with healthy individuals (39.4 kU (22.2)/μg).
CONCLUSION Impression cytology can be regarded as a valuable method for obtaining samples of glycoconjugates of mucin. The decrease of sialylated chains observed with this method confirms the hypothesis that some quantitative changes in the tear film may be encountered in ocular surface disorders.