Elevated tear fluid levels of MIP-1α in patients with cystic fibrosis

Cystic fibrosis (CF) is the commonest multisystem genetic disease of white races, caused by mutations in the cystic fibrosis transmembrane regulator (CFTR), encoded on the long arm of chromosome 7. Mutations in the CFTR gene result in defective sodium, chloride, and water transport in the epithelial cells of the respiratory, hepatobiliary, gastrointestinal, and reproductive tracts, the pancreas, and the eye. The pathogenesis of ocular changes in CF is still unknown, but CF belongs to the large pathologic group of ocular surface epithelial diseases, termed keratoconjunctivitis sicca (KCS), that develop in dry eye syndrome. The aim of this study was to evaluate the levels of macrophage inflammatory protein-1 alpha (MIP-1 alpha) in the tear fluid of CF patients. We also investigated the correlation between the tear levels of this chemokine and clinical severity of CF and ocular surface disease. We studied 25 patients with CF with a mean age of 14 years. Chemokine levels were determined by ELISA. Complete ophthalmic examination, including dry eye tests, were used to study the ocular surface. The tear levels of MIP-1 alpha in the CF patients were significantly higher when compared with healthy controls. We found a negative correlation between the tear levels of MIP-1 alpha and clinical severity in CF patients and a positive correlation between the tear levels of MIP-1 alpha and the presence of dry eye findings in CF patients. This current study indicates that chemokines play an important role in the ongoing inflammatory response. Our findings may help to explain one of the key factors contributing to the pathogenesis of ocular surface changes in CF patients.