In cystic fibrosis (CF), mucus plugging in the airways and in the gastrointestinal tract leads to severe morbidity and mortality. The mucin-associated antigens CA 19-9 and CA 125 are markers of gastrointestinal malignancy, and CA 19-9 has also been reported in association with pulmonary function in CF.
Aim: To test whether these antigens might serve as markers for the severity of pulmonary and gastrointestinal disease in CF.
Methods: In 99 patients, aged 1 to 48 y, serum levels of CA 19-9 and CA 125 were measured by RIA and ELISA and related to clinical data.
Results: Patients with severe mutations had significantly increased serum levels of CA 125, indicating an association with a more severe CF phenotype. This was further supported by the association with lung function, chronic pulmonary colonization of Pseudomonas aeruginosa and pancreatic insufficiency. CA 19-9 was also shown to be associated with lung function and Ps. aeruginosa colonization. No gastrointestinal malignancy was found in our patients despite very high values of CA 19-9 in some patients. During a 5-y follow-up, the very high serum levels of CA 19-9 decreased along with improved general condition of the patients.
Conclusion: Increased serum levels of CA 125 in CF patients were associated with severe cystic fibrosis transmembrane conductance regulator mutations and a severe phenotype. Both antigens were associated with pseudomonas colonization and lung function and CA 125 also with pancreatic insufficiency. The estimates of CA 19-9 are hampered by the influence of the Lewis histo-blood group system on the synthesis of CA 19-9.