Changes in the CA 19-9 antigen and Lewis blood group with pulmonary disease severity in cystic fibrosis.

The altered carbohydrate structure of sputum from patients with cystic fibrosis (CF) has been thought to be due to the inflammatory airway response. Carcinoembryonic antigen (CEA) and CA 19-9 detect sialosylated carbohydrates in mucus. The epitope of CA 19-9 is part of the Lewis A (Le(a)) blood group antigen. Serum concentrations of CEA and CA 19-9 were determined by radioimmunoassay in 41 CF patients, aged 6-34 years; 16 were asymptomatic Outpatients, and 25 had been admitted for pulmonary exacerbations. There was no difference in CEA between groups. The CA 19-9 serum concentration was elevated in 90% of patients who had at least one of the two Lewis antigens. The CA 19-9 concentration of Inpatients with exacerbations was 2.7 times that of stable Outpatients (263 +/- 44 versus 99 +/- 13 U/mL; P less than 0.02). CA 19-9 correlated significantly with age (r = 0.35, P less than 0.05), Brasfield score (r = 0.39, P less than 0.015), pulmonary function tests, cough severity (r = 0.50, P less than 0.001) and NIH clinical score (r = 0.57, P less than 0.001). CA 19-9 concentration of Inpatients decreased by 44% from admission to discharge (302 +/- 45 to 169 +/- 39, P less than 0.02). Fourteen of 25 (56%) of the Inpatients were Le(a) positive versus only 3/15 (20%) of Outpatients who had milder lung disease (P less than 0.002). Of the Inpatients, 25% with more advanced lung disease were Le(a+b+), a rare blood group in the normal population, and one not observed in the Outpatients with milder disease.(ABSTRACT TRUNCATED AT 250 WORDS)