Serum CA 19-9 levels as a diagnostic marker in cystic fibrosis patients with borderline sweat tests.
Patients with normal or borderline sweat tests present a diagnostic challenge. In spite of the availability of genetic analysis and measurement of nasal potential difference, there is still uncertainty in diagnosing cystic fibrosis in some patients. CA 19-9 is a tumor-associated antigen whose levels were previously found to be elevated in some cystic fibrosis patients. We investigated whether serum CA 19-9 levels can contribute to establishing the diagnosis of cystic fibrosis in patients with a borderline sweat test, and evaluated the influence of different clinical variables on CA 19-9 levels. Serum CA 19-9 levels were measured in 82 cystic fibrosis patients grouped according to their genotype and in 38 healthy individuals. Group A included 50 patients who carried two mutations previously found to be associated with a pathological sweat test and pancreatic insufficiency (DeltaF508, W1282X, G542X, N1303K, and S549R). Group B included 13 compound heterozygote cystic fibrosis patients who carried one mutation known to cause mild disease with a borderline or normal sweat test and pancreatic sufficiency (3849+10kb C-->T, 5T). Group C included 38 normal controls. Nineteen cystic fibrosis patients carried at least one unidentified mutation. An association between CA 19-9 levels and age, pulmonary function, pancreatic status, sweat chloride, previous pancreatitis, serum lipase, meconium ileus, distal intestinal obstruction, liver disease, and diabetes was investigated. The distribution of CA 19-9 levels was significantly different between the three groups ( p<0.01); high CA 19-9 levels were found in 60% (30/50) of group Apatients and in 46.6% (6/13) of group B patients, but in only 5.2% (2/38) of the controls. CA 19-9 levels were inversely related to forced expiratory volume in 1 s, while no association was found with the other clinical parameters examined. Our findings suggest that the serum CA 19-9 in cystic fibrosis patients originates in the respiratory system, and has a useful ancillary role, particularly when diagnostic uncertainty exists. Hence, the diagnosis of cystic fibrosis should be considered in patients with borderline sweat tests and high CA 19-9 levels, but normal levels do not exclude cystic fibrosis.
Augarten
A
A
National Cystic Fibrosis Center, The Chaim Sheba Medical Center, Tel-Hashomer, Israel 52621. augarten@post.tau.ac.il
Berman
H
H
Aviram
M
M
Diver-Habber
A
A
Akons
H
H
Ben Tur
L
L
Blau
H
H
Kerem
E
E
Rivlin
J
J
Katznelson
D
D
Szeinberg
A
A
Kerem
B-S
BS
Theodor
L
L
Paret
G
G
Yahav
Y
Y
D000293:Adolescent; D000328:Adult; D018395:CA-19-9 Antigen / Q000097:blood*; D002648:Child; D003550:Cystic Fibrosis / Q000097:blood / Q000175:diagnosis*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics / Q000502:physiology; D004573:Electrolytes / Q000032:analysis*; D006801:Humans; D009154:Mutation; D013542:Sweat / Q000737:chemistry*
D018395:CA-19-9 Antigen; C505032:CFTR protein, human; D004573:Electrolytes; D019005:Cystic Fibrosis Transmembrane Conductance Regulator