Follow-up of serum KL-6 lung fibrosis biomarker levels in 173 patients with systemic sclerosis.
OBJECTIVE
A single-centre retrospective longitudinal study to investigate the predictive value of KL-6 serum levels for the outcome of interstitial lung fibrosis in a large systemic sclerosis (SSc) patient cohort.


METHODS
ELISA tests for the mucin like glycoprotein KL-6 were performed in sera of 173 SSc patients. The clinical and laboratory data were evaluated by a standardised protocol of chest x-ray, lung function tests, echocardiography and high-resolution computed tomography. 158 patients were 29 ± 22 months later reinvestigated, 9 patients (2 lcSSc, 7 dcSSc) died from SSc-related causes, and 6 patients were lost to follow-up.


RESULTS
Serum titer of KL-6 was negatively correlated with lung function parameters, independent of the time of investigation. There was a significantly higher probability of death among patients with high level of baseline KL-6. There was no statistically significant difference in the deterioration and improvement rates between groups with normal and elevated KL-6 level at study entry, even in patients in early phase of disease (disease duration <3 years). Serum levels of KL-6 significantly decreased in patients receiving cyclophosphamide treatment in spite of the fact that the spirometry results (FVC and DLCO) did not show a significant change.


CONCLUSIONS
KL-6 can be used as a lung fibrosis severity marker, but its role as a marker for disease activity is questionable. Furthermore, following cyclophosphamide treatment serum KL-6 levels may decrease independently of the lung function parameters.
Department of Rheumatology and Immunology, Medical Faculty, University of Pécs, Pécs, Hungary. kumanovics.gabor@pte.hu.
G
G
Kumánovics
E
E
Görbe
T
T
Minier
D
D
Simon
T
T
Berki
L
L
Czirják
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000503:physiopathology; D017563:Lung Diseases, Interstitial / Q000097:blood / Q000175:diagnosis / Q000209:etiology; D008297:Male; D008875:Middle Aged; D018396:Mucin-1 / Q000097:blood*; D011653:Pulmonary Diffusing Capacity; D011658:Pulmonary Fibrosis / Q000097:blood* / Q000175:diagnosis / Q000209:etiology; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D012595:Scleroderma, Systemic / Q000097:blood* / Q000150:complications; D014057:Tomography, X-Ray Computed; D014797:Vital Capacity
D015415:Biomarkers; C060192:MUC1 protein, human; D018396:Mucin-1