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Serum YKL ‐40 is a reliable biomarker for pulmonary alveolar proteinosis
Author(s) -
Bonella Francesco,
Long Xiaoping,
He Xuan,
Ohshimo Shinichiro,
Griese Matthias,
Guzman Josune,
Costabel Ulrich
Publication year - 2017
Publication title -
respirology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 85
eISSN - 1440-1843
pISSN - 1323-7799
DOI - 10.1111/resp.13082
Subject(s) - medicine , pulmonary alveolar proteinosis , bronchoalveolar lavage , biomarker , gastroenterology , interstitial lung disease , diffusing capacity , surfactant protein d , lung , immunology , pathology , receptor , lung function , biochemistry , chemistry , innate immune system
Background and objective Pulmonary alveolar proteinosis ( PAP ) is a rare disease characterized by alveolar filling. YKL ‐40, a chitinase‐like protein produced by macrophages and epithelial cells, is increased in patients with interstitial lung diseases. We aimed to evaluate the role of YKL ‐40 as a biomarker for PAP . Methods A total of 34 patients with autoimmune PAP and 50 healthy controls were studied. YKL ‐40 was measured by ELISA in serum and bronchoalveolar lavage fluid ( BALF ). Chitinase coding gene polymorphisms ( CHI3L1 −329 and −131) were detected by PCR and pyrosequencing. Correlations between serum YKL ‐40 levels and disease outcome were analysed. Results Baseline serum and BALF levels of YKL ‐40 were higher in PAP patients than in controls (286 ± 27 ng/ mL vs 42 ± 4 ng/ mL , P < 0.0001; 323 ± 36 ng/ mL vs 3 ± 1 ng/ mL , P < 0.0001, respectively). Serum YKL ‐40 levels correlated with diffusing capacity of the lung for carbon monoxide ( DL CO ) at baseline ( P = 0.002) and over time ( P < 0.0001). Patients with disease progression had higher baseline serum YKL ‐40 levels than those who remained stable or improved ( P < 0.0001). A baseline cut‐off level of 300 ng/ mL was predictive of disease progression ( HR (hazard ratio): 7.875, P = 0.001). The presence of the G allele was associated with higher serum and BALF levels of YKL ‐40. Conclusion YKL ‐40 is elevated in serum and BALF of PAP patients, and may be of clinical utility to predict outcome in PAP .