MUC1 gene polymorphisms are associated with serum KL-6 levels and pulmonary dysfunction in pulmonary alveolar proteinosis

BACKGROUND: KL-6, a human MUC1 mucin, is a sensitive biomarker for interstitial lung diseases including pulmonary alveolar proteinosis (PAP). A correlation between MUC1 gene single nucleotide polymorphism (SNP) rs4072037 genotype and serum KL-6 levels has been reported. This study was aimed at investigating the correlation between MUC1 SNP genotype, severity of disease and disease outcome in PAP. METHODS: Twenty four patients with PAP and 30 healthy volunteers were studied. MUC1 rs4072037 was detected by using a real-time polymerase chain reaction (RT-PCR). Genotyping was performed by pyrosequencing. KL-6 levels were measured in serum by Nanopia KL-6 assay (SEKISUI Diagnostics). RESULTS: The frequency of MUC1 rs4072037 alleles was significantly different between PAP patients and healthy volunteers (PAP, A/A 46%, A/G 54%, G/G 0%; healthy controls, A/A 30%, A/G 40%, G/G 30%; p = 0.013). Serum KL-6 levels were significantly higher in PAP patients than in controls (p < 0.0001), and significantly higher in PAP patients with A/A genotype than in those with A/G genotype (p = 0.007). Patients with A/A genotype had higher alveolar-arterial oxygen difference (A-aDO2) and lower DLco compared to those with A/G genotype (p = 0.027 and p = 0.012, respectively). Multivariate analysis, Kaplan-Meier analysis and C statistics showed that the rs4072037 A/A genotype was associated with higher rate of disease progression (HR: 5.557, p = 0.014). CONCLUSIONS: MUC1 rs4072037 A/A genotype is associated with more severe pulmonary dysfunction and a higher rate of disease progression in PAP patients.

• Bonella, F.
• Long, X.
• Ohshimo, S.
• Horimasu, Y.
• Griese, M.
• Guzman, J.
• Kohno, N.
• Costabel, U.