MUC5B Polymorphism in Patients with Idiopathic Pulmonary Fibrosis-Does It Really Matter?

Abstract

Idiopathic pulmonary fibrosis (IPF) is a rare disorder concerning elderly people, predominantly men, active or former smokers, with a progressive nature and leading to premature mortality. The cause of the disease is unknown. However, there are some risk factors, among which genetic predisposition plays a role. The aim of our single-centered observational study was to assess the correlation between single nucleotide polymorphism (SNP) of the MUC5B gene (rs35705950) and the disease course, antifibrotic treatment effect, and survival in patients with IPF. A total of 93 patients entered the study, of whom 88 were treated with either nintedanib or pirfenidone. The GG genotype was found in 28 (30.1%) subjects, while the GT or TT genotypes were found in the remaining 65 (63.4%) and 6 (6.5%) patients, respectively. The T allele minor allele frequency (MAF) accounted for 38.2% of the whole group. Patients with different genotypes did not differ significantly regarding age, sex, pulmonary function tests' results, response to the antifibrotic treatment, or survival. However, we found a survival advantage in female patients and patients with higher pre-treatment TL,co. Treatment with antifibrotics significantly decreased the magnitude of FVC and TL,co decline compared to the time before treatment initiation, regardless of MUC5B status. In conclusion, we found high prevalence of T allele of MUC5B gene in patients with IPF; however, it showed no influence on disease trajectory, survival, or antifibrotic treatment effect in the presented cohort.

Keywords: IPF; MUC5B; survival; treatment effect.

Figure 1

Changes in PFTs before and after treatment. (A). FVC %pred, (B). TL,co %pred. FVC %pred—forced vital capacity, %predicted; TL,co %pred—transfer factor of the lungs for carbon monoxide, %predicted; T (−12)—within a year before treatment initiation, T (0)—at treatment initiation, T (+12)—after 12 months of treatment.

Figure 2

Kapplan–Meier survival curves according to different factors. (A)—genotype (GG versus GT/TT), (B)—GAP (stage 1 versus stages 2 or 3), (C)—sex (male versus female), (D)—HRCT pattern (UIP versus probable UIP). GAP—Gender–Age–Physiology Index, UIP—usual interstitial pneumonia, pUIP—probable usual interstitial pneumonia.