Presence of nanoplastics in sputum of patients with severe asthma: a novel environmental perspective

Studies suggest that environmental exposure to micro-and-nanoplastics (MNPs) may influence asthma pathophysiology given their potential to trigger and maintain immune responses. Evidence is lacking regarding the link between the presence of MNPs and disease severity and phenotypes. We aim to understand their possible role in the immune respose of severe asthma. This cross-section study analyzes the presence of MNPs in sputum samples from patients with severe asthma, classified into allergic T2 (ASA, n=13), non-allergic eosinophilic T2 (ASE, n=11), and non-T2 phenotypes (ASNE, n=8), compared to a healthy control group (n=11). We detected MNPs via spectral flow cytometry with Nile Red staining and MULTIPLEX panel for inflammatory cytokines. We used used ANOVA to determine statistical significance (p<0.05). We found a statistically significant difference between the studied groups and mean MNPs per uL of sputum (F(3, 39)=3.53, p=0.02). Tukey’s HSD test only found significant differences in the mean number of MNPs found in sputum between ASE (76,8, n=11) ASA patients (20,7, n=13)(p=0.03), and ASNE (18, n=8)(p=0.05), but not with control participants (27,4, n=11)(p=0.08). ASE also had significantly increased levels of PDGFB-b (F(3, 29)=7, p=0.001), while no significant difference was estabilshed on the other studied cytokines. The higher concentration of MNPs and PDGFB-b in the ASE phenotype could suggest an interaction between MNPs and airway remodelling and eosinophilic inflammatory pathway in severe asthma. Given the limited number of studies on this topic and our small sample size, further research is needed to understand the exact mechanisms they excert their role in severe asthma.