Inhaled Microplastics Suppress Lung Immune Cells and May Impact Overall Health

Microplastics, tiny plastic particles pervasive in our environment, are increasingly being inhaled by people worldwide. A recent study presented at the ATS 2025 International Conference reveals that inhaled microplastics can significantly impair the function of pulmonary macrophages, vital immune cells in the lungs responsible for defending against pathogens and maintaining tissue health.

The research highlights a crucial pathway through which microplastic exposure could lead to long-term immune system disruption, raising concerns about higher risks of developing lung diseases, cancer, and other systemic health issues. According to Dr. Adam Soloff of the University of Pittsburgh, microplastics are not just harmless pollutants; they can disseminate beyond the lungs, affecting organs such as the liver, spleen, and even the brain.

The scientists conducted experiments exposing macrophages to polystyrene microplastics of various sizes and concentrations. They also exposed mice to inhaled microplastics and observed similar impairments. Within 24 hours, macrophages showed reduced ability to perform phagocytosis, the process of engulfing bacteria and debris, compromising their immune response. Trace amounts of microplastics were detected in several organs for up to a week after inhalation.

Interestingly, certain drugs like Acadesine, an AMP kinase activator, were able to partially restore macrophage function after exposure. Dr. Soloff expressed surprise that macrophages struggled not only to digest microplastics but also retained particles over time, which may worsen immune dysfunction.

These findings emphasize the need for public health strategies to limit plastic use and reduce microplastic inhalation. Moreover, they open avenues for potential treatments, especially in populations exposed to poor air quality. Ongoing research aims to identify biomarkers indicating early lung damage and lung cancer risk, helping in timely diagnosis and intervention.

This study underscores the broader implications of microplastic pollution on human health and the importance of addressing environmental pollutants to protect immune health and prevent diseases.