Background: The hygiene hypothesis suggests that early life exposure to helminth infections can reduce hypersensitivity in the immune system. Objective: The present study aims to evaluate the effects of Toxocara cati (T. cati) somatic products on allergic airway inflammation. Methods: Between 2018 and 2020, T. cati adult worms were collected from stray cats in Mashhad, Iran (31 out of 186 cats), and their somatic extract was collected. Thirty BALB/c mice were equally divided into three groups, including the OVA group (sensitized and challenged with ovalbumin), the somatic administered group (received somatic extract along with ovalbumin sensitization), and the PBS group (sensitized and challenged with phosphate buffer saline). Bronchoalveolar lavage (BAL) fluid was collected to assess the number of cells, and lung homogenates were prepared for cytokine analysis. Histopathological analysis of the lungs was performed, and inflammatory cells and mucus were detected. Cytokine levels (IL‐4, IL‐5, IL‐10) were measured using enzyme‐linked immunosorbent assay (ELISA), and ovalbumin‐specific immunoglobulin E (IgE) levels were determined using a capture ELISA. Results: The somatic group significantly decreased regarding the lung pathological changes, including peribronchiolitis, perivasculitis, and eosino- phil influx, compared to the group treated with ovalbumin alone. These changes were accompanied by a decrease in proinflammatory cytokines IL‐4 and IL‐5 and an increase in the anti‐inflammatory cytokine IL‐10, indicating a shift toward a more balanced immune response. The number of inflammatory cells in the BAL fluid was also significantly reduced in the somatic group, indicating a decrease in inflammation. Conclusion: These preclinical findings suggest that in experimental models, T. cati somatic extract exhibits promising potential as a therapeutic agent for mitigating allergic airway inflammation. Its observed effects on immune response modulation and reduction of inflammatory cell infiltration warrant

Keywords