Evaluation of Eosinophil-Derived Neurotoxin Level and Asthma Severity in Isolated Asthma in Comparison to Asthma with Allergic Comorbidity

Abstract Background Asthma and associated type 2 inflammation are observed in 50–70% of patients with asthma and eosinophilic inflammation is a common feature in many asthma patients, and is associated with a higher risk of a more severe disease. Esinophilic Derived Neurotoxin (EDN) it’s useful as a clinical biomarker for the diagnosis and monitoring of asthma. High levels of EDN have been observed in patients with asthma, with higher levels measured during asthma exacerbations than in those with stable asthma. Objective To compare the association of the level of Esinophilic Derived Neurotoxin and burden of asthma in patients with asthma with Allergic comorbidities such as rhinitis and / or eczema compared to patients with asthma alone. Methods A cross sectional study included 100 adult patients, 50 patients diagnosed as asthma according to GINA guidelines and 50 patients diagnosed as asthma with allergic comorbidity such as Allergic rhinitis and/or eczema were selected from those who presented to the Allergy and clinical immunology clinics at Ain Shams University Hospitals during the period between January to July 2022. Results 50% of the studied population had bronchial asthma alone while the remaining had asthma with allergic comorbidities with most of them had asthma with allergic rhinitis and Most of the patients with allergic rhinitis had mod/severe persistent AR. 77% of total patients had positive SPT and 23% had negative SPT. Most of the patients had positive result for dust mites (Dermatophagoides farina 35% and Dermatophagoides pteronyssinus 30%) followed by pollens (mugwort 27%, rye grass 26% and tobacco 13%) and Animal dander (horse hair 15%, sheep wool 14%, cat hair 13% and dog hair 12%). The Median (IQR) of absolute eosinophil count and total IgE were higher in patients with asthma with Allergic comorbidities [0.68 (0.58 – 0.83) cells/mm3 and 155 (120 – 350) IU/ml respectively] while patients with asthma alone were 0.25 (0.12 – 0.45) cells/mm3 and 68.5 (29 – 123) IU/ml respectively. Our study showed the Median (IQR) of Serum EDN level was higher in patients with asthma with Allergic comorbidities [34 (28 – 40) ng/ml] compared to the patients with asthma alone [15(11 – 18) ng/m]. The quality of life and asthma control test was poor in asthmatic patients with allergic comorbidities compared to patients with asthma alone. Conclusion Serum EDN, Absolute Eosinophilis and total IgE can be used as a marker of T2 inflammation of air ways as their levels were higher in asthma with Allergic comorbidities. Asthma with comorbidities has more symptom burden with poorer quality of life and lower asthma control test than asthma alone; with more concern to be taken for those patients with asthma comorbidities as they have more severe asthma and poorer quality of life