SERUM thymic stromal lymphopoietin (TSLP) has emerged as a key regulator of Type 2 immune responses, yet its role in adult asthma remains incompletely understood. A recent real-world cohort study in Japan, involving 1,344 patients across 30 hospitals, explored how high serum TSLP levels correlate with clinical features and the late-onset eosinophilic asthma phenotype.
Adult Asthma and Late-Onset Eosinophilic Patterns
The study revealed that patients with TSLP-high adult asthma were generally older, had a later onset of disease, and displayed an eosinophilic, less atopic profile. They were more likely to have a higher body mass index (BMI), a history of smoking, and asthma–COPD overlap (ACO). Comorbidities such as sleep apnoea syndrome (SAS), hypertension, and heart disease were also more prevalent. Clinically, these patients experienced lower lung function, more severe asthma symptoms, and higher reliance on oral corticosteroids and biologic therapies.
Multivariable regression analyses confirmed that high TSLP levels were strongly associated with late-onset eosinophilic adult asthma, longer asthma duration, higher blood eosinophils, and comorbid conditions such as hypertension and SAS. Interestingly, high TSLP was negatively associated with pollinosis, highlighting its specificity for particular asthma subtypes. Among a panel of serum cytokines, TSLP exhibited the strongest link to late-onset eosinophilic asthma, suggesting it could serve as a biomarker for this subgroup.
Implications for Targeted Therapy
Understanding the characteristics of TSLP-high adult asthma has practical implications. Patients with elevated TSLP may represent a unique target population for specific therapies, including biologics that modulate Type 2 inflammation. Recognising this subgroup can guide personalised treatment strategies and improve disease management, particularly for those with severe or long-standing asthma and comorbid conditions.
In conclusion, high serum TSLP identifies a distinct adult asthma phenotype marked by late onset, eosinophilia, and multiple comorbidities. Targeted therapeutic approaches that consider TSLP levels could offer better symptom control and improved quality of life for affected patients.
Reference
Suzukawa M et al. High serum TSLP is characteristic of late-onset, long-duration, eosinophilic asthma. Allergy. 2025;DOI:10.1111/all.70109.
