Periostin as a Biomarker in Allergic Diseases: Current Evidence and Clinical Implications

Periostin, a matricellular protein originally identified in osteoblasts and fibroblasts, has emerged as a promising biomarker in allergic diseases, particularly those driven by type 2 inflammation. Elevated periostin levels are consistently observed in conditions such as asthma, allergic rhinitis, atopic dermatitis, and eosinophilic esophagitis, reflecting its role in tissue remodeling and fibrotic responses. As research advances, periostin is gaining attention not only as a diagnostic indicator but similarly as a potential therapeutic target and biomarker for treatment response.

Understanding Periostin and Its Biological Role

Periostin (encoded by the POSTN gene) is a secreted protein that modulates extracellular matrix organization and cellular adhesion. It is upregulated in response to interleukin-4 (IL-4) and interleukin-13 (IL-13), key cytokines in type 2 immune pathways. This upregulation promotes fibroblast activation, collagen deposition, and airway or skin remodeling — hallmark features of chronic allergic inflammation.

In healthy tissues, periostin expression is low but increases significantly during tissue injury and repair. In allergic diseases, persistent type 2 inflammation drives sustained periostin production, making it a measurable surrogate for pathway activity.

Periostin in Asthma: A Well-Established Biomarker

Among allergic diseases, asthma has the most robust evidence linking periostin to disease severity and phenotype. Studies show that serum periostin levels are elevated in patients with severe, uncontrolled asthma, particularly those with eosinophilic inflammation and elevated fractional exhaled nitric oxide (FeNO).

A 2020 study published in The Journal of Allergy and Clinical Immunology found that high serum periostin levels correlated with increased airway wall thickness on CT scans and greater exacerbation frequency in adults with severe asthma. Periostin levels decreased in response to biologic therapies targeting IL-4Rα (such as dupilumab) or IL-5 (such as mepolizumab), supporting its use as a pharmacodynamic biomarker.

The U.S. Food and Drug Administration (FDA) recognized periostin’s utility by approving a serum periostin assay as an enrichment biomarker for clinical trials of dupilumab in uncontrolled asthma. This endorsement underscores its value in identifying patients most likely to benefit from type 2-targeted biologics.

Role in Allergic Rhinitis and Atopic Dermatitis

Beyond asthma, periostin is increasingly studied in upper airway and skin allergic conditions.

Allergic Rhinitis

In allergic rhinitis, nasal tissue and serum periostin levels are elevated compared to healthy controls. A 2021 study in Allergy demonstrated that periostin expression in nasal epithelium correlates with symptom severity and endoscopic scores, suggesting its potential as a non-invasive biomarker for disease activity.

Atopic Dermatitis

Periostin is markedly upregulated in lesional skin of patients with atopic dermatitis. Research published in Journal of Investigative Dermatology (2022) showed that serum periostin levels correlate with SCORAD index scores and epidermal thickness, reflecting its involvement in dermal remodeling and fibrosis. Notably, dupilumab treatment reduces both clinical symptoms and serum periostin levels in moderate-to-severe atopic dermatitis, further validating its role as a treatment-responsive biomarker.

Periostin in Eosinophilic Gastrointestinal Disorders

Emerging data suggest periostin may also serve as a biomarker in eosinophilic esophagitis (EoE), a chronic immune-mediated condition characterized by esophageal eosinophil infiltration and fibrosis. Biopsies from EoE patients show strong periostin expression in the basal layer of the epithelium and subepithelial fibrosis. Serum periostin levels are elevated in both pediatric and adult EoE cohorts and decrease with dietary elimination or topical corticosteroid therapy.

A 2023 multicenter study in Gastroenterology found that periostin, alongside eosinophil count and endoscopic features, improved diagnostic accuracy for EoE when used in a composite score. While not yet standalone diagnostic, periostin adds value in assessing fibrotic burden and treatment response.

Mechanistic Insights: Why Periostin Matters

Periostin’s significance extends beyond correlation — it actively contributes to disease pathology. By binding to integrins and extracellular matrix proteins like tenascin-C and fibronectin, periostin activates signaling pathways that promote fibroblast proliferation, epithelial-mesenchymal transition (EMT), and collagen synthesis. These processes underlie subepithelial fibrosis in asthma, dermal thickening in atopic dermatitis, and esophageal strictures in EoE.

Animal models confirm this pathogenic role: mice deficient in Postn exhibit reduced airway hyperresponsiveness and fibrosis despite eosinophilic inflammation, indicating that periostin drives structural changes independently of immune cell infiltration.

Clinical Applications and Limitations

Periostin shows promise in several clinical contexts:

• Phenotyping: Helps identify patients with active type 2 inflammation who may respond to biologics.
• Treatment Monitoring: Declining levels post-therapy suggest biological efficacy, even before symptom improvement.
• Risk Stratification: Elevated baseline periostin may predict future exacerbations or lung function decline.

However, limitations exist. Periostin is not disease-specific — elevations can occur in non-allergic fibrotic conditions such as idiopathic pulmonary fibrosis or cirrhosis. Variability in assay methods and lack of standardization across laboratories hinder widespread clinical adoption. Most evidence remains associative, and interventional trials targeting periostin directly are still preclinical.

Future Directions

Ongoing research explores periostin as a dual biomarker and therapeutic target. Monoclonal antibodies inhibiting periostin (e.g., anti-POSTN) are under investigation in animal models of asthma and fibrosis, with early results showing reduced airway remodeling without immunosuppression. Human trials are awaited.

Integrating periostin with other biomarkers — such as FeNO, eosinophil counts, and serum IgE — may improve precision phenotyping in allergic diseases. Point-of-care assays and dried blood spot testing could enhance accessibility in primary care and pediatric settings.

Key Takeaways

• Periostin is a matricellular protein upregulated by IL-4 and IL-13, serving as a biomarker of type 2 inflammation and tissue remodeling.
• It is elevated in asthma, allergic rhinitis, atopic dermatitis, and eosinophilic esophagitis, correlating with disease severity and fibrotic changes.
• Serum periostin levels decrease in response to biologics like dupilumab, supporting its use as a pharmacodynamic marker.
• The FDA has recognized periostin as an enrichment biomarker for asthma clinical trials.
• While not yet routine in clinical practice, periostin holds promise for phenotyping, monitoring treatment response, and predicting outcomes.
• Standardization of assays and further validation in diverse populations are needed before widespread adoption.

Frequently Asked Questions

What is periostin, and why is it key in allergic diseases?

Periostin is a protein involved in tissue repair and remodeling. In allergic diseases, it is overproduced due to type 2 inflammation (driven by IL-4 and IL-13), contributing to fibrosis and structural changes in airways, skin, and gastrointestinal tract. Its levels reflect disease activity and response to therapy.

Can a periostin blood test diagnose asthma or allergies?

Not currently. While elevated periostin suggests type 2-inflammatory asthma, it is not diagnostic on its own due to lack of specificity. It is best used alongside clinical evaluation, spirometry, FeNO, and eosinophil counts to phenotype severe asthma or monitor biologic therapy.

Does periostin level change with treatment?

Yes. In patients treated with dupilumab, mepolizumab, or other anti-type 2 biologics, serum periostin levels often decrease significantly, sometimes preceding clinical improvement. This makes it a useful pharmacodynamic biomarker in research and specialized clinics.

Is periostin only relevant in asthma?

No. Although best studied in asthma, periostin is also elevated in allergic rhinitis, atopic dermatitis, and eosinophilic esophagitis, where it correlates with tissue remodeling and fibrosis.

Are there risks associated with high periostin levels?

High periostin itself is not harmful but serves as a marker of underlying inflammatory and fibrotic processes. Persistent elevation may indicate ongoing tissue remodeling that could lead to long-term complications like airway fibrosis or esophageal strictures if untreated.

Conclusion

Periostin has transitioned from a novel matrix protein to a clinically relevant biomarker in allergic diseases. Its strong association with type 2 inflammation, tissue remodeling, and response to targeted therapies positions it as a valuable tool for precision medicine. While challenges in standardization and specificity remain, ongoing research continues to clarify its role. As biologic therapies expand and biomarker-guided approaches gain traction, periostin is poised to inform better diagnosis, monitoring, and treatment of allergic conditions — moving us closer to truly personalized care.