Evaluation of Serum Levels of Osteopontin and IgG Anti-Osteopontin Autoantibodies As Potential Biomarkers of Immune Activation in Patients with Allergic Diseases
Sunday, March 6, 2016
South Exhibit Hall H (Convention Center)
Elisa Villa, MD, Rosalba Minisini, Olaf Rötzschke, Kia Joo Puan, Boris Buenbrazo San Luis, Anand Andiappan, Nausicaa Clemente, Luca Gigliotti, Elena Boggio, Annalisa Chiocchetti, Umberto Dianzani, Mario Pirisi
Rationale: Osteopontin (OPN) is a pleomorphic cytokine known to influence a wide range of immune cells; high OPN and IgG anti-OPN autoantibodies (AutoAbs) levels are associated with an increased risk of autoimmune lymphoproliferative syndrome, multiple sclerosis and systemic lupus erythematosus. We aimed to verify if serum levels of OPN and IgG anti-OPN AutoAbs may qualify as biomarkers of an activated immune response also in allergic patients.

Methods: Serum OPN levels were measured by ELISA test (Human Osteopontin Duoset, R&D Systems, for OPN detection; “in-house” kit for anti-OPN AutoAbs). A series of 121 adult patients affected by asthma, allergic rhinitis (AR), Hymenoptera venom allergy (HVA), food allergy (FA), allergic contact dermatitis (ACD) and IgE-mediated hypersensitivity to beta-lactams (IEHB) was studied. 116 healthy subjects served as controls.

Results: OPN serum levels were significantly higher in cases in comparison to controls (p=0.0010 by the Mann-Whitney test). Statistically higher levels were found in asthma (p=0.0269) and FA (p=0.046) groups in comparison to controls. Prevalence and titers of serum IgG anti-OPN AutoAbs were significantly lower in cases with respect to controls (p<0.0001). Lower levels of AutoAbs versus controls were found in patients with HVA (p<0.0001), AR (p=0.0009), ACD (p=0.0011) and asthma (p=0.0013), but not in FA group (p=0.0575). Patients with IEHB presented heterogeneous results for OPN and anti-OPN AutoAbs.

Conclusions: Serum OPN levels may represent a novel, potentially useful biomarker for allergic asthma and, interestingly, for food allergy.