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Expression of Filaggrin in Skin Biopsies: Role in Maintenance of Symptoms Among Brazilian Patients with Moderate-to-Severe Atopic Dermatitis
Sunday, March 6, 2016
South Exhibit Hall H (Convention Center)
Karine Boufleur, MD, Renata Nahas Cardili Sr., Janaina M. L. Melo, MD, Adriana S Moreno, PhD, Ana Maria Roselino, Edson Soares, Luisa Karla P. Arruda, MD PhD FAAAAI
Rationale: Atopic dermatitis (AD) is a chronic disease characterized by epidermal barrier failure and immune-mediated inflammation. Loss-of-function mutations within the filaggrin (FLG) gene have been associated with AD in populations from Northern Europe and Asia. We aimed to investigate FLG expression in skin lesions of Brazilian patients with moderate-to-severe AD.

Methods: Skin biopsies of active AD lesions from 20 adult patients, aged 19- 75 years-old (65% female), were obtained. All patients were in treatment with emollients, topical corticosteroids and/or calcineurin inhibitors, and 9/20 patients were taking oral cyclosporine A.  SCORAD averaged 44.5 (range 11-75), and no withdrawal of medications was attempted prior to biopsies due to severity of symptoms.  Normal skin was available from 20 individuals who underwent plastic surgery, with no history of allergic diseases. Immunohistochemical analysis for FLG expression was performed using mouse monoclonal anti-filaggrin antibody SPM181(ABCAM).

Results: Total IgE levels were elevated in all patients (geometric mean 4,224UI/mL, range 145- 63,000IU/mL).  IgE to mite>3,5 KU/L was found in 18/18 patients who underwent this evaluation. FLG expression in AD patients was as strong as that observed in normal controls, with no difference on a blind evaluation.

Conclusions: Our results showed that patients with moderate-to-severe AD who remain symptomatic despite anti-inflammatory and immunosuppressant therapy presented FLG expression comparable to control individuals. The results suggested that among patients from southeast Brazil, FLG expression may not be a determinant factor for maintenance of clinical disease.  Further studies investigating the presence of FLG loss-of-function mutations will be necessary for better interpretation of these results.