Autoantibody Profile of a Cohort of 54 Italian Patients with Linear IgA Bullous Dermatosis: LAD-1 Denoted as a Major Auto-antigen of the Lamina Lucida Subtype

• Main Authors: Emanuele Cozzani, Giovanni di Zenzo, Giulia Gasparini, Adele Salemme, Arianna Fay Agnoletti, Camilla Vassallo, Marzia Caproni, Emiliano Antiga, Angelo V. Marzano, Riccardo Cavalli, Corrado Ocella, Clara De Simone, Aurora Parodi
• Format: Article
• Language: English
• Published: Society for Publication of Acta Dermato-Venereologica 2020-02-01
• Series: Acta Dermato-Venereologica
• Subjects: linear iga bullous disease; humoral immune response; lad-1; bp180; bp230; diagnostic sensitivity
• Online Access: https://www.medicaljournals.se/acta/content/html/10.2340/00015555-3415
• ISSN: 0001-5555; 1651-2057

Linear IgA bullous dermatosis (LABD) is characterized by presence of multiple IgA autoantibodies, and a comparatively lesser number of IgG antibodies, directed against different hemidesmosomal antigens. The main autoantigens are LAD-1, LABD-97, BP180 and BP230, type VII collagen and laminin 332. We retrospectively studied the serology of 54 Italian patients with LABD using enzyme-linked immunosorbent assay (ELISA), immunoblotting assay, and indirect immunofluorescence on monkey oesophagus and salt-split skin. Among these, indirect immunofluorescence of salt-split skin elicits the greatest sensitivity. Sixty-three percent of the sera were observed to be positive, with a lamina lucida pattern observed in 48%, a sub-lamina densa pattern in 2% and a mixed pattern in 13% of the cases. IgA reactivity to LAD-1 on immunoblotting was found in 52% of sera, to BP180-NC16A by ELISA in 32% and to BP230 in 26%. Only 17% of patients possessed circulating IgG autoantibodies. LAD-1 was determined to be a major autoantigen of the lamina lucida subtype. Combined serological assays demonstrated a high sensitivity (82%), suggesting that this approach could support diagnosis when a biopsy is not feasible or direct immunofluorescence results are negative.