Direct Immunofluorescence of IgG on Formalin-Fixed Paraffin-Embedded Tissue by Heat-Induced Antigen Retrieval as a Sensitive Method for the Diagnosis of Pemphigus

Abstract

Wenzhe Zhao,1 Haiqin Zhu,1 Xiaoqing Zhao,1 Xinyi Wu,1 Fei Sun,1 Meng Pan,1,* Shengru Zhou2,* 1Department of Dermatology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, People’s Republic of China; 2Department of Dermatology, Dushu Lake Hospital Affiliated to Soochow University (Medical Center of Soochow University, Suzhou Dushu Lake Hospital), Suzhou, 215123, People’s Republic of China*These authors contributed equally to this workCorrespondence: Shengru Zhou, Department of Dermatology, Dushu Lake Hospital Affiliated to Soochow University, (Medical Center of Soochow University, Suzhou Dushu Lake Hospital), No. 9, Chongwen Road, Suzhou, 215123, People’s Republic of China, Tel [phone], Fax [phone], Email [email protected]: Direct immunofluorescence (DIF) on frozen sections (DIF-F) plays a key role in the identification and differential diagnosis of bullous dermatoses, which are a group of critical autoimmune diseases that include pemphigus, bullous pemphigoid (BP), and epidermolysis bullosa acquisita (EBA). However, this technique requires specialized laboratory equipment conditions, sample acquisition and sample preservation. In this study, the application value of DIF on paraffin-embedded tissue sections (DIF-P) detecting IgG using heat-induced antigen retrieval (HIAR) in the diagnosis of bullous dermatosis was explored.Patients and Methods: Samples from 12 patients with pemphigus vulgaris (PV), 10 patients with pemphigus foliaceus (PF), 17 patients with BP, and 4 patients with EBA were retrospectively studied for DIF-P IgG detection. Formalin-fixed, paraffin-embedded tissue (FFPE) was used, and the antigen retrieval method used in the experiment was HIAR. All patients were diagnosed with the autoimmune bullous disease (AIBD) based on clinical presentation, histopathology, DIF-F, and enzyme-linked immunosorbent assay (ELISA).Results: Intercellular staining for IgG in the epidermis was successful in paraffin-embedded tissue sections in 11 of 12 PV samples and in all 10 PF samples. IgG at the basement membrane zone (BMZ) was not detected by immunofluorescent staining in 17 BP samples and 4 EBA samples.Conclusion: The detection of IgG by DIF-P using HIAR can be used for the diagnosis of pemphigus as an alternative method to DIF-F.Keywords: pemphigus, bullous dermatoses, direct immunofluorescence, IgG, paraffin-embedded section, heat-induced antigen retrieval

Keywords

• pemphigus
• bullous dermatoses
• direct immunofluorescence
• igg
• paraffin-embedded section
• heat-induced antigen retrieval