Abstract: 【Abstract】 Objective To prepare human epidermal extracts by thermal separation, and to evaluate the value of epidermal extract-based Western blot analysis in the diagnosis of bullous pemphigoid （BP）. Methods Human epidermal extracts were prepared by thermal separation from circumcised foreskins of healthy males. Serum samples were obtained from 22 inpatients with BP and 25 inpatients without BP in Hospital for Skin Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College between January 2015 and August 2017. These serum samples were subjected to Western blot analysis with epidermal extracts as substrates, as well as to BP180-NC16A enzyme-linked immunosorbent assay （ELISA）. Statistical analysis was carried out using chi-square test and Fisher′s exact test with the SPSS22.0 software. Results The sensitivities of epidermal extract-based Western blot analysis and BP180-NC16A ELISA in the diagnosis of BP were 86.36% （95％CI: 64.03%－96.41％） and 95.45% （95％CI: 75.11%－99.76％） respectively （χ2 = 1.10, P = 0.294）, and the specificities were 100% （95％ CI: 83.42%－100％） and 92% （95％ CI: 75.11%－99.76％） respectively （χ2 = 20.8, P = 0.149）. Epidermal extract-based Western blot analysis in the 22 patients with BP showed a protein band with relative molecular mass （RMM） of 230 000 in 4 patients, a protein band with RMM of 180 000 in 18, a protein band with RMM of 120 000 in 1, and a protein band with RMM of 97 000 in 1. The BP180-NC16A ELISA showed that the antibody titers were more than 50 U/ml in the BP patients with protein bands of RMM of 180 000. Conclusions The epidermal extract-based Western blot analysis mainly showed the protein band with RMM of 180 000 in the patients with BP. The sensitivity of the epidermal extract-based Western blot analysis was lower than that of the BP180-NC16A ELISA, and the epidermal extract-based Western blot analysis tends to be negative when the titer of the autoantibody is low.

Key words: Pemphigoid, bullous, Blotting, Western, Epidermis, Autoantigens, Enzyme?linked immunosorbent assay, Thermal separation, Human epidermal extract