Chemiluminescence Immunoassay and Enzyme-Linked Immunosorbent Assay in the Diagnosis of Autoimmune Bullous Diseases: A Comparative Study

Introduction: Autoimmune bullous diseases (AIBDs), such as bullous pemphigoid (BP), pemphigus vulgaris (PV), and pemphigus foliaceus (PF), are characterized by autoantibodies against desmogleins (DSG1, DSG3) or hemidesmosomal proteins (BP180, BP230). While enzyme-linked immunosorbent assay (ELISA) is widely used for autoantibody detection, the newly developed chemiluminescent immunoassay (CLIA) offers advantages including a broader dynamic range and higher automation. This study aimed to evaluate CLIA and ELISA for detecting four key antibodies in both serum and blister fluid samples. Materials and Methods A total of 255 serum samples (92 controls, 84 BP, 69 PV, and 10 PF) and 91 blister fluid samples (44 controls, 43 BP, and 4 PV) were collected. All samples were tested for anti-BP180, BP230, DSG1, DSG3 antibodies using both ELISA and CLIA. Results Using established laboratory cut-offs for serum samples, both ELISA and CLIA demonstrated good diagnostic performance for anti-BP180, DSG1, and DSG3 antibodies detection, with accuracy values approaching or exceeding 0.85. Overall, ELISA exhibited higher clinical sensitivity, while CLIA showed enhanced specificity. ROC analysis indicated acceptable to excellent diagnostic value for both serum and blister fluid samples, with CLIA generally achieving higher AUC values. Moreover, the two assays showed excellent concordance (> 90%) in serum testing. Spearman's correlation and linear regression analyses further revealed moderate to strong correlations for all serum antibodies. In blister fluid, however, strong correlations between the two methods were observed only for anti-BP180 and BP230, whereas correlations for anti-DSG1 and DSG3 were weak. Conclusion CLIA demonstrated strong agreement and comparable accuracy with ELISA in the serodiagnosis of AIBDs. Furthermore, blister fluid shows potential as a supplementary sample type.