The use of BIOCHIP mosaics in diagnostics of bullous pemphigoid: Evaluation and comparison to conventional multistep procedures

Background: Bullous pemphigoid (BP) is an autoimmune blistering disease associated with autoantibodies against BP180 and/or BP230 antigens. The immunoassays available for serological diagnostics include indirect immunofluorescence (IIF) on monkey esophagus (ME), salt-split skin (SSS), and enzyme-linked immunosorbent assay (ELISA) for BP180-NC16a and BP230. Only a few studies validated innovative BIOCHIP mosaic, but none compared agreement between BIOCHIP substrates with conventional methods separately. Methods: We evaluated the agreement between BIOCHIP and conventional methods and assessed sensitivity and specificity in BP diagnosis. The study comprised 51 BP patients and 39 controls. Results: Analysis showed very good agreement between BIOCHIP-SSS vs classic IIF-SSS (0.933, P < 0.001) and for BIOCHIP-BP180-NC16a vs ELISA-BP180-NC16a (0.933, P < 0.001). A good strength of agreement between BIOCHIP-ME vs classic IIF-ME was observed (0.694, P < 0.001) similar to BIOCHIP-BP230 vs ELISA-BP230 (0.793, P < 0.001). BIOCHIP-ME sensitivity was 51.0%, whereas IIF-ME was 76.5%. Epidermal reaction on BIOCHIP-SSS was found in 94.1% of BP patients and in all patients on IIF-SSS (sensitivity 100%). BIOCHIP-BP180-NC16a sensitivity was lower than in ELISA-BP180-NC16a (76.5% vs 82.4%). BP230 sensitivity of both methods was similar (45.1% vs 43.1%). The specificity for all antigens was 100%. Conclusion: BIOCHIP mosaic is a useful method presenting satisfactory agreement with conventional immunoassays.