Comparison of C3d immunohistochemical staining to enzyme-linked immunosorbent assay and immunofluorescence for diagnosis of bullous pemphigoid

J Am Acad Dermatol. 2020 Jul;83(1):172-178. doi: 10.1016/j.jaad.2020.02.020. Epub 2020 Feb 14.


Background: Bullous pemphigoid (BP), the most common autoimmune blistering disease, may be diagnostically challenging. Direct immunofluorescence (DIF), indirect immunofluorescence (IIF), enzyme-linked immunosorbent assay (ELISA), and recently, C3d immunohistochemistry (IHC), are used as adjuncts to diagnosis.

Objective: To compare C3d IHC to DIF, IIF, and ELISA testing in BP diagnosis.

Methods: C3d IHC was performed on skin biopsy specimens from 51 patients (27 with BP and 24 with other blistering diseases) and compared to DIF and IIF, with anti-BP180 or anti-BP230 ELISA results used as the gold standard.

Results: We found C3d IHC, DIF, and IIF had similar sensitivity (74.1%, 63.1%, and 70.4%), specificity (95.8%, 100%, and 100%), positive predictive value (95.2%, 100%, and 100%), and negative predictive value (76.7%, 70.6%, and 75%) for BP. Cases with positive C3d IHC, DIF, and IIF had significantly higher anti-BP180 and anti-BP230 by ELISA than cases with negative testing (P < .0001). False-negative IIF results were associated with lower BP230 compared with true-positive results (P = .03).

Limitations: This was a single-center, retrospective study.

Conclusion: Our study compared C3d IHC to DIF and IIF in BP diagnosis, demonstrating C3d IHC on fixed tissue provides similar diagnostic utility to immunofluorescence and ELISA.

Keywords: C3d immunohistochemistry; ELISA; bullous pemphigoid; diagnosis; direct immunofluorescence; indirect immunofluorescence.

Publication types

  • Comparative Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • CD3 Complex / analysis*
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Fluorescent Antibody Technique
  • Humans
  • Immunohistochemistry
  • Male
  • Middle Aged
  • Pemphigoid, Bullous / diagnosis*
  • Pemphigoid, Bullous / immunology
  • Retrospective Studies


  • CD3 Complex