{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,30]],"date-time":"2026-10-30T23:48:10Z","timestamp":1793404090014,"version":"4.5.0"},"reference-count":12,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2024,12,19]],"date-time":"2024-12-19T00:00:00Z","timestamp":1734566400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Dermatopathology"],"abstract":"<jats:p>The diagnostic utility of immunohistochemistry on paraffin-embedded sections in bullous disorders is useful when frozen tissue is not available. In pemphigus vulgaris and pemphigus foliaceus, an intercellular lace-like staining pattern of IgG4 on lesional tissue by immunohistochemistry has been described, with a comparable sensitivity and specificity to direct immunofluorescence on perilesional tissue. This study aimed to evaluate the staining pattern of IgG4 in non-immunobullous disorders to highlight the potential pitfalls when using this stain. In this study, we conducted a retrospective review of our institution\u2019s database of non-immunobullous disorders where immunohistochemistry of IgG4 was performed to rule out pemphigus. We identified 27 cases where IgG4 immunohistochemistry was performed and observed intercellular IgG4 staining in some cases of Grover disease, bullous impetigo, irritated dermal hypersensitivity reaction, acantholytic actinic keratosis, and graft versus host disease. Our results indicate that the interpretation of IgG4 staining by immunohistochemistry in cutaneous acantholytic disorders should be approached with caution. Confirmation on cryosections with direct immunofluorescence study results is important in these settings.<\/jats:p>","DOI":"10.3390\/dermatopathology11040041","type":"journal-article","created":{"date-parts":[[2024,12,19]],"date-time":"2024-12-19T08:04:14Z","timestamp":1734595454000},"page":"377-382","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Potential Pitfalls of IgG4 Immunohistochemical Staining on Lesional Tissue in Cutaneous Acantholytic Disorders"],"prefix":"10.3390","volume":"11","author":[{"given":"Carla","family":"Stephan","sequence":"first","affiliation":[{"name":"Department of Pathology and Laboratory Medicine, Weill Cornell Medical Center, NewYork-Presbyterian, New York, NY 10065, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Linglei","family":"Ma","sequence":"additional","affiliation":[{"name":"Department of Pathology, University of Virginia, Charlottesville, VA 22903, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,12,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1402","DOI":"10.5858\/arpa.2011-0425-OA","article-title":"Immunohistochemistry for immunoglobulin G4 on paraffin sections for the diagnosis of pemphigus","volume":"136","author":"Zhang","year":"2012","journal-title":"Arch. Pathol. Lab. Med."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2050313X211072982","DOI":"10.1177\/2050313X211072982","article-title":"Utility of IgG4 immunohistochemistry detection in pemphigus diagnosis","volume":"10","year":"2022","journal-title":"SAGE Open Med. Case Rep."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"337","DOI":"10.1046\/j.1365-2133.2000.03659.x","article-title":"The distribution of pemphigus vulgaris-IgG subclasses and their reactivity with desmoglein 3 and 1 in pemphigus patients and their first-degree relatives","volume":"143","author":"Kricheli","year":"2000","journal-title":"Br. J. Dermatol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1016\/S0923-1811(00)00158-4","article-title":"Predominant IgG4 subclass in autoantibodies of pemphigus vulgaris and foliaceus","volume":"26","author":"Futei","year":"2001","journal-title":"J. Dermatol. Sci."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"575","DOI":"10.1016\/j.jaad.2018.02.021","article-title":"Diagnosis and management of pemphigus: Recommendations of an international panel of experts","volume":"82","author":"Murrell","year":"2020","journal-title":"J. Am. Acad. Dermatol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"358","DOI":"10.1111\/cup.14176","article-title":"Impact of adding an IgG4 conjugate to routine direct immunofluorescence testing for subepithelial and intraepithelial autoimmune blistering disorders","volume":"49","author":"Lehman","year":"2022","journal-title":"J. Cutan. Pathol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"183","DOI":"10.5114\/ceji.2021.107028","article-title":"Conceptualization and validation of an innovative direct immunofluorescence technique utilizing fluorescein conjugate against IgG + IgG4 for routinely diagnosing autoimmune bullous dermatoses","volume":"46","author":"Kaczmarek","year":"2021","journal-title":"Cent. Eur. J. Immunol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"338","DOI":"10.4103\/ijd.IJD_87_18","article-title":"Immunohistochemistry for Immunoglobulin G4 in the Diagnosis of Pemphigus","volume":"64","author":"Heidarpour","year":"2019","journal-title":"Indian J. Dermatol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1578","DOI":"10.47191\/ijmscrs\/v3-i8-24","article-title":"Use of IgG4 Immunohistochemistry as a Diagnostic Tool for Pemphigus","volume":"3","author":"Shaji","year":"2023","journal-title":"Int. J. Med. Sci. Clin. Res. Stud."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"114","DOI":"10.1111\/apm.12643","article-title":"Can immunohistochemistry replace immunofluorescence in diagnosis of skin bullous diseases?","volume":"125","year":"2017","journal-title":"APMIS"},{"key":"ref_11","unstructured":"Aslanova, M., Yarrarapu, S.N.S., Syed, H.A., and Zito, P.M. (2024). IgA Pemphigus, StatPearls."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"86","DOI":"10.3390\/dermatopathology10010012","article-title":"Post-Pemphigus Acanthomata Presenting as an Isolated, Hyperkeratotic Plaque","volume":"10","author":"Pandya","year":"2023","journal-title":"Dermatopathology"}],"container-title":["Dermatopathology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2296-3529\/11\/4\/41\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T16:55:27Z","timestamp":1760115327000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2296-3529\/11\/4\/41"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,12,19]]},"references-count":12,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2024,12]]}},"alternative-id":["dermatopathology11040041"],"URL":"https:\/\/doi.org\/10.3390\/dermatopathology11040041","relation":{},"ISSN":["2296-3529"],"issn-type":[{"value":"2296-3529","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,12,19]]}}}