{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,6]],"date-time":"2026-04-06T04:14:12Z","timestamp":1775448852035,"version":"3.50.1"},"reference-count":34,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,4,3]],"date-time":"2026-04-03T00:00:00Z","timestamp":1775174400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Hematology Reports"],"abstract":"<jats:p>Background\/Objectives: Multicentric Castleman Disease (MCD) is a rare lymphoproliferative disorder that can mimic IgG4-related disease (IgG4-RD), particularly in patients presenting with elevated serum IgG4. Accurate diagnosis is crucial given differing treatments and prognoses. Case Presentation: We describe a 76-year-old male with fever, lymphadenopathy, and elevated inflammatory markers. Labs revealed an elevated IgG4 of 133 mg\/dL and total IgG of 1410 mg\/dL, yielding an IgG4\/IgG ratio of 9.43%. Lymph node biopsy showed nodular sclerosing classical Hodgkin lymphoma, for which he received five cycles of A + AVD. Persistent symptoms, elevated IL-6, and HHV8 viremia prompted repeat biopsy, which demonstrated HHV8-positive MCD. Rituximab was initiated, which resulted in clinical and radiographic resolution. Methods: We performed a systematic review of the English-language literature from 2000 to 2025, identifying 23 studies that contained MCD cases with individual-level serum IgG4 and IgG data. A total of 36 unique cases were included. Results: The mean IgG4\/IgG ratio was 14.61%, which is substantially lower than ratios typically seen in IgG4-RD. To our knowledge, our case is the only reported instance of HHV8-associated MCD with elevated IgG4. Conclusions: A mildly elevated IgG4\/IgG ratio may favor the diagnosis of MCD over IgG4-RD. Serum IgG4 and total IgG should be considered when suspecting Castleman Disease.<\/jats:p>","DOI":"10.3390\/hematolrep18020026","type":"journal-article","created":{"date-parts":[[2026,4,6]],"date-time":"2026-04-06T02:06:21Z","timestamp":1775441181000},"page":"26","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["The Utility of IgG4\/IgG Ratio in the Diagnosis of Multicentric Castleman Disease: A Case Report of HHV8+ Castleman Disease in a Patient with Classical Hodgkin\u2019s Lymphoma"],"prefix":"10.3390","volume":"18","author":[{"given":"Adam","family":"Hagele","sequence":"first","affiliation":[{"name":"Department of Medicine, Loma Linda University Medical Center, Loma Linda, CA 92350, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Philip","family":"Kay","sequence":"additional","affiliation":[{"name":"Independent Researcher, Orinda, CA 94563, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kevin","family":"Nishino","sequence":"additional","affiliation":[{"name":"Department of Medicine, Loma Linda University Medical Center, Loma Linda, CA 92350, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Akhil","family":"Mehta","sequence":"additional","affiliation":[{"name":"Houston Methodist Dr. Mary and Ron Neal Cancer Center, Houston, TX 77030, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yan","family":"Liu","sequence":"additional","affiliation":[{"name":"Department of Pathology, Loma Linda University Medical Center, Loma Linda, CA 92350, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Anthony L.","family":"Nguyen","sequence":"additional","affiliation":[{"name":"Division of Hematology\/Oncology, Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Eric","family":"Lau","sequence":"additional","affiliation":[{"name":"Department of Hematology and Oncology, Palo Alto Medical Foundation, Palo Alto, CA 94301, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,4,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"6691","DOI":"10.18632\/oncotarget.24068","article-title":"Idiopathic multicentric Castleman\u2019s disease: A clinicopathologic study in comparison with IgG4-related disease","volume":"9","author":"Otani","year":"2018","journal-title":"Oncotarget"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"331","DOI":"10.1056\/NEJMoa1708984","article-title":"Brentuximab vedotin with chemotherapy for stage III or IV Hodgkin\u2019s lymphoma","volume":"378","author":"Connors","year":"2018","journal-title":"N. 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