Q21. Which following statement about multicentric Castleman disease (MCD) is WRONG?¶

(A) HHV-8 infection is one of the etiological driver in MCD.
(B) HHV-8 can replicate in lymph node plasmablasts and transcribe the viral homolog of interleukin-6.
(C) Diagnostic criteria of idiopathic MCD includes exclusion of underlying autoimmune disease or malignant lymphoproliferative neoplasm.
(D) Idiopathic MCD-TAFRO describes an indolent clinical subtype involving thrombocytosis, ascites, reticulin fibrosis, hepatic dysfunction, and organomegaly.
(E) Anti-IL-6 directed therapy is suggested as first line therapy for idiopathic MCD.

點此顯示正解

(D) Idiopathic MCD-TAFRO describes an indolent clinical subtype involving thrombocytosis, ascites, reticulin fibrosis, hepatic dysfunction, and organomegaly.

詳解¶

Why Option (D) is WRONG¶

Option (D) is incorrect on two counts: it describes iMCD-TAFRO as "indolent" when it is actually aggressive, and it states "thrombocytosis" when the correct feature is thrombocytopenia.

iMCD-TAFRO is an aggressive, not indolent, clinical subtype. The literature consistently describes iMCD-TAFRO as having "rapid onset cytokine storm with severe inflammation, anasarca, thrombocytopenia, and small volume lymphadenopathy, similar to hemophagocytic lymphohistiocytosis or sepsis"¹⁶. It is characterized as "the most severe cytokine storm among all iMCD patients"[^8] and "often has more severe clinical symptomatology and worse outcome" compared to other iMCD subtypes[^8].

The TAFRO acronym stands for Thrombocytopenia (not thrombocytosis). The correct acronym is: Thrombocytopenia, Anasarca, Fever, Reticulin fibrosis/renal dysfunction, Organomegaly¹[^7][8]. The option also incorrectly states "hepatic dysfunction" when the "R" actually refers to renal dysfunction (though reticulin fibrosis is also included).

Why the Other Options are CORRECT¶

(A) is correct: HHV-8 (human herpesvirus-8, also known as Kaposi sarcoma herpesvirus/KSHV) is indeed an etiologic driver of MCD. HHV-8 infection causes approximately 50% of MCD cases (HHV-8-associated MCD)²³[^7]. The remaining cases are HHV-8-negative/idiopathic MCD (iMCD)⁴.

(B) is correct: HHV-8 replicates in lymph node plasmablasts and produces viral IL-6 (vIL-6), the viral homolog of human IL-6, which drives the hypercytokinemia characteristic of HHV-8-associated MCD²⁵.

(C) is correct: The international, evidence-based consensus diagnostic criteria for iMCD published by Fajgenbaum et al. (Blood 2017) explicitly require exclusion of infectious, malignant, and autoimmune disorders that can mimic iMCD⁴. This includes exclusion of autoimmune diseases (such as rheumatoid arthritis, systemic lupus erythematosus, adult-onset Still's disease) and malignant lymphoproliferative neoplasms (such as lymphoma and POEMS syndrome)¹⁴.

(E) is correct: Anti-IL-6 directed therapy (specifically siltuximab, an IL-6 antagonist) is recommended as first-line therapy for all subtypes of iMCD according to the Castleman Disease Collaborative Network (CDCN) consensus treatment guidelines¹⁶[^7]. Siltuximab became the first FDA-approved treatment for iMCD in 2014 and consensus guidelines recommend it as front-line therapy³[^7].

詳解 · 中文翻譯¶

為什麼選項 (D) 是錯誤的¶

選項 (D) 在兩個方面不正確：當它實際上是攻擊性的時，它描述 iMCD-TAFRO 為「惰性的」，當正確特徵是血小板減少症時，它敘述「血小板增多症」。

iMCD-TAFRO 是攻擊性而不是惰性的臨床亞型。 文獻持續將 iMCD-TAFRO 描述為具有「快速發作細胞因子風暴伴嚴重炎症、anasarca、血小板減少症和小體積淋巴結病變，類似於噬血細胞淋巴組織細胞增生症或敗血症」¹⁶。它被特徵化為「所有 iMCD 患者中最嚴重的細胞因子風暴」[^8]和「常常具有比其他 iMCD 亞型更嚴重的臨床症狀和更差預後」[^8]。

TAFRO 首字母縮略詞代表血小板減少症（而不是血小板增多症）。 正確的首字母縮略詞是：Thrombocytopenia、Anasarca、Fever、Reticulin fibrosis/renal dysfunction、Organomegaly¹[^7][8]。選項也不正確地敘述「肝功能障礙」當「R」實際上指腎功能障礙（儘管網狀纖維母細胞纖維化也包括）。

為什麼其他選項是正確的¶

(A) 正確： HHV-8（人皰疹病毒 8、也稱為 Kaposi 肉瘤皰疹病毒/KSHV）確實是 MCD 的病因驅動因素。HHV-8 感染導致約 50% 的 MCD 病例（HHV-8 相關 MCD）²³[^7]。其餘病例為 HHV-8 陰性/特發性 MCD（iMCD）⁴。

(B) 正確： HHV-8 在淋巴節漿細胞母細胞中複製並產生病毒 IL-6（vIL-6），人 IL-6 的病毒同源物，驅動 HHV-8 相關 MCD 特徵的高細胞因子血症²⁵。

(C) 正確： Fajgenbaum 等人（Blood 2017）發表的 iMCD 國際、基於證據的共識診斷標準明確需要排除可模擬 iMCD 的傳染性、惡性和自身免疫疾病⁴。這包括排除自身免疫病（例如類風濕關節炎、系統性紅斑狼瘡、成人發作 Still 病）和惡性淋巴增生性腫瘤（例如淋巴瘤和 POEMS 綜合症）¹⁴。

(E) 正確： 根據 Castleman 病協作網絡（CDCN）共識治療指南，抗 IL-6 指導療法（具體而言，siltuximab，IL-6 拮抗劑）推薦作為所有 iMCD 亞型的一線療法¹⁶[^7]。Siltuximab 在 2014 年成為第一個 FDA 批准的 iMCD 治療方法，共識指南推薦其作為前線療法³[^7]。

參考文獻 (AMA)¶

Chen LYC, Zhang L, Fajgenbaum DC. Expert Perspective: Diagnosis and Treatment of Castleman Disease. Arthritis & Rheumatology (Hoboken, N.J.). 2026;78(1):12-25. doi:10.1002/art.43269. PMID:40457814. ↩↩↩↩↩↩↩↩
Zhang L, Ge JY, Li SY, et al. Idiopathic Multicentric Castleman Disease-Tafro: A Potentially Curable Disease?. American Journal of Hematology. 2026;101(3):447-455. doi:10.1002/ajh.70199. PMID:41518092. ↩↩↩↩
Fajgenbaum DC. Novel Insights and Therapeutic Approaches in Idiopathic Multicentric Castleman Disease. Blood. 2018;132(22):2323-2330. doi:10.1182/blood-2018-05-848671. PMID:30487129. ↩↩↩↩
Carbone A, Borok M, Damania B, et al. Castleman Disease. Nature Reviews. Disease Primers. 2021;7(1):84. doi:10.1038/s41572-021-00317-7. PMID:34824298. ↩↩↩↩↩↩
Fajgenbaum DC, Uldrick TS, Bagg A, et al. International, Evidence-Based Consensus Diagnostic Criteria for HHV-8-negative/idiopathic Multicentric Castleman Disease. Blood. 2017;129(12):1646-1657. doi:10.1182/blood-2016-10-746933. PMID:28087540. ↩↩
Fajgenbaum DC, van Rhee F, Nabel CS. HHV-8-negative, Idiopathic Multicentric Castleman Disease: Novel Insights Into Biology, Pathogenesis, and Therapy. Blood. 2014;123(19):2924-33. doi:10.1182/blood-2013-12-545087. PMID:24622327. ↩↩↩↩