Virome capture sequencing does not identify active viral infection in unicentric and idiopathic multicentric Castleman disease.

Christopher S Nabel,Stephen Sameroff,Alexander Fosså,Yasuharu Sato,Federico Valdivieso,Michael D Feldman,Katie Stone,Dustin Shilling,Mitsuhiro Kawano,W Ian Lipkin,David C Fajgenbaum,Amy Chadburn,Jason R Ruth,Daisy Alapat,Signe Spetalen,Frits Van Rhee

doi:10.1371/journal.pone.0218660

Abstract

Castleman disease (CD) describes a spectrum of heterogeneous disorders defined by characteristic lymph node histopathology. Enlarged lymph nodes demonstrating CD histopathology can occur in isolation (unicentric CD; UCD) sometimes accompanied by mild symptoms, or at multiple sites (multicentric CD, MCD) with systemic inflammation and cytokine-driven multi-organ dysfunction. The discovery that Kaposi sarcoma herpesvirus/human herpesvirus (HHV)-8 drives MCD in a subset of patients has led to the hypotheses that UCD and MCD patients with negative HHV-8 testing by conventional methods may represent false negatives, or that these cases are driven by another virus, known or unknown. To investigate these hypotheses, the virome capture sequencing for vertebrate viruses (VirCapSeq-VERT) platform was employed to detect RNA transcripts from known and novel viruses in fresh frozen lymph node tissue from CD patients (12 UCD, 11 HHV-8-negative MCD [idiopathic MCD; iMCD], and two HHV-8-positive MCD) and related diseases (three T cell lymphoma and three Hodgkin lymphoma). This assay detected HHV-8 in both HHV-8-positive cases; however, HHV-8 was not found in clinically HHV-8-negative iMCD or UCD cases. Additionally, no novel viruses were discovered, and no single known virus was detected with apparent association to HHV-8-negative CD cases. Herpesviridae family members, notably including Epstein-Barr virus (EBV), were detected in 7 out of 12 UCD and 5 of 11 iMCD cases with apparent correlations with markers of disease severity in iMCD. Analysis of a separate cohort of archival formalin-fixed, paraffin-embedded lymph node tissue by In situ hybridization revealed significantly fewer EBV-positive cells in UCD and iMCD compared to tissue from HHV-8-positive MCD and EBV-associated lymphoproliferative disorder. In an additional cohort, quantitative testing for EBV by PCR in peripheral blood during disease flare did not detect systemic EBV viremia, suggesting detection lymph node tissue is due to occult, local reactivation in UCD and iMCD. This study confirms that HHV-8 is not present in UCD and iMCD patients. Further, it fails to establish a clear association between any single virus, novel or known, and CD in HHV-8-negative cases. Given that distinct forms of CD exist with viral and non-viral etiological drivers, CD should be considered a group of distinct and separate diseases with heterogeneous causes worthy of further study.

Highlights

Castleman disease (CD) describes a group of heterogeneous and poorly-understood lymphoproliferative disorders that share characteristic lymph node histopathology, including atrophic or hyperplastic germinal centers, prominent follicular dendritic cells, hypervascularization, polyclonal lymphoproliferation, and/or polytypic plasmacytosis
The disease was first classified as unicentric CD (UCD)—featuring a solitary enlarged lymph node with CD histopathology—or multicentric CD (MCD)—in patients with enlarged lymph nodes located in multiple body regions
There is an additional cohort of MCD patients that do not test positive for human herpesvirus (HHV)-8 infection using current clinical or histopathological assays and are referred to as idiopathic MCD because the etiology is unknown [11,12]

Summary

Introduction

Castleman disease (CD) describes a group of heterogeneous and poorly-understood lymphoproliferative disorders that share characteristic lymph node histopathology, including atrophic or hyperplastic germinal centers, prominent follicular dendritic cells, hypervascularization, polyclonal lymphoproliferation, and/or polytypic plasmacytosis. The disease was first classified as unicentric CD (UCD)—featuring a solitary enlarged lymph node with CD histopathology—or multicentric CD (MCD)—in patients with enlarged lymph nodes located in multiple body regions. Most UCD patients do not experience systemic symptoms and are successfully treated by removal of the enlarged node. HHV-8-positive MCD patients often respond to rituximab and correction of the underlying causes of immunosuppression. There is an additional cohort of MCD patients that do not test positive for HHV-8 infection using current clinical or histopathological assays and are referred to as idiopathic MCD (iMCD) because the etiology is unknown [11,12]. A subset of patients with iMCD may have a severe clinical presentation featuring thrombocytopenia, anasarca, myelofibrosis, renal dysfunction and organomegaly, referred to as TAFRO syndrome[13,14]

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Conclusion