Fatal HHV-8-Associated Hemophagocytic Syndrome in an HIV-Negative Immunocompetent Patient With Plasmablastic Variant of Multicentric Castleman Disease (Plasmablastic Microlymphoma)

Molecular Features of HHV8 Monoclonal Microlymphoma Associated with Kaposi Sarcoma and Multicentric Castleman Disease in an HIV-Negative Patient

Human herpesvirus 8 (HHV8)-associated diseases include Kaposi sarcoma (KS), multicentric Castleman disease (MCD), germinotropic lymphoproliferative disorder (GLPD), Kaposi sarcoma inflammatory cytokine syndrome (KICS), HHV8-positive diffuse large B-cell lymphoma (HHV8+ DLBCL), primary effusion lymphoma (PEL), and extra-cavitary PEL (ECPEL). We report the case of a human immunodeficiency virus (HIV)-negative male treated for cutaneous KS, who developed generalized lymphadenopathy, hepatosplenomegaly, pleural and abdominal effusions, renal insufficiency, and pancytopenia. The excised lymph node showed features of concomitant involvement by micro-KS and MCD, with aggregates of HHV8+, Epstein Barr virus (EBV)-negative, IgM+, and lambda+ plasmablasts reminiscent of microlymphoma. Molecular investigations revealed a somatically hypermutated (SHM) monoclonal rearrangement of the immunoglobulin heavy chain (IGH), accounting for 4% of the B-cell population of the lymph node. Mutational analyses identified a pathogenic variant of KMT2D and variants of unknown significance in KMT2D, FOXO1, ARID1A, and KMT2A. The patient died shortly after surgery. The histological features (HHV8+, EBV-, IgM+, Lambda+, MCD+), integrated with the molecular findings (monoclonal IGH, SHM+, KMT2D mutated), supported the diagnosis of a monoclonal HHV8+ microlymphoma, with features intermediate between an incipient HHV8+ DLBCL and an EBV-negative ECPEL highlighting the challenges in the accurate classification of HHV8-driven lymphoid proliferations.

KSHV/HHV8-mediated hematologic diseases

Kaposi sarcoma (KS) herpesvirus (KSHV), also known as human herpesvirus 8, is the causal agent of KS but is also pathogenetically related to several lymphoproliferative disorders, including primary effusion lymphoma (PEL)/extracavitary (EC) PEL, KSHV-associated multicentric Castleman disease (MCD), KSHV+ diffuse large B-cell lymphoma, and germinotropic lymphoproliferative disorder. These different KSHV-associated diseases may co-occur and may have overlapping features. KSHV, similar to Epstein-Barr virus (EBV), is a lymphotropic gammaherpesvirus that is preferentially present in abnormal lymphoid proliferations occurring in immunecompromised individuals. Notably, both KSHV and EBV can infect and transform the same B cell, which is frequently seen in KSHV+ EBV+ PEL/EC-PEL. The mechanisms by which KSHV leads to lymphoproliferative disorders is thought to be related to the expression of a few transforming viral genes that can affect cellular proliferation and survival. There are critical differences between KSHV-MCD and PEL/EC-PEL, the 2 most common KSHV-associated lymphoid proliferations, including viral associations, patterns of viral gene expression, and cellular differentiation stage reflected by the phenotype and genotype of the infected abnormal B cells. Advances in treatment have improved outcomes, but mortality rates remain high. Our deepening understanding of KSHV biology, clinical features of KSHV-associated diseases, and newer clinical interventions should lead to improved and increasingly targeted therapeutic interventions.

Disseminated Kaposi sarcoma following COVID-19 in a 61-year-old Albanian immunocompetent man: a case report and review of the literature

Background

COVID-19 and its related anti-inflammatory treatment (steroids, immunomodulators) may induce the reactivation of latent bacterial, parasitic, and viral infections. According to our knowledge, no case of disseminated HHV-8-related Kaposi sarcoma (KS) after COVID-19 and its treatment has been described so far. Only one case of cutaneous KS concurrently with COVID-19 has been previously reported.

Case presentation

We describe a case of disseminated KS in a 61-year-old immunocompetent Albanian man after hospitalization for COVID-19.

Methods for literature research

We used PubMed as biomedical database for the literature research. We selected keyword combinations including “Kaposi sarcoma,” “HHV-8,” “immunocompetent,” “COVID-19,” “SARS-CoV-2,” and “steroids.” No time or language limitation was set. Titles and abstracts of selected articles were systematically screened. Articles were included in the examination if they were published under free access through the digital library of the University of Brescia (Italy), and provided full text. Articles were excluded if the topic was beyond the aim of our study. Finally, we selected 15 articles.

Results

We describe a case of KS in COVID-19 patient and postulate that Interleukin-6 (IL-6) activity and steroid-induced immunodeficiency may play a major role in KS emergence. No published case of disseminated KS following COVID-19 in otherwise healthy individuals was found through the systematic literature review, despite the high incidence of COVID-19 in areas with medium–high prevalence of HHV-8 infection. This observation might be explained by the role of individual genetic susceptibility factors.

Conclusions

SARS-CoV-2 infection and its treatment may lead to reactivation of several latent infections, including HHV-8 and its related clinical syndrome, Kaposi sarcoma.

KSHV/HHV8-positive large B-cell lymphomas and associated diseases: a heterogeneous group of lymphoproliferative processes with significant clinicopathological overlap

In this review, we focus on the current understanding of the diagnosis of human herpesvirus 8 (HHV8)-associated lymphoproliferative disorders-a group of entities that range from hyperplastic proliferations to frank lymphomas. These diseases tend to occur in immunodeficient patients, but may occur in immunocompetent individuals as well. In recent years, we have learned of occasional cases with overlapping features among HHV8 entities, such as lesions intermediate between primary effusion lymphoma and HHV8-positive diffuse large B-cell lymphoma, not otherwise specified or cases sharing features of multicentric Castleman disease and germinotropic lymphoproliferative disorder. There is also a significant clinical overlap between these entities. It is important to have a better understanding of the biology of these lesions and to refine diagnostic criteria of these lesions, as the use of immunosuppressive agents to treat a variety of diseases, the expanded use of transplant as a therapeutic modality for a variety of cancers and organ failure patients, and the extended longevity of HIV-positive patients will likely result in an increased incidence of these lymphoproliferative processes in the future.

Human Herpes-8 virus copy to cell ratio: A diagnostic tool in primary effusion lymphoma

Primary effusion lymphoma (PEL) is a serious sequel to Human Herpes Virus 8 (HHV8) infection in the immunosuppressed host. Usually requiring a cytological diagnosis, body cavity effusions are often referred for investigation for possible PEL. Although absence of HHV8 effectively refutes this, the presence of HHV8 DNA, though indicative is not diagnostic. Referred effusion and plasma samples from 10 patients with HHV8-related pleural and pericardial effusions were submitted for quantitative investigations. HHV8 DNA and human DNA from unseparated effusion extracts have been quantified allowing estimation of virus-to-cell ratios in effusion fluid. These ratios varied widely between 0.003 and 700. Five fluids had in excess of 10⁶ HHV-8 DNA genome equivalents per ML (GEq/ML), ranging between 18 and 300 million GEq/ML. Four of these five effusions were from patients with cytologically proven PEL and had virus to cell (V:C) ratios between 100 and 700 to 1. The remaining high load effusion exhibited a ratio of 1.6 to 1 and came from a patient with extensive thoracic Kaposi's sarcoma. Five effusion fluids with low viral loads exhibited virus to cell ratios between 0.003 and 0.5. High effusion HHV8 load, though supportive of a diagnosis of PEL is less accurate than using virus to cell ratios.

HHV-8-associated haemophagocytic lymphohistiocytosis in a patient with advanced AIDS

We present a patient with advanced AIDS admitted with recurrent shock of unclear aetiology, fevers, altered mental status and refractory cytopenias. His case posed a diagnostic challenge because evaluation of septic shock in the setting of advanced AIDS requires a time-consuming work-up for broad infectious aetiologies that can delay consideration of other diagnoses, including primary or secondary haemophagocytic lymphohistiocytosis (HLH). After this patient did not improve with supportive care and empiric antimicrobials, there was concern for HLH given that he met ≥5 of the HLH consortium criteria. He underwent bone marrow biopsy, which was non-diagnostic. Empiric therapy for HLH was initiated, but unfortunately, the patient died. Autopsy revealed extensive haemophagocytosis in the spleen, bone marrow and liver, confirming the diagnosis of HLH. Postmortem, his soluble CD-25 returned 18 890 pg/mL (<1033 pg/mL), and his serum HHV-8 PCR resulted positive. The diagnosis was HLH secondary to Human Herpes Virus 8 (HHV-8) in a patient with advanced AIDS.

Recurrent Inflammatory Flares in HIV-Infected Patients: Consider Castleman Disease!

Background. Transient inflammatory flares are common in clinical care of human immunodeficiency virus (HIV)–infected patients. In-depth investigations are not performed routinely because patients often recover without therapeutic interventions, and therefore, the etiologies of these inflammatory flares frequently remain unknown. Case. We report a case of an HIV-infected patient with recurrent inflammatory flares during several years in whom diagnostic workup with a lymph node biopsy finally revealed multicentric Castleman disease (MCD). The patient was treated with etoposide and rituximab until November 2013 and achieved ongoing complete clinical remission. Conclusion. Recent effective therapeutic regimens offer an opportunity to prevent serious complications of MCD including its malignant transformation, provided that the diagnosis is established early enough. Therefore, clinicians should consider MCD in the differential diagnosis of self-limiting inflammatory flares, especially in HIV-infected patients.

An Unusual Triad of Hemophagocytic Syndrome, Lymphoma and Tuberculosis in a Non-HIV Patient

BACKGROUND Lymphoma complicated with hemophagocytic syndrome and tuberculosis has been rarely reported. The clinical and radiological presentation of these potentially fatal conditions can be easily confused and there is a potential for misdiagnosis. CASE REPORT We present a 58-year-old Hispanic female who was admitted to the hospital with dizziness and fever. Her initial admission diagnosis was severe sepsis secondary to community acquired pneumonia. She was started on intravenous antibiotics. Due to mediastinal lymphadenopathy, lymphoma was considered as a differential diagnosis for which she underwent bronchoscopy and endobronchial ultrasound-guided sampling of her mediastinal lymph nodes. Lymph node aspirate was suggestive of lymphoma. Initial cultures were negative. Her clinical course was complicated with respiratory failure, cytopenia, and rapidly progressive cervical lymphadenopathy. The patient underwent cervical lymph node excision and bone marrow biopsy. The pathology of the lymph nodes confirmed T cell lymphoma, and bone marrow revealed hemophagocytosis. The patient was started on chemotherapy but she continued to deteriorate and died on day 20 of her hospital admission. Post-mortem results of cultures from a cervical lymph node biopsy and PCR were positive for Mycobacterium tuberculosis. CONCLUSIONS We suggest an aggressive tissue diagnosis with staining for acid-fast bacilli for early diagnosis in patients presenting with hemophagocytic syndrome secondary to lymphoma as coexisting tuberculosis is a consideration. Tuberculosis re-activation should be considered in patients from an endemic region who present with lymphoma and a deteriorating clinical condition.

HHV8/KSHV-Positive Lymphoproliferative Disorders and the Spectrum of Plasmablastic and Plasma Cell Neoplasms: 2015 SH/EAHP Workshop Report-Part 3

OBJECTIVES

The 2015 Workshop of the Society for Hematopathology/European Association for Haematopathology aimed to review immunodeficiency-related lymphoproliferative disorders with plasmablastic and plasma cell differentiation.

METHODS

The workshop panel reviewed human herpes virus 8 (HHV8)/Kaposi sarcoma herpesvirus (KSHV)-associated lesions and other lesions exhibiting plasma cell differentiation, including plasmablastic proliferations with features of myeloma/plasmacytoma, plasmablastic neoplasms presenting in extranodal sites and effusion-based lymphomas, and rendered a consensus diagnosis.

RESULTS

The spectrum of HHV8/KSHV-associated proliferations ranged from multicentric Castleman disease (MCD) to MCD with plasmablastic aggregates to HHV8+ diffuse large B-cell lymphoma and germinotrophic lymphoproliferative disorder. Comparisons across effusion-based lymphomas with and without HHV8/KSHV and plasmablastic lymphomas in immunodeficient and immunocompetent patients were discussed.

CONCLUSIONS

The presence or absence of HHV8/KSHV is a defining feature in disorders associated with Castleman disease, although their differential diagnosis and recognition of progression may be challenging. Plasmablastic proliferations overlap with myeloma/plasmacytoma as well as extranodal and effusion-based lymphomas. The involvement of Epstein-Barr virus is typically variable.

Multicentric Castleman disease: Where are we now?

Multicentric Castleman disease (MCD) encompasses a spectrum of conditions that give rise to overlapping clinicopathological manifestations. The fundamental pathogenetic mechanism involves dysregulated cytokine activity that causes systemic inflammatory symptoms as well as lymphadenopathy. The histological changes in lymph nodes resemble in part the findings originally described in the unicentric forms Castleman disease, both hyaline vascular and plasma cell variants. In MCD caused by Kaposi sarcoma-associated herpesvirus/human herpesvirus-8 (KSHV/HHV8), the cytokine over activity is caused by viral products, which can also lead to atypical lymphoproliferations and potential progression to lymphoma. In cases negative for KSHV/HHV8, so-called idiopathic MCD, the hypercytokinemia can result from various mechanisms, which ultimately lead to different constellations of clinical presentations and varied pathology in lymphoid tissues. In this article, we review the evolving concepts and definitions of the various conditions under the eponym of Castleman disease, and summarize current knowledge regarding the histopathology and pathogenesis of lesions within the MCD spectrum.

Novel insights into the early histopathogenesis of immunodeficiency-associated Burkitt lymphoma: a case report of Burkitt microlymphoma arising within HIV lymphadenitis

AIMS

To report a case detailing the early histopathogenesis of Burkitt lymphoma (BL), Epstein-Barr virus (EBV) positive, in the clinical setting of HIV infection.

METHODS AND RESULTS

We describe a 57 year-old woman with newly diagnosed HIV infection who presented with unilateral localized axillary lymphadenopathy. Histopathological, immunohistochemical, and flow cytometric analyses were performed and showed EBV-positive nests of Burkitt cells, including rare nests also positive for cytomegalovirus, exclusively located within hyperplastic monocytoid B-cell areas of HIV lymphadenitis. Due to positron emission tomography/computed tomography findings of persistent localized lymphadenopathy with markedly increased fludeoxyglucose avidity a core needle biopsy was performed. Histopathological, immunohistochemical, fluorescence in situ hybridization, and flow cytometric analyses confirmed BL.

CONCLUSIONS

Early histopathogenesis of HIV-associated BL occurred as nests of EBV-positive Burkitt cells within prominent monocytoid B-cell areas in our case. The results equip the pathologist to identify a very subtle Burkitt microlymphoma which would allow for prompt and appropriate chemotherapeutic intervention and may promote research into the possible relationship between monocytoid B cells and BL.

Systemic expression of Kaposi sarcoma herpesvirus (KSHV) Vflip in endothelial cells leads to a profound proinflammatory phenotype and myeloid lineage remodeling in vivo

KSHV is the causative agent of Kaposi sarcoma (KS), a spindle-shaped endothelial cell neoplasm accompanied by an inflammatory infiltrate. To evaluate the role of KSHV vFLIP in the pathogenesis of KS, we constructed mice with inducible expression of vFLIP in endothelial cells. Abnormal cells with endothelial marker expression and fusiform appearance were observed in several tissues reminiscent of the spindle cells found in KS. Serum cytokines displayed a profound perturbation similar to that described in KSHV inflammatory cytokine syndrome (KICS), a recently described clinical condition characterized by elevated IL6 and IL10. An increased myeloid component with suppressive immune phenotype was found, which may contribute to functional changes in the microenvironment and cellular heterogeneity as observed in KS. These mice represent the first in vivo demonstration that vFLIP is capable of inducing vascular abnormalities and changes in host microenvironment with important implications for understanding the pathogenesis and treating KSHV-associated diseases.

Kaposi’s sarcoma (KS) is the most common cancer in men infected with HIV, and also among the most frequent malignancies in Sub-Equatorial Africa. KS is a tumor of endothelial cell origin that is caused by infection with a gamma-herpesvirus, called KS herpesvirus (KSHV) or human herpesvirus 8 (HHV-8). KSHV vFLIP is a viral oncoprotein expressed during latent infection. We report here the generation and characterization of mice expressing KSHV vFLIP in an inducible manner in endothelial cells. Transgenic mice showed: 1) systemic endothelial abnormalities, with the presence of fusiform cells reminiscent of the spindle cells found in KS, 2) development of a profound perturbation in serum cytokines, reminiscent of the cytokine storm characteristic of KSHV-associated cytokine syndrome (KICS), and 3) remodeling of myeloid differentiation with expansion of myeloid cells displaying a suppressive immunophenotype that potentially favors host immune evasion, angiogenesis and tumor progression. This is the first example of significant changes in myeloid differentiation, vascular abnormalities and cytokine perturbation entirely initiated by ectopic expression of a single viral gene, making this mouse model a useful system to dissect the mechanisms viruses use to manipulate the host microenvironment culminating in sabotage of immunity and development of vascular lesions.

Diverse clinicopathologic features in human herpesvirus 8-associated lymphomas lead to diagnostic problems

OBJECTIVES

Human herpesvirus 8 (HHV8)-associated lymphomas are uncommon, mainly affect men infected with the human immunodeficiency virus (HIV), and usually have a poor prognosis. We sought to characterize the HHV8+ lymphomas seen at our institution since the mid-1990s.

METHODS

We identified 15 patients with HHV8-associated lymphomas and evaluated their clinical and pathologic features.

RESULTS

Diagnoses included primary effusion lymphoma (PEL) (n = 2), extracavitary PEL (n = 8), intravascular large B-cell lymphoma (n = 1), HHV8+ plasmablastic microlymphoma (n = 3), and germinotropic lymphoproliferative disorder (GLD) (n = 1). The case of GLD progressed to a high-grade HHV8+ Epstein-Barr virus-positive lymphoma, an evolution that has not been previously reported. Four patients were HIV-(three from an HHV8-endemic area). Potentially misleading pathologic features in our series of extracavitary PEL included classic Hodgkin lymphoma-like features, lymph node sinus involvement, and T-cell antigen expression.

CONCLUSIONS

HHV8-associated lymphomas can be clinically and pathologically heterogeneous, with features that may lead to misdiagnosis as other types of lymphoma.

Bone Marrow Involvement in Multicentric Castleman Disease in a HIV Negative Patient

There are few reports on the bone marrow involvement in multicentric Castleman disease in human immunodeficiency virus (HIV) negative patients, mostly the characteristic morphologic findings within the bone marrow are reported in HIV-positive patients. Here we describe bone marrow involvement in a HIV-negative patient with multicentric Castleman disease.

Hemophagocytic lymphohistiocytosis: an update on diagnosis and pathogenesis

Hemophagocytic lymphohistiocytosis (HLH) is a frequently fatal and likely underdiagnosed disease involving a final common pathway of hypercytokinemia, which can result in end-organ damage and death. Although an early diagnosis is crucial to decrease mortality, the definitive diagnosis is often challenging because of the lack of specificity of currently accepted diagnostic criteria and the absence of confirmatory gold standards. Because of the wide range of laboratory assays involved in the diagnosis of HLH, practicing pathologists from a broad spectrum of clinical specialties need to be aware of the disease so that they may appropriately flag results and convey them to their clinical counterparts. Our article summarizes these new advances in the diagnosis of HLH and includes a review of clinical findings, updated understanding of the pathogenesis, and promising new testing methods.

Human herpesvirus 8-related Castleman disease in the absence of HIV infection

BACKGROUND

Castleman disease (CD) in the context of human immunodeficiency virus (HIV) infection is well described. It is almost always multicentric (MCD) and linked to human herpesvirus 8 (HHV-8). There are limited published data surrounding HHV-8-related CD among HIV-negative patients.

METHODS

From January 1995 through June 2012, we identified in a single center 18 HIV-seronegative patients with HHV-8-related CD. We report on their clinical, pathological, and laboratory features.

RESULTS

All cases were multicentric. Patients were aged 42-83 years and were referred with a relapsing remitting syndrome of fever (94%), constitutional symptoms (100%), peripheral lymphadenopathy (100%), splenomegaly (72%), hepatomegaly (50%), and edema (28%). Kaposi sarcoma was observed in 9 cases. Anemia and serum markers of inflammation were present in all cases. Polymerase chain reaction for HHV-8 DNA was positive on blood samples in all cases, whereas only 12 of 16 patients tested had positive HHV-8 serology at diagnosis. All cases showed the classic histological features of MCD, and LANA-1 immunostaining identified HHV-8-infected plasmablasts in 16 of 16 tested cases. Reactive hemophagocytic syndrome (44%), autoimmune hemolytic anemia (33%), and lymphoma (22%) were the commonest associated complications. Remission was obtained with etoposide in 13 of 15 cases. Rituximab allowed prolonged remission off therapy in 10 cases. Death occurred in 3 patients not treated with rituximab. These features were similar to those described in HIV-positive HHV-8-related MCD. Comparison between these 18 cases and 12 HIV-negative HHV-8-unrelated MCD cases showed marked discrepancies.

CONCLUSIONS

HHV-8-associated MCD may be considered as a single clinicopathological entity regardless of HIV status.

HHV-8-related hemophagocytic lymphohistiocytosis in a boy with XLP phenotype

We report a 2.5-year-old boy with an X-linked lymphoproliferative disease (XLP) phenotype who presented with human herpes virus-8 (HHV-8)-related hemophagocytic lymphohistiocytosis (HLH). XLP is a rare primary immunodeficiency characterized by extreme susceptibility to herpes viruses, mainly Epstein-Barr virus (EBV). Approximately 60% of patients with XLP present with fulminant mononucleosis associated with HLH, whereas remaining patients present with hypogammaglobulinemia or lymphoproliferative disease. Most commonly, one of the XLP phenotypes appears after exposure to EBV, but at least 12% of affected individuals developed symptoms without an evidence of EBV infection. Rarely, patients with XLP may present with central nervous system vasculitis or aplastic anemia. HHV-8 is lymphotrophic and it is associated with lymphoproliferative disorders and Kaposi sarcoma in immunodeficient hosts. Kaposi sarcoma rarely occurs in children with well-defined primary immunodeficiency. Also, HHV-8-related HLH was previously reported in 2 siblings with a perforin gene deficiency. Recently, it became evident that besides EBV, other viruses may trigger the symptoms in XLP. We report for the first time HHV-8-related HLH in EBV-negative pediatric patient with an XLP phenotype.

Kaposi sarcoma herpes virus-associated hemophagocytic syndrome complicated by multicentric castleman disease and kaposi sarcoma in a HIV-negative immunocompetent patient: an autopsy case

Kaposi sarcoma herpes virus (KSHV), also known as human herpesvirus-8, plays an important role in the pathogenesis of Kaposi sarcoma (KS), multicentric Castleman disease (MCD) of the plasma cell type, and primary effusion lymphoma. KSHV is rarely associated with the hemophagocytic syndrome (HPS), but when it does occur, it most occurs in immunocompromised patients. We report herein an unusual case of KSHV-associated HPS in an immunocompetent patient. A previously healthy 62-yr-old male was referred for evaluation of leukocytopenia and multiple lymphadenopathies. After a lymph node biopsy, he was diagnosed with MCD of the plasma cell type. KSHV DNA was detected in the lymph node tissue by polymerase chain reaction. Following a short-term response of the leukocytopenia to prednisolone, mental change, left side weakness, fever, thrombocytopenia, hemolytic anemia, and renal failure developed. Despite intravenous immunoglobulin therapy and plasmapheresis, he expired. The lymph nodes were infiltrated by hemophagocytic histiocytes in the sinuses. Pulmonary nodules and gastric erosions were shown to be KS. KSHV DNA was detected in the stomach, lung, and liver. This is the first case of multiple KSHV associated diseases including MCD and KS with KSHV-associated hemophagocytic syndrome in an HIV-negative, non-transplant, immunocompetent patient.

The successful treatment of haemophagocytic syndrome in patients with human immunodeficiency virus-associated multi-centric Castleman's disease

Both virus-associated haemophagocytic syndrome (HPS) and human immunodeficiency virus-associated multi-centric Castleman's disease (HIV-MCD) induced by human herpesvirus-8 (HHV-8) are extremely rare. We therefore wished to investigate their occurrence together, and establish the degree of cytokine activation present. From a prospective cohort of individuals with HIV-MCD, we investigated the incidence and outcomes of HPS and measured 15 inflammatory cytokines and the plasma HHV-8 viral loads before and during follow-up. Of 44 patients with HIV-MCD with an incidence of 4.3/10,000 patient years, four individuals (9%) were diagnosed with HPS. All are in remission (range 6-28 months) following splenectomy, etoposide and rituximab-based therapy. Plasma HHV-8 levels were raised markedly at presentation (median 3,840,000 copies/ml). Histological samples from spleen, splenic hilar lymph nodes and bone marrow demonstrated increased phagocytosis by histiocytes and presence of HHV-8-infected plasmablasts outside the follicles. Surprisingly, many known inflammatory plasma cytokines were not elevated, although interleukin (IL)-8 and interferon-gamma were increased in all cases and IL-6 levels were raised in three of four patients. HPS in the setting of HIV-MCD is common and treatment can be successful provided the diagnosis is made appropriately. Systemic activation of cytokines was limited, suggesting that immunosuppressive therapy with steroids is not indicated in HHV-8-driven HPS.

Immunophenotypic analysis of the Kaposi sarcoma herpesvirus (KSHV; HHV-8)-infected B cells in HIV+ multicentric Castleman disease (MCD)

AIMS

Kaposi sarcoma herpesvirus (KSHV) is aetiologically related to Kaposi sarcoma, classical and extracavitary primary effusion lymphoma (PEL; EC-PEL) and multicentric Castleman disease (MCD), entities preferentially occurring in HIV-infected individuals. Characterization of HIV-associated PELs/EC-PELs suggests that the KSHV-infected malignant cells originate from a pre-terminal stage of B-cell differentiation. However, only limited phenotypic studies have been performed on HIV+ MCD, including for PR domain containing 1 with zinc finger domain/B lymphocyte-induced maturation protein 1 (PRDM1/BLIMP1), a key regulator of terminal B-cell differentiation. The aim was to characterize KSHV-infected cells in 17 cases of HIV+ MCD.

METHODS AND RESULTS

Double immunohistochemistry and immunohistochemistry-in situ hybridization were used to characterize the KSHV-infected cells in MCD; the results were compared with the phenotypic profiles of 39 PELs/EC-PELs and seven PEL cell lines. Whereas the immunophenotype of KSHV-infected cells in MCD and malignant KSHV+ PEL cells was similar (PAX5, Bcl-6-; PRDM1/BLIMP1, IRF4/MUM1+; Ki67+), the MCD KSHV-infected cells differed, as they expressed OCT2, cytoplasmic lambda immunoglobulin; variably expressed CD27; lacked CD138; and were Epstein-Barr virus negative.

CONCLUSIONS

Although both PEL and MCD originate from KSHV-infected pre-terminally differentiated B cells, these findings, with previously reported genetic studies, indicate HIV+ MCD may arise from extrafollicular B cells, whereas PELs may originate from cells that have traversed the germinal centre.

Viral studies in burkitt lymphoma: association with Epstein-Barr virus but not HHV-8

Burkitt lymphoma (BL) is a highly aggressive non-Hodgkin lymphoma, composed of a monomorphic population of medium-sized B cells with a high proliferation rate and a consistent MYC translocation. Epstein-Barr virus (EBV) has been associated with BL with different frequencies depending on the clinical variant. Kaposi sarcoma-associated herpesvirus, or human herpesvirus 8 (HHV-8), infects a wide range of normal cells, having a well-established role in the pathogenesis of various neoplasms, including Kaposi sarcoma, primary effusion lymphoma, multicentric Castleman disease (MCD) and MCD-associated plasmablastic lymphoma. In secondary immunodeficiencies, such as HIV-1 infection and organ transplantation, HHV-8 is considered an opportunistic pathogen linked to the development of lymphomas in patients with AIDS and HIV + patients. We studied the association of EBV and HHV-8 by immunohistochemical analysis, in situ hybridization, and polymerase chain reaction in a large number of well-characterized BLs. EBV was present in 45.0% of all BL cases with higher incidence in the pediatric group; most cases were EBV type A. We found no association of BL with HHV-8 in EBV + BL or in EBV-cases, including the HIV + BL group.

Understanding organ dysfunction in hemophagocytic lymphohistiocytosis

OBJECTIVE

This review aims to help critical care clinicians maintain a high level of suspicion regarding the diagnosis of Hemophagocytic Histiolymphocytosis (HLH). It describes the clinical and laboratory features of HLH, outlines its pathophysiology and reviews the most frequent etiologies related to HLH. Prognostic factors and therapeutic options are also reported.

DATA SOURCES

Review of the literature.

RESULTS

The diagnosis of HLH relies on the association of clinical abnormalities and hemophagocytosis in bone marrow, spleen, or lymph node specimens. Liver, pulmonary, renal, cardiac and skin involvement may occur at various degrees possibly leading to multiple organ failure. Three main etiologies can be found, namely infections, lymphoproliferative diseases, or connective tissue diseases. Immune deficiency is often retrieved. Mortality can be as high as 50%. Although clinically mimicking severe sepsis, HLH has a distinct pathophysiology on which specific therapy is based. Early diagnosis and treatment is mandatory to increase the chances of survival.

CONCLUSION

The comprehensive management of severe HLH requires the involvement of a multidisciplinary team in order to determine the best therapeutic strategy and to identify the underlying cause.

Infections associated with haemophagocytic syndrome

Haemophagocytic syndrome or haemophagocytic lymphohistiocytosis is a rare disease that is often fatal despite treatment. Haemophagocytic syndrome is caused by a dysregulation in natural killer T-cell function, resulting in activation and proliferation of lymphocytes or histiocytes with uncontrolled haemophagocytosis and cytokine overproduction. The syndrome is characterised by fever, hepatosplenomegaly, cytopenias, liver dysfunction, and hyperferritinaemia. Haemophagocytic syndrome can be either primary, with a genetic aetiology, or secondary, associated with malignancies, autoimmune diseases, or infections. Infections associated with haemophagocytic syndrome are most frequently caused by viruses, particularly Epstein-Barr virus (EBV). We present a case of EBV-associated haemophagocytic syndrome in a young adult with no known immunosuppression. We briefly review haemophagocytic syndrome and then discuss its associated infections, particularly EBV and other herpes viruses, HIV, influenza, parvovirus, and hepatitis viruses, as well as bacterial, fungal, and parasitic organisms.

Kaposi sarcoma-associated herpesvirus/human herpesvirus 8 and lymphoproliferative disorders

Kaposi sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV8), is a recent addition to the list of human viruses that are directly associated with lymphoproliferative disorders. KSHV was first shown to be involved in multicentric Castleman disease and primary effusion lymphoma (PEL). Subsequently, the virus was identified in solid lymphomas, often of extranodal sites, with morphological and immunophenotypic characteristics similar to those of PEL, and in other lymphoproliferative disorders with heterogeneous clinicopathological presentations. The recent advances in our understanding of the histology, immunophenotype and pathogenesis of these KSHV-associated lymphoproliferative disorders are reviewed.

HHV-8+, EBV+ Multicentric Plasmablastic Microlymphoma in an HIV+ Man: The Spectrum of HHV-8+ Lymphoproliferative Disorders Expands

Human herpesvirus-8 (HHV-8) is associated with several distinct lymphoproliferative disorders: primary effusion lymphoma, multicentric Castleman disease (MCD), MCD-associated plasmablastic lymphoma and HHV-8+, Epstein-Barr virus (EBV)+ germinotropic lymphoproliferative disorder. We report the case of a human immunodeficiency virus (HIV)+ male with fever, generalized lymphadenopathy, and splenomegaly. Two peripheral lymph nodes were excised and showed features of MCD and a prominent proliferation of HHV-8+, EBV+, CD20, CD138, MUM1+, lambda dim+, Ig heavy chain plasmablasts and immunoblasts replacing some follicles. Subsequently, a splenectomy and biopsy of retroperitoneal lymph nodes were performed; the retroperitoneal and splenic hilar lymph nodes showed changes similar to those in the peripheral lymph nodes while the markedly enlarged spleen showed replacement of occasional white pulp by the HHV-8+, EBV+ large cells. The histologic features and coinfection by EBV and HHV-8 suggested a diagnosis of HHV-8+ germinotropic lymphoproliferative disorder. However, the occurrence in an HIV+ individual, the background of MCD, the widespread anatomic distribution and the aggressive clinical course tended to exclude germinotropic lymphoproliferative disorder, and to favor multifocal plasmablastic microlymphoma. The patient died shortly after surgery; postmortem examination showed progression to overt lymphoma. The marrow showed extensive hemophagocytosis, consistent with development of a hemophagocytic syndrome. This unique case has clinical features compatible with a MCD-associated plasmablastic lymphoproliferative disorder, with pathologic features intermediate between HHV-8+ plasmablastic microlymphoma, and HHV-8+ germinotropic lymphoproliferative disorder, although in contrast to both of these, in our case, light chain expression was dim and heavy chain was not detected.

Absence of human herpesvirus-8 in pulmonary inflammatory myofibroblastic tumor: immunohistochemical and molecular analysis of 20 cases

Inflammatory myofibroblastic tumors are uncommon lesions composed of spindled myofibroblasts within a variable background of collagen and inflammatory cells. Although the true nature of these lesions is not fully elucidated, identification of consistent cytogenetic alterations in the anaplastic lymphoma kinase (ALK) gene suggests that they may be neoplastic. A small number of inflammatory myofibroblastic tumors have been reported to harbor human herpesvirus-8 (HHV-8), implicating the virus in its pathogenesis. In this study, 20 cases of pulmonary inflammatory myofibroblastic tumor were analyzed for the presence of HHV-8 with immunohistochemical and molecular methods. In all cases, antibodies to the latent nuclear antigen of the virus were applied. Four open reading frames (ORFs), including ORFs K2, 16, 26, and 72, were targeted utilizing real-time polymerase chain reaction (PCR). The cohort included 9 men and 11 women with a mean age of 37 years (range, 1-81). Microscopically, the tumors were composed of cytologically bland spindle cells with myofibroblastic differentiation. On immunohistochemical studies, 20% of cases (4/20) demonstrated diffuse cytoplasmic positivity with ALK. Immunohistochemical staining for the latent nuclear protein of the virus was negative in all cases (0/20). All tumors (100%, 20/20) tested with real-time PCR were negative for all four ORFs, whereas 100% (10/10) of positive control Kaposi sarcoma cases were positive. Her2 gene expression was present in all (20/20) inflammatory myofibroblastic tumors confirming the presence of amplifiable deoxyribonucleic acid in the tissue lysate. This study documents the absence of HHV-8 in pulmonary inflammatory myofibroblastic tumors, suggesting that further investigation is required to clarify the pathogenesis of this lesion.

Plasmablastic cytomorphologic features in plasma cell neoplasms in immunocompetent patients are significantly associated with EBV

Multiple myeloma (MM) is rarely associated with Epstein-Barr virus (EBV) irrespective of HIV status, in contrast with its morphologic mimic, plasmablastic lymphoma, which occurs mainly in immunocompromised patients with frequent EBV association. Among 58 consecutive immunocompetent patients, we found plasmablastic cytomorphologic features in 2 of 4 with plasmacytomas and 14 (26%) of 54 with MM. Of the tumors, 4 (7%; 1 plasmacytoma and 3 MMs) were EBV-encoded RNA (EBER)-positive with plasmablastic cytomorphologic features in 3. The patient with plasmacytoma was disease free for 75 months, and the remaining 3 patients with MM died at 15, 74, and 97 months, respectively; the median survival of patients with EBER- MM was 12 months. EBV+ tumors were associated with plasmablastic cytomorphologic features and high labeling indices. Rare EBER+ plasmablastic plasma cell tumors exist in immunocompetent patients. These tumors may have been driven by EBV to gain the plasmablastic cytomorphologic features and high proliferation fraction. A large cohort study is needed to clarify the prognostic impact of EBV on immunocompetent patients with MM.

Plasmablastic microlymphoma occurring in human herpesvirus 8 (HHV-8)-positive multicentric Castleman's disease and featuring a follicular growth pattern

Plasmablastic microlymphoma (PML) is defined as the accumulation of monotypic but polyclonal plasmablasts in lymphoid tissues involved in human herpes virus 8 (HHV-8)-positive multicentric Castleman's disease (MCD). So far, the nature of this very rare condition remains poorly determined. In this study, we describe a human immunodeficiency virus (HIV)-seropositive patient who developed a PML in the setting of HHV-8-positive MCD. In contrast to the cases previously reported, most of the plasmablasts in our patient were localized within the germinal center (GC) of lymphoid follicles. These plasmablasts expressed the multiple myeloma-1/interferon regulatory factor-4 (MUM1/IRF4) protein as well as IgMlambda in a monotypic fashion. They did not show any immunoreactivity with antibodies directed against Pax-5, CD20, CD79a, CD10, CD30, CD23, CD138, epithelial membrane antigen (EMA) or BCL-6. These cells exhibited a high proliferation rate, expressed the HHV-8 latent nuclear antigen-1, and secreted the HHV-8 viral homologue of human interleukin-6. Polymerase chain reaction analysis did not demonstrate any clonal rearrangement of the genes coding for the heavy chain of the immunoglobulin. Moreover, no Epstein-Barr virus (EBV) RNA transcript could be found, using in situ hybridization. The present case illustrates that PML may arise within the GC of lymphoid follicles in the absence of EBV coinfection. In our opinion, PML occurring in MCD likely represents a variant of HHV-8-positive MCD in which lytic HHV-8 replication is particularly prominent, due to a local or systemic immune imbalance.

Bone Marrow Findings in Multicentric Castleman Disease in HIV-negative Patients

Because bone marrow histology in multicentric Castleman disease in human immunodeficiency virus-negative patients is not well reported, we investigated sequential bone marrow biopsies of 3 affected human immunodeficiency virus-negative patients, of which one was human herpes virus 8 (HHV8)-positive. The histologic evaluation of the bone marrow revealed lymphoid follicles with regressed germinal centers in 1 patient. Another patient showed tumorlike but bland polyclonal plasmacytosis with large perivascular plasma cell clusters. The HHV8-positive patient revealed interstitial HHV8-positive cells accompanied by a mild plasmacytosis. The atypical lymphoid follicles could be regarded as a bone marrow manifestation of multicentric Castleman disease, whereas the plasmacytosis most likely is the result of excess interleukin 6 production. The presence of HHV8-positive cells within the bone marrow may indicate the dissemination of the virus in a compromised immune system.

Fatal hemophagocytic syndrome related to active human herpesvirus-8/Kaposi sarcoma-associated herpesvirus infection in human immunodeficiency virus-negative, non-transplant patients without related malignancies

Hemophagocytic syndrome (HS) may occur as a consequence of herpes viral infections. Human herpesvirus 8 (HHV-8)/Kaposi sarcoma-associated herpesvirus has so far been recognized as a trigger of HS only in immunosuppressed subjects or in patients with Kaposi sarcoma and/or HHV-8-related lymphoproliferative diseases. We report two Italian human immunodeficiency virus (HIV)-negative elderly men who developed an HS with a rapidly fatal course, following treatment with corticosteroids for autoimmune hemolytic anemia. An overwhelming active infection with HHV-8 was unequivocally documented by molecular and immunohistochemical methods, in the absence of HHV-8-related tumors. The occurrence of HHV-8-associated HS, although rare, may be considered, even out of the HIV or the transplantation settings, at least in areas endemic for HHV-8 infection.