Survival rates and prognostic factors of Epstein-Barr virus-associated hydroa vacciniforme and hypersensitivity to mosquito bites

Fifth Edition of the World Health Classification of Tumors of the Hematopoietic and Lymphoid Tissues: Mature T-cell, NK-cell and Stroma-Derived Neoplasms of Lymphoid Tissues

This review focuses on mature T-cell, NK cell, and stroma-derived neoplasms in the 5th edition of the World Health Organization (WHO) classification of hematolymphoid tumors (WHO-HEM5), including changes from the revised 4th edition (WHO-HEM4R). Overall, information has expanded, primarily due to advancements in genomic understanding. The updated classification adopts a hierarchical format. The updated classification relies on a multidisciplinary approach, incorporating insights from a diverse group of pathologists, clinicians, and geneticists. Indolent NK-cell lymphoproliferative disorder of the gastrointestinal tract, EBV-positive nodal T- and NK-cell lymphoma, and several stroma-derived neoplasms of lymphoid tissues have been newly introduced or included. The review also provides guidance on how the WHO-HEM5 can be applied in routine clinical practice.

A comparison of the International Consensus and 5th WHO classifications of T-cell lymphomas and histiocytic/dendritic cell tumours

Since the publication in 2017 of the revised 4th Edition of the World Health Organization (WHO) classification of haematolymphoid tumours, here referred to as WHO-HAEM4, significant clinicopathological, immunophenotypic and molecular advances have been made in the field of lymphomas, contributing to refining the diagnostic criteria of several diseases, upgrading entities previously defined as provisional and identifying new entities. This process has resulted in two recent classification proposals of lymphoid neoplasms: the International Consensus Classification (ICC) and the 5th edition of the WHO classification (WHO-HAEM5). In this paper, we review and compare the two classifications in terms of diagnostic criteria and entity definition, focusing on T-cell lymphomas and histiocytic/dendritic cell tumours. Moreover, we update the genetic data of the various pathological entities. The main goal is to provide a tool to facilitate the work of the pathologists, haematologists and researchers involved in the diagnosis and treatment of these haematological malignancies.

A Comparison of the Fifth World Health Organization and the International Consensus Classifications of Mature T-Cell Lymphomas

Peripheral T-cell lymphomas (PTCLs) are a rare subset of non-Hodgkin lymphomas that often carry significant difficulty in diagnosis and classification because of their rarity and biological complexity. Previous editions of the World Health Organization (WHO) classifications of hemopoietic neoplasms in 2001, 2008, and 2017 aimed to standardize hemopoietic neoplasm diagnosis in general. Since then, crucial clinico-pathological, immunophenotypic, and recent molecular discoveries have been made in the field of lymphomas, contributing to refining diagnostic criteria of several diseases, upgrading entities previously defined as provisional, and identifying new entities. In 2022, two different models were proposed to classify hematolymphoid neoplasms: the 5th edition of the WHO classification (WHO-HAEM5) and the International Consensus Classification (ICC). Of note, a common nosography is mandatory to ensure progress in health science and ensure the basis for a real precision medicine. In this article, the authors summarized the main differences with the previous fourth WHO edition and reviewed the main discrepancies between the two newest classifications, as far as PTCLs are concerned.

Clinicoprognostic Study of Hydroa Vacciniforme-like Lymphoproliferative Diseases: A Systematic Review

BACKGROUND

Limited clinicopathological and prognostic data are available on hydroa vacciniforme (HV)-like lymphoproliferative diseases (HVLPD).

METHODS

This systematic review searched HVLPD reports in Medline via PubMed, Embase, Cochrane, and CINAHL databases in October 2020.

RESULTS

A total of 393 patients (65 classic HV, 328 severe HV/HV-like T-cell lymphoma [HVLL]) were analyzed. Among severe HV/HVLL cases, 56.0% were Asians, whereas 3.1% were Caucasians. Facial edema, hypersensitivity to mosquito bites, the onset of skin lesion, and percentage of severe HV/HVLL differed significantly by race. Progression to systemic lymphoma was confirmed in 9.4% of HVLPD patients. Death occurred in 39.7% patients with severe HV/HVLL. Facial edema was the only risk factor associated with progression and overall survival. Mortality risk was higher in Latin Americans than in Asians and Caucasians. CD4/CD8 double-negativity was significantly associated with the worst prognosis and increased mortality.

CONCLUSION

HVLPD is a heterogeneous entity with variable clinicopathological features associated with genetic predispositions.

Coexpression of natural killer cell antigens by T-cell large granular lymphocytes in hydroa vacciniforme lymphoproliferative disorder and the involvement of Vδ1 + epithelial-type γδT cells

Hydroa vacciniforme lymphoproliferative disorder (HV-LPD) is a cutaneous variant of chronic active Epstein-Barr virus disease. We examined the coexpression of T- and natural killer (NK)-cell antigens in five patients with classic HV (cHV) and five with systemic HV (sHV). T-cell receptor (TCR) repertoire analysis was performed with high‑throughput sequencing. All five cHV patients had increased γδT cells (> 5%), whereas five sHV patients showed γδT- and αβT-cell dominance in two patients each, and a mixture of abnormal γδT and αβT cells in one. Circulating CD3 + T cells expressed CD16/CD56 at 7.8-42.3% and 1.1-9.7% in sHV and cHV, respectively. The percentage of CD16/CD56 + T cells was higher in the large granular lymphocyte or atypical T-cell fractions in sHV, but no TCR Vα24 invariant chain characteristic of NKT cells was detected. Considerable numbers of CD3 + cells expressing CD56 were observed in sHV skin infiltrates. Of the circulating γδT cells tested, TCR Vδ1 + cells characteristic of the epithelial type of γδT cells were dominant in two sHV cases. Thus, atypical αβT and γδT cells in HV-LPD can express NK-cell antigens, such as CD16 and CD56, and Vδ1 + epithelial-type γδT cells are a major cell type in some HV-LPD cases.

Clinical and Pathological Features of Hydroa Vacciniforme-Like Lymphoproliferative Disorder Along with Risk Factors Indicating Poor Prognosis

Purpose

To examine the clinical and pathological features, laboratory markers, therapeutic options and risk factors indicating poor prognosis of hydroa vacciniforme-like lymphoproliferative disorder (HVLPD).

Patients and Methods

Seven patients with HVLPD had their clinical and pathological data collected. Immunohistochemical staining, Epstein-Barr virus-encoded RNA (EBER) in situ hybridization experiments, T-cell receptor (TCR) gene rearrangement, RT-PCR tests and the Elisa assay were carried out.

Results

The main clinical manifestations were papulovesicular lesions and ulcers on the face, neck, or trunk. Five cases had systemic symptoms. Three of the deceased patients had significant facial edema, deep body necrosis, and ulceration. The pathological results demonstrated that lymphocytes infiltrated blood vessels and sweat glands in addition to the dermis and subcutaneous tissues. All patients tested positive for CD3 and EBER. Six cases tested positive for TCRβF1, but none tested positive for TCRδ. TCRγ monoclonal rearrangement, strongly positive expression of TIA-1 and a Ki67 proliferation index of 40% occurred in 3 fatal cases. When compared to the survival group, the plasma EBV DNA in the deceased group was considerably higher (P<0.05). IFN-γ and TNF-α cytokine levels in patients were higher than in the control group, particularly in the deceased group (P<0.05). The skin lesions on all patients recovered quickly underwent conservative care. Nonetheless, 3 patients passed away as the disease progressed in its latter stages.

Conclusion

In our cases, the main infiltrating cells were T cells and the dominant lymphocyte subclass was αβT cells. A significant increase in lgE level, plasma EBV DNA, IFN-γ, and TNF-α cytokine levels, decreased hemoglobin level, strongly positive expression of TIA-1, high Ki67 proliferation index, and positive TCR gene rearrangement are all indicators of a poor prognosis.

The International Consensus Classification of Mature Lymphoid Neoplasms: a report from the Clinical Advisory Committee

Since the publication of the Revised European-American Classification of Lymphoid Neoplasms in 1994, subsequent updates of the classification of lymphoid neoplasms have been generated through iterative international efforts to achieve broad consensus among hematopathologists, geneticists, molecular scientists, and clinicians. Significant progress has recently been made in the characterization of malignancies of the immune system, with many new insights provided by genomic studies. They have led to this proposal. We have followed the same process that was successfully used for the third and fourth editions of the World Health Organization Classification of Hematologic Neoplasms. The definition, recommended studies, and criteria for the diagnosis of many entities have been extensively refined. Some categories considered provisional have now been upgraded to definite entities. Terminology for some diseases has been revised to adapt nomenclature to the current knowledge of their biology, but these modifications have been restricted to well-justified situations. Major findings from recent genomic studies have impacted the conceptual framework and diagnostic criteria for many disease entities. These changes will have an impact on optimal clinical management. The conclusions of this work are summarized in this report as the proposed International Consensus Classification of mature lymphoid, histiocytic, and dendritic cell tumors.

Case report: Cellular therapy for hydroa vacciniforme-like lymphoproliferative disorder in pediatric common variable immunodeficiency with chronic active Epstein-Barr virus infection

Hydroa vacciniforme-like lymphoproliferative disorder (HV-LPD) is a cutaneous form of chronic active Epstein-Barrvirus (EBV) infection, which can develop into the extremely rare systemic lymphoma. Patients with Inborn errors of immunity (IEI), such as common variable immunodeficiency (CVID), are at higher risk of developing a severe course of infections especially viral and malignancies than the general population. The aim of the study was to present complex diagnostic and therapeutic management of HV-LPD. The clinical diagnosis was confirmed at the histological and molecular level with next generation sequencing. HV-LPD was diagnosed in a patient with CVID and chronic active Epstein–Barr virus (CAEBV) infection. The patient was refractory to CHOP chemotherapy and immunosuppressive treatment in combination with antiviral drugs (prednisone, bortezomib, gancyclovir). The third-party donor EBV-specific cytotoxic T cells (EBV-CTL, tabelecleucel) were used, which stabilised the disease course. Finally, matched unrelated donor hematopoietic cell transplantation (MUD-HCT) was performed followed by another cycle of EBV-CTL.

The 5th edition of the World Health Organization Classification of Haematolymphoid Tumours: Lymphoid Neoplasms

We herein present an overview of the upcoming 5^th edition of the World Health Organization Classification of Haematolymphoid Tumours focussing on lymphoid neoplasms. Myeloid and histiocytic neoplasms will be presented in a separate accompanying article. Besides listing the entities of the classification, we highlight and explain changes from the revised 4^th edition. These include reorganization of entities by a hierarchical system as is adopted throughout the 5^th edition of the WHO classification of tumours of all organ systems, modification of nomenclature for some entities, revision of diagnostic criteria or subtypes, deletion of certain entities, and introduction of new entities, as well as inclusion of tumour-like lesions, mesenchymal lesions specific to lymph node and spleen, and germline predisposition syndromes associated with the lymphoid neoplasms.

Hydroa vacciniforme-like lymphoproliferative disorder: A retrospective study on clinicopathological characteristics of 32 cases

The clinicopathological features of 32 patients (17 females and 15 males) with a median age of 8 years (range, 1.5-21 years) from Southwestern China diagnosed with hydroa vacciniforme-like lymphoproliferative disorder (HVLPD) were reviewed. At presentation, 6 patients showed only skin lesions, while 26 patients showed both skin lesions and systemic symptoms, including fever, lymphadenopathy and hepatosplenomegaly. As the disease progressed, systemic symptoms occurred in all patients. Follow-up data of 29 patients showed that 14 patients were still alive with disease with a median follow-up time of 22 months (range 3.6-71 months), and 15 patients died within a median follow-up of 6 months (range 0-60 months).

New insights into Epstein‑Barr virus‑associated tumors: Exosomes (Review)

Epstein-Barr virus (EBV) is endemic worldwide and is associated with a number of human tumors. EBV-associated tumors have unique mechanisms of tumorigenesis. EBV encodes multiple oncogenic molecules that can be loaded into exosomes released by EBV⁺ tumor cells to mediate intercellular communication. Moreover, different EBV⁺ tumor cells secrete exosomes that act on various target cells with various biological functions. In addition to oncogenicity, EBV⁺ exosomes have potential immunosuppressive effects. Investigating EBV⁺ exosomes could identify the role of EBV in tumorigenesis and progression. The present review summarized advances in studies focusing on exosomes and the functions of EBV⁺ exosomes derived from different EBV-associated tumors. EBV⁺ exosomes are expected to become a new biomarker for disease diagnosis and prognosis. Therefore, exosome-targeted therapy displays potential.

Hypersensitivity to mosquito bites: A versatile Epstein-Barr virus disease with allergy, inflammation, and malignancy

Hypersensitivity to mosquito bites (HMB) is a rare disease characterized by transient intense skin reaction and systemic inflammation. Clinical presentation of HMB resembles other mosquito allergic responses, and it can also be difficult to clinically distinguish HMB from other severe allergic reactions. However, a distinctive pathophysiology underlies HMB. HMB belongs to a category of Epstein-Barr virus (EBV)-associated natural killer (NK) cell lymphoproliferative disorders (LPD). Hence, HMB may progress to systemic diseases, such as hemophagocytic lymphohistiocytosis, chronic active EBV disease, and EBV-associated malignancies. A triad of elevated serum IgE, NK lymphocytosis, and detection of EBV DNA in peripheral blood is commonly observed, and identification of EBV-infected NK cells usually facilitates the diagnosis. However, the effective treatment is limited, and its precise etiology remains unknown. Local CD4+ T cell proliferation triggered by mosquito bites appears to help induce EBV reactivation and EBV-infected NK-cell proliferation. These immunological interactions may explain the transient HMB signs and symptoms and the disease progression toward malignant LPD. Further research to elucidate the mechanism of HMB is warranted for better diagnosis and treatment of HMB and other forms of EBV-associated LPD.

Hydroa vacciniforme-like lymphoproliferative disorder with eye involvement

Hydroa vacciniforme-like lymphoproliferative disorder (HVLPD) is characterized by vesiculopapular eruptions on sun-exposed and sometimes unexposed skin. Though ocular involvement in HVLPD is rare, it may present with conjunctivitis, corneal opacities, uveitis, and interstitial keratitis. We report a case of a 7-year-old boy with HVLPD, whose ophthalmic symptoms were neglected for over 2 years, who developed anterior uveitis and corneal nebulae without vision impairment. Awareness of eye involvement in patients with HVLPD may help to prevent severe complications.

Oral manifestations of Hydroa vacciniforme-like lymphoproliferative disorder: a clinicopathological study of a Peruvian population

BACKGROUND

Hydroa vacciniforme-like lymphoproliferative disorder (HVLPD) is a chronic Epstein-Barr virus (EBV)-positive lymphoproliferative disease which may either present as an indolent condition or progress to a systemic T-cell lymphoma.

METHODS

All HVLPD diagnosed over a 10-year period were retrieved, and clinical data regarding sex, age, oral and systemic manifestations, and clinical follow-up were obtained. Immunohistochemistry was done in order to characterize the lymphoid cells, and in situ hybridization was used to demonstrate the presence of EBV.

RESULTS

Eleven cases were included, with a male predominance and a mean age of 25.1 years. Buccal mucosa and the lips were the most affected oral sites, appearing as painful ulcers. All patients exhibited facial oedema, usually affecting the lips, nose and periorbital region. The clinical course was gradual but progressive, with four patients having fever and 3 showing lymphadenopathies. All cases showed a moderate to severe lymphocytic infiltrate with angiotropism, angiocentricity and epidermotropism. Two cases affecting the lip skin exhibited a periappendageal lymphocytic infiltrate. Few large pleomorphic cells were found, surrounded by smaller and medium-sized lymphoid cells, as well as reactive plasma cells, macrophages, neutrophils and eosinophils. All lesions exhibited a cytotoxic T-cell (CD8+) phenotype with a variable proliferative index. All cases were associated with EBV, and all patients died due to complications of the disease.

CONCLUSIONS

HVLPD is a rare disease that may show oral involvement with a cytotoxic T-cell phenotype, and is strongly associated with EBV. As shown in this series, HVLPD may show aggressive clinical behaviour.

Hydroa Vacciniforme-Like Lymphoproliferative Disorder in Korea: Prognostic Implication of Clinical Signs and Whole Blood Epstein-Barr Virus DNA

Background

Hydroa vacciniforme-like lymphoproliferative disorder (HVLPD) is rare Epstein-Barr virus (EBV)-associated disease. The classic form of HVLPD is a self-resolving disease, whereas the systemic form can progress to malignant lymphoma, resulting in fatal outcomes. However, the prognostic factors remain unclear.

Objective

This study aimed to evaluate the clinical characteristics of HVLPD and the association between whole blood EBV DNA and clinical outcomes.

Methods

We retrospectively reviewed our 25-year experience involving 11 patients with HVLPD from a single tertiary center in South Korea and evaluated the clinical characteristics of HVLPD and the correlation between whole blood EBV DNA and clinical outcomes.

Results

Of the total 11 patients, 54.5% (6/11) manifested classic HVLPD that resolved with conservative treatment, while 45.5% (5/11) patients had systemic HVLPD, four of whom died of progressive disease or hemophagocytic syndrome. Five patients with systemic HVLPD manifested severe skin lesions such as prominent facial edema, deep ulcers and necrotic skin lesions involving sun-protected areas. Median EBV DNA levels at initial diagnosis were higher in three dead patients than in those alive (2,290 vs. 186.62 copies/µl).

Conclusion

When EBV DNA levels were high, patients showed severe skin lesions and when EBV DNA levels were low, skin lesions tended to improve. Thus, patients with high EBV DNA levels showed an increased risk of severe skin lesions and disease progression.

Hydroa Vacciniforme-like Lymphoproliferative disorder in an adult invades the liver and bone marrow with clear pathological evidence: a case report and literature review

Background

Hydroa Vacciniforme-like Lymphoproliferative Disorder (HV-LPD) is the name given to a group of Epstein-Barr virus (EBV)-associated diseases. It resembles hydroa vacciniforme (HV), the rarest form of photosensitivity, and is a T-cell disorder associated with an Epstein-Barr virus infection. The majority of diagnosed cases occur in East Asia and South America. It is rare in the United States and Europe. Multiple studies have revealed the clinical manifestation of an enlarged liver, but no gold standard such as pathology has yet supported this as a clinical sign of HV-LPD.

Case presentation

Here, we report a case of a 34-year-old Asian female with definite liver invasion. The patient had complained of a recurring facial rash for many years. The patient was admitted to the hospital because of an enlarged liver. After hospitalization, she was given an EB virus nucleic acid test. The EB virus nucleic acid test was positive, and pathological examination suggested that HV-LPD had invaded the skin, bone marrow, and liver. After being given antiviral treatment, the patient’s symptoms were mitigated.

Conclusions

Our case confirms the liver damage was caused by HV-LPD and the effectiveness of antiviral treatment.

Hydroa Vacciniforme and Hydroa Vacciniforme-Like Lymphoproliferative Disorder: A Spectrum of Disease Phenotypes Associated with Ultraviolet Irradiation and Chronic Epstein-Barr Virus Infection

Hydroa vacciniforme (HV) is a rare form of photosensitivity disorder in children and is frequently associated with Epstein–Barr virus (EBV) infection, whereas HV-like lymphoproliferative disorders (HVLPD) describe a spectrum of EBV-associated T-cell or natural killer (NK)-cell lymphoproliferations with HV-like cutaneous manifestations, including EBV-positive HV, atypical HV, and HV-like lymphoma. Classic HV occurs in childhood with papulovesicules on sun-exposed areas, which is usually induced by sunlight and ultraviolet irradiation, and mostly resolves by early adult life. Unlike classic HV, atypical or severe HV manifests itself as recurrent papulovesicular eruptions in sun-exposed and sun-protected areas associated occasionally with facial edema, fever, lymphadenopathy, oculomucosal lesions, gastrointestinal involvement, and hepatosplenomegaly. Notably, atypical or severe HV may progress to EBV-associated systemic T-cell or natural killer (NK)-cell lymphoma after a chronic course. Although rare in the United States and Europe, atypical or severe HV and HV-like lymphoma are predominantly reported in children from Asia and Latin America with high EBV DNA levels, low numbers of NK cells, and T cell clones in the blood. In comparison with the conservative treatment used for patients with classic HV, systemic therapy such as immunomodulatory agents is recommended as the first-line therapy for patients with atypical or severe HV. This review aims to provide an integrated overview of current evidence and knowledge of HV and HVLPD to elucidate the pathophysiology, practical issues, environmental factors, and the impact of EBV infection.

The aim of the measurement of Epstein-Barr virus DNA in hydroa vacciniforme and hypersensitivity to mosquito bites

Epstein-Barr virus (EBV) DNA load in the blood increases in posttransplant lymphoproliferative disorders and chronic active EBV infection. In this report, we analyzed the EBV DNA load in the peripheral blood mononuclear cells (PBMCs) and plasma of patients with hydroa vacciniforme (HV) and/or hypersensitivity to mosquito bites (HMB) to understand the clinical significance of EBV DNA load. All 30 patients showed high DNA loads in the PBMCs over the cut-off level. Of 16 plasma samples, extremely high in two samples obtained from patients with hemophagocytic lymphohistiocytosis (HLH). The amount of cell-free DNA in plasma was correlated to the serum levels of lactate dehydrogenase and inversely correlated to platelet counts. These results indicate that the EBV DNA load in PBMCs can provide one of the diagnostic indicators for HV and HMB and marked elevation of cell-free EBV DNA in plasma might be related to cytolysis such as that observed in HLH.

Hydroa vacciniforme-like lymphoproliferative disorder: A study of clinicopathology and whole-exome sequencing in Chinese patients

BACKGROUND

Hydroa vacciniforme-like lymphoproliferative disorder (HVLPD) encompasses a rare group of Epstein-Barr virus (EBV)-associated lymphoproliferative diseases.

OBJECTIVE

To define the clinical and pathologic characteristics of HVLPD and to identify mutant genes that may be related to the development of HVLPD.

METHODS

Clinical data and archived formalin-fixed, paraffin-embedded tissue were obtained from 19 patients. Specimens were analyzed by immunohistochemistry and in situ hybridization to detect EBV-encoded RNA (EBER1/2) and for T cell receptor (TCR) gene rearrangements. Whole-exome sequencing (WES) analysis was also performed in this study.

RESULTS

Thirteen patients survived between 3-58 months (median, 21 months) during the follow-up. Six patients who were almost adults (>15 years old) and died of the disease presented with facial edema. Lactate dehydrogenase (LDH) levels were elevated, and the TCR gene rearrangement test was positive more frequently in the patients who died. Compared with Chinese patients in a similar previous report, our patients had significantly higher proliferation (in all cases, the Ki-67 index was greater than 10 %) and a more aggressive clinical course. Moreover, after WES and Sanger verification, STAT3, IKBKB, ELF3, CHD7, KMT2D, ELK1, RARB and HPGDS were screened out in our patients.

CONCLUSIONS

HVLPD refers to a heterogeneous group of cutaneous lymphoproliferative diseases with different clinical and pathological features that affect patient outcomes. Gene mutations may be correlated with the development of HVLPD, and our study may provide new therapeutic targets for HVLPD.

A Systematic Approach to the Cutaneous Lymphoid Infiltrates: A Clinical, Morphologic, and Immunophenotypic Evaluation

CONTEXT.—

The evaluation of cutaneous lymphoid infiltrates, both neoplastic and inflammatory, occurs very frequently in routine dermatopathologic examination and consultation practices. The "tough" cutaneous lymphoid infiltrate is feared by many pathologists; skin biopsies are relatively small, whereas diagnostic possibilities are relatively broad. It is true that cutaneous lymphomas can be difficult to diagnose and that in many circumstances multiple biopsies are required to establish a correct diagnostic interpretation. As a reminder, one should understand that low-grade cutaneous lymphomas are indolent disorders that usually linger for decades and that therapy does not result in disease cure. It is also important to remember that in most circumstances, those patients will die from another process that is completely unrelated to a diagnosis of skin lymphoma (even in the absence of specific therapy).

OBJECTIVE.—

To use a clinicopathologic, immunophenotypic, and molecular approach in the evaluation of common lymphocytic infiltrates.

DATA SOURCES.—

An in-depth analysis of updated literature in the field of cutaneous lymphomas was done, with particular emphasis on updated terminology from the most recent World Health Organization classification of skin and hematologic tumors.

CONCLUSIONS.—

A diagnosis of cutaneous lymphoid infiltrates can be adequately approached using a systematic scheme following the proposed ABCDE system. Overall, cutaneous T- and B-cell lymphomas are rare and "reactive" infiltrates are more common. Evaluation of lymphoid proliferations should start with a good sense of knowledge of the clinical presentation of the lesions, the clinical differential considerations, and a conscientious and appropriate use of immunohistochemistry and molecular tools.

Epstein-Barr virus NK and T cell lymphoproliferative disease: report of a 2018 international meeting

Epstein-Barr virus (EBV) normally infects B cells, but in some persons the virus infects T or NK cells. Infection of B cells can result in infectious mononucleosis, and the virus is associated with several B cell malignancies including Hodgkin lymphoma, Burkitt lymphoma, and diffuse large B cell lymphoma. Infection of T or NK cells with EBV is associated with extranodal NK/T cell lymphoma, aggressive NK-cell leukemia, systemic EBV-associated T-cell lymphoma, and chronic active EBV disease, which in some cases can include hydroa vacciniforme-like lymphoproliferative disease and severe mosquito bite allergy. While NK and T cell lymphoproliferative disease is more common in Asia and Latin America, increasing numbers of cases are being reported from the United States and Europe. This review focuses on classification, clinical findings, pathogenesis, and recent genetic advances in NK and T cell lymphoproliferative diseases associated with EBV.

Recent Advances in Cutaneous T-cell Lymphoma: Diagnostic and Prognostic Considerations

This review describes the latest advances in the diagnosis of cutaneous T-cell lymphoma focusing on the most clinically useful features introduced since the publication of the World Health Organization revision in 2017. Clinical entities described include mycosis fungoides, Sézary syndrome, lymphomatoid papulosis, primary cutaneous anaplastic large cell lymphoma, primary cutaneous gamma delta T-cell lymphoma, primary cutaneous acral CD8⁺ T-cell lymphoma, primary cutaneous CD4⁺ small/medium T-cell lymphoproliferative disorder, and hydroa-vacciniforme-like lymphoproliferative disorder. Distinguishing histologic clues to diagnosis are discussed, and important molecular advances are described. Key prognostic indicators that may assist clinicians with timely and appropriate management options are presented.

Hydroa vacciniforme-like lymphoproliferative disorder: an EBV disease with a low risk of systemic illness in whites

Patients with classic hydroa vacciniforme-like lymphoproliferative disorder (HVLPD) typically have high levels of Epstein-Barr virus (EBV) DNA in T cells and/or natural killer (NK) cells in blood and skin lesions induced by sun exposure that are infiltrated with EBV-infected lymphocytes. HVLPD is very rare in the United States and Europe but more common in Asia and South America. The disease can progress to a systemic form that may result in fatal lymphoma. We report our 11-year experience with 16 HVLPD patients from the United States and England and found that whites were less likely to develop systemic EBV disease (1/10) than nonwhites (5/6). All (10/10) of the white patients were generally in good health at last follow-up, while two-thirds (4/6) of the nonwhite patients required hematopoietic stem cell transplantation. Nonwhite patients had later age of onset of HVLPD than white patients (median age, 8 vs 5 years) and higher levels of EBV DNA (median, 1 515 000 vs 250 000 copies/ml) and more often had low numbers of NK cells (83% vs 50% of patients) and T-cell clones in the blood (83% vs 30% of patients). RNA-sequencing analysis of an HVLPD skin lesion in a white patient compared with his normal skin showed increased expression of interferon-γ and chemokines that attract T cells and NK cells. Thus, white patients with HVLPD were less likely to have systemic disease with EBV and had a much better prognosis than nonwhite patients. This trial was registered at www.clinicaltrials.gov as #NCT00369421 and #NCT00032513.

How I treat T-cell chronic active Epstein-Barr virus disease

T-cell chronic active Epstein-Barr virus (CAEBV) is a rare disease in which EBV is present predominantly in T cells that infiltrate the tissues; patients have high levels of EBV in the blood. If untreated, patients often develop liver failure, hemophagocytic lymphohistiocytosis, coronary artery aneurysms, EBV infiltrating T cells impairing organ function, or T-cell lymphomas refractory to treatment. At present, hematopoietic stem-cell transplantation is the only curative therapy, and it is critical to make a proper diagnosis and initiate transplantation before the disease progresses to an irreversible stage. Specific medications such as high-dose systemic corticosteroids or ganciclovir combined with either histone deacetylase inhibitors or bortezomib may temporarily reduce systemic toxicity associated with T-cell CAEBV and allow the patient time to receive a transplant. Relapses of the disease after transplantation have also occurred, and the use of donor-derived virus-specific T cells may help to treat these relapses.

The Immunomodulatory Capacity of an Epstein-Barr Virus Abortive Lytic Cycle: Potential Contribution to Viral Tumorigenesis

Epstein-Barr virus (EBV) is characterized by a bipartite life cycle in which latent and lytic stages are alternated. Latency is compatible with long-lasting persistency within the infected host, while lytic expression, preferentially found in oropharyngeal epithelial tissue, is thought to favor host-to-host viral dissemination. The clinical importance of EBV relates to its association with cancer, which we think is mainly a consequence of the latency/persistency mechanisms. However, studies in murine models of tumorigenesis/lymphomagenesis indicate that the lytic cycle also contributes to cancer formation. Indeed, EBV lytic expression is often observed in established cell lines and tumor biopsies. Within the lytic cycle EBV expresses a handful of immunomodulatory (BCRF1, BARF1, BNLF2A, BGLF5 & BILF1) and anti-apoptotic (BHRF1 & BALF1) proteins. In this review, we discuss the evidence supporting an abortive lytic cycle in which these lytic genes are expressed, and how the immunomodulatory mechanisms of EBV and related herpesviruses Kaposi Sarcoma herpesvirus (KSHV) and human cytomegalovirus (HCMV) result in paracrine signals that feed tumor cells. An abortive lytic cycle would reconcile the need of lytic expression for viral tumorigenesis without relaying in a complete cycle that would induce cell lysis to release the newly formed infective viral particles.

Cytologic Analysis of Epstein-Barr Virus-Associated T/Natural Killer-Cell Lymphoproliferative Diseases

Rapid, precise diagnosis of Epstein-Barr virus-associated T lymphocyte or natural killer cell lymphoproliferative diseases is clinically important to prevent disease progression and avoid fatal outcomes for patients. In addition to detecting increased copy numbers of Epstein-Barr virus, identification of the lymphocyte subpopulation targeted by the virus infection is crucial to reaching the final diagnosis. However, these procedures are laborious and require large amounts of sample. In contrast, flowcytometric analysis may provide crucial information for initial screening of diseases using only small amounts of sample and involves little labor. In addition to the increase of a particular subpopulation, selective HLA-DR expression indicates selective activation and expansion of a virus-infected clone. Presence of a characteristic HLA-DR^high CD5^dim/negative fraction within CD8⁺ T lymphocytes indicates a possible diagnosis of Epstein-Barr virus-associateds hemophagocytic lymphohistiocytosis. One should note, however, that cases with familial hemophagocytic lymphohistiocytosis may exhibit a similar abnormal fraction within CD8⁺ T lymphocytes. These T cells are oligoclonally expanded reactive T cells expanding in response to B cells infected with Epstein-Barr virus.

Hematopoietic Stem Cell Transplantation for the Treatment of Epstein-Barr Virus-Associated T- or NK-Cell Lymphoproliferative Diseases and Associated Disorders

Chronic active Epstein-Barr virus infection (CAEBV) is a prototype of EBV-associated T- and/or NK-cell (EBV⁺ T/NK-cell) lymphoproliferative disorders. Most subtypes of these are lethal. We established a unified treatment strategy composed of step 1 (immunochemotherapy: steroids, cyclosporine A, and etoposide), step 2 (multi-drug block chemotherapy), and step 3 (allogeneic hematopoietic stem cell transplantation; HSCT) for CAEBV and its related diseases. Allogeneic HSCT is the only cure for CAEBV with few exceptions. Primary-EBV infection-associated hemophagocytic lymphohistiocytosis (primary-EBV HLH) is also an EBV⁺ T/NK-cell lymphoproliferation. The nature of EBV⁺ T/NK cells in CAEBV and those in primary-EBV HLH differ. In primary-EBV HLH, most patients need step 1 only and some require step 2 for the successful induction of apoptosis in EBV-infected T cells; however, some exceptional patients require HSCT. We herein present our single institutional experience of CAEBV and primary-EBV HLH, together with that of post-transplant EBV⁺ T/NK-cell lymphoproliferative disease. We also discuss some practical points on HCST with a review of the literature.

Overview of EBV-Associated T/NK-Cell Lymphoproliferative Diseases

Epstein-Barr virus-associated T/natural killer-cell lymphoproliferative diseases (EBV-T/NK-LPDs) are a group of rare diseases resulting from ectopic infection of T or natural killer (NK) lymphocytes with Epstein-Barr virus (EBV). EBV-T/NK-LPDs include chronic active EBV infection, EBV-associated hemophagocytic lymphohistiocytosis, hydroa vacciniforme-like lymphoproliferative disease, and severe mosquito bite allergy. Extra-nodal NK/T-cell lymphoma-nasal type and aggressive NK-cell leukemia can also be included in this broad spectrum. Currently, the etiology of EBV-T/NK-LPDs is unknown and no curative therapy has been established, except for hematopoietic stem cell transplantation. While most cases of EBV-T/NK-LPDs have been documented in specific areas of the world, they have also been documented more broadly across East Asia and Latin America. Consequently, active research and discussion of EBV-T/NK-LPDs are both necessary and important within the extensive international community of scientists and clinicians, to elucidate their etiology and develop a standard therapy.

Epstein-Barr Virus-Associated Lymphoproliferative Disorders: Review and Update on 2016 WHO Classification

Epstein-Barr virus (human herpesvirus-4) is very common virus that can be detected in more than 95% of the human population. Most people are asymptomatic and live their entire lives in a chronically infected state (IgG positive). However, in some populations, the Epstein-Barr virus (EBV) has been involved in the occurrence of a wide range of B-cell lymphoproliferative disorders (LPDs), including Burkitt lymphoma, classic Hodgkin’s lymphoma, and immune–deficiency associated LPDs (post-transplant and human immunodeficiency virus–associated LPDs). T-cell LPDs have been reported to be associated with EBV with a subset of peripheral T-cell lymphomas, angioimmunoblastic T-cell lymphomas, extranodal nasal natural killer/T-cell lymphomas, and other rare histotypes. This article reviews the current evidence covering EBV-associated LPDs based on the 2016 classification of the World Health Organization. These LPD entities often pose diagnostic challenges, both clinically and pathologically, so it is important to understand their unique pathophysiology for correct diagnoses and optimal management.

Mosquito salivary allergen Aed a 3: cloning, comprehensive molecular analysis, and clinical evaluation

BACKGROUND

Allergic reactions to mosquito bites are an increasing clinical concern. Due to the lack of availability of mosquito salivary allergens, they are underdiagnosed. Here, we reported a newly cloned mosquito Aedes (Ae.) aegypti salivary allergen.

METHODS

A cDNA encoding a 30-kDa Ae. aegypti salivary protein, designated Aed a 3, was isolated from an expression library. The full-length cDNA was cloned into a baculovirus expression vector, and recombinant Aed a 3 (rAed a 3) was expressed, purified, and characterized. Skin prick tests with purified rAed a 3 and Ae. aegypti bite tests were performed in 43 volunteers. Serum rAed a 3-specific IgE levels were measured in 28 volunteers.

RESULTS

The primary nucleotide sequence, deduced amino acid sequence, and IgE-binding sites of Aed a 3 were identified. rAed a 3-selected antibodies recognized a 30-kDa Ae. aegypti saliva protein. rAed a 3 bound IgE in mosquito-allergic volunteers and the binding could be inhibited by the addition of natural mosquito extract dose dependently. Immediate skin test reactions to rAed a 3 correlated significantly with mosquito bite-induced reactions. Of the bite test-positive volunteers, 32% had a positive rAed a 3 skin test and 46% had specific IgE. No bite test-negative volunteers reacted to rAed a 3 in either the skin tests or the IgE assays, confirming the specificity of the assay.

CONCLUSIONS

Aed a 3 that corresponds to the Aegyptin protein is a major mosquito salivary allergen. Its recombinant form has biological activity and is suitable for use in skin tests and specific IgE assays in mosquito-allergic individuals.

Epstein-Barr virus reactivation is induced, but abortive, in cutaneous lesions of systemic hydroa vacciniforme and hypersensitivity to mosquito bites

BACKGROUND

Epstein-Barr virus (EBV)-associated T/natural killer (NK)-lymphoproliferative disorders (LPDs) include hydroa vacciniforme (HV) and hypersensitivity to mosquito bites (HMB). The pathomechanisms of these diseases are still unclear.

OBJECTIVE

To understand the inflammatory process, we examined EBV reactivation markers, BZLF1 and BDRF1 mRNA in the tissue and blood from patients with EBV-associated T/NK-LPDs.

METHODS

Sixty-four patients with EBV-associated LPDs and epithelial neoplasms, and EBV+ cell line cells were studied. DNase-treated and resistant EBV DNA load in blood and cell culture supernatants were calculated. An EBV reactivation signal was analyzed in the tissue, blood and cell line cells.

RESULTS

In the tissue, BZLF1 mRNA was detected in 5 of 6 (83%) samples of EBV+ epithelial neoplasms, 16 of 21 (76%) of EBV+ lymphomas, and 5 of 15 (33%) of systemic HV and/or HMB, but negative in all 15 patients with classical HV. In the blood, BZLF1 mRNA was detected in only one of 19 (5.3%) samples of EBV-associated T/NK-LPDs. A down-stream reactivation signal, BDRF1 mRNA was expressed in all 6 samples of EBV+ epithelial neoplasms, but it was positive in only one of 15 (6.7%) samples from systemic HV and HMB in the tissue. EBV+ T/NK-cell line cells treated with phorbol 12-myristate 13-acetate produced BZLF1 and BDRF1 mRNA, and encapsidated EBV DNA was detected in the culture supernatants of cell line cells.

CONCLUSION

Stimulation-induced EBV reactivation occurred both in vivo and in vitro, but it was almost abortive in vivo. Reactivation-related EBV antigens might be responsible for induction of systemic HV and HMB.