Presence of Epstein-Barr virus in cutaneous lesions of mycosis fungoides and Sézary syndrome

The role of NLRP1 and NLRP3 inflammasomes in the etiopathogeneses of pityriasis lichenoides chronica and mycosis fungoides: an immunohistochemical study

Mycosis fungoides (MF) is the most common subtype of primary cutaneous T cell lymphomas, whereas pityriasis lichenoides chronica (PLC) is a chronic inflammatory skin disorder. The inflammasome is a part of the natural immune system which has a multimeric structure consisting of the receptor, adaptor and effector protein that show specificity for various ligands or activators. After the activation of the inflammasome complex, caspase 1 becomes activated which subsequently triggers interleukin-18 (IL-18) and interleukin-1β (IL-1β) production. In our study we aimed to examine the roles of nucleotide-binding oligomerization domain-like receptor containing pyrin domain 1 (NLRP1) and nucleotide-binding oligomerization domain-like receptor containing pyrin domain (NLRP3) inflammasomes in the etiopathogeneses of PLC and MF. NLRP1, NLRP3, caspase 1, IL-18 and IL-1β levels were examined and compared immunohistochemically in the skin biopsies belonging to 16 control patients; 16 PLC cases, 12 cases with stage 1 MF and 12 cases with other stages of MF (stage 2-4). In the paired comparisons of NLRP1, stage 2-4 MF group and PLC group were shown to have increased levels of NLRP1 expression compared to the control group. IL-1β was also expressed at statistically significantly higher levels in each of the stage 1 MF, stage 2-4 MF and PLC groups compared to the control group. In the paired comparisons of caspase 1 and IL-18, it was found that stage 1 MF, stage 2-4 MF and PLC groups had increased levels of expression compared to the control group. Our findings suggest that the NLRP1 inflammasome pathway might play a role in the etiopathogenesis and progression of PLC and MF.

Environmental and Other Extrinsic Risk Factors Contributing to the Pathogenesis of Cutaneous T Cell Lymphoma (CTCL)

The applications of disease cluster investigations in medicine have developed rather rapidly in recent decades. Analyzing the epidemiology of non-random aggregation of patients with a particular disease fostered identification of environmental and external exposures as disease triggers and promoters. Observation of patient clusters and their association with nearby exposures, such as Dr. John Snow's astute mapping analysis in the mid-1800's, which revealed proximity of cholera patients in London to a contaminated water pump infected with Vibrio cholerae, have paved the way for the field of epidemiology. This approach enabled the identification of triggers for many human diseases including infections and cancers. Cutaneous T-cell lymphomas (CTCL) represent a group of non-Hodgkin lymphomas that primarily affect the skin. The detailed pathogenesis by which CTCL develops remains largely unknown. Notably, non-random clustering of CTCL patients was reported in several areas worldwide and this rare malignancy was also described to affect multiple members of the same family. These observations indicate that external factors are possibly implicated in promoting CTCL lymphomagenesis. Here, we review the epidemiology of CTCL worldwide and the clinical characteristics of CTCL patients, as revealed by global epidemiological data. Further, we review the known risk factors including sex, age, race as well as environmental, infectious, iatrogenic and other exposures, that are implicated in CTCL lymphomagenesis and discuss conceivable mechanisms by which these factors may trigger this malignancy.

Increased Levels of Plasma Epstein Barr Virus DNA Identify a Poor-Risk Subset of Patients With Advanced Stage Cutaneous T-Cell Lymphoma

INTRODUCTION

Outcomes in advanced stage (AS) cutaneous T-cell lymphomas (CTCL) are poor but with great variability. Epstein-Barr virus (EBV) is associated with a subset of non-Hodgkin lymphomas. Frequency of plasma EBV-DNA (pEBVd) detection, concordance with EBV RNA (EBER) in tumor tissue, codetection of plasma cytomegalovirus DNA (pCMVd), and prognostic effect in AS CTCL are unknown.

PATIENTS AND METHODS

Patients (n = 46; 2006-2013) with AS CTCL (≥IIB) were retrospectively studied. pEBVd and pCMVd were longitudinally measured using quantitative real-time polymerase chain reaction. EBER in situ hybridization (ISH) was performed on tumor samples. Survival from time of diagnosis (ToD) and time of progression to AS was assessed.

RESULTS

Plasma EBV-DNA and pCMVd were detected in 37% (17 of 46) and 17% (8 of 46) of AS CTCL patients, respectively. pCMVd detection was significantly more frequent in pEBVd-positive (pEBVd(+)) than pEBVd(-) patients (35% vs. 7%; P = .038). Tumor tissue for EBER-ISH was available in 14 of 17 pEBVd(+) and 22 of 29 pEBVd(-) patients; 12 of 14 (85.7%) pEBVd(+) patients were EBER(+) versus 0 of 22 pEBVd(-) patients. Frequency of large cell transformation (LCT) tended to be greater in pEBVd(+) patients, but was not significant (10 of 14 pEBVd(+) vs. 10 of 23 pEBVd(-); P = .17). No notable differences in rates of increased levels of serum lactate dehydrogenase (LDH) were observed (17 of 17 pEBVd(+) vs. 27 of 29 pEBVd(-)). pEBVd detection was associated with significantly worse survival from ToD (P = .021) and time of progression to AS (P = .0098).

CONCLUSION

Detection of cell-free plasma EBV-DNA was highly concordant with the presence of EBERs in tumor tissue, predicted survival independent of LDH and LCT, and should be further studied as a biomarker in AS CTCL.

Evaluation of the Association Between Epstein-Barr Virus and Mycosis Fungoides

INTRODUCTION

Mycosis fungoides (MF) is the most common cutaneous T-cell lymphomas. Despite extensive studies, etiopathogenesis of MF is unknown. Environmental, infectious and genetic factors have been proposed as potential risk factors of MF. Herpes virus family members, especially Epstein-Barr virus (EBV), have been among the viral factors of interest in recent years. The aim of this study was to investigate the possible association of EBV infection with MF.

MATERIALS AND METHODS

This case-control study was performed on skin biopsy samples of 57 MF patients referred to Pathology Department of Mashhad Emam Reza Hospital from 2000 to 2011 and also on 57 melanocytic nevus samples matched with patients for age and sex. The presence of EBV in samples was evaluated by polymerase chain reaction. Statistical analysis of the data was conducted with the Statistical Package for the Social Sciences version 11.5 (SPSS Inc., Chicago, IL, USA).

RESULTS

In this study, out of 57 MF samples, there were 34 male and 23 female patients, with male:female ratio of 1.04. Mean patient age was 51.4 years. There were 22 and 4 positive cases of EBV in the case and control groups, respectively. Chi-square statistical test showed that EBV was significantly higher in case group than control (P = 0.000). There was no correlation between the presence of EBV in samples with lesion type, age and gender of the patients.

CONCLUSION

According to our study results, EBV is a likely etiologic agent or potential promoter in the pathogenesis of MF.

Epstein-Barr virus (EBV)-infected monocytes facilitate dissemination of EBV within the oral mucosal epithelium

Epstein-Barr virus (EBV) causes hairy leukoplakia (HL), a benign lesion of oral epithelium that occurs primarily in the setting of human immunodeficiency virus (HIV)-associated immunodeficiency. However, the mechanisms of EBV infection of oral epithelium are poorly understood. Analysis of HL tissues shows a small number of EBV-positive intraepithelial macrophages and dendritic/Langerhans cells. To investigate a role for these cells in spreading EBV to epithelial cells, we used tongue and buccal explants infected ex vivo with EBV. We showed that EBV first infects submucosal CD14(+) monocytes, which then migrate into the epithelium and spread virus to oral epithelial cells, initiating productive viral infection within the terminally differentiated spinosum and granulosum layers. Incubation of EBV-infected monocytes and oral explants with antibodies to CCR2 receptor and monocyte chemotactic protein 1 prevented entry of monocytes into the epithelium and inhibited EBV infection of keratinocytes. B lymphocytes played little part in the spread of EBV to keratinocytes in our explant model. However, cocultivation of EBV-infected B lymphocytes with uninfected monocytes in vitro showed that EBV may spread from B lymphocytes to monocytes. Circulating EBV-positive monocytes were detected in most HIV-infected individuals, consistent with a model in which EBV may be spread from B lymphocytes to monocytes, which then enter the epithelium and initiate productive viral infection of keratinocytes.

Prevalence of mycosis fungoides and its association with EBV and HTLV-1 in Pakistanian patients

Mycosis fungoides (MF) is an indolent T cell lymphoma that is distinguished from other lymphomas by its initial appearance on the skin. The histologic diagnosis of MF may be difficult because there is significant overlap in the histologic features of neoplastic T-cell infiltrates and inflammatory dermatoses. This T-cell neoplasm commonly occurs in a mixed, reactive background and can show only a subtle degree of cytologic atypia, rendering histologic diagnosis difficult. In this study MF constituted 0.86% of all non-Hodgkin s lymphoma (NHL) both T and B, as compared to the Western studies which have reported 0.5% prevalence for MF of all NHL. Polymerase chain reaction (PCR) technique was used to assess T-cell clonality in paraffin-embedded skin biopsies clinically and pathologically suspicious for early MF. Out of the 14 cases diagnosed as MF, amplifiable DNA was isolated from 6 cases, which were further studied for T-cell receptor (TcR) beta, gamma, and delta chain gene rearrangements. Clonal product was seen in 4 out of 6 cases for beta, gamma, and delta TcR chain genes. Association for Epstein Barr virus (EBV) was observed in 3 out of 6 cases (50%) of MF. Although these 3 cases were positive for EBV by PCR, but were negative by in-situ hybridization (ISH). No heterogeneity was noted in these 3 cases of MF for BamHI E, K, N, and Z regions of EBV. All six cases were negative for HTLV-1 (tax region) by PCR. It was concluded that the prevalence of MF in Pakistani population is comparable to the Western data, and that EBV association to MF cases was higher than in Western studies.