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

From Molecules to Microbes: Tracing Cutaneous T-Cell Lymphoma Pathogenesis through Malignant Inflammation

The etiology of CTCL is a subject of extensive investigation. Researchers have explored links between CTCL and environmental chemical exposures, such as aromatic hydrocarbons (eg, pesticides and benzene), as well as infectious factors, including various viruses (eg, human T-lymphotropic virus [HTLV]-I and HTLV-II) and bacteria (eg, Staphylococcus aureus). There has been growing emphasis on the role of malignant inflammation in CTCL development. In this review, we synthesize studies of environmental and infectious exposures, along with research on the aryl hydrocarbon receptor and the involvement of pathogens in disease etiology, providing insight into the pathogenesis of CTCL.

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.

Role of infectious agents in cutaneous T-cell lymphoma: facts and controversies

The etiology of cutaneous T-cell lymphoma (CTCL) remains unknown, with potential infectious causes having been explored. This contribution evaluates the evidence suggesting an infectious etiology and pathogenesis of the disease, characterizes the relationships between various specific pathogens and CTCL, and discusses some of the difficulties in establishing a causal link between infectious agents and CTCL carcinogenesis. Researchers have evaluated CTCL specimens for evidence of infection with a variety of agents, including human T-lymphotropic virus, Epstein-Barr virus, human herpesvirus-8, and Staphylococcus aureus, although other pathogens also have been detected in CTCL. Although there is significant evidence implicating one or more infectious agents in CTCL, studies to date have not linked definitively any pathogen to disease development, and various studies have yielded conflicting results.

Evidence of multiple infectious agents in mycosis fungoides lesions

The etiology of mycosis fungoides (MF) remains to be determined. Several studies have proposed a viral etiology with controversial results. In this case-control study we investigated the presence of Epstein-Barr virus (EBV) and the debated presence of Human T-cell lymphotrophic virus I (HTLV-I) sequences, by polymerase chain reaction on nucleic acid extracts from formalin-fixed paraffin-embedded skin biopsies. Moreover, by a multivariate approach we analyzed in the same case-control study also the contribution of two previously examined pathogens: Hepatitis C virus (HCV) and Borrelia burgdorferi (Bb). Significant differences in the frequency of infectious agents in cases and controls were detected for Bb, HTLV-I and EBV. In MF patients we found the concurrent presence of two or three of these pathogen sequences in 21 out of 83 cases, but only in 1 out of 83 healthy controls. Our results suggest that the persistence of multiple infectious agents may cause a long-term antigenic stimulation contributing to the malignant transformation of T lymphocytes, especially when associated with HTLV-I like sequences. However, these infectious agents do not seem to have effects on disease progression.

Concomitant occurrence of kimura disease and mycosis fungoides in a Lebanese woman: significance and response to rituximab

Kimura disease (KD) is a rare condition that predominantly affects young middle-aged Asian men. It is classically characterized by tumors in the head and neck region with associated eosinophilia and elevated serum immunoglobulin E levels. The exact pathogenesis of this condition remains unknown. Although some regard it as a reactive condition, others believe that it is a T-cell-mediated disease. T-cell clonality has been recently demonstrated in a few cases. We report a 37-year-old Lebanese woman who had both KD and mycosis fungoides (MF). T-cell receptor gene rearrangement studies using 2 different techniques did not detect any clonality for T-cell receptor in both KD and MF lesions. Due to the presence on histology of lymphoid follicles and the persistent high serum immunoglobulin E levels, we elected to attempt treatment with rituximab. Although the KD lesions persisted, they became softer and less nodular. As for the MF lesions, they flared transiently and then exhibited a sustained improvement over a follow-up period of 1 year.