Viruses and lymphoma/leukaemia

Immune control in acute myeloid leukemia

Acute myeloid leukemia (AML) is a genetically heterogeneous disease, in that a multitude of oncogenic drivers and chromosomal abnormalities have been identified and associated with the leukemic transformation of myeloid blasts. However, little is known as to how individual mutations influence the interaction between the immune system and AML cells and the efficacy of the immune system in AML disease control. In this review, we will discuss how AML cells potentially activate the immune system and what evidence there is to support the role of the immune system in controlling this disease. We will specifically examine the importance of antigen presentation in fostering an effective anti-AML immune response, explore the disruption of immune responses during AML disease progression, and discuss the emerging role of the oncoprotein MYC in driving immune suppression in AML.

Viral Agents as Potential Drivers of Diffuse Large B-Cell Lymphoma Tumorigenesis

Among numerous causative agents recognized as oncogenic drivers, 13% of total cancer cases occur as a result of viral infections. The intricacy and diversity of carcinogenic processes, however, raise significant concerns about the mechanistic function of viruses in cancer. All tumor-associated viruses have been shown to encode viral oncogenes with a potential for cell transformation and the development of malignancies, including diffuse large B-cell lymphoma (DLBCL). Given the difficulties in identifying single mechanistic explanations, it is necessary to combine ideas from systems biology and viral evolution to comprehend the processes driving viral cancer. The potential for more efficient and acceptable therapies lies in targeted medicines that aim at viral proteins or trigger immune responses to either avoid infection or eliminate infected or cancerous cells. In this review, we aim to describe the role of viral infections and their mechanistic approaches in DLBCL tumorigenesis. To the best of our knowledge, this is the first review summarizing the oncogenic potential of numerous viral agents in DLBCL development.

HIV/AIDS Associated Lymphoma: Review

Lymphoma is one of the hematologic malignancies that occur at a higher rate in human immunodeficiency virus-infected individuals. It is one of the most frequent neoplastic causes of death in those individuals. Non-Hodgkin's lymphoma and Hodgkin's lymphomas are acquired immunodeficiency syndrome defining lymphoma and non-acquired immunodeficiency syndrome defining lymphoma, respectively. Non-Hodgkin's lymphoma is the most common type of lymphoma in human immunodeficiency virus-positive people. The lymphoma that develops in patients infected with the human immunodeficiency virus/acquired immunodeficiency syndrome is heterogeneous in terms of morphology, pathogenesis pathways, and cellular derivation. A narrative review was conducted on the basis of relevant literature on the current topic to summarize the current epidemiology, pathogenesis, laboratory diagnosis, and treatment of lymphoma in human immunodeficiency virus-infected patients. The finding showed that although the incidence of non-Hodgkin's lymphoma has decreased after the advent of highly active antiretroviral therapy, it has remained higher in human immunodeficiency virus-infected people than in the general population. On the other hand, the incidence of Hodgkin's lymphoma has increased after the introduction of highly active antiretroviral therapy. Therefore, it is recommended that people living with human immunodeficiency virus/ acquired immunodeficiency syndrome be screened for the development of lymphoma to increase their survival time and quality of life, and further research is required regarding the pathogenesis, treatment, and laboratory diagnosis of human immunodeficiency virus/ acquired immunodeficiency syndrome-associated lymphoma.

Evaluation of plasma Epstein-Barr virus DNA as a biomarker for Epstein-Barr virus-associated Hodgkin lymphoma

Objectives:

Epstein–Barr virus is a tumorigenic virus and has been extensively studied as a causative agent for Hodgkin lymphoma. Although immunostaining of the tumor biopsy is the standard method for diagnosis of Epstein–Barr virus-driven Hodgkin lymphoma, the invasiveness of the procedure renders it difficult and less desirable for the patients. Therefore, we designed this study to evaluate the efficiency of plasma Epstein–Barr virus DNA detection as an alternative diagnostic and prognostic method for Epstein–Barr virus–associated Hodgkin lymphoma.

Methods:

This analytical cross-sectional study was conducted during March 2017 to December 2018 including 43 Hodgkin lymphoma patients diagnosed histopathologically followed by the latent membrane protein-1 immunohistochemistry to determine their Epstein–Barr virus association. Plasma Epstein–Barr virus DNA in these samples was measured using quantitative polymerase chain reaction (qPCR).

Results:

Of total, 29 (67.44%) patients tested positive for plasma Epstein–Barr virus DNA. On comparing results of latent membrane protein-1 immunohistochemistry (IHC) with plasma Epstein–Barr virus DNA, plasma Epstein–Barr virus DNA was found in 25 of 30 patients with latent membrane protein-1 expression and 4 of 13 patients without latent membrane protein-1 expression. The sensitivity and the specificity of plasma Epstein–Barr virus DNA detection with respect to latent membrane protein-1 IHC were found to be 83.33% and 69.23%, respectively (p = 0.0014).

Conclusion:

Determination of plasma Epstein–Barr virus DNA was found to be highly sensitive and specific in characterizing Epstein–Barr virus–associated Hodgkin lymphoma, suggesting that this diagnostic method holds promise as an alternative and more convenient method of diagnosis compared with tissue biopsy.

Self-Renewal and Toll-like Receptor Signaling Sustain Exhausted Plasmacytoid Dendritic Cells during Chronic Viral Infection

Although characterization of T cell exhaustion has unlocked powerful immunotherapies, the mechanisms sustaining adaptations of short-lived innate cells to chronic inflammatory settings remain unknown. During murine chronic viral infection, we found that concerted events in bone marrow and spleen mediated by type I interferon (IFN-I) and Toll-like receptor 7 (TLR7) maintained a pool of functionally exhausted plasmacytoid dendritic cells (pDCs). In the bone marrow, IFN-I compromised the number and the developmental capacity of pDC progenitors, which generated dysfunctional pDCs. Concurrently, exhausted pDCs in the periphery were maintained by self-renewal via IFN-I- and TLR7-induced proliferation of CD4^- subsets. On the other hand, pDC functional loss was mediated by TLR7, leading to compromised IFN-I production and resistance to secondary infection. These findings unveil the mechanisms sustaining a self-perpetuating pool of functionally exhausted pDCs and provide a framework for deciphering long-term exhaustion of other short-lived innate cells during chronic inflammation.

Primary effusion lymphoma: current perspectives

Primary effusion lymphoma (PEL) is a rare and aggressive disease, affecting a unique population of patients who are often elderly or immunocompromised. PEL is associated with human herpesvirus type-8 infection and most commonly presents as malignant effusions of the body cavities. Patients diagnosed with PEL often have a compromised immune system from secondary conditions such as HIV. Chemotherapy has traditionally been the cornerstone of treatment for patients with a good performance status and no significant comorbidities. However, an optimal regimen does not exist. Most patients with PEL experience a relapse after frontline therapy within 6-8 months and subsequently require further treatment. In recent years, our understanding of the molecular drivers and environmental factors affecting the pathogenesis of PEL has expanded. This review will discuss the pathogenesis of PEL and various management approaches available in the frontline and relapsed setting as well as targeted agents that have shown promise in this disease.

The roles of the exoribonucleases DIS3L2 and XRN1 in human disease

RNA degradation is a vital post-transcriptional process which ensures that transcripts are maintained at the correct level within the cell. DIS3L2 and XRN1 are conserved exoribonucleases that are critical for the degradation of cytoplasmic RNAs. Although the molecular mechanisms of RNA degradation by DIS3L2 and XRN1 have been well studied, less is known about their specific roles in the development of multicellular organisms or human disease. This review focusses on the roles of DIS3L2 and XRN1 in the pathogenesis of human disease, particularly in relation to phenotypes seen in model organisms. The known diseases associated with loss of activity of DIS3L2 and XRN1 are discussed, together with possible mechanisms and cellular pathways leading to these disease conditions.

Differential expression of viral agents in lymphoma tissues of patients with ABC diffuse large B-cell lymphoma from high and low endemic infectious disease regions

Diffuse large B-cell lymphoma (DLBCL), the most common type of non-Hodgkin's lymphoma (NHL) in adults, accounts for approximately 30-40% of newly diagnosed lymphomas worldwide. Environmental factors, such as viruses and bacteria, may contribute to cancer development through chronic inflammation and the integration of oncogenes, and have previously been indicated in cervical cancer, hepatocellular carcinoma, gastric cancer and lymphoproliferative disorders. In the present study, the presence of microbial agents was analyzed in the lymphoma tissue of patients with activated B-cell like (ABC) DLBCL. The present study compared two groups of patients from geographically varied regions that possess a difference in the prevalence of viral and other microbial agents. The patient populations were from Sweden (a low endemic infectious disease region) and Egypt (a high endemic infectious disease region). A differential expression of several viruses in lymphoma tissues was noted when comparing Swedish and Egyptian patients. JC polyomavirus (JCV) was detected in Swedish and Egyptian patients and, uniquely, the complete hepatitis B virus (HBV) genome was detected only in Egyptian lymphoma patients. None of these viruses were detected in control lymph tissues from Sweden or Egypt. In total, 38% of the Egyptian patients were found to have HBV surface antigens (HBsAgs) in their serum; however, HBsAgs were not found in any of the Swedish patients. The percentage of serum HBsAgs in Egyptian patients with ABC DLBCL was significantly increased compared with the general Egyptian population (P<0.05). The present study may support a notion that viral agents, including JCV and HBV, may be involved in the tumorigenesis of DLBCL in regions of high infectious disease.

Heterogeneity of respiratory distress syndrome: risk factors and morbidity associated with early and late gestation disease

BACKGROUND

Although respiratory distress syndrome (RDS) is considered a disease of prematurity, there is evidence to suggest heterogeneity between early and late gestation RDS. We examined the epidemiologic features of RDS occurring at early and late gestation.

METHODS

We conducted a retrospective cohort study including live births in the United States in 2005-06, with information obtained from the National Center for Health Statistics. Early (<32 weeks) and late gestation RDS (≥39 weeks) were contrasted in terms of risk factors and associations with pregnancy complications, obstetric intervention and co-morbidity. Logistic regression was used to quantify the effects of risk factors, while other associations were quantified descriptively.

RESULTS

There were 27,971 RDS cases, yielding an incidence of 6.4 per 1000 live births. Early and late gestation RDS differed in terms of risk factors, with factors such as multi-fetal gestation more strongly associated with early (adjusted odds ratio [aOR] 11.6, 95 % confidence interval 11.0-12.2) compared with late gestation RDS (aOR 3.66, 95 % confidence interval 2.68-4.98). The morbidity correlates of early and late gestation RDS also differed substantially; neonatal seizures were less strongly associated with early (OR 5.90, 95 % confidence interval 3.67-9.47) compared with late gestation RDS (OR 33.1, 95 % confidence interval 27.2-40.2), while meconium aspiration syndrome was not significantly associated with early gestation RDS (OR 1.87, 95 % confidence interval 0.94-3.72) and very strongly associated with late gestation RDS (OR 39.8, 95 % confidence interval 34.7-45.6).

CONCLUSIONS

Differences in risk factors and morbidity correlates of early and late gestation RDS suggest that these entities represent two distinct diseases.

Splenic diffuse red-pulp small B-cell lymphoma associated with hepatitis B virus: a report of two cases

CONTEXT

Splenic diffuse red-pulp small B-cell lymphoma is a rare disease, representing less than 1% of all non-Hodgkin lymphomas (NHL). This entity is characterized by involvement of bone marrow sinusoids and peripheral blood. The majority of cases are at an advanced stage when diagnosed. Its pathogenesis is still poorly understood.

CASE REPORTS

We report on two patients with chronic non-replicating hepatitis B virus (HBV) who developed splenic diffuse red-pulp small B-cell lymphoma. Both of them were in stage IV at diagnosis and evolved with aggressive disease. Both of them achieved a complete response through chemotherapy, but one of them died due to infectious complications during bone marrow transplantation. The other decided not to undergo transplantation and continues not to show any evidence of disease today (three years after treatment). Some studies have shown a possible association between B-cell NHL and HBV. Nonetheless, the mechanism through which this oncogenic virus interacts with B-cell NHL is still poorly understood. HBV is lymphotropic and may insert into the host's genome, thus causing overexpression of oncogenes and downregulation of tumor suppressor genes. Therefore, chronic stimulation by HBV can increase B-cell proliferation, which promotes monoclonal expansion of these cells and results in malignancy.

CONCLUSION

HBV may be implicated in the pathogenesis of this lymphoma, although no direct association between these two entities could be proved in the present study. Further investigations are necessary.

Plasma Epstein Barr virus (EBV) DNA as a biomarker for EBV associated Hodgkin lymphoma

OBJECTIVE

To assess plasma Epstein-Barr virus (EBV) DNA as a biomarker of tumour burden at diagnosis and during therapy in children with Hodgkin lymphoma.

DESIGN

Case-control study, with prospective follow-up of the Hodgkin lymphoma cohort (2007-2012).

SETTING

Pediatric Hematology Oncology unit of a tertiary care hospital in Delhi.

PATIENTS

Thirty children with Hodgkin lymphoma and 70 sex and age-matched controls (benign lymphadenopathy 19, non-lym-phoid malignancy 29, Burkitt lymphoma 5, healthy children 17).

INTERVENTION

Positive EBV-staining on immunohistochemistry was defined as EBV-associated Hodgkin lymphoma. Plasma EBV real-time quantitative polymerase chain reaction (PCR) was tested at presentation, after first and last chemotherapy cycles, and on follow-up.

MAIN OUTCOME MEASURES

Plasma EBV quantitative PCR was compared between cases and controls. Its kinetics was assessed during and after chemotherapy.

RESULTS

EBV quantitative PCR was positive in 19 (63%) Hodgkin lymphoma cases (range 500 to 430,000 copies/mL), with 87.5% accuracy (kappa=0.69) as compared with EBV immunohistochemistry. Sensitivity and specificity of the quantitative PCR were 87.5% and 81.8%, respectively. Only boys showed positive EBV immunohistochemistry and,or quantitative PCR positivity. All controls were quantitative PCR negative. All quantitative PCR positive cases with follow up blood sample showed EBV clearance after the first cycle. A quantitative PCR negative case in long-term remission became positive at relapse. EBV status did not influence survival.

CONCLUSION

Plasma EBV-DNA, detectable in EBV-associated Hodgkin lymphoma, becomes undetectable early after initiating therapy. It can be used as a biomarker of treatment response in EBV-associated Hodgkin lymphoma.

Effects of lymphocyte profile on development of EBV-induced lymphoma subtypes in humanized mice

Epstein-Barr virus (EBV) infection causes both Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL). The present study reveals that EBV-induced HL and NHL are intriguingly associated with a repopulated immune cell profile in humanized mice. Newborn immunodeficient NSG mice were engrafted with human cord blood CD34(+) hematopoietic stem cells (HSCs) for a 8- or 15-wk reconstitution period (denoted (8w)hN and (15w)hN, respectively), resulting in human B-cell and T-cell predominance in peripheral blood cells, respectively. Further, novel humanized mice were established via engraftment of hCD34(+) HSCs together with nonautologous fetal liver-derived mesenchymal stem cells (MSCs) or MSCs expressing an active notch ligand DLK1, resulting in mice skewed with human B or T cells, respectively. After EBV infection, whereas NHL developed more frequently in B-cell-predominant humanized mice, HL was seen in T-cell-predominant mice (P = 0.0013). Whereas human splenocytes from NHL-bearing mice were positive for EBV-associated NHL markers (hBCL2(+), hCD20(+), hKi67(+), hCD20(+)/EBNA1(+), and EBER(+)) but negative for HL markers (LMP1(-), EBNA2(-), and hCD30(-)), most HL-like tumors were characterized by the presence of malignant Hodgkin's Reed-Sternberg (HRS)-like cells, lacunar RS (hCD30(+), hCD15(+), IgJ(-), EBER(+)/hCD30(+), EBNA1(+)/hCD30(+), LMP(+)/EBNA2(-), hCD68(+), hBCL2(-), hCD20(-/weak,) Phospho STAT6(+)), and mummified RS cells. This study reveals that immune cell composition plays an important role in the development of EBV-induced B-cell lymphoma.

Childhood determination of Hodgkin lymphoma among U.S. servicemen

BACKGROUND

Hodgkin lymphoma in young adults is inexplicably linked to economic development.

METHODS

We conducted a nested case-control study of the 656 servicemen with Hodgkin lymphoma diagnosed between ages 17 to 32 while on active duty in the U.S. military during 1950-68. Controls, chosen randomly from the servicemen on duty at the time, were matched on service, birth year, and induction date. Information came from preinduction records and military records for the period ending at onset or the equivalent date.

RESULTS

Risk was independently increased with small sib-ship size [OR, 2.3; confidence interval (CI), 1.6-3.5], low birth order (OR, 1.9; CI, 1.4-2.6), and an interval of at least 5 years between birth and that of a previous or subsequent sibling (OR, 2.1; CI, 1.5-3.1). Other factors independently and significantly associated with elevated risk of Hodgkin lymphoma were: tallness, high body mass index, more education (but not higher income) in the county of birth, BB or AB blood type, and past infectious mononucleosis (but a deficit of other childhood viral infections). Early fatherhood conveyed high risk (OR, 2.6; CI, 1.4-4.8), especially if with a high-risk sibling configuration. Factors unrelated to risk included personal education, preinduction or military occupation, induction test score, and rank. Findings were similar for nodular sclerosis and mixed cell histologic subtypes.

CONCLUSIONS

Protection from the environment in childhood, but not in adulthood, increases the likelihood of young adult Hodgkin lymphoma, which may result from nonspecific isolation from early infections and/or exposure to late infection by a specific but unidentified ubiquitous childhood virus.

IMPACT

Events in childhood protect against later Hodgkin lymphoma.

Molecular insights of protein contour recognition with ligand pharmacophoric sites through combinatorial library design and MD simulation in validating HTLV-1 PR inhibitors

Retroviruses HIV-1 and HTLV-1 are chiefly considered to be the most dangerous pathogens in Homo sapiens. These two viruses have structurally unique protease (PR) enzymes, which are having common function of its replication mechanism. Though HIV PR drugs failed to inhibit HTLV-1 infections, they emphatically emphasise the need for designing new lead compounds against HTLV-1 PR. Therefore, we tried to understand the binding level interactions through the charge environment present in both ligand and protein active sites. The domino effect illustrates that libraries of purvalanol-A are attuned to fill allosteric binding site of HTLV-1 PR through molecular recognition and shows proper binding of ligand pharmacophoric features in receptor contours. Our screening evaluates seven compounds from purvalanol-A libraries, and these compounds' pharmacophore searches for an appropriate place in the binding site and it places well according to respective receptor contour surfaces. Thus our result provides a platform for the progress of more effective compounds, which are better in free energy calculation, molecular docking, ADME and molecular dynamics studies. Finally, this research provided novel chemical scaffolds for HTLV-1 drug discovery.

Hodgkin lymphoma incidence in California Hispanics: influence of nativity and tumor Epstein-Barr virus

PURPOSE

For classical Hodgkin lymphoma (HL), migrant studies could elucidate contributions of environmental factors (including Epstein-Barr virus (EBV)) to the lower rates in non-whites. Given the well-described etiologic complexity of HL, this research requires a large, immigrant population, such as California Hispanics.

METHODS

With 1988-2004 California Cancer Registry data (2,595 Hispanic, 8,637 white HL cases) and tumor cell EBV status on a subset (218 Hispanics, 656 whites), we calculated ethnicity- and nativity-specific HL incidence rates simultaneously by age, sex, and histologic subtype, and tumor cell EBV prevalence.

RESULTS

Compared with white rates, Hispanic HL rates were lower overall (70 %) and for nodular sclerosis HL, particularly among young adults (60-65 % for females). However, they were higher among children (200 %) and older adults, and for mixed cellularity HL. Compared with rates in foreign-born Hispanics, rates in US-born Hispanics were higher among young adults (>threefold in females), lower for children and adults over age 70, and consistently intermediate compared with rates in whites. EBV tumor prevalence was 67, 32, and 23 % among foreign-born Hispanics, US-born Hispanics, and whites, respectively, although with variation by age, sex, and histology.

CONCLUSIONS

Findings strongly implicate environmental influences, such as nativity-related sociodemographic differences, on HL occurrence. In addition, lower young adult rates and higher EBV prevalence in US-born Hispanics than in whites raise questions about the duration/extent of environmental change for affecting HL rates and also point to ethnic differences in genetic susceptibility. Lesser variation in mixed cellularity HL rates and greater variation in rates for females across groups suggest less modifiable factors interacting with environmental influences.

AIDS-Associated Cardiac Lymphoma-A Review: Apropos a Case Report

Despite treatment with potent and effective combination antiretroviral medications, the incidence of non-Hodgkin lymphoma (NHL) in the population living with HIV/AIDS remains significantly higher than that in noninfected individuals. The majority of the HIV-infected patients with NHL present with advanced stage extranodal disease of the B-cell phenotype. Lymphomas are the second most common tumors involving the heart in HIV-infected patients. Although the heart may serve as the primary focus of the lymphoma, in most HIV-related cases, cardiac lymphomatous involvement is part of a metastatic process that originated elsewhere.

Molecular methods of virus detection in lymphoma

The herpesviruses Epstein-Barr virus (EBV) and human herpesvirus 8 and the retrovirus human T-cell leukemia virus type 1 are directly implicated in the pathogenesis of lymphoma and leukemia in man. EBV is associated with an expanding spectrum of lymphomas and it would appear likely that additional, possibly novel, viruses will be implicated in lymphoma pathogenesis in the future. This chapter describes techniques that may be useful in the analysis of viruses and lymphoma including a standard EBV EBER in situ hybridization assay and a degenerate PCR assay for detection of novel herpesviruses. Lastly, a method for analysis of next-generation sequences in the quest for novel viruses is described.

Patients with activated B-cell like diffuse large B-cell lymphoma in high and low infectious disease areas have different inflammatory gene signatures

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous disease with an association with inflammation and viral infections. We hypothesize that environmental factors may be involved in the pathogenesis of DLBCL. In this study, we compared gene expression profiles of lymph node tissues from patients with DLBCL from two different geographical areas with diverse environmental exposures. Specimens from Egyptian and Swedish patients with DLBCL as well as controls were studied. Gene expression analysis using microarray and quantitative polymerase chain reaction demonstrated significantly higher expression of signal transducer and activator of transcription 3 (STAT3) in Swedish as compared to Egyptian patients and control materials from both countries. This was confirmed at protein level using confocal microscopy. The receptor tyrosine kinase ROR1, a "survival factor" for malignant cells, was overexpressed and significantly related to the STAT3 expression pattern. The difference in the expression of genes involved in inflammatory responses and in the tumorigenic process of DLBCL might relate to infectious agents and/or other environmental exposures.

Herpes zoster is associated with an increased risk of subsequent lymphoid malignancies - a nationwide population-based matched-control study in Taiwan

Background

Infectious agents have been shown to contribute to the development of lymphoid malignancies. The different distribution of lymphoid malignancies in Asian and Western populations suggests possibly different etiologies in Asian populations. Herpes zoster infection, commonly seen in immunocompromised persons, has been reported to be associated with lymphoid malignancies in retrospective case–control studies from Western populations, but the results are controversial and large-scale prospective studies from Asian populations are lacking.

Methods

A nationwide population-based matched-controlled prospective study on Taiwanese patients was performed using the National Health Insurance Research Database from 1996 to 2007. Herpes zoster and malignancies were defined by compatible ICD-9-CM (International Classification of Disease, 9^th Revision, Clinical Modification) codes. Patients who had been diagnosed with any malignancies before herpes zoster, with known viral infections including human immunodeficiency virus, and duration from herpes zoster to diagnosis of malignancies less than 6 months were excluded.

Results

Of 42,498 patients with herpes zoster prior to the diagnosis of any malignancies, the cumulative incidence for lymphoid malignancies was 0.11% (n = 48), compared with 0.06% (n = 106) in 169,983 age- and gender-matched controls (univariate hazard ratio (HR): 1.82, 95%CI: 1.29-2.55). The most common lymphoid malignancy was non-Hodgkin’s lymphoma (60.4%, n = 29), followed by multiple myeloma (27.1%, n = 13). Risk for developing lymphoid malignancies is significantly higher in herpes zoster patients (log rank P = 0.005). After adjusting for presence of any comorbidities in Charlson comorbidity index, time-dependent covariate for herpes group, and income category using Cox proportional hazard regressions, herpes zoster patients had an increased risk of developing lymphoid malignancies (adjusted HR: 1.68, 95%CI: 1.35-2.42, P = 0.0026), but did not have an increased risk of developing non-lymphoid malignancies (adjusted HR: 1.00, 95%CI: 0.91-1.05, P = 0.872).

Conclusion

Preceding herpes zoster infection is an independent risk marker for subsequent lymphoid malignancies in Taiwanese subjects. Further studies are warranted for pathogenesis exploration and preventive strategies in Asian populations.

Role of immune escape mechanisms in Hodgkin's lymphoma development and progression: a whole new world with therapeutic implications

Hodgkin's lymphoma represents one of the most frequent lymphoproliferative syndromes, especially in young population. Although HL is considered one of the most curable tumors, a sizeable fraction of patients recur after successful upfront treatment or, less commonly, are primarily resistant. This work tries to summarize the data on clinical, histological, pathological, and biological factors in HL, with special emphasis on the improvement of prognosis and their impact on therapeutical strategies. The recent advances in our understanding of HL biology and immunology show that infiltrated immune cells and cytokines in the tumoral microenvironment may play different functions that seem tightly related with clinical outcomes. Strategies aimed at interfering with the crosstalk between tumoral Reed-Sternberg cells and their cellular partners have been taken into account in the development of new immunotherapies that target different cell components of HL microenvironment. This new knowledge will probably translate into a change in the antineoplastic treatments in HL in the next future and hopefully will increase the curability rates of this disease.

Genetics of primary intraocular tumors

Primary intraocular neoplasms are tumors that originate within the eye. The most common malignant primary intraocular tumor in adults is uveal melanoma and the second is primary intraocular lymphoma or vitreoretinal (intraocular) lymphoma. The most common malignant intraocular tumor in children is retinoblastoma. Genetics plays a vital role in the diagnosis and detection of ocular tumors. In uveal melanoma, monosomy 3 is the most common genetic alteration and somatic mutations of BAP1, a tumor suppressor gene, have been reported in nearly 50% of primary uveal melanomas. The retinoblastoma gene RB1 is the prototype tumor suppressor gene-mutations in RB1 alleles lead to inactivated RB protein and the development of retinoblastoma. Immunoglobulin heavy chain (IgH) or T-cell receptor (TCR) gene rearrangement is observed in B-cell or T-cell primary vitreoretinal lymphoma, respectively. Other factors related to the genetics of these three common malignancies in the eye are discussed and reviewed.

The Smac mimetic RMT5265.2HCL induces apoptosis in EBV and HTLV-I associated lymphoma cells by inhibiting XIAP and promoting the mitochondrial release of cytochrome C and Smac

The inhibitors of apoptosis (IAP) are important regulators of apoptosis. However, little is known about the capacity of Smac mimetics (IAP inhibitor) to overcome virally associated-lymphoma's (VAL) resistance to apoptosis. Here, we explored the pro-apoptotic effect of a novel Smac mimetic, RMT5265.2HCL (RMT) in VAL cells. RMT improved the sensitivity to apoptosis in EBV- and to some extend in HTLV-1- but not in HHV-8-VAL. Furthermore, we identified that RMT promotes caspase 3 and 9 cleavage by inhibiting XIAP and inducing the mitochondrial efflux of Smac and cytochrome C. This investigation further support exploring the use of Smac inhibitors in VAL.

Challenges and opportunities in research on early-life events/exposures and cancer development later in life

It is becoming increasingly evident that early-life events and exposures have important consequences for cancer development later in life. However, epidemiological studies of early-life factors and cancer development later in life have had significant methodological challenges such as the long latency period, the distinctiveness of each cancer, and large number of subjects that must be studied, all likely to increase costs. These traditional hurdles might be mitigated by leveraging several existing large-scale prospective studies in the United States (US) and globally, as well as birth databases and birth cohorts, in order to launch both association and mechanistic studies of early-life exposures and cancer development later in life. Dedicated research funding will be needed to advance this paradigm shift in cancer research, and it seems justified by its potential to produce transformative understanding of how cancer develops over the life-course. This in turn has the potential to transform cancer prevention strategies through interventions in early-life rather than later in life, as is the current practice, where it is perhaps less effective.

Hepatitis B virus and lymphomagenesis: novel insights into an occult relationship

BACKGROUND

Increasing evidence shows that Hepatitis B virus infection associates with B-cell but not T-cell malignancies. It remains unclear (a) whether this association is restricted to discrete subtypes of B-cell neoplasms and (b) if occult hepatitis B virus infection can impact on the risk of B-cell malignancy.

METHODS

We analysed the prevalence of occult hepatitis B virus infection in three age and sex matched groups: patients with multiple myeloma, chronic lymphocytic leukaemia and healthy volunteers (N=80 each group). Hepatitis B virus sequences were detected by PCR in blood mononuclear cells isolated prior to treatment.

RESULTS

Fifteen subjects tested positive for occult hepatitis B virus infection and its distribution significantly favoured chronic lymphocytic leukaemia (p<0.02) over the other groups. No difference in age, gender and proportion of anti-HBc seropositivity was noted according to occult hepatitis B virus infection status. Chronic lymphocytic leukaemia had an odds ratio of 4.6 (95% CI 1.5-13.9) for the presence of occult hepatitis B virus infection in comparison to multiple myeloma and controls. Most occult hepatitis B virus infection cases (10/15, 67%) were detected in completely hepatitis B virus seronegative subjects.

CONCLUSIONS

Our data support a potentially causal relationship for hepatitis B virus in chronic lymphocytic leukaemia but not in multiple myeloma. HBsAg seropositivity alone may bias the study of this association, potentially leading to underestimation. Primary occult hepatitis B virus infection appears the most frequent setting in our patients, extending the clinical relevance of hepatitis B virus vaccination to a preventative measure for B-cell neoplasms.

Epidemiology and etiology of mantle cell lymphoma and other non-Hodgkin lymphoma subtypes

We aimed to give an overview of the descriptive epidemiology and etiology of mantle cell lymphoma (MCL) in the context of all non-Hodgkin lymphoma (NHL) and major NHL subtypes, based on available published reports. In retrospective case series, MCL cases represent between 2 and 10% of all NHL. Population-based studies of MCL incidence by basic demographic characteristics are limited to the past 15-20 years and to Europe and the US. In both regions, average incidence rates of approximately 0.5 cases per 100,000 person-years were reported, with a male-to-female ratio of 2.3-2.5:1, and a median age at diagnosis of close to 70 years. Some data suggest a possible increase in MCL incidence over the last two decades, but the observation may also reflect improved diagnostics. The causes of MCL are not known. Studies of potential risk factors of MCL are few and conducted primarily within the framework of all NHL. Moderate associations with MCL risk have been reported for Borrelia burgdorferi infection, family history of hematopoietic malignancies, and genetic variation in the interleukin-10 and tumor necrosis factor genes, but findings remain unconfirmed. Large multicenter studies are needed to address these and other factors in risk of MCL with sufficient statistical power in the future.

The molecular pathogenesis of Hodgkin lymphoma

Hodgkin lymphoma (HL) is an unusual malignancy in that the tumour cells, the Hodgkin and Reed-Sternberg (HRS) cells, are a minor component of the tumour mass, the bulk of which is a mixed cellular infiltrate. There is compelling evidence that HRS cells are clonal B cells that have lost their B cell phenotype. Mature B cells lacking B cell receptors would normally die by apoptosis, and therefore HRS cells must have developed mechanisms to facilitate survival. The escape from apoptosis and transcriptional reprogramming of HRS cells are interlinked and appear central to disease pathogenesis. Epstein-Barr virus (EBV) is present in the HRS cells of a proportion of cases and expresses genes with a plausible oncogenic function. It is likely that EBV plays a role in reprogramming and survival through dysregulation of several signalling networks and transcription factors, including nuclear factor (NF)-κB. Activation of NF-κB is a feature of all HRS cells and gene mutations affecting this pathway appear common in EBV-negative HL. The HRS cell furthers its own survival by attracting a supportive microenvironment of immune and stromal cells, and suppressing local immune responsiveness. Although many questions remain unanswered, the last two decades have witnessed a considerable increase in our knowledge of this complex disease.

Frailty modeling of the bimodal age-incidence of Hodgkin lymphoma in the Nordic countries

BACKGROUND

The bimodality of the age-incidence curve of Hodgkin lymphoma (HL) has been ascribed to the existence of subgroups with distinct etiologies. Frailty models can be usefully applied to age-incidence curves of cancer to aid the understanding of biological phenomena in these instances. The models imply that for a given disease, a minority of individuals are at high risk, compared with the low-risk majority.

METHODS

Frailty modeling is applied to interpret HL incidence on the basis of population-based cancer registry data from the five Nordic countries for the period 1993 to 2007. There were a total of 8,045 incident cases and 362,843,875 person-years at risk in the study period.

RESULTS

A bimodal frailty analysis provides a reasonable fit to the age-incidence curves, employing 2 prototype models, which differ by having the sex covariate included in the frailty component (model 1) or in the baseline Weibull hazard (model 2). Model 2 seemed to fit better with our current understanding of HL than model 1 for the male-to-female ratio, number of rate-limiting steps in the carcinogenic process, and proportion of susceptibles; whereas model 1 performed better related to the heterogeneity in HL among elderly males.

CONCLUSION

The present analysis shows that HL age-incidence data are consistent with a bimodal frailty model, indicating that heterogeneity in cancer susceptibility may give rise to bimodality at the population level, although the individual risk remains simple and monotonically increasing by age.

IMPACT

Frailty modeling adds to the existing body of knowledge on the heterogeneity in risk of acquiring HL.

Serological detection of Epstein-Barr virus infection in dogs and cats

Epstein-Barr virus (EBV) is widespread in humans world-wide. The virus, which is linked to Burkitt's and Hodgkin lymphoma in humans, has recently been detected in pet dogs in Taiwan. The aim of this study was to determine if EBV is present in other canine populations, whether infection is associated with lymphoma in dogs, and whether infection is present in cats. Canine and feline serum samples were analysed by immunofluorescence assay. Antibodies to EBV or an EBV-like virus were detected in 38.4% of UK dog sera, 64% of US dog sera and 38% of cat sera. Canine blood samples, tissue samples from the palatine tonsil and formalin-fixed, paraffin-embedded biopsy samples from canine lymphoma cases were analysed by PCR. Using EBV-specific primers, EBV was detected in one tonsil sample, whereas all other samples tested were negative. PCR using consensus herpesvirus primers identified canine herpesvirus in twelve tonsil samples and one biopsy but no gammaherpesviruses were detected. Canine blood samples from EBV antibody-positive dogs were analysed by RT-PCR to determine if transcripts associated with lytic EBV infection (BcLF1) or latency (LMP2) were present, however all samples tested were negative. In conclusion, there is serological evidence of exposure to EBV or an EBV-like virus in dogs and cats but persistent infection in the canine palatine tonsil is rare and no evidence was found of EBV in canine peripheral blood mononuclear cells. The effect of EBV on canine and feline cells and the possible outcome of the infection for the host require further investigation.

Tonsillitis, tonsillectomy and Hodgkin's lymphoma

It has been debated whether the reported increased risk of Hodgkin's lymphoma (HL) after tonsillectomy could be due to some underlying factor rather than the surgery itself. We studied whether not only tonsillectomy but also tonsillitis was associated with HL. This nationwide cohort study included all Danish residents during 1977-2001. Information on a diagnosis of tonsillitis, tonsillectomy, or HL was obtained from national registries. During 124 million person-years we observed 2,988 HL patients of whom 58 were tonsillectomized (most with preceding tonsillitis) and 14 were diagnosed with only tonsillitis at more than 1 year before HL diagnosis. Tonsillectomy was associated with a significantly increased HL risk in persons under 15 years of age as follows: 1-4 years after tonsillectomy, relative risk (RR) = 3.9 [95% CI: 1.4-11; n = 4]; >5 years after tonsillectomy, RR = 3.5 [1.4-8.5; n = 5]. No young cases of HL occurred among persons diagnosed with only tonsillitis. In contrast, 1-4 years after a hospital diagnosis of tonsillitis without subsequent tonsillectomy we found an increased HL risk in persons aged 15 years or above as follows: 15-34 years of age at HL diagnosis, RR = 3.5 [1.6-7.7; n = 6]; 35+ years, RR = 5.9 [2.2-16; n = 4]. Age at tonsillitis or tonsillectomy did not modify HL risk within the 3 age strata. An increased HL risk was found both after tonsillectomy and after an isolated diagnosis of tonsillitis. These results suggest that tonsillitis is a risk factor for HL and not that, as previously reported, only the surgical removal of tonsils is a risk factor.

Nanomaterials and nanoparticles: sources and toxicity

This review is presented as a common foundation for scientists interested in nanoparticles, their origin,activity, and biological toxicity. It is written with the goal of rationalizing and informing public health concerns related to this sometimes-strange new science of "nano," while raising awareness of nanomaterials' toxicity among scientists and manufacturers handling them.We show that humans have always been exposed to tiny particles via dust storms, volcanic ash, and other natural processes, and that our bodily systems are well adapted to protect us from these potentially harmful intruders. There ticuloendothelial system, in particular, actively neutralizes and eliminates foreign matter in the body,including viruses and nonbiological particles. Particles originating from human activities have existed for millennia, e.g., smoke from combustion and lint from garments, but the recent development of industry and combustion-based engine transportation has profoundly increased an thropogenic particulate pollution. Significantly, technological advancement has also changed the character of particulate pollution, increasing the proportion of nanometer-sized particles--"nanoparticles"--and expanding the variety of chemical compositions. Recent epidemiological studies have shown a strong correlation between particulate air pollution levels, respiratory and cardiovascular diseases, various cancers, and mortality. Adverse effects of nanoparticles on human health depend on individual factors such as genetics and existing disease, as well as exposure, and nanoparticle chemistry, size, shape,agglomeration state, and electromagnetic properties. Animal and human studies show that inhaled nanoparticles are less efficiently removed than larger particles by the macrophage clearance mechanisms in the lungs, causing lung damage, and that nanoparticles can translocate through the circulatory, lymphatic, and nervous systems to many tissues and organs, including the brain. The key to understanding the toxicity of nanoparticles is that their minute size, smaller than cells and cellular organelles, allows them to penetrate these basic biological structures, disrupting their normal function.Examples of toxic effects include tissue inflammation, and altered cellular redox balance toward oxidation, causing abnormal function or cell death. The manipulation of matter at the scale of atoms,"nanotechnology," is creating many new materials with characteristics not always easily predicted from current knowledge. Within the nearly limitless diversity of these materials, some happen to be toxic to biological systems, others are relatively benign, while others confer health benefits. Some of these materials have desirable characteristics for industrial applications, as nanostructured materials often exhibit beneficial properties, from UV absorbance in sunscreen to oil-less lubrication of motors.A rational science-based approach is needed to minimize harm caused by these materials, while supporting continued study and appropriate industrial development. As current knowledge of the toxicology of "bulk" materials may not suffice in reliably predicting toxic forms of nanoparticles,ongoing and expanded study of "nanotoxicity" will be necessary. For nanotechnologies with clearly associated health risks, intelligent design of materials and devices is needed to derive the benefits of these new technologies while limiting adverse health impacts. Human exposure to toxic nanoparticles can be reduced through identifying creation-exposure pathways of toxins, a study that may someday soon unravel the mysteries of diseases such as Parkinson's and Alzheimer's. Reduction in fossil fuel combustion would have a large impact on global human exposure to nanoparticles, as would limiting deforestation and desertification.While nanotoxicity is a relatively new concept to science, this review reveals the result of life's long history of evolution in the presence of nanoparticles, and how the human body, in particular, has adapted to defend itself against nanoparticulate intruders.

EBV and HIV-Related Lymphoma

HIV-associated lymphoproliferative disorders represent a heterogeneous group of diseases, arising in the presence of HIV-associated immunodeficiency. The overall prevalence of HIV-associated lymphoma is significantly higher compared to that of the general population and it continues to be relevant even after the wide availability of highly active antiretroviral therapy (HAART) (1). Moreover, they still represent one of the most frequent cause of death in HIV-infected patients. Epstein-Barr virus (EBV), a γ-Herpesviruses, is involved in human lymphomagenesis, particularly in HIV immunocompromised patients. It has been largely implicated in the development of B-cell lymphoproliferative disorders as Burkitt lymphoma (BL), Hodgkin disease (HD), systemic non Hodgkin lymphoma (NHL), primary central nervous system lymphoma (PCNSL), nasopharyngeal carcinoma (NC). Virus-associated lymphomas are becoming of significant concern for the mortality of long-lived HIV immunocompromised patients, and therefore, research of advanced strategies for AIDS-related lymphomas is an important field in cancer chemotherapy. Detailed understanding of the EBV lifecycle and related cancers at the molecular level is required for novel strategies of molecular-targeted cancer chemotherapy The linkage of HIV-related lymphoma with EBV infection of the tumor clone has several pathogenetic, prognostic and possibly therapeutic implications which are reviewed herein.

A protective role for early oral exposures in the etiology of young adult Hodgkin lymphoma

The pattern of adolescent/young adult Hodgkin lymphoma (YAHL) suggests causation by a relatively late infection with a common childhood virus, but no causal virus has been found. Susceptibility is heritable and linked to lower interleukin 12 (IL12) levels, which can also result from fewer fecal-oral microbial exposures early in life. We studied twin pairs discordant for YAHL to examine exposures capable of altering the IL12 response and T-helper type 1 (Th1)-Th2 balance. One hundred eighty-eight YAHL-discordant twin pairs from the International Twin Study returned questionnaires (70% response). Exposure history of YAHL case-twins was compared with that of their unaffected control-twins using conditional logistic regression for matched pairs to calculate odds ratios (ORs). Behaviors likely to produce oral exposure to microbes conveyed decreases in risk (univariable OR range = 0.2-0.5, P = .003-.11). Significant adjusted ORs were seen for appendectomy (OR = 4.3, P = .001), eczema (OR = 4.2, P = .025), smoking (OR = 2.2, P = .054), and relatively more frequent behaviors associated with oral exposures (OR = 0.1; P = .004). Kappa statistics for intrapair agreement were higher than 0.8 for each significant finding. Our observations support a protective role for increased early oral exposure to the microbiome, suggesting that factors associated with increased Th2 and decreased Th1 cytokines are etiologically relevant to YAHL.

Delayed exposure to infections and childhood lymphomas: a case-control study

OBJECTIVES

Delayed exposure to common infections during childhood, have been implied to cause strong immunological response to a single infectious agent that eventually triggers leukemogenesis. The aim of the present study was to investigate whether decreased exposure to infections, as reflected in a more seronegative spectrum to several common infectious agents, is associated with increased risk for the development of childhood lymphomas.

METHODS

All 125 children (up to 14 years old), with Hodgkin (HL, n = 52) and non-Hodgkin lymphomas (NHL, n = 73) diagnosed through the national network of childhood Hematology-Oncology units during an 8-year period were enrolled in the study along with 125 age- and gender-matched controls. Past exposure to nine common infections [respiratory syncytial virus (RSV), influenza A and B, parainfluenza type 1, adenovirus, Epstein-Barr virus (EBV), cytomegalovirus (CMV), human herpes virus 6 (HHV6), Bartonella henselae] was assessed using serological markers.

RESULTS

After controlling for possible confounding factors, the overall seronegativity status upon diagnosis was statistically significantly associated with NHL [odds ratio; 95% CI: 1.45 (1.10-1.93), p = 0.01] and less so with HL risk [odds ratio; 95% CI: 1.30 (0.83-2.05), p = 0.25]. A statistically significant association of seronegativity with the development of NHL was evident for RSV [odds ratio; 95% CI: 7.27 (1.59-33.28), p = 0.01], EBV [odds ratio; 95% CI: 6.73 (1.45-31.20), p = 0.01] and suggestive association for influenza B [odds ratio; 95% CI: 2.60 (0.90-7.55), p = 0.08] and influenza A [odds ratio; 95% CI: 2.35 (0.81-6.80), p = 0.11]. In contrast, there was no evidence for association of HL with negative serology for any of the infectious agents tested.

CONCLUSIONS

The risk of lymphomas, especially NHL, might be higher when, due to lower exposure to several infectious agents, the relatively unmodulated immune system of a child is challenged by environmental stimuli that can trigger development of lymphomas. The results, however, need further confirmation, through more pertinent methodological designs.

Essential function for the GTPase TC21 in homeostatic antigen receptor signaling

T cell antigen receptors (TCRs) and B cell antigen receptors (BCRs) transmit low-grade signals necessary for the survival and maintenance of mature cell pools. We show here that TC21, a small GTPase encoded by Rras2, interacted constitutively with both kinds of receptors. Expression of a dominant negative TC21 mutant in T cells produced a rapid decrease in cell viability, and Rras2(-/-) mice were lymphopenic, possibly as a result of diminished homeostatic proliferation and impaired T cell and B cell survival. In contrast, TC21 was overexpressed in several human lymphoid malignancies. Finally, the p110delta catalytic subunit of phosphatidylinositol-3-OH kinase (PI(3)K) was recruited to the TCR and BCR in a TC21-dependent way. Consequently, we propose TC21 directly links antigen receptors to PI(3)K-mediated survival pathways.

Hodgkin lymphoma: an update on its biology with new insights into classification

In the past few years, there has been a greater understanding of the spectrum and biology of Hodgkin lymphoma (HL). In standard texts, HL is classified as 2 distinct entities, namely nodular lymphocyte-predominant HL and classical HL (CHL). However, recent evidence suggests that CHL is not a single disease. Although the mixed cellularity and lymphocyte-depleted subtypes might be part of a biologic continuum, the nodular sclerosis subtype has a distinct epidemiology, clinical presentation, and histology. Nodular sclerosis HL might also be related to primary mediastinal B-cell lymphoma and mediastinal gray-zone lymphomas. We present an update on the pathobiology of HL and discuss these biologic and clinical differences in this review.

Infectious aetiology of Hodgkin and non-Hodgkin lymphomas: a review of the epidemiological evidence

Lymphomas constitute a heterogeneous group of malignant disorders with different clinical behaviours, pathological features and epidemiological characteristics. For some lymphoma subtypes, epidemiological evidence has long pointed to infectious aetiologies. A subset of Hodgkin lymphoma is strongly linked to Epstein-Barr virus (EBV) infection. In addition, infectious agents can directly infect and transform lymphocytes (e.g. EBV, human herpesvirus 8), induce immunosuppression (human immunodeficiency virus), or cause chronic immune stimulation (hepatitis C virus, Helicobacter pylori), all of which may play a role in the development of various non-Hodgkin lymphoma subtypes. Here, we review the epidemiological evidence linking infections with malignant lymphoma.

Racial/ethnic variation in EBV-positive classical Hodgkin lymphoma in California populations

Epstein-Barr virus (EBV) is detected in the tumor cells of some but not all Hodgkin lymphoma (HL) patients, and evidence indicates that EBV-positive and -negative HL are distinct entities. Racial/ethnic variation in EBV-positive HL in international comparisons suggests etiologic roles for environmental and genetic factors, but these studies used clinical series and evaluated EBV presence by differing protocols. Therefore, we evaluated EBV presence in the tumors of a large (n = 1,032), racially and sociodemographically diverse series of California incident classical HL cases with uniform pathology re-review and EBV detection methods. Tumor EBV-positivity was associated with Hispanic and Asian/Pacific Islander (API) but not black race/ethnicity, irrespective of demographic and clinical factors. Complex race-specific associations were observed between EBV-positive HL and age, sex, histology, stage, neighborhood socioeconomic status (SES), and birth place. In Hispanics, EBV-positive HL was associated not only with young and older age, male sex, and mixed cellularity histology, but also with foreign birth and lower SES in females, suggesting immune function responses to correlates of early childhood experience and later environmental exposures, respectively, as well as of pregnancy. For APIs, a lack of association with birth place may reflect the higher SES of API than Hispanic immigrants. In blacks, EBV-positive HL was associated with later-stage disease, consistent with racial/ethnic variation in certain cytokine polymorphisms. The racial/ethnic variation in our findings suggests that EBV-positive HL results from an intricate interplay of early- and later-life environmental, hormonal, and genetic factors leading to depressed immune function and poorly controlled EBV infection.

Hepatitis C infection and risk of malignant lymphoma

The association between hepatitis C virus (HCV) infection and risk of malignant lymphoma remains controversial, perhaps due to small-sized studies and low prevalence of HCV in the general population. On the basis of a large Danish-Swedish population-based case-control study, 2,819 lymphoma patients and 1,856 controls of second-generation Danish-Swedish origin were screened for HCV infection using an enzyme-linked immunosorbent assay and a confirming recombinant immunoblot assay (RIBA) test. Positive samples were tested with real-time PCR for the presence of HCV RNA. The association between HCV infection and risk of malignant lymphoma was assessed by logistic regression. When intermediate RIBA test results were interpreted as positive, anti-HCV antibody positivity was associated with a nonsignificant increased risk of non-Hodgkin lymphoma (NHL) overall (odds ratio (OR) = 2.2; 95% confidence interval (CI) 0.9-5.3; n = 20 cases), of B-cell lymphomas combined (OR = 2.4 [1.0-5.8]; n = 20) and of lymphoplasmacytic lymphoma (OR = 5.2 [1.0-26.4]; n = 2). No patients with T-cell or Hodgkin lymphoma were HCV-positive. A more conservative definition of HCV positivity (disregarding intermediate RIBA results) resulted in an OR = 1.6 (0.3-8.5; n = 5) for NHL overall. When the definition was further restricted to require HCV RNA positivity, OR was 1.7 (0.2-16.2; n = 3) for NHL overall. Our findings from a population with a low prevalence of HCV suggest a positive association between HCV and risk of NHL, in particular of B-cell origin.

HIV infection and lymphoma

The incidence of lymphoma in patients with HIV infection greatly exceeds that of the general population. The increased risk for lymphoma appears related to multiple factors, including the transforming properties of the retrovirus itself, the immunosuppression and cytokine dysregulation that results from the disease, and, most importantly, opportunistic infections with other lymphotrophic herpes viruses such as Epstein-Barr virus and human herpesvirus 8. Histologically lymphomas fall into three groups: (1) those also occurring in immunocompetent patients; (2) those occurring more specifically in HIV-positive patients; and (3) those also occurring in patients with other forms of immunosuppression. Aggressive lymphomas account for the vast majority cases. They frequently present with advanced stage, bulky disease with high tumour burden and, typically, involve extranodal sites. Clinical outcome appears to be worse than in similar aggressive lymphomas in the general population. However, following the introduction of highly active antiretroviral therapy, the risk for developing lymphoma in the context of HIV infection has decreased and the clinical outcome has improved.

KSHV/HHV8-associated lymphomas

This review looks at the current state of knowledge on primary effusion lymphoma (PEL) and other Kaposi sarcoma herpesvirus (KSHV)/human herpesvirus 8 (HHV8)-associated lymphomas. In 1995, KSHV DNA sequences were identified within a distinct subgroup of acquired immunodeficiency syndrome-related non-Hodgkin lymphomas localized in body cavities and presenting as pleural, peritoneal and pericardial lymphomatous effusions. Subsequently, the spectrum of KSHV/HHV8-associated lymphomas has been expanded by the identification of cases of extracavitary solid lymphomas without serous effusions. Despite the diversification in the clinical presentation of KSHV/HHV8-associated lymphomas, the majority of the cases reported demonstrated similar morphology, immunophenotype and KSHV/HHV8 viral status. KSHV/HHV8 infection is also in multicentric Castleman disease-associated plasmablastic lymphoma. The exact oncogenic mechanisms of KSHV/HHV8 are not clearly defined. The prognosis for KSHV/HHV8-associated lymphomas is poor. Novel approaches for therapy, outside traditional chemotherapy with CHOP (cyclophosphamide, doxorubicin, prednisone, vincristine), have been suggested. These include the addition of antiviral therapy as well as inhibition of specific cellular targets.