Risk of T-cell lymphomas in persons with AIDS

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.

Role of Antigenic Stimulation in Cutaneous T-Cell Lymphomas

Cutaneous T-cell lymphoma (CTCL) involves a clonal expansion of malignant cells accumulating in the skin, a primary barrier site. CTCL has long been hypothesized to be caused or perpetuated by chronic antigen stimulation due to unknown exposures. These antigenic triggers, defined as any element that may cause activation of malignant T cells through TCR signaling, have been hypothesized to range from chemicals to microbes. This review covers current evidence supporting chemical and microbial stimuli that may act as antigenic triggers of CTCL and summarizes novel areas of investigation, in which the potential antigenicity of the exposure is still unknown.

Centrosome amplification and aneuploidy driven by the HIV-1-induced Vpr•VprBP•Plk4 complex in CD4+ T cells

HIV-1 infection elevates the risk of developing various cancers, including T-cell lymphoma. Whether HIV-1-encoded proteins directly contribute to oncogenesis remains unknown. We observe that approximately 1-5% of CD4+ T cells from the blood of people living with HIV-1 exhibit over-duplicated centrioles, suggesting that centrosome amplification underlies the development of HIV-1-associated cancers by driving aneuploidy. Through affinity purification, biochemical, and cellular analyses, we discover that Vpr, an accessory protein of HIV-1, hijacks the centriole duplication machinery and induces centrosome amplification and aneuploidy. Mechanistically, Vpr forms a cooperative ternary complex with an E3 ligase subunit, VprBP, and polo-like kinase 4 (Plk4). Unexpectedly, however, the complex enhances Plk4's functionality by promoting its relocalization to the procentriole assembly and induces centrosome amplification. Loss of either Vpr's C-terminal 17 residues or VprBP acidic region, the two elements required for binding to Plk4 cryptic polo-box, abrogates Vpr's capacity to induce these events. Furthermore, HIV-1 WT, but not its Vpr mutant, induces multiple centrosomes and aneuploidy in human primary CD4+ T cells. We propose that the Vpr•VprBP•Plk4 complex serves as a molecular link that connects HIV-1 infection to oncogenesis and that inhibiting the Vpr C-terminal motif may reduce the occurrence of HIV-1-associated cancers.

Isolated Central Nervous System Involvement after Brentuximab Vedotin Treatment for HIV-Positive ALK-Negative Anaplastic Large Cell Lymphoma

Human immunodeficiency virus (HIV)-associated lymphoma poses a high mortality risk despite antiretroviral therapy (ART). Although intermediate- or high-grade B-cell lymphomas are common, anaplastic large-cell lymphomas (ALCLs) are rare and seldom affect the central nervous system (CNS). Herein, we present a case of HIV-associated ALCL with isolated CNS involvement that occurred following the discontinuation of ART that was administered after treatment with brentuximab vedotin (BV)-which does not cross the blood-brain barrier. At the time of CNS recurrence, the patient's CD4 count was 9 cells/mm3. This is the first report of CNS recurrence in HIV-associated ALCL. Considering the high risk of CNS relapse, we suggest initiating CNS prophylaxis in cases of HIV-associated ALCL, particularly in patients receiving CNS-impermeable agents such as BV.

Clusters, crop dusters, and myth busters: a scoping review of environmental exposures and cutaneous T-cell lymphoma

INTRODUCTION

Cutaneous T-cell lymphoma (CTCL) is a heterogenous group of non-Hodgkin lymphomas. Similar presentation to benign conditions, significant genetic variation, and lack of definitive biomarkers contributes to diagnostic delay. The etiology of CTCL is unknown, and environmental exposures, such as geographic, occupational, chemicals, sunlight, and insects have been investigated.

EVIDENCE ACQUISITION

Review of the literature for CTCL and exposures was performed in PubMed and Google Scholar in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Extension for Scoping Reviews. This search yielded 193 total results, which were initially screened with defined inclusion and exclusion criteria. The 45 remaining articles were reviewed and classified by exposure type.

EVIDENCE SYNTHESIS

The most frequently investigated CTCL exposure type was geographic (13/45 articles, 29%). Chemical exposures were commonly discussed (10/45 articles, 22%), along with occupational (10/45 articles, 22%). Insect exposures (6/45, 13%) and sun exposure (3/45, 7%) were also reviewed, along with articles describing multiple exposure types (3/45, 7%). Article types ranged from cases to systematic reviews and case-control studies. Evidence linking CTCL and these exposures was mixed. Limitations of this investigation include reliance on patient reporting and frequent speculation on disease association versus causality.

CONCLUSIONS

This investigation synthesizes the current literature on exposures potentially implicated in the pathogenesis of CTCL, while offering guidance on patient history-taking to ensure potential exposures are captured. Awareness of these possible associations may improve understanding of disease pathogenesis and diagnosis. Moreover, these insights may help with public health decision-making and disease mitigation.

Disparities in Cutaneous T-Cell Lymphoma Incidence by Race/Ethnicity and Area-Based Socioeconomic Status

Cutaneous T-cell lymphoma (CTCL) is a rare type of extranodal non-Hodgkin lymphoma (NHL). This study uses population-based data from the New Jersey (NJ) State Cancer Registry to examine geographic variation in CTCL incidence and evaluates whether CTCL risk varies by race/ethnicity and census tract socioeconomic status (SES). The study included 1163 cases diagnosed in NJ between 2006 and 2014. Geographic variation and possible clustering of high CTCL rates were assessed using Bayesian geo-additive models. The associations between CTCL risk and race/ethnicity and census tract SES, measured as median household income, were examined using Poisson regression. CTCL incidence varied across NJ, but there were no statistically significant geographic clusters. After adjustment for age, sex, and race/ethnicity, the relative risk (RR) of CTCL was significantly higher (RR = 1.47, 95% confidence interval: 1.22-1.78) in the highest income quartile than in the lowest. The interactions between race/ethnicity and SES indicated that the income gradients by RR were evident in all groups. Compared to non-Hispanic White individuals in low-income tracts, CTCL risk was higher among non-Hispanic White individuals in high-income tracts and among non-Hispanic Black individuals in tracts of all income levels. Our findings suggest racial disparities and a strong socioeconomic gradient with higher CTCL risk among cases living in census tracts with higher income compared to those living in lower-income tracts.

HIV-Associated Lymphomas: Progress and New Challenges

The association of human immunodeficiency virus (HIV) and aggressive lymphomas was first reported in 1982. Before the development of effective HIV antiviral therapy, the incidence and the mortality of these lymphomas was high, with patients frequently succumbing to the disease. More lately, the combination of cART with chemoimmunotherapy significantly improved the survival outcome of the HIV-lymphomas. In this review, we discuss on describing the incidence of HIV-associated lymphomas, their clinical features, and the latest advances in the management of the various lymphoma subtypes.

Accuracy of Pathologic Diagnosis in Patients With Lymphoma and Survival: A Prospective Analysis From Botswana

PURPOSE

With intense HIV epidemics, southern African countries have a high burden of classic Hodgkin lymphoma (CHL) and non-Hodgkin lymphoma (NHL). However, suboptimal access to pathology resources limits subtype classification. We sought to assess the diagnostic accuracy of specimens classified as lymphoma and to determine association between discordant pathologic diagnosis and overall survival.

METHODS

Seventy patients with CHL or NHL and treated at three Botswana hospitals from 2010 to 2016 were analyzed. Local pathologic assessment relied primarily on morphology. All cases underwent secondary US hematopathology review, which is considered gold standard.

RESULTS

The median follow-up was 58 months. The overall reclassification rate was 20 of 70 cases (29%). All 20 CHL cases were correctly classified in Botswana, and mixed cellularity was the most common subtype, diagnosed in 11 (55%) cases. Of 47 confirmed NHL cases, diffuse large B-cell lymphoma was the final US diagnosis in 28 cases (60%), another aggressive B-cell NHL in nine (19%), an indolent B-cell NHL in six (13%), and T-cell NHL in four (9%). Common types of diagnostic discordance included NHL subtype reclassification (11 of 20, 55%) and CHL reclassified as NHL (7 of 20, 35%). Concordant versus discordant diagnosis after secondary review was associated with improved 5-year overall survival (60.1% v 26.3%, P = .0066). Discordant diagnosis was independently associated with increased risk of death (adjusted hazard ratio 2.733; 95% CI, 1.102 to 6.775; P = .0300) even after stratifying results by CHL versus NHL.

CONCLUSION

In this single prospective cohort, discordant pathologic diagnosis was associated with a nearly three-fold increased risk of death. Limited access to relatively basic diagnostic techniques impairs treatment decisions and leads to poor patient outcomes in low-resource countries.

Clonal Expansion of Infected CD4+ T Cells in People Living with HIV

HIV infection is not curable with current antiretroviral therapy (ART) because a small fraction of CD4+ T cells infected prior to ART initiation persists. Understanding the nature of this latent reservoir and how it is created is essential to development of potentially curative strategies. The discovery that a large fraction of the persistently infected cells in individuals on suppressive ART are members of large clones greatly changed our view of the reservoir and how it arises. Rather than being the products of infection of resting cells, as was once thought, HIV persistence is largely or entirely a consequence of infection of cells that are either expanding or are destined to expand, primarily due to antigen-driven activation. Although most of the clones carry defective proviruses, some carry intact infectious proviruses; these clones comprise the majority of the reservoir. A large majority of both the defective and the intact infectious proviruses in clones of infected cells are transcriptionally silent; however, a small fraction expresses a few copies of unspliced HIV RNA. A much smaller fraction is responsible for production of low levels of infectious virus, which can rekindle infection when ART is stopped. Further understanding of the reservoir will be needed to clarify the mechanism(s) by which provirus expression is controlled in the clones of cells that constitute the reservoir.

Insertional activation of STAT3 and LCK by HIV-1 proviruses in T cell lymphomas

Retroviruses cause cancers in animals by integrating in or near oncogenes. Although HIV-1 infection increases the risk of cancer, most of the risk is associated with immunodeficiency and coinfection by oncogenic virus (Epstein-Barr virus, Kaposi sarcoma herpesvirus, and human papillomavirus). HIV-1 proviruses integrated in some oncogenes cause clonal expansion of infected T cells in vivo; however, the infected cells are not transformed, and it is generally believed that HIV-1 does not cause cancer directly. We show that HIV-1 proviruses integrated in the first introns of signal transducer and activator of transcription 3 (STAT3) and lymphocyte-specific protein tyrosine kinase (LCK) can play an important role in the development of T cell lymphomas. The development of these cancers appears to be a multistep process involving additional nonviral mutations, which could help explain why T cell lymphomas are rare in persons with HIV-1 infection.

Geographic clustering of cutaneous T-cell lymphoma in New Jersey: an exploratory analysis using residential histories

PURPOSE

Cutaneous T-cell lymphoma (CTCL) is a rare type of non-Hodgkin lymphoma. Previous studies have reported geographic clustering of CTCL based on the residence at the time of diagnosis. We explore geographic clustering of CTCL using both the residence at the time of diagnosis and past residences using data from the New Jersey State Cancer Registry.

METHODS

CTCL cases (n = 1,163) diagnosed between 2006-2014 were matched to colon cancer controls (n = 17,049) on sex, age, race/ethnicity, and birth year. Jacquez's Q-Statistic was used to identify temporal clustering of cases compared to controls. Geographic clustering was assessed using the Bernoulli-based scan-statistic to compare cases to controls, and the Poisson-based scan-statisic to compare the observed number of cases to the number expected based on the general population. Significant clusters (p < 0.05) were mapped, and standard incidence ratios (SIR) reported. We adjusted for diagnosis year, sex, and age.

RESULTS

The Q-statistic identified significant temporal clustering of cases based on past residences in the study area from 1992 to 2002. A cluster was detected in 1992 in Bergen County in northern New Jersey based on the Bernoulli (1992 SIR 1.84) and Poisson (1992 SIR 1.86) scan-statistics. Using the Poisson scan-statistic with the diagnosis location, we found evidence of an elevated risk in this same area, but the results were not statistically significant.

CONCLUSION

There is evidence of geographic clustering of CTCL cases in New Jersey based on past residences. Additional studies are necessary to understand the possible reasons for the excess of CTCL cases living in this specific area some 8-14 years prior to diagnosis.

Two Different Extranodal Lymphomas in an HIV+ Patient: A Case Report and Review of the Literature

Human immune deficiency virus- (HIV-) infected individuals present a higher risk of developing malignancies. Herein, we are presenting an unusual case of an untreated HIV+ patient, who developed two distinct lymphoproliferative disorders in a period of 4 years: a primary cutaneous T-cell lymphoma (PCTCL) and a diffuse large B-cell lymphoma (DLBCL) not otherwise specified (NOS), the latter developed while commencing combined antiretroviral therapy (cART). The two lymphomas also showed peculiar features: PCTCL are rarely described in HIV+ setting and particularly at such a low clinical stage, and the DLBCL showed uncommon cytology, non-GCB phenotype, EBER negativity, and absence of c-MYC translocation, all atypical features in this clinical context. This report not only confirms the increased risk of lymphoma for HIV+ patients and HIV infection being one of the major risk factors for lymphoid disorders but draws the attention on the possible occurrence of unusual features, suggesting that HIV serology should always be investigated in the clinical suspicion of lymphoma.

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.

The role of integration and clonal expansion in HIV infection: live long and prosper

Integration of viral DNA into the host genome is a central event in the replication cycle and the pathogenesis of retroviruses, including HIV. Although most cells infected with HIV are rapidly eliminated in vivo, HIV also infects long-lived cells that persist during combination antiretroviral therapy (cART). Cells with replication competent HIV proviruses form a reservoir that persists despite cART and such reservoirs are at the center of efforts to eradicate or control infection without cART. The mechanisms of persistence of these chronically infected long-lived cells is uncertain, but recent research has demonstrated that the presence of the HIV provirus has enduring effects on infected cells. Cells with integrated proviruses may persist for many years, undergo clonal expansion, and produce replication competent HIV. Even proviruses with defective genomes can produce HIV RNA and may contribute to ongoing HIV pathogenesis. New analyses of HIV infected cells suggest that over time on cART, there is a shift in the composition of the population of HIV infected cells, with the infected cells that persist over prolonged periods having proviruses integrated in genes associated with regulation of cell growth. In several cases, strong evidence indicates the presence of the provirus in specific genes may determine persistence, proliferation, or both. These data have raised the intriguing possibility that after cART is introduced, a selection process enriches for cells with proviruses integrated in genes associated with cell growth regulation. The dynamic nature of populations of cells infected with HIV during cART is not well understood, but is likely to have a profound influence on the composition of the HIV reservoir with critical consequences for HIV eradication and control strategies. As such, integration studies will shed light on understanding viral persistence and inform eradication and control strategies. Here we review the process of HIV integration, the role that integration plays in persistence, clonal expansion of the HIV reservoir, and highlight current challenges and outstanding questions for future research.

A case-control study of HIV infection and cancer in the era of antiretroviral therapy in Rwanda

The aim of this study was to assess the association between HIV infection and cancer risk in Rwanda approximately a decade after the introduction of antiretroviral therapy (cART). All persons seeking cancer care at Butaro Cancer Center of Excellence (BCCOE) in Rwanda from 2012 to 2016 were routinely screened for HIV, prior to being confirmed with or without cancer (cases and controls, respectively). Cases were coded according to ICD-O-3 and converted to ICD10. Associations between individual cancer types and HIV were estimated using adjusted unconditional logistic regression. 2,656 cases and 1,196 controls differed by gender (80.3% vs. 70.8% female), age (mean 45.5 vs. 37.7 years), place of residence and proportion of diagnoses made by histopathology (87.5% vs. 67.4%). After adjustment for these variables, HIV was significantly associated with Kaposi Sarcoma (n = 60; OR = 110.3, 95%CI 46.8-259.6), non-Hodgkin lymphoma (NHL) (n = 265; OR = 2.5, 1.4-4.6), Hodgkin lymphoma (HL) (n = 76; OR = 5.2, 2.3-11.6) and cancers of the cervix (n = 560; OR = 5.9, 3.8-9.2), vulva (n = 23; OR = 17.8, 6.3-50.1), penis (n = 29; OR = 8.3, 2.5-27.4) and eye (n = 17; OR = 4.7, 1.0-25.0). Associations varied by NHL/HL subtype, with that for NHL being limited to DLBCL (n = 56; OR = 6.6, 3.1-14.1), particularly plasmablastic lymphoma (n = 6, OR = 106, 12.1-921). No significant associations were seen with other commonly diagnosed cancers, including female breast cancer (n = 559), head and neck (n = 116) and colorectal cancer (n = 106). In conclusion, in the era of cART in Rwanda, HIV is associated with increased risk of a range of infection-related cancers, and accounts for an important fraction of cancers presenting to a referral hospital.

Clinicopathological characteristics of T-cell non-Hodgkin lymphoma arising in patients with immunodeficiencies: a single-center case series of 25 patients and a review of the literature

Although it is known that B-cell lymphomas occur more frequently in immunocompromised patients, thus far such an association has not been clearly established for T-cell lymphomas. Of the 251 patients who were diagnosed with a T-cell non-Hodgkin lymphoma in our center between 1999 and 2014, at least 25 were identified in immunocompromised patients. Herein, we retrospectively analyzed the clinical and pathological characteristics of these 25 cases. In addition, we searched the literature and present an overview of 605 previously published cases. The actual number of patients with B-cell chronic lymphocytic leukemia and patients on immunosuppressive drugs for inflammatory bowel disease or rheumatoid arthritis in the total cohort of 251 patients diagnosed with T-cell non-Hodgkin lymphoma was much higher than the number of patients expected to have these diseases in this cohort, based on their prevalence in the general population. This, together with the large number of additional cases found in the literature, suggest that the risk of developing T-cell non-Hodgkin lymphoma is increased in immunocompromised patients. Compared to T-cell non-Hodgkin lymphoma in the general population, these lymphomas are more often located extranodally, present at a younger age and appear to have a poor outcome. The observations made in the study herein should raise awareness of the possible development of T-cell non-Hodgkin lymphoma in immunodeficient patients, and challenge the prolonged use of immunosuppressive drugs in patients who are in clinical remission of their autoimmune disease.

T-cell Lymphoma Epidemiology: the Known and Unknown

T-cell lymphoma, a collection of subtypes of Non-Hodgkin lymphoma, is a rare malignancy. The low prevalence of this disease has made it challenging to identify subtype-specific risk factors. Potential risk factors could enable us to identify high-risk patients and predict patient outcomes. Here, we report on the current epidemiologic and prognostic factors data associated with the individual subtypes both of peripheral T-cell lymphoma (PTCL) and cutaneous T-cell lymphoma (CTCL) found in large cohort and case studies. Additionally, with recent findings, as well as updates in the new World Health Organization (WHO) classification of lymphoid neoplasms, we consider what this could do to change our approach to this group of diseases.

Cutaneous extranodal NK/T-cell lymphoma mimicking cellulitis an HIV positive patient without lymphopenia

We present the case of a 28-year-old male with a history of human immunodeficiency virus (HIV) with a 1-month history of a steadily enlarging, firm painful lesion on the right posterior shoulder. The patient was initially treated for cellulitis given his clinical picture. Histopathologic examination revealed an angiocentric and dermal proliferation of markedly atypical lymphoid cells with numerous mitoses and apoptotic bodies along with broad zones of necrosis. Biopsy revealed the presentation to be consistent with NK/T-cell lymphoma. The cutaneous lesions from NK/T-cell lymphoma can often be initially mistaken for cellulitis, therefore this malignancy should be included on the differential in a patient HIV/acquired immune deficiency syndrome (AIDS).

Etiologic heterogeneity among non-Hodgkin lymphoma subtypes: the InterLymph Non-Hodgkin Lymphoma Subtypes Project

BACKGROUND

Non-Hodgkin lymphoma (NHL) comprises biologically and clinically heterogeneous subtypes. Previously, study size has limited the ability to compare and contrast the risk factor profiles among these heterogeneous subtypes.

METHODS

We pooled individual-level data from 17 471 NHL cases and 23 096 controls in 20 case-control studies from the International Lymphoma Epidemiology Consortium (InterLymph). We estimated the associations, measured as odds ratios, between each of 11 NHL subtypes and self-reported medical history, family history of hematologic malignancy, lifestyle factors, and occupation. We then assessed the heterogeneity of associations by evaluating the variability (Q value) of the estimated odds ratios for a given exposure among subtypes. Finally, we organized the subtypes into a hierarchical tree to identify groups that had similar risk factor profiles. Statistical significance of tree partitions was estimated by permutation-based P values (P NODE).

RESULTS

Risks differed statistically significantly among NHL subtypes for medical history factors (autoimmune diseases, hepatitis C virus seropositivity, eczema, and blood transfusion), family history of leukemia and multiple myeloma, alcohol consumption, cigarette smoking, and certain occupations, whereas generally homogeneous risks among subtypes were observed for family history of NHL, recreational sun exposure, hay fever, allergy, and socioeconomic status. Overall, the greatest difference in risk factors occurred between T-cell and B-cell lymphomas (P NODE < 1.0×10(-4)), with increased risks generally restricted to T-cell lymphomas for eczema, T-cell-activating autoimmune diseases, family history of multiple myeloma, and occupation as a painter. We further observed substantial heterogeneity among B-cell lymphomas (P NODE < 1.0×10(-4)). Increased risks for B-cell-activating autoimmune disease and hepatitis C virus seropositivity and decreased risks for alcohol consumption and occupation as a teacher generally were restricted to marginal zone lymphoma, Burkitt/Burkitt-like lymphoma/leukemia, diffuse large B-cell lymphoma, and/or lymphoplasmacytic lymphoma/Waldenström macroglobulinemia.

CONCLUSIONS

Using a novel approach to investigate etiologic heterogeneity among NHL subtypes, we identified risk factors that were common among subtypes as well as risk factors that appeared to be distinct among individual or a few subtypes, suggesting both subtype-specific and shared underlying mechanisms. Further research is needed to test putative mechanisms, investigate other risk factors (eg, other infections, environmental exposures, and diet), and evaluate potential joint effects with genetic susceptibility.

Rationale and Design of the International Lymphoma Epidemiology Consortium (InterLymph) Non-Hodgkin Lymphoma Subtypes Project

BACKGROUND

Non-Hodgkin lymphoma (NHL), the most common hematologic malignancy, consists of numerous subtypes. The etiology of NHL is incompletely understood, and increasing evidence suggests that risk factors may vary by NHL subtype. However, small numbers of cases have made investigation of subtype-specific risks challenging. The International Lymphoma Epidemiology Consortium therefore undertook the NHL Subtypes Project, an international collaborative effort to investigate the etiologies of NHL subtypes. This article describes in detail the project rationale and design.

METHODS

We pooled individual-level data from 20 case-control studies (17471 NHL cases, 23096 controls) from North America, Europe, and Australia. Centralized data harmonization and analysis ensured standardized definitions and approaches, with rigorous quality control.

RESULTS

The pooled study population included 11 specified NHL subtypes with more than 100 cases: diffuse large B-cell lymphoma (N = 4667), follicular lymphoma (N = 3530), chronic lymphocytic leukemia/small lymphocytic lymphoma (N = 2440), marginal zone lymphoma (N = 1052), peripheral T-cell lymphoma (N = 584), mantle cell lymphoma (N = 557), lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (N = 374), mycosis fungoides/Sézary syndrome (N = 324), Burkitt/Burkitt-like lymphoma/leukemia (N = 295), hairy cell leukemia (N = 154), and acute lymphoblastic leukemia/lymphoma (N = 152). Associations with medical history, family history, lifestyle factors, and occupation for each of these 11 subtypes are presented in separate articles in this issue, with a final article quantitatively comparing risk factor patterns among subtypes.

CONCLUSIONS

The International Lymphoma Epidemiology Consortium NHL Subtypes Project provides the largest and most comprehensive investigation of potential risk factors for a broad range of common and rare NHL subtypes to date. The analyses contribute to our understanding of the multifactorial nature of NHL subtype etiologies, motivate hypothesis-driven prospective investigations, provide clues for prevention, and exemplify the benefits of international consortial collaboration in cancer epidemiology.

Risk of non-Hodgkin lymphoma subtypes in HIV-infected people during the HAART era: a population-based study

OBJECTIVE

HIV-infected people have greatly elevated risk of non-Hodgkin lymphoma (NHL), particularly the AIDS-defining NHL subtypes: diffuse large B-cell lymphoma, Burkitt lymphoma and primary lymphomas arising in the central nervous system. The goals of this analysis were to comprehensively describe risks of NHL subtypes, especially those not well studied, among HIV/AIDS patients; examine risks specifically in the HAART era; and distinguish risks in HIV-infected individuals prior to diagnosis with AIDS.

DESIGN

Population-based registry linkage study.

METHODS

We used data from the US HIV/AIDS Cancer Match Study from 1996 to 2010 (N = 273 705) to calculate standardized incidence ratios (SIRs) comparing subtype-specific NHL risks in HIV-infected people to those in the general population, and used Poisson regression to test for differences in SIRs between the HIV-only and AIDS periods.

RESULTS

NHL risk was elevated 11-fold compared to the general population, but varied substantially by subtype. AIDS-defining NHL subtypes comprised the majority, and risks were high (SIRs ≥17), but risks were also increased for some T-cell lymphomas (SIRs = 3.6-14.2), marginal zone lymphoma (SIR = 2.4), lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (SIR = 3.6), and acute lymphoblastic leukemia/lymphoma (SIR = 2.4).

CONCLUSION

HIV-infected people in the HAART era continue to have elevated risk of AIDS-defining NHL subtypes, highlighting the contribution of moderate and severe immunosuppression to their cause. Whereas non-AIDS-defining subtypes are much less common, immunosuppression or other dysregulated immune states likely play a role in the cause of some T-cell lymphomas, marginal zone lymphoma, lymphoplasmacytic lymphoma/Waldenström macroglobulinemia, and acute lymphoblastic leukemia/lymphoma.

HIV-associated peripheral T-cell lymphoma with a cytotoxic phenotype

Most human immunodeficiency virus (HIV)-related lymphomas are of B-cell origin, and the T-cell type is very rare. We experienced a Japanese case of HIV-associated peripheral T-cell lymphoma (HIV-PTCL). Sudden intestinal hemorrhage necessitated emergent surgical resection of the small intestine, in which an ulcerative lesion was detected. A histopathological examination revealed large tumor cells in the base of the ulcer, which were immunohistochemically CD30(+), CD56(+), granzyme B(+), CD3(+) (focally), CD4(-), CD8(-) and EBER(+). A diagnosis of PTCL, not otherwise specified, was therefore made. The differential diagnosis and significance of Epstein-Barr virus infection are also herein discussed.

Unusual clinical presentation of anaplastic large cell lymphoma

Anaplastic large cell lymphoma (ALCL), a well-recognized entity, presents a varied clinical picture and epidemiological characteristics associated with the expression of the anaplastic lymphoma kinase (ALK) protein. When classic symptoms are present (weight loss, fever, and night sweats) and combine with enlarged and easily accessible peripheral lymph nodes, diagnosis is not that difficult. But when the clinical presentation is nonspecific, a tough diagnostic task is required. HIV infection is highly associated with neoplastic disorders-mainly with those of hematological origin. However, ALCL is exceptionally associated with HIV infection, and the few reported cases are ALK- ALCL. The authors report two cases of ALK+ ALCL with the unusual clinical presentation: one is associated with the HIV infection and the other presents as a fever of unknown origin (FUO) without peripheral lymphadenopathy. The latter was autopsied and was characterized by nodal and extra nodal involvement. The authors call attention to the plurality of clinical presentation of this group of lymphomas, and the early indication of bone marrow examination in cases of an FUO with elevated hepatic enzymes and lactic dehydrogenase.

A Rare Case of Primary Gastric HIV-Associated Peripheral T-Cell Lymphoma: Relapsed Disease Treated With Pemetrexed

We present a case of a patient with HIV/AIDS who presented with abdominal pain and melena and was found to have gastric peripheral T-cell lymphoma (PTCL). He was treated with 6 cycles of EPOCH with a complete response. Within 3 months, he had central nervous system (CNS) and soft-tissue relapse. He was subsequently treated with 3 cycles of intravenous pemetrexed and experienced a second complete response. To our knowledge, there are fewer than 100 reports of HIV-associated PTCL worldwide as of 2010, and among these cases involvement of the stomach as the primary site of extranodal disease is exceptionally rare. The disease carries a poor prognosis and current standard therapies highlight the importance of HIV/AIDS disease control and the need for more studies on therapies and the role of transplantation in refractory or relapsed HIV-associated PTCL.

Peripheral T-cell lymphoma in HIV-infected patients: a study of 17 cases in the combination antiretroviral therapy era

Most cases of human immunodeficiency virus (HIV)-associated non-Hodgkin Lymphoma (NHL) are of B-cell origin; T-cell NHLs are rarely reported. Within a single centre prospective cohort of 370 HIV-NHL, 17 (5%) were of T-cell origin (82% male; median age, 39 years). Median CD4+ cell count was 0·194 × 10(9) /l and 41% had undetectable plasma HIV-RNA at lymphoma diagnosis. All patients received combination antiretroviral therapy during chemotherapy. All histological samples were centrally reviewed. The distribution of the histological subtypes differed from the general population with absence of angioimmunoblastic subtype. Lymphoma was disseminated in 14 patients, and seven patients had performance status >2. All patients received full-dose chemotherapy: eight standard and nine intensive regimens. Two patients who received intensive chemotherapy died during therapy. The complete remission rate was 53%; 62·5% with standard therapy and 44% with intensive therapy. After a median follow-up of 7·2 years, the median overall survival was 9·4 months. Most deaths (85%) occurred within the first year following diagnosis, as a consequence of lymphoma progression in 10/13 cases. In this rare but severe complication of HIV infection the use of intensive chemotherapy does not appear to be beneficial for response, with increased toxicity.

The epidemic of non-Hodgkin lymphoma in the United States: disentangling the effect of HIV, 1992-2009

BACKGROUND

For decades, non-Hodgkin lymphoma (NHL) incidence has been increasing worldwide. NHL risk is strongly increased among HIV-infected people. Our understanding of trends in NHL incidence has been hampered by difficulties in separating HIV-infected NHL cases from general population rates.

METHODS

NHL incidence data during 1992-2009 were derived from 10 U.S. SEER cancer registries with information on HIV status at NHL diagnosis. The CDC estimated the number of people living with HIV in the registry areas. The proportion of NHL cases with HIV and NHL rates in the total and the HIV-uninfected populations were estimated. Time trends were assessed with Joinpoint analyses.

RESULTS

Of 115,643 NHL cases diagnosed during 1992-2009, 5.9% were HIV-infected. The proportions of NHL cases with HIV were highest for diffuse large B-cell (DLBCL; 7.8%), Burkitt (26.9%), and peripheral T-cell lymphomas (3.2%) with low proportions (≤1.1%) in the other subtypes. NHL rates in the total population increased 0.3% per year during 1992-2009. However, rates of NHL in HIV-uninfected people increased 1.4% per year during 1992-2003, before becoming stable through 2009. Similar trends were observed for DLBCLs and follicular lymphoma in HIV-uninfected people; rates increased 2.7% per year until 2003 and 1.7% per year until 2005, respectively, before stabilizing.

CONCLUSIONS

NHL incidence rates in the United States have plateaued over the last 5-10 years, independent of HIV infection.

IMPACT

Although the causes of the long-term increase in NHL incidence rates in the United States remain unknown, general population rates of NHL have stabilized since the early 2000s, independent of HIV.

Anaplastic Large Cell Lymphoma Occurring in an HIV-Positive Patient

Cases of anaplastic large-cell lymphoma (ALCL) of T phenotype are sparse in the setting of HIV patients. We report herein a case of T-ALCL, with an advanced stage, pulmonary involvement, high HIV viral load, and low CD4 level. Anaplastic lymphoma kinase (ALK) protein expression was negative. Anthracyclin-based chemotherapy was unsuccessful. The literature review was performed focusing on incidence, clinical characteristics, prognosis, and physiopathology of ALCL in HIV patients. More data are needed to improve the knowledge of such cases and to define a better treatment approach.

Depletion and dysfunction of Vγ2Vδ2 T cells in HIV disease: mechanisms, impacts and therapeutic implications

Infection with human immunodeficiency virus (HIV) disrupts the balance among γδ T cell subsets, with increasing Vδ1+ cells and substantial depletion of circulating Vδ2+ cells. Depletion is an indirect effect of HIV in CD4-negative Vδ2 cells, but is specific for phosphoantigen-responsive subpopulations identified by the Vγ2-Jγ1.2 (also called Vγ9-JγP) T cell receptor rearrangement. The extent of cell loss and recovery is related closely to clinical status, with highest levels of functional Vδ2 cells present in virus controllers (undetectable viremia in the absence of antiretroviral therapy). We review the mechanisms and clinical consequences for Vδ2 cell depletion in HIV disease. We address the question of whether HIV-mediated Vδ2 cell depletion, despite being an indirect effect of infection, is an important part of the immune evasion strategy for this virus. The important roles for Vδ2 cells, as effectors and immune regulators, identify key mechanisms affected by HIV and show the strong relationships between Vδ2 cell loss and immunodeficiency disease. This field is moving toward immune therapies based on targeting Vδ2 cells and we now have clear goals and expectations to guide interventional clinical trials.

Increased risk of histologically defined cancer subtypes in human immunodeficiency virus-infected individuals: clues for possible immunosuppression-related or infectious etiology

BACKGROUND

Malignancies that occur in excess among human immunodeficiency virus (HIV)-infected individuals may be caused by immunosuppression or infections. Because histologically defined cancer subtypes have not been systematically evaluated, their risk was assessed among people with acquired immunodeficiency syndrome (AIDS).

METHODS

Analyses included 569,268 people with AIDS from the HIV/AIDS Cancer Match Study, a linkage of 15 US population-based HIV/AIDS and cancer registries during 1980 to 2007. Standardized incidence ratios (SIRs) were estimated to compare cancer risk in people with AIDS to the general population overall, and stratified by age, calendar period (a proxy of changing HIV therapies), and time since onset of AIDS (a proxy of immunosuppression).

RESULTS

Sixteen individual cancer histologies or histology groupings manifested significantly elevated SIRs. Risks were most elevated for adult T cell leukemia/lymphoma (SIR = 11.3), neoplasms of histiocytes and accessory lymphoid cells (SIR = 10.7), giant cell carcinoma (SIR = 7.51), and leukemia not otherwise specified (SIR = 6.69). SIRs ranged from 1.4 to 4.6 for spindle cell carcinoma, bronchioloalveolar adenocarcinoma, adnexal and skin appendage neoplasms, sarcoma not otherwise specified, spindle cell sarcoma, leiomyosarcoma, mesothelioma, germ cell tumors, plasma cell tumors, immunoproliferative diseases, acute lymphocytic leukemia, and myeloid leukemias. For several of these cancer subtypes, significant declines in SIRs were observed across calendar periods (consistent with decreasing risk with improved HIV therapies) or increase in SIRs with time since onset of AIDS (ie, prolonged immunosuppression).

CONCLUSIONS

The elevated risk of certain cancer subtypes in people with AIDS may point to an etiologic role of immunosuppression or infection. Future studies are needed to further investigate these associations and evaluate candidate infectious agents.

Prognostic factors in patients with HIV-associated peripheral T-cell lymphoma: a multicenter study

HIV infection has been associated with an increased risk of developing several types of malignancies, including aggressive peripheral T-cell lymphomas (PTCL). However, this is a rare occurrence with no more than a hundred cases reported in the literature. The purpose of this multicenter study is to describe the characteristics and to identify prognostic factors in patients with HIV-associated PTCL. Data from HIV-positive patients with a pathological diagnosis of non-primary cutaneous, non-leukemic PTCL were gathered retrospectively and are reported using descriptive statistics. Univariate and multivariate survival analyses were also performed. Fifty one patients were included in our analysis. Median age was 38 years with a 5:1 male-to-female ratio. Patients presented with a median CD4(+) count of 173 cells mm⁻³, and a median HIV viral load of 334,787 copies ml⁻¹. The median time from HIV diagnosis to PTCL diagnosis was 4.5 years. About 75% of patients presented with advanced clinical stage and 66% with B symptoms. The most common subtypes were PTCLU (61%) and anaplastic large cell lymphoma (ALCL, 22%). None of the ALCL patients tested expressed ALK. The median overall survival (OS) for the group was 12 months. In the multivariate survival analysis, the use of HAART and patients' performance status were independently associated with OS. HIV-associated PTCL presents predominantly in young men with low CD4(+) counts and high HIV viral loads. Both HIV-related and lymphoma-related factors were associated with OS.

Skin cancers associated with HIV infection and solid-organ transplantation among elderly adults

Immunosuppression may be etiologic for some skin cancers. We investigated the impact of human immunodeficiency virus (HIV) infection and solid-organ transplantation on skin cancer risk. We conducted a population-based case-control study among elderly U.S. adults (non-Hispanic whites, age 67 years or older), using Surveillance, Epidemiology and End Results Medicare linked data. The study comprised 29,926 skin cancer cases (excluding basal cell and squamous cell carcinomas) and 119,704 controls, frequency-matched by gender, age and calendar year (1987-2002). Medicare claims identified solid-organ transplantation or HIV infection before cancer diagnosis/control selection. As negative controls, we evaluated other medical conditions (e.g., hypertension and depression) and cancers (breast, colon and prostate) not linked to immunosuppression. Odds ratios (ORs) compared prevalence in cases and controls, adjusted for matching factors and number of prior physician claims. Risks of Kaposi sarcoma (N = 602) and cutaneous non-Hodgkin lymphoma (N = 1,836) were increased with solid-organ transplantation (OR [95%CI]: 11.06 [5.27-23.23] and 2.27 [1.00-5.15], respectively) and HIV infection (21.58 [11.94-38.99] and 2.41 [1.05-5.52], respectively). Solid-organ transplantation was also associated with increased risks of Merkel cell carcinoma (N = 1,286; OR [95%CI] 4.95 [2.62-9.34]) and other cutaneous sarcomas (N = 972; 4.19 [1.83-9.56]). Solid-organ transplantation was nonsignificantly associated with melanoma (N = 23,974; (OR 1.36 [95%CI 0.98-1.88]). Null or weak associations were observed for negative control medical conditions and cancers. Solid-organ transplantation and HIV infection were followed by increased risk for some skin cancer subtypes among elderly adults. These results highlight the potential role of immunity in development of skin cancers.

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.

Hyper interleukin-10 in an HIV-positive child with t-cell lymphoma and candidal sepsis

We describe a case in which a human immunodeficiency virus (HIV)-positive child presented in severe metabolic acidosis secondary to his candidal sepsis and T-cell lymphoma, a rare finding in pediatric AIDS. Significantly elevated levels of Interleukin-10 (IL-10) were found in the patient's serum, which may have played a role in acute demise.

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.

Mycosis fungoides--analysis of the duration of disease stages in patients who progress and the time point of high-grade transformation

BACKGROUND

Mycosis fungoides (MF) is a low-grade malignant primary cutaneous T-cell lymphoma which, in its evolution, passes through five distinct stages (patch, plaque, and tumor stages, lymph node infiltration, and, finally, multiple organ infiltration). Furthermore, a blast transformation into a high-grade malignant lymphoma can occur. In order to better understand the dynamics of the disease and the prognostic implications in patients who progress, we studied the duration of each stage and the time at which blast transformation occurred.

METHODS

We reviewed the records of 48 MF patients who had been followed in the lymphoma clinic of the Department of Dermatology, University Hospital Zurich, Zurich, Switzerland for a median of 10 years. Forty-two cases were eligible for evaluation.

RESULTS

Our study showed that MF in patients who progress is a disease which, after an initial patch stage with an average duration of 7.2 years, a plaque stage lasting for an average of 2.3 years, and a tumor stage with an average duration of 1.8 years, leads to a stage of lymph node infiltration with an average duration of 0.6 years, internal organ infiltration lasting for an average of 0.5 years and, finally, a fatal outcome. Consequently, the overall average disease duration in progressing patients is 12.4 years. Blast transformation occurs in 85% of all cases in the tumor stage.

CONCLUSIONS

The course of progressing MF is chronic and advancing. The progression is initially slow and later accelerates. Important prognostic factors are the stage of disease and the presence of blast transformation. The prognosis is better in the early stage and when blast transformation is absent.

Population-based linkage of AIDS and cancer registries: importance of linkage algorithm

BACKGROUND

This study evaluates linkage algorithms used in 1997 for Los Angeles County by the AIDS-Cancer Match Registry to estimate the risk of cancer among people with HIV/AIDS.

METHODS

In 2001, a linkage between the Los Angeles County cancer and AIDS registries using a five-pass algorithm was compared with the 1997 linkage results that used a two-pass algorithm.

RESULTS

The five-pass linkage detected all of the previously identified matches (6571) as well as another 431 (6.2%), which had been missed.

CONCLUSIONS

Record linkage methodologic decisions can markedly affect matching sensitivity and specificity. It is probable that the AIDS-Cancer Match Registry two-pass linkage has underestimated the risks of some cancers among people with AIDS.

The lack of cancer surveillance data on sexual minorities and strategies for change

OBJECTIVE

To consider options for gathering cancer incidence and risk factor data in sexual minority individuals.

METHODS AND RESULTS

Sexual minority individuals may experience cancer risk disparities, due to lifestyle and reproductive differences compared with heterosexual people. However, cancer registry systems do not routinely collect sexual minority status. Other methods of obtaining such data and comparing cancer rates and risks between sexual minority and heterosexual people are discussed. These include building on existing registry membership with a targeted survey, using existing data sources, and estimating sexual orientation status with related data.

CONCLUSIONS

Efforts described here could provide support for or refute the hypothesis that disparities exist in selected cancer rates in sexual minority populations and could guide targeted efforts to reduce any disparities.

The emerging concept of antigen-driven lymphomas: epidemiology and treatment implications

PURPOSE OF REVIEW

Dramatic increases in the incidence of lymphomas worldwide have stimulated considerable efforts to identify factors that contribute to the etiology of this heterogeneous group of malignancies. The treatment and, ultimately, the prevention of lymphoma depend on our understanding of the complex interaction of exogenous agents with the molecular milieu which initiates and sustains a lymphoid malignancy. This review discusses the current evidence for the role of foreign or self antigens in the initiation of lymphomagenesis.

RECENT FINDINGS

Recent data have demonstrated an increased risk of lymphoma among individuals with chronic inflammatory conditions, persistent infections or immunodeficient states. Common to these clinical conditions is antigenic stimulation leading to an inflammatory cascade of cellular and cytokine reactions that may tax the host immune response, provoke tissue injury and eventually result in lymphoid neoplasia.

SUMMARY

Efforts to detect and suppress chronic, antigen-driven inflammation have suggested that neoplastic progression may often be interrupted and controlled. Elucidation of the etiologic mechanisms critical to the survival of these malignancies would provide promising alternatives for the prevention and treatment of some lymphomas.

High proportion of T-cell systemic non-Hodgkin lymphoma in HIV-infected patients in Lima, Peru

OBJECTIVE

Few reports have described the clinical and pathologic characteristics of HIV-related systemic non-Hodgkin lymphoma (sNHL) in developing countries. We aimed to determine these characteristics from a national HIV reference center in Peru and to evaluate factors associated with survival.

METHODS

A retrospective/prospective study of patients with HIV-related sNHL from the Guillermo Almenara General Hospital in Lima, Peru between 1993 and 2004. Clinical characteristics at diagnosis included age, gender, risk behavior, previous AIDS diagnosis, opportunistic diseases, previous highly active antiretroviral therapy, Karnofsky score, origin, clinical stage and B-cell symptoms of sNHL, and CD4 cell count. Cases of sNHL were classified according to the criteria of the World Health Organization.

RESULTS

Thirty-three cases were identified (26 male, age range: 38 +/- 10 years). Ten patients (30%) had a prior history of AIDS, 14 (42%) had a Karnofsky score of <or=70, and 18 (56%) had clinical stage IV sNHL. The CD4 cell count median value was 111 cells/microL (n = 25). Twenty-four cases (73%) were B-cell sNHL, and 9 cases (27%) were T-cell sNHL, both from peripheral cells. Nineteen cases of sNHL were extranodal: 15 of B-cell origin and 4 of T-cell origin. Eighteen cases of B-cell sNHL had diffuse large cell histologic findings, and all cases of T-cell sNHL were unspecified. Although there were no significant differences in clinical characteristics between phenotypes, patients with T-cell sNHL had less aggressive disease and a better survival rate.

CONCLUSIONS

A high proportion of T-cell sNHL cases was found at an HIV reference center in Peru. Clinical characteristics were similar between B-cell and T-cell lymphoma patients. T-cell lymphoma was less aggressive, and patients with T-cell lymphoma had a better survival rate than those with B-cell lymphoma.

Immunosuppressive treatment for mixed connective tissue disease may facilitate the development of adult T cell leukemia/lymphoma in a HTLVI carrier

A 66-year-old woman who was positive for human T-lymphotropic virus type I (HTLV-I) antibody developed mixed connective tissue disease (MCTD) with interstitial pneumonia, and was successfully treated with corticosteroid. One year later, under maintenance treatment of prednisolone (PSL), she contracted acute type adult Tcell leukemia/lymphoma (ATLL) without flaring of MCTD. MCTD is considered to be as one of the HTL-V-I-related inflammatory diseases, however the development of ATLL during the treatment of HTL-V-I-related MCTD has not been well studied. Here, we review the literature and raise the issue of the mutual interactions between MCTD-causative anti-HTLV-I immune response and anti-ATLL immune response.

Risk of lymphatic or haematopoietic cancer mortality with occupational exposure to animals or the public

BACKGROUND

Occupational exposure to animals or the public could result in exposure to infectious agents, which may play a role in the aetiology of lymphohaematopoietic (LH) cancers.

AIMS

To conduct a population based, case-control study of death certificate data from 1984 to 1998 in 24 US states in order to evaluate the risk of mortality from LH neoplasms associated with occupational exposure to animals or the public.

METHODS

Cases were selected as those with an underlying cause of death of non-Hodgkin's lymphoma (NHL, n = 72,589), Hodgkin's disease (HD, n = 5479), multiple myeloma (n = 35,857), or leukaemia (n = 68,598); 912 615 controls were randomly selected from all remaining deaths, frequency matched on age, sex, race, and geographic region.

RESULTS

Occupational exposure to animals was associated with modest increased risks of mortality from all four LH cancers; these associations varied by region. Occupational exposure to the public was associated with only negligible increased risk with LH cancer outcomes. Occupations involving animal exposure were predominantly agricultural, and the risks associated with employment in the livestock industry exceeded the corresponding risks associated with the crop industry for all outcomes except HD.

CONCLUSIONS

Increased risks of NHL, HD, multiple myeloma, and leukaemia were associated with occupations that involved animal exposure. Regional differences in risk imply that the risks may be associated with exposure to specific livestock or farming practices. However, these associations may be confounded by other farming related exposures, such as pesticides. Because the use of death certificates to classify occupation may result in misclassification during aetiologically relevant time periods, these hypotheses should be further explored in studies with detailed information on lifetime occupation.

T‐Cell Lymphoma of the Rectum in a Patient with AIDS and Hepatitis C: A Case Report and Discussion

Primary T-cell non-Hodgkin's lymphoma (NHL) occurring in the context of acquired immune deficiency syndrome (AIDS) is uncommon. Here, we report and discuss such a case presenting in the rectum, and review relevant literature. Although typical in some respects, the case is, in other ways, somewhat unusual for an AIDS-related NHL (ARL); ARL tends to be B cell and advanced stage and our case was T cell and stage IE. In addition, the patient suffered from concomitant cirrhosis related to hepatitis C. Chemotherapeutic options for ARL were limited early in the AIDS epidemic due to poor tolerability. Although this has largely been mitigated by the advent of highly active antiretroviral therapy, our patient eventually suffered complications of chemotherapy, apparently related more to his liver disease than to either his lymphoma or AIDS, that ultimately brought about his demise.

AIDS-related cancer in the era of highly active antiretroviral therapy (HAART): a model of the interplay of the immune system, virus, and cancer. "On the offensive--the Trojan Horse is being destroyed"--Part B: Malignant lymphoma

The impact of highly active antiretroviral therapy (HAART) on the incidence of non-Hodgkin's lymphoma was less obvious initially, although primary central nervous system lymphoma (PCNSL) has dropped precipitously since the introduction of HAART. The pathogenesis of acquired immunodeficiency syndrome-related lymphoma is multifactorial. Epstein-Barr virus plays a significant role in these diseases, especially Burkitt lymphoma and PCNSL. Data regarding the effect of HAART on the natural history and treatment outcomes of these malignancies are emerging. The possibility of direct and indirect roles of human immunodeficiency virus in the carcinogenesis suggests that antiretroviral therapy may be an important component of the treatment for these malignancies. The simultaneous administration of HAART and chemotherapy does not appear to significantly alter the toxicity profile, although the information with respect to the interaction of HAART and chemotherapy is limited. The use of biological agents, for example, monoclonal antibody against CD-20, is being explored to improve the clinical outcome of this disease.

Lymphomatoid papulosis in an HIV-positive man

Lymphomatoid papulosis (LyP) is a rare cutaneous lymphoproliferative condition characterized by a chronic, recurrent eruption of papules and nodules that undergo spontaneous regression. The disorder is usually clinically benign; with a minority of cases progressing to malignant lymphoma. LyP is divided into two subtypes based on histologic appearance. Type A resembles Hodgkin's disease with up to 20% of large CD30+ lymphocytes. Type B resembles mycosis fungoides showing an infiltrate of CD4+ lymphocytes and scattered CD30+ cells. Clinically LyP often resembles pityriasis lichenoides et varioliformis acuta but has a strikingly different histological appearance. Histologically, LyP resembles lymphoma (anaplastic T-cell or Hodgkin's) but is distinguished by its benign course. Here we present a case of LyP in a severely immune-repressed HIV-positive patient. This patient presented with pruritic papules involving the upper extremities and a CD4+ T-cell count of 4. Histopathologic examination showed a dense superficial dermal infiltrate comprising normal-sized lymphocytes admixed with larger lymphocytes. Immunophenotyping showed most of the lymphocytes to be CD3+ (T cells). The scattered larger cells were CD30+. The smaller lymphocytes were CD8+ rather than CD4+ as expected for non-HIV-appointed LyP. This may be because of the immune disregulation of HIV disease and the absolute and relative paucity of CD4+ T cells relative to CD8+ T cells.

The epidemiology of non-Hodgkin's lymphoma

The incidence of non-Hodgkin's lymphoma (NHL) has doubled over the past two decades in the US and most other westernized countries. While improved cancer reporting, changes in lymphoma classification, and increases in AIDS-associated lymphomas have contributed to the startling escalation of disease incidence, these factors are estimated to account for only about 50% of the increase in observed incidence. The elucidation of etiologic factors and their mechanistic role in the pathogenesis of this malignancy are critical to advancements in disease prevention and treatment. Current evidence suggests that factors/conditions that precipitate either chronic antigenic stimulation or immunosuppression may provide a preferential milieu for development of NHL. High rates of lymphoma have been observed among individuals with autoimmune disease, organ transplants, and primary or acquired immunodeficiencies. Ultraviolet radiation, previously demonstrated to have an immunosuppressive effect, has also been suggested as a possible risk factor for NHL. Several pathogens have been linked to the risk of lymphoma, including Epstein-Barr virus, human immunodeficiency virus, human T-cell lymphotropic virus-1, Helicobacter pylori, hepatitis C, and simian virus 40. Whether these microbes are responsible for specific genetic mutations that initiate tumor growth, antigenic stimulation leading to B-cell proliferation, and increased potential of random cell replication errors, or immunosuppression, which thereby promotes tumor growth, has not been clearly delineated. Other exogenous factors which have been implicated in lymphomagenesis are chemicals and agricultural exposures, hair dyes, and blood transfusions. We must build on our current knowledge regarding the etiology of NHL in order that prevention, treatment, and ultimately, cure of this malignancy becomes a reality.

T-Cell Lymphoma in HIV-Infected Patients

Linkage of AIDS and cancer registries has indicated an increase in T-cell lymphomas among individuals infected with the HIV. The characteristics of T-cell versus B-cell lymphoma in HIV-infected patients are not well described. Retrospectively, 11 cases of T-cell lymphoma were identified from the AIDS-Lymphoma Registry at the University of Southern California. These patients were compared with 418 consecutive HIV-seropositive patients with B-cell lymphoma diagnosed and treated within the same time period. T-cell lymphomas comprised 3% of all AIDS lymphomas. Pathologic types included peripheral T-cell lymphoma in 5; anaplastic large cell lymphoma in 3; and angioimmunoblastic, enteropathy type, and human T-cell lymphotropic virus-I-related adult T-cell lymphoma/leukemia in 1 case each. No differences in demographic characteristics, history of prior opportunistic infection, or immunologic characteristics were observed between T-cell and B-cell cases. Extranodal involvement of the skin (36% vs. 2%, P < 0.001) and bone marrow (45% vs. 15%, P = 0.019) was significantly more common in T-cell lymphomas. The median survival of patients with T-cell lymphomas was not significantly different from that of B-cell lymphoma patients (10.6 vs. 6.6 months, P = 0.13). T-cell lymphomas in HIV-infected patients represent a spectrum of pathologic types. T-cell lymphomas differ from B-cell cases in terms of a higher propensity for skin and bone marrow involvement. The median survival of patients with T-cell lymphoma is comparable to that of patients with B-cell AIDS-related lymphoma.