Effect of human T-lymphotropic virus type I infection on non-Hodgkin's lymphoma incidence

A Textbook Case of Human T-lymphotropic Virus-1 (HTLV-1)-Induced Adult T-cell Leukemia Treated With Cyclophosphamide, Hydroxydaunorubicin, Oncovin, and Prednisone/Prednisolone (CHOP)

Human T-lymphotropic virus-1 (HTLV-I) is an enveloped, single-stranded RNA virus of the Retroviridae family. The virus causes two well-recognized disease associations: adult T-cell leukemia/lymphoma (ATL) and HTLV-I-associated myelopathy (HAM), also known as tropical spastic paraparesis (TSP). We report a case of HTLV-1-induced adult T-cell lymphoma/leukemia in a 45-year-old female who presented with complaints of swelling on the right side of her neck and rash on her upper and lower extremities and abdomen. The patient also had a history of strongyloidiasis infection and Crohn's disease. She was found to have hypercalcemia and multiple lytic lesions of the bone found on the imaging. She also tested positive for HTLV-1 and T cell-positive for cluster of differentiation (CD) 2, CD3, partial CD5, and minimal CD56, later confirmed by the bone marrow (BM) and skin punch biopsies. ATL is characterized by the clonal proliferation of CD4+ T cells containing randomly integrated HTLV-I provirus, often associated with T-cell receptor gene rearrangements. ATL, in its aggressive forms, has one of the poorest prognoses of non-Hodgkin lymphoma. It is essential to raise awareness of ATL, although further research and trials are needed to solidify the treatment options to prevent mortality.

Epidemiology and Etiology of Leukemia and Lymphoma

Available evidence suggests that the incidence of leukemia and lymphoma tends to be higher in highly developed regions of the world and among Whites in the United States. Temporal trends in incidence are dynamic and multifactorial; for instance, the incidence of non-Hodgkin's lymphoma increased around the turn of the century, in part because of the acquired immune deficiency syndrome (AIDS) epidemic. Most leukemias and lymphomas are sporadic and the specific etiology remains elusive. Still, research shows that these malignancies often develop in the context of genetic abnormalities, immunosuppression, and exposure to risk factors like ionizing radiation, carcinogenic chemicals, and oncogenic viruses. The prognosis varies by subtype, with poorer survival outcomes for acute leukemias among adults, and more favorable outcomes for Hodgkin's lymphoma. At a time when specific prevention efforts targeting these malignancies are nonexistent, there is a great need to ensure equitable access to diagnostic services and treatments worldwide.

Cancer in Africa 2018: The role of infections

We estimate the fractions of cancer attributed to infections in Africa in 2018. The number of new cancer cases occurring was taken from Globocan2018 with some additional estimations based on data from African population-based registries. Population attributable fractions were calculated using prevalence of infection and relative risk in exposed vs. nonexposed. The greatest share of infection-associated cancers is due to the human papillomaviruses (12.1% of all cancers in Africa and 15.4% in sub-Saharan Africa [SSA]); of these, cervical cancer is by far the most common. Kaposi sarcoma-associated herpesvirus is responsible for 3.1% of all cancers in Africa, the hepatitis viruses (B and C) for 2.9% and Helicobacter pylori for 2.7% (non-Cardia Gastric cancer and primary gastric lymphomas). Two percent of cancers are attributable to the Epstein-Barr virus, Schistosoma haematobium increases the risk of bladder cancer resulting in 1.0% of all cancers. HIV-related NHL and squamous cell carcinoma of the conjunctiva account for 0.6% of cancers. Altogether 24.5% of cancers in Africa and 28.7% in SSA are due to infectious agents. Infections are by far the most common cancer risk factor for cancer in Africa-the traditional risk factors (smoking, alcohol and unhealthy diet) probably cause only one in eight cancers in Africa. Prevention should focus on those infectious diseases preventable through vaccination (HPV and hepatitis B) which could reduce two-thirds of the burden. Helicobacter pylori and schistosomiasis are treatable with antibiotics and praziquantel, with a potential reduction of one in eight infection-associated cancers.

p30 protein: a critical regulator of HTLV-1 viral latency and host immunity

The extraordinarily high prevalence of HTLV-1 subtype C (HTLV-1C) in some isolated indigenous communities in Oceania and the severity of the health conditions associated with the virus impress the great need for basic and translational research to prevent and treat HTLV-1 infection. The genome of the virus’s most common subtype, HTLV-1A, encodes structural, enzymatic, and regulatory proteins that contribute to viral persistence and pathogenesis. Among these is the p30 protein encoded by the doubly spliced Tax-orf II mRNA, a nuclear/nucleolar protein with both transcriptional and post-transcriptional activity. The p30 protein inhibits the productive replication cycle via nuclear retention of the mRNA that encodes for both the viral transcriptional trans-activator Tax, and the Rex proteins that regulate the transport of incompletely spliced viral mRNA to the cytoplasm. In myeloid cells, p30 inhibits the PU-1 transcription factor that regulates interferon expression and is a critical mediator of innate and adaptive immunity. Furthermore, p30 alters gene expression, cell cycle progression, and DNA damage responses in T-cells, raising the hypothesis that p30 may directly contribute to T cell transformation. By fine-tuning viral expression while also inhibiting host innate responses, p30 is likely essential for viral infection and persistence. This concept is supported by the finding that macaques, a natural host for the closely genetically related simian T-cell leukemia virus 1 (STLV-1), exposed to an HTLV-1 knockout for p30 expression by a single point mutation do not became infected unless reversion and selection of the wild type HTLV-1 genotype occurs. All together, these data suggest that inhibition of p30 may help to curb and eventually eradicate viral infection by exposing infected cells to an effective host immune response.

Evaluation of Elecsys HTLV-I/II assay in comparison with ARCHITECT rHTLV-I/II assay with Korean samples

BACKGROUND

The seroprevalence rate of human T-lymphotropic virus I and II (HTLV-I/II) in Korean blood donors has been known as 0.004%, and HTLV-I/II Ab screening test has been performed since 2008 in Korea. Korea Ministry of Food and Drug Safety (MFDS) approved two chemiluminescent microparticle immunoassays (CMIA) for testing HTLV-I/II antibody, ABBOTT PRISM HTLV-I/HTLV-II and ARCHITECT rHTLV-I/II. A multicenter performance evaluation study in Europe and Japan was carried out with the new electrochemiluminescence immunoassay (ECLIA) for HTLV-I/II antibody detection, Elecsys HTLV-I/II assay which launched in 2017, but not in Korea. We aimed to evaluate the clinical performance of Elecsys HTLV-I/II assay in comparison with ARCHITECT rHTLV-I/II for the detection of HTLV-I/II antibody with Korean samples.

METHODS

For sensitivity evaluation, 100 HTLV-I/II-positive Korean standards from Korean Red Cross and two HTLV-II-positive samples that were purchased from Seracure were used. For the specificity, 500 potential donor specimens from Korea University Hospital healthcare center were used. All the samples were simultaneously analyzed by the two HTLV-I/II assays, Elecsys HTLV-I/II assay and ARCHITECT rHTLV-I/II assay.

RESULTS

Elecsys HTLV-I/II assay and ARCHITECT rHTLV-I/II assay showed a complete agrement. Elecsys HTLV-I/II assay showed 100% sensitivity (95% CI: 96.38-100.0) and specificity (95% CI: 99.26-100.0).

CONCLUSIONS

Elecsys HTLV-I/II assay is as reliable as ARCHITECT rTHLV-I/II assay, and can be used as a screening test for HTLV-I/II in Korea.

A genetic IFN/STAT1/FAS axis determines CD4 T stem cell memory levels and apoptosis in healthy controls and Adult T-cell Leukemia patients

Adult T-cell leukemia (ATL) is an aggressive, chemotherapy-resistant CD4+CD25+ leukemia caused by HTLV-1 infection, which usually develops in a minority of patients several decades after infection. IFN + AZT combination therapy has shown clinical benefit in ATL, although its mechanism of action remains unclear. We have previously shown that an IFN-responsive FAS promoter polymorphism in a STAT1 binding site (rs1800682) is associated to ATL susceptibility and survival. Recently, CD4 T stem cell memory (TSCM) Fashi cells have been identified as the hierarchical cellular apex of ATL, but a possible link between FAS, apoptosis, proliferation and IFN response in ATL has not been studied. In this study, we found significant ex vivo antiproliferative, antiviral and immunomodulatory effects of IFN-α treatment in short-term culture of primary mononuclear cells from ATL patients (n = 25). Bayesian Network analysis allowed us to integrate ex vivo IFN-α response with clinical, genetic and immunological data from ATL patients, thereby revealing a central role for FAS -670 polymorphism and apoptosis in the coordinated mechanism of action of IFN-α. FAS genotype-dependence of IFN-induced apoptosis was experimentally validated in an independent cohort of healthy controls (n = 20). The same FAS -670 polymorphism also determined CD4 TSCM levels in a genome-wide twin study (p = 7 × 10-11, n = 460), confirming a genetic link between apoptosis and TSCM levels. Transcriptomic analysis and cell type deconvolution confirmed the FAS genotype/TSCM link and IFN-α-induced downregulation of CD4 TSCM-specific genes in ATL patient cells. In conclusion, ex vivo IFN-α treatment exerts a pleiotropic effect on primary ATL cells, with a genetic IFN/STAT1/Fas axis determining apoptosis vs. proliferation and underscoring the CD4 TSCM model of ATL leukemogenesis.

Adult T-cell leukemia/lymphoma in South and Central America and the Caribbean: systematic search and review

Adult T-cell leukemia/lymphoma (ATL) is caused by the human T-cell lymphotropic virus type 1 (HTLV-1) which is endemic in countries of Caribbean and Central and South America. We performed a systematic search and review to identify publications on ATL in these countries to verify if this disease was getting recognition in these regions as well as the characteristics of the observed cases. The median age of 49.4 years was lower than that referred to in Japan. According to our findings in most Brazilian states and in some other countries, ATL is not being recognized and should be strongly considered in the differential diagnosis of T-cell leukemias/lymphomas. Failure to identify these cases may be due to the unsystematic realization of serology for HTLV-1 and phenotypic identification of non-Hodgkin lymphomas that may result from lack of resources. Detection of ATL cases has been more feasible with cooperation from foreign research centers. A huge effort should be made to improve the surveillance system for ATL diagnosis in most of the South- and Central-American and Caribbean countries, and this attitude should be embraced by public organs to support health professionals in this important task.

Marseillevirus in lymphoma: a giant in the lymph node

The family Marseilleviridae is a new clade of giant viruses whose original member, marseillevirus, was described in 2009. These viruses were isolated using Acanthamoeba spp primarily from the environment. Subsequently, a close relative of marseillevirus was isolated from the faeces of a healthy young man, and others were detected in blood samples of blood donors and recipients and in a child with lymph node adenitis. In this Grand Round we describe the detection of marseillevirus by PCR, fluorescence in-situ hybridisation, direct immunofluorescence, and immunohistochemistry in the lymph node of a 30-year-old woman diagnosed with Hodgkin's lymphoma, together with IgG antibodies to marseillevirus. A link with viruses and bacteria has been reported for many lymphomas. We review the literature describing these associations, the criteria used to consider a causal association, and the underlying mechanisms of lymphomagenesis. Our observations suggest that consideration should be given to marseillevirus infections as an additional viral cause or consequence of Hodgkin's lymphoma, and that this hypothesis should be tested further.

Epidemiology and etiology of non-hodgkin lymphoma

Non-Hodgkin lymphoma (NHL) consists of many histologically and biologically distinct lymphoid malignancies with poorly understood, but possibly distinct, etiologies. The patterns of incidence and time trend vary not only by age, sex, and race/ethnicity in the USA, but also show significant geographic differences, suggesting the potential role of infectious agents, environmental factors, and lifestyle factors in addition to host genetic status in the development of NHL. Important pathogenetic mechanisms include immune modulation and chronic antigen stimulation. Epidemiologic studies in the past two decades have provided intriguing new insights on the possible causes of lymphoma and support the idea that there is some mechanistic commonality of lymphomagenesis, but significant etiologic heterogeneity clearly exists. This review presents a summary of the current understanding of the descriptive epidemiology and etiology of NHL and suggests areas of focus for future epidemiologic research.

Oncogenes and RNA splicing of human tumor viruses

Approximately 10.8% of human cancers are associated with infection by an oncogenic virus. These viruses include human papillomavirus (HPV), Epstein–Barr virus (EBV), Merkel cell polyomavirus (MCV), human T-cell leukemia virus 1 (HTLV-1), Kaposi's sarcoma-associated herpesvirus (KSHV), hepatitis C virus (HCV) and hepatitis B virus (HBV). These oncogenic viruses, with the exception of HCV, require the host RNA splicing machinery in order to exercise their oncogenic activities, a strategy that allows the viruses to efficiently export and stabilize viral RNA and to produce spliced RNA isoforms from a bicistronic or polycistronic RNA transcript for efficient protein translation. Infection with a tumor virus affects the expression of host genes, including host RNA splicing factors, which play a key role in regulating viral RNA splicing of oncogene transcripts. A current prospective focus is to explore how alternative RNA splicing and the expression of viral oncogenes take place in a cell- or tissue-specific manner in virus-induced human carcinogenesis.

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

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

L233P mutation of the Tax protein strongly correlated with leukemogenicity of bovine leukemia virus

The bovine leukemia virus (BLV) Tax protein is believed to play a crucial role in leukemogenesis by the virus. BLV usually causes asymptomatic infections in cattle, but only one-third develop persistent lymphocytosis that rarely progress after a long incubation period to lymphoid tumors, namely enzootic bovine leucosis (EBL). In the present study, we demonstrated that the BLV tax genes could be divided into two alleles and developed multiplex PCR detecting an L233P mutation of the Tax protein. Then, in order to define the relationship between the Tax protein and leukemogenicity, we examined 360 tumor samples randomly collected from dairy or breeding cattle in Japan, of which Tax proteins were categorized, for age at the time of diagnosis of EBL. The ages of 288 animals (80.0%) associated with L233-Tax and those of 70 animals (19.4%) with P233-Tax individually followed log-normal distributions. Only the two earliest cases (0.6%) with L233-Tax disobeyed the log-normal distribution. These findings suggest that the animals affected by EBL were infected with the virus at a particular point in life, probably less than a few months after birth. Median age of those with P233-Tax was 22 months older than that with L233-Tax and geometric means exhibited a significant difference (P<0.01). It is also quite unlikely that viruses carrying the particular Tax protein infect older cattle. Here, we conclude that BLV could be divided into two categories on the basis of amino acid at position 233 of the Tax protein, which strongly correlated with leukemogenicity.

Lung miliary micro-nodules in human T-cell leukemia virus type I carriers

Human T-cell leukemia virus type 1 (HTLV-1) carriers are rarely subject to inflammatory disorders in multiple organs, other than the well-known complication, adult T-cell leukemia/lymphoma (ATLL). HTLV-1 associated bronchiolo-alveolar disorder (HABA) has been proposed as an immune mediated pulmonary reaction seen rarely in HTLV-1 carriers. The reported clinico-pathological patterns of HABA are diffuse panbronchiolitis (DPB) and lymphoid interstitial pneumonia (LIP). We here report three cases of HTLV-1 carriers showing miliary micro-nodules throughout both lungs. Microscopic examination in the video assisted thoracic surgery biopsies demonstrated that all cases had multiple discrete micro-nodules which consisted of marked lymphoid infiltration, granulomas, eosinophils and a few foci of necrosis inside the granuloma. No findings indicating ATLL, other neoplastic conditions, infection or interstitial pneumonia, including DPB and LIP, were present following panels of special staining and immunohistochemical examinations. Two patients improved without treatment within one month, with no evidence of recurrence after 7 years. One patient showed slow deterioration of lung reticular shadows in spite of a low dose corticosteroid therapy (prednisolone 10 mg/day). We believe these cases may be a newly recognized variant of HABA.

Adult T cell leukemia/lymphoma: FoxP3(+) cells and the cell-mediated immune response to HTLV-1

Human T-lymphotropic virus type 1 (HTLV-1) causes adult T-cell leukaemia/lymphoma (ATLL) in ∼5% of HTLV-1-infected people. ATLL cells frequently express several molecules that are characteristic of regulatory T cells (Tregs), notably CD4, CD25 and the transcription factor FoxP3. It has therefore recently been suggested that HTLV-1 selectively infects and transforms Tregs. We show that HTLV-1 induces and maintains a high frequency of FoxP3+ T cells by inducing expression of the chemokine CCL22; the frequency is especially high in patients with chronic ATLL. In turn, the FoxP3+ T cells exert both potentially beneficial and harmful effects: they suppress the growth of autologous ATLL clones and may also suppress the host's cytotoxic T lymphocyte response, which normally limits HTLV-1 replication and reduces the risk of HTLV-1-associated diseases. Although ATLL cells may exert immune suppressive effects, we conclude that ATLL is not necessarily a tumour of classical FoxP3+ Tregs.

Clinical manifestations in individuals with recent diagnosis of HTLV type I infection

BACKGROUND

Human T-lymphotropic virus type 1 (HTLV-1) is known to cause HTLV-associated myelopathy (HAM)/tropical spastic paraparesis and adult T cell leukemia. A growing body of evidence links HTLV-1 infection with an increasing spectrum of disease, including uveitis, periodontal disease, arthropathy, sicca syndrome, and neurologic deficits.

OBJECTIVES

Despite recent findings, the natural history of HTLV-1 infection remains poorly defined. This study was designed to better characterize initial clinical and neurological findings in individuals diagnosed with HTLV-1 infection.

STUDY DESIGN

We conducted a cross-sectional study of 71 individuals recently diagnosed with HTLV-1 and 71 uninfected age- and sex-matched blood donors in Salvador, Brazil. Subjects were administered a standardized questionnaire and underwent physical exam.

RESULTS

HTLV-1 infected subjects were significantly more likely than controls to report complaints of hand and foot numbness (OR=5.3; 95% CI: 1.8-15.3; p=0.002 and OR=4.0; 95% CI: 1.3-12; p=0.013 respectively), difficulty running (OR=4.0; 95% CI: 1.1-14.2; p=0.032), nocturia (OR=5.0; 95% CI: 1.1-22.8; p=0.038), arthralgia (OR=3.3; 95% CI: 1.4-7.7; p=0.006), and photophobia (OR=3.3; 95% CI: 1.4-7.7; p=0.006).

CONCLUSIONS

Neurologic, ocular and rheumatologic complaints may be the first manifestations of HTLV-1 infection. Therefore, all patients presenting with initial diagnosis should be rigorously screened for these symptoms.

Pharmaceutical production workers and the risks of mortality from respiratory system cancer and lymphatic and hematopoietic tissue cancers

OBJECTIVES

To evaluate further elevated mortality risks from respiratory system cancer (RSC) and lymphatic and hematopoietic tissue cancers (LHTC) in a cohort of 1466 male workers employed full-time in pharmaceutical production.

METHODS

We computed standardized mortality ratios, and in nested case-control studies of RSC and LHTC, evaluated mortality risks by plant exposures with adjustment for potential confounding factors.

RESULTS

Subjects with potential plant exposure had no elevated RSC risk and a statistically significant LHTC excess. The case-control study found many RSC risks reduced with adjustment for smoking, and LHTC risks increased with increasing levels of average exposure to dimethyl-formamide.

CONCLUSIONS

RSC mortality risks decreased, and we found limited evidence that positive confounding by smoking may explain some remaining excess risks. For LHTC, increased mortality risks and exposure-response patterns in the case-control study may indicate a possible workplace association.

Treatment of adult T-cell leukemia/lymphoma: past, present, and future

Adult T-cell leukemia/lymphoma (ATLL) is a peripheral T-cell malignancy caused by human T-cell lymphotrophic virus type I. Clinical manifestations of ATLL range from smoldering to chronic, lymphoma and acute. Patients with acute and lymphoma type ATLL require therapeutic intervention. Conventional chemotherapeutic regimens used against other malignant lymphoma have been administered to ATLL patients, but the therapeutic outcomes of acute and lymphoma type ATLL remain very poor. Promising results of allogeneic stem cell transplantation (SCT) for ATLL patients have recently been reported and the treatment outcome might be improved for some ATLL patients. Besides conventional chemotherapy and SCT, interferon, zidovudine, arsenic trioxide, targeted therapy against surface molecule on ATLL cells, retinoid derivatives, and bortezomib have been administered to ATLL patients in pilot or phase I/II studies. Further studies are required to confirm the clinical benefits of these novel therapeutics. This article reviews the current status and future directions of ATLL treatment.

Diabetes mellitus associated with the occurrence and prognosis of non-Hodgkin's lymphoma

The aim of this case-control study was to assess the effect of preexisting diabetes mellitus on the risk of developing non-Hodgkin's lymphoma, and also to investigate whether preexisting diabetes mellitus could further affect survival after diagnosis of non-Hodgkin's lymphoma. The retrospective cohort consisted of 242 study participants with pathologically confirmed non-Hodgkin's lymphoma who were referred to the Department of Radiation Oncology in Chang-Gung Memorial Hospital between January 2000 and March 2004. The controls were derived from a population-based multiple screening program. A logistic regression model was employed to calculate the odds ratios of the risk factors we examined and then to evaluate the association between preexisting diabetes mellitus and the occurrence of non-Hodgkin's lymphoma. The results showed that preexisting diabetes mellitus was an independent risk factor for the occurrence of non-Hodgkin's lymphoma (odds ratio, 1.88; 95% confidence interval, 1.22-2.89; P=0.0045). When subgroup analyses regarding certain tumor or disease characteristics were performed, the impact of preexisting diabetes mellitus was found to be particularly evident in some subgroups such as the tumors of T-cell origin (P=0.0266), those with extranodal involvement (P=0.0346), and those that were not localized or low grade (P=0.0096). The effect of preexisting diabetes mellitus on the risk of death from non-Hodgkin's lymphoma varied with follow-up time. Such an effect modification was statistically significant (P=0.05). In the current study, preexisting diabetes mellitus was an independent risk factor for the occurrence of non-Hodgkin's lymphoma, and it was also an accelerated factor for the risk of death from causes related to non-Hodgkin's lymphoma.

Human T-lymphotropic virus 1: recent knowledge about an ancient infection

Human T-lymphotropic virus 1 (HTLV-1) has infected human beings for thousands of years, but knowledge about the infection and its pathogenesis is only recently emerging. The virus can be transmitted from mother to child, through sexual contact, and through contaminated blood products. There are areas in Japan, sub-Saharan Africa, the Caribbean, and South America where more than 1% of the general population is infected. Although the majority of HTLV-1 carriers remain asymptomatic, the virus is associated with severe diseases that can be subdivided into three categories: neoplastic diseases (adult T-cell leukaemia/lymphoma), inflammatory syndromes (HTLV-1-associated myelopathy/tropical spastic paraparesis and uveitis among others), and opportunistic infections (including Strongyloides stercoralis hyperinfection and others). The understanding of the interaction between virus and host response has improved markedly, but there are still no clear surrogate markers for prognosis and there are few treatment options.

Molecular and epidemiological characteristics of blood-borne virus infections among recent immigrants in Spain

The increased immigration from developing regions to Western countries raises public health concerns related to blood-borne viruses. The prevalence of human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), and human T-lymphotropic virus (HTLV) infections among recent immigrants attending several Spanish diagnostic centers in years 2002 and 2003 was examined. Genetic characterization of viral subtypes and its relationship with distinct at-risk populations was carried out. A total of 1,303 immigrants were identified. They originated in Latin America (46.9%), Sub-Saharan Africa (23.7%), Eastern Europe (9.4%), and the Maghreb (9.2%). Seroprevalence rates were as follows: HIV-1 4.2%, HBV 4.1%, HCV 2.9%, and HTLV-1 0.8%. All patients with HIV-1 non-B subtypes, HBV genotypes E and A3, and HCV genotype 4 were sub-Saharan Africans, and had been infected mainly through heterosexual contacts. In contrast, Latin American homo/bisexual men carried HIV-1 subtype B most likely acquired after their arrival to Spain. In conclusion, while Sub-Saharan Africans carry wide diverse genetic variants of blood-borne viruses, the absence of high-risk practices in most cases could limit the spread of these variants. In contrast, Latin Americans with high-risk sexual practices may be a particularly vulnerable collective to acquire blood-borne viruses in the receptor country.

Occupational exposure to solvents and the risk of lymphomas

BACKGROUND

A number of studies have shown possible associations between occupational exposures, particularly solvents, and lymphomas. The present investigation aimed to evaluate the association between exposure to solvents and lymphomas (Hodgkin and non-Hodgkin) in a large population-based, multicenter, case-control study in Italy.

METHODS

All newly diagnosed cases of malignant lymphoma in men and women age 20 to 74 years in 1991-1993 were identified in 8 areas in Italy. The control group was formed by a random sample of the general population in the areas under study stratified by sex and 5-year age groups. We interviewed 1428 non-Hodgkin lymphoma cases, 304 Hodgkin disease cases, and 1530 controls. Experts examined the questionnaire data and assessed a level of probability and intensity of exposure to a range of chemicals.

RESULTS

Those in the medium/high level of exposure had an increased risk of non-Hodgkin lymphoma with exposure to toluene (odds ratio = 1.8; 95% confidence interval = 1.1-2.8), xylene 1.7 (1.0-2.6), and benzene 1.6 (1.0-2.4). Subjects exposed to all 3 aromatic hydrocarbons (benzene, toluene, and xylene; medium/high intensity compared with none) had an odds ratio of 2.1 (1.1-4.3). We observed an increased risk for Hodgkin disease for those exposed to technical solvents (2.7; 1.2-6.5) and aliphatic solvents (2.7; 1.2-5.7).

CONCLUSION

This study suggests that aromatic and chlorinated hydrocarbons are a risk factor for non-Hodgkin lymphomas, and provides preliminary evidence for an association between solvents and Hodgkin disease.

Human T-cell lymphotropic virus type-1 infection and risk of cancer: 15.4 year longitudinal study among atomic bomb survivors in Nagasaki, Japan

The objective of the present study was to investigate the association between human T-lymphotropic virus type-1 (HTLV-1) infection and cancer risk in a longitudinal study. The study population consisted of 2729 atomic bomb survivors in Nagasaki Prefecture, Japan, who had no previous history of cancer at baseline. The baseline survey, including analysis of antibody to HTLV-1, took place during 1985-1987 and follow-up was performed until the end of 2001. There were 553 incident cases of malignant neoplasms during the observation period. After adjustment for sex, age and other variables, HTLV-1 infection was not associated with the risk of developing cancers of all sites, excluding adult T-cell leukemia (rate ratio 1.0, 95% confidence interval [CI] 0.76-1.4), stomach, colon and rectum, lung, female breast or other minor sites, but was associated with increased risk of liver cancer (rate ratio 2.1, 95%CI 1.0-4.6). The point estimate of the rate ratio for thyroid cancer was 3.0, but this was not significantly higher than 1 because of the small number of events (n = 11) and low prevalence of HTLV-1 seropositivity. These findings support the idea that HTLV-1 infection is not associated with an increased general cancer risk. Confounding by hepatitis C virus (HCV) and the interaction between HTLV-1 and HCV may explain the increased risk of liver cancer among HTLV-1 carriers. Further follow-up may be required to determine if HTLV-1 carriers are at increased risk of thyroid cancer.

Seroprevalence of human T-cell lymphotropic virus type I among pregnant women in Accra, Ghana

Infection with human T-cell lymphotropic virus type I (HTLV-I) occurs mainly in Japan, Central and West Africa and the Caribbean Basin. Although antibody to HTLV-I has been reported among pregnant women in several endemic countries, there is no information regarding the seroprevalence in pregnant Ghanaian women. The reported seroprevalence of HTLV-I among healthy Ghanaian blood donors is between 0.5 and 4.2 %. Therefore, this study was conducted to determine the seroprevalence of HTLV-I among pregnant women attending the antenatal clinic at the 37 Military Hospital, Accra, Ghana, between the months of January and December 2003. The presence of antibodies specific for HTLV-I/II was tested using a particle agglutination test (PAT) kit and confirmed by Western blotting (WB). Of the 960 sera tested, HTLV-I/II antibodies were detected in 24 samples using the PAT kit. WB results indicated that, of the 24 positive PAT specimens, 20 specimens (83.3 %) were HTLV-I positive, one (4.2 %) was HTLV-II positive, two (8.3 %) were HTLV positive and one (4.2 %) was indeterminate. Therefore, the overall seroprevalence of HTLV-I was 2.1 %. Seroprevalence increased with age, suggesting sexual contact as the primary mode of transmission among women of childbearing age, rather than breastfeeding during infancy. The seroprevalence of 2.1 % reported here for HTLV-I in pregnant women in Accra is comparable to that of human immunodeficiency virus among the same population. In conclusion, the results indicate that HTLV-I is prevalent among asymptomatic Ghanaian pregnant women and thus there is a need to consider introducing antenatal screening for HTLV-I in Ghana.

Adult T-cell leukemia presenting with acute liver failure

Malignant infiltration of the liver is a rare cause of acute liver failure accounting for less than 1% of cases. We describe a case of adult T-cell leukemia (ATL) that presented with a prodromal illness that progressed to jaundice, hepatic encephalopathy, multisystem failure and death within 8 weeks. Liver histology revealed massive infiltration with atypical lymphocytes typical of ATL and liver necrosis.

The global health burden of infection-associated cancers in the year 2002

Several infectious agents are considered to be causes of cancer in humans. The fraction of the different types of cancer, and of all cancers worldwide and in different regions, has been estimated using several methods; primarily by reviewing the evidence for the strength of the association (relative risk) and the prevalence of infection in different world areas. The estimated total of infection-attributable cancer in the year 2002 is 1.9 million cases, or 17.8% of the global cancer burden. The principal agents are the bacterium Helicobacter pylori (5.5% of all cancer), the human papilloma viruses (5.2%), the hepatitis B and C viruses (4.9%), Epstein-Barr virus (1%), human immunodeficiency virus (HIV) together with the human herpes virus 8 (0.9%). Relatively less important causes of cancer are the schistosomes (0.1%), human T-cell lymphotropic virus type I (0.03%) and the liver flukes (0.02%). There would be 26.3% fewer cancers in developing countries (1.5 million cases per year) and 7.7% in developed countries (390,000 cases) if these infectious diseases were prevented. The attributable fraction at the specific sites varies from 100% of cervix cancers attributable to the papilloma viruses to a tiny proportion (0.4%) of liver cancers (worldwide) caused by liver flukes.

HTLV-1 Tax nucleocytoplasmic shuttling, interaction with the secretory pathway, extracellular signaling, and implications for neurologic disease

The human T cell leukemia virus type 1 (HTLV-1) oncoprotein Tax interacts with numerous cellular pathways promoting both the survival and pathogenesis of the virus in the human population. Tax has been studied extensively with respect to its role in transcriptional transactivation and its involvement in the up-regulation of a number of cellular genes during the process of oncogenic transformation. These processes are dependent on Tax localization to the nucleus where it interacts with a number of cellular transcription factors during its course of nuclear action. However, there is mounting evidence suggesting that Tax may shuttle between the nucleus and cytoplasm, localize to several cytoplasmic organelles with subsequent secretion from both Tax-transfected cells as well as HTLV-1-infected cells. In addition, the presence of cell-free Tax in cerebral spinal fluid (CSF) was recently demonstrated to occur during all stages of HAM/TSP. This has brought about an increased interest in the cytoplasmic localization of Tax and the implications this localization may have with respect to the progression of HTLV-1-associated disease processes. This review addresses the functional implications relevant to the localization and accumulation of Tax in the cytoplasm including the Tax amino acid signals and cellular protein interactions that may regulate this process. Specifically, we have discussed three important processes associated with the cytoplasmic localization of Tax. First, the process of Tax shuttling between the nucleus and cytoplasm will be described and how this process may be involved in regulating different transcriptional activation pathways. Second, cytoplasmic localization of Tax will be discussed with relevance to Tax secretion and the interaction of Tax with proteins in the cellular secretory pathway. Finally, the secretion of Tax and the effects of extracellular Tax on HTLV-1 pathogenesis will be addressed.

Animal models for human T-lymphotropic virus type 1 (HTLV-1) infection and transformation

Over the past 25 years, animal models of human T-lymphotropic virus type 1 (HTLV-1) infection and transformation have provided critical knowledge about viral and host factors in adult T-cell leukemia/lymphoma (ATL). The virus consistently infects rabbits, some non-human primates, and to a lesser extent rats. In addition to providing fundamental concepts in viral transmission and immune responses against HTLV-1 infection, these models have provided new information about the role of viral proteins in carcinogenesis. Mice and rats, in particular immunodeficient strains, are useful models to assess immunologic parameters mediating tumor outgrowth and therapeutic invention strategies against lymphoma. Genetically altered mice including both transgenic and knockout mice offer important models to test the role of specific viral and host genes in the development of HTLV-1-associated lymphoma. Novel approaches in genetic manipulation of both HTLV-1 and animal models are available to address the complex questions that remain about viral-mediated mechanisms of cell transformation and disease. Current progress in the understanding of the molecular events of HTLV-1 infection and transformation suggests that answers to these questions are approachable using animal models of HTLV-1-associated lymphoma.

Familial risk for non-Hodgkin lymphoma and other lymphoproliferative malignancies by histopathologic subtype: the Swedish Family-Cancer Database

Non-Hodgkin lymphoma (NHL) consists of a heterogeneous group of tumors. Population-based data on the familial risk for specific histopathologic subtypes have not been established. Such data are useful for clinical counseling and for searching tumor subtypes sharing common genetic pathways. We used the Swedish Family-Cancer Database to calculate standardized incidence ratios (SIRs) for histopathology-specific subtypes of NHL in 4455 offspring with NHL whose parents or siblings were affected with different types of lymphoproliferative malignancies. A familial history of NHL significantly increased the risk for NHL (SIRparent = 1.8; SIRsibling = 1.9) and for diffuse large B-cell lymphoma (SIRparent = 2.3), follicular lymphoma (SIRsibling = 2.3), and B-cell lymphoma not otherwise specified (NOS) (SIRsibling = 3.4). For a parental history of histopathology-specific concordant cancer, the risks were significantly increased for diffuse large B-cell lymphoma (SIR = 11.8), follicular NHL (SIR = 6.1), plasma cell myeloma (SIR = 2.5), and chronic lymphocytic leukemia (SIR = 5.9). Familial clusters for NHL seemed stronger in females and in siblings. Our study provides the first quantification of the familial risks for NHL by histopathology. The present findings give evidence for a strong familial association of NHL, with little differences in the magnitude of risks for various histopathologic subtypes. The patterns of risks in parents and siblings support the hypothesis of an autosomal-dominant component for diffuse large B-cell NHL and a recessive one for follicular NHL.

Complicated and fatal Strongyloides infection in Canadians: risk factors, diagnosis and management

Strongyloidiasis, which is caused by the nematode Strongyloides stercoralis, is a common and persistent infection, particularly in developing countries. In the setting of compromised cellular immunity, it can result in fulminant dissemination with case-fatality rates of over 70%. The majority of new Canadian immigrants come from countries where Strongyloides is highly endemic; therefore, the burden of Strongyloides may be underappreciated in Canada. Because early diagnosis and therapy can have a marked impact on disease outcome, screening for this infection should be considered mandatory for patients who have a history of travel or residence in a disease-endemic area and risk factors for disseminated disease (e.g., corticosteroid use and human T-lymphotropic virus type I infection).

Dietary Factors and Risk of Non-Hodgkin Lymphoma by Histologic Subtype: A Case-Control Analysis

There is speculation that etiologic heterogeneity exists among tumors classified as non-Hodgkin lymphoma (NHL), although it is not known whether diet-related associations vary between tumor subgroups. We analyzed data on 1,642 NHL cases and 5,039 controls aged 20 to 74 years from a population-based case-control study conducted in eight Canadian provinces to explore associations between dietary factors and NHL by histologic subtype. Dietary information was collected using a 69-item food frequency questionnaire. Tumors were categorized into histologic subtypes using the contents of pathology reports from the original histopathologic review of diagnostic material. Odds ratios (OR) relating consumption of dietary factors (divided into three categories) to each NHL subtype (diffuse, follicular, small lymphocytic, high grade, peripheral T cell, and unspecified lymphomas) were calculated using polytomous logistic regression. We found an increased risk of NHL with high (versus low) intake of processed meat (OR, 1.49), cheese (OR, 1.38), eggs (OR, 1.49), and dessert foods (OR, 1.24). Positive associations with NHL were also found for high consumption of total fat (OR, 1.28), saturated fat (OR, 1.29), and monounsaturated fat (OR, 1.27). Associations for consumption of some vegetables and fats were found to differ between lymphoma subtypes. Given the large number of diet/subtype comparisons done, however, the possibility that this heterogeneity arose by chance cannot be ruled out. In conclusion, these findings generally do not support the existence of etiologic heterogeneity between histologic subtypes of NHL in their associations with components of dietary intake.

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.

An update of the epidemiology of non-Hodgkin's lymphoma

The incidence of non-Hodgkin's lymphoma (NHL) has increased approximately 80% since the 1970s, and is now the fifth most common cancer in the United States. The incidence of NHL is approximately 50% higher among men than women and 35% higher among white people than black people. The incidence rates of all subtypes of NHL have increased, especially diffuse large-cell and immunoblastic subtypes. Extranodal NHL has increased more rapidly than nodal NHL. The overall NHL incidence rates stabilized in the early 1990s and then began to decrease between 1996 and 2000, resulting in part from a decrease in the incidence of AIDS. The incidence of NHL types not associated with AIDS and NHL in groups at low risk of AIDS has continued to increase throughout the 1990s. The increasing incidence of NHL is poorly understood. Improved diagnostic techniques, the effects of the human immunodeficiency virus epidemic, and immunosuppressive therapies accounted for only one third of the increase. Increase in NHL may be attributed to immunodeficiency, various infections, familial aggregation, blood transfusion, genetic susceptibility to NHL, diet, and chemical exposures to pesticides and solvents. Some studies also suggest that associations between risk factors and specific NHL subtypes may be stronger than associations between the same risk factors and NHL in aggregate. Future epidemiologic studies should incorporate the new World Health Organization classification of NHL and new techniques such as cytogenetic molecular analyses to identify subtype-specific etiologic factors. Evaluation of polymorphisms in genes involved in immune function, inflammation, and the activation or detoxification of environmental and occupational chemicals is also warranted.

A cohort study of health effects of human T-cell lymphotropic virus type I infection in Jamaican children

OBJECTIVE

Human T-cell lymphotropic virus type I (HTLV-I) infection in childhood is believed to play an important role in risk for adult T-cell leukemia/lymphoma. Although HTLV-I is known to be associated with infective dermatitis in childhood, other HTLV-I-associated morbidity in children has not been well studied. We sought to determine the HTLV-I-associated health effects in Jamaican children.

METHODS

We compared incidence rates of several health outcomes in 28 HTLV-I-infected and 280 uninfected children clinically followed from age 6 weeks to a maximum of 10 years. Cox proportional hazards regression analysis was used to analyze these prospectively collected data, adjusting for confounding effects of other variables as necessary.

RESULTS

HTLV-I-infected children had significantly higher incidence rates of seborrheic dermatitis (rate ratio [RR] = 4.8, 95% confidence interval [CI] = 1.9-12.5), eczema (RR = 3.1, CI = 1.2-7.9) and persistent hyperreflexia (RR = 3.7, CI = 1.6-8.2). Additionally, HTLV-I infected children had increased rates of severe anemia (RR = 2.5, CI = 0.8-7.9) and abnormal lymphocytes (RR = 2.4, CI = 0.8-7.6) that were of borderline statistical significance.

CONCLUSIONS

Our study suggests that HTLV-I-associated skin diseases of childhood may include seborrheic dermatitis and eczema. Additionally, these data suggest that persistent hyperreflexia of the lower limbs may be an early sign of HTLV-I-associated neurologic involvement in children. Expansion and continued clinical observation of this cohort would be valuable.

Epidemiology of Hodgkin's disease and non-Hodgkin's lymphoma

This review considers in detail the descriptive and aetiological epidemiology of Hodgkin's disease and non-Hodgkin's lymphoma (NHL), with attention to histological subcategories when the literature allows. The aetiology of Hodgkin's disease remains only partially understood. There is evidence that Epstein-Barr virus (EBV) may be involved in the causation of some cases, and clinical immune deficiency is a risk factor for a few, but the evidence is not entirely consistent and other factors may also be important in causing the EBV-associated cases of Hodgkin's disease. The cause of EBV-unassociated cases remains obscure. For NHL, although it has been shown that some cases are related to immune deficiency and chronic antigenic stimulation, and especially to EBV in the context of immune deficiency, the causation of the majority of cases remains unknown. The increasing incidence of NHL, other than that related to AIDS, is also essentially unexplained. Epidemiological investigation of the aetiology of NHL and Hodgkin's disease is making steady progress, however, and there remain leads to be followed that may result in a better understanding and hence prevention.

Hospital admissions for human T-cell lymphotropic virus type-1 (HTLV-1) associated diseases in Dominica

Human T-cell lymphotropic virus type 1 (HTLV-1) is a retrovirus that is endemic in certain regions of the world, and may account for significant morbidity and mortality among hospitalised patients. Sixty six HTLV-1 seropositive patients admitted to hospital with HTLV-1 associated diseases from 1995-99 were studied. HTLV-1 screening was done with ELISA and confirmed on western blot testing. There were 32 females (48.5%) and 34 males (51.5%). The mean age was 56 years and the age range was 9-89 years. The main associated diseases were tropical spastic paraparesis or HTLV-1 associated myelopathy in 18.2% of cases, acute form of adult T-cell leukaemia/lymphoma 7.6%, lymphomas 15.2%, and ectoparasites/endoparasites in 40.9%. HTLV-1 is associated with diseases in Dominica and association with severe forms of strongyloidiasis and scabies is particularly noted.

Detection of TT virus in lymph node biopsies of B-cell lymphoma and Hodgkin's disease, and its association with EBV infection

Human TT virus (TTV) recently isolated from the serum of a patient with post-transfusion hepatitis does seem to have only hepatopathic effect. The virus can also infect the serum, peripheral blood mononuclear cells (PBMC) and bone marrow cells (BMC ). Additional evidence has indicated that TTV is also present in the serum of people with hematopoietic malignancies. A significant increase in the incidence of lymphoma has recently been observed worldwide. We have investigated the presence of TTV DNA in lymph node biopsies of Italian patients affected with the most common lymphoma types in Western Countries: follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL) and nodular sclerosis Hodgkin's disease (NS-HD). The possible role of a co-infection with Epstein-Barr virus (EBV) has also been investigated. DNA was extracted from 73 paraffin-embedded and 38 snap-frozen tissue specimens. From these, only 67 samples (29 paraffin-embedded and 38 snap-frozen tissues) from a total of 56 patients, were suitable for PCR analysis. TTV and EBV were detected by PCR using primers from two different conserved region in TTV and EBV genomes respectively. TTV DNA was detected in 30.0-50.0% of FL, 30.8% of DLBCL and 30.0-50.0% of NS-HD cases, depending on the primers used. All cases of non-specific reactive lymphoid hyperplasia (RLH), used as a putative control, were negative. The two major TTV genotypes circulating in Italy (G1 and G2) were detected in the analysed lymphoid neoplasms. EBV DNA was detected in 40.0% of FL, in 72.7%of DLBCL, in 80.0% of SN-HD and in 40.0% of RLH cases. EBV co-infection was found in 90% of TTV positive cases. The in situ hybridization assay was performed in TTV positive frozen samples. The significant prevalence of TTV DNA in lymphocytes circulating in the lymph nodes of both B-cell lymphomas and HD reported herewith suggests an implication of TTV infection in the development of these lymphoproliferative disorders.

Human T-cell lymphotrophic virus infection in organ donors: a need to reassess policy?

Human T-cell lymphotrophic virus (HTLV)-I/II infection has been considered a contra-indication to organ donation due to the risk of transmission of infection and the subsequent development of either adult T-cell leukemia or HTLV-I-associated myelopathy. However, neither the incidence of HTLV-I/II infection in organ donors nor the risk of transmission of HTLV-I/II by solid organ transplantation has been defined. Further, it is not known if HTLV infection contributes to significant morbidity in solid organ recipients. The purpose of this study was to evaluate the incidence of HTLV-I/II infection in organ donors in USA and to determine if transplanting these organs resulted in HTLV-related morbidity or mortality. We utilized the UNOS database to: (i) identify organ donors that were positive for HTLV-I or II infection between 1988 and 2000, and (ii) evaluate outcomes in the recipients of these organs. There were 25 HTLV-I/II-positive organ donors reported to UNOS between 1988 and 2000. Based on organ donors with a known HTLV-I/II status, the prevalence of HTLV-I infection in organ donors is 0.027% and the prevalence of HTLV-II is 0.064%. Twenty-two organs were transplanted from these HTLV-positive donors. There have been no reports of HTLV-I/II-related disease in the recipients with a median follow-up of 11.9 months. At our center, over the last 1.5 years there have been four multiorgan donors with false-positive HTLV-I/II screening assays, which resulted in the decision not to use organs from these donors. Based on the minimal chance of HTLV-related disease following transplantation of HTLV-I/II organs in this series, we recommend that careful consideration be given to transplanting organs from HTLV-I/II-positive organ donors.

Update on epidemiology and therapeutics for non-Hodgkin's lymphoma

This chapter presents updated information on the trends and patterns of non-Hodgkin's lymphoma (NHL) diagnoses as well as new information on chemotherapeutic and immunotherapeutic options for NHL treatment. In Section I, Dr. Brian Chiu summarizes the current knowledge regarding the etiologic factors and patterns of NHL as well as suggests future epidemiologic studies based on these preliminary results. In Section II, Dr. Bruce Cheson and colleagues outline new chemotherapeutic and small molecule antineoplastic agents with unique mechanisms of action such as protease inhibitors, farnesyl transferase or histone deacetylase inhibitors, and antisense oligonucleotides. In Section III, Dr. Julie Vose reviews the anti-lymphoma effects of monoclonal antibodies, radioimmunoconjugates, idiotype vaccines, and immunologic enhancing adjuvants with respect to mechanisms of action, clinical trials, and their potential for patient therapy.

Sex-specific mortality from adult T-cell leukemia among carriers of human T-lymphotropic virus type I

Perinatal infection with human T-lymphotropic virus type I (HTLV-I) is considered a risk factor for adult T-cell leukemia (ATL). Incidence of ATL in Japan is generally higher in males compared with females, perhaps partly due to an earlier average age of infection among males. We estimated sex-specific ATL mortality among perinatally-infected HTLV-I carriers in the prospective Miyazaki Cohort Study in Japan. Based on the approximated proportion of perinatally-infected carriers, the relative risk (RR) of ATL for males compared with females was calculated. Six ATL deaths (4 males, 2 females) occurred among the 550 HTLV-I carriers in the cohort during 13 years of follow-up. The overall ATL mortality was 190.5 (95% CI 51.9-487.7) per 10(5) person-years for males and 51.7 (6.3-186.8) per 10(5) person-years for females (age-standardized RR = 3.9, p=0.02). By approximating the number of persons who acquired infection perinatally, the estimated mortality among those perinatally-infected HTLV-I carriers was 209.1 (57.0-535.2) per 10(5) person-years for males and 60.9 (7.4-219.9) per 10(5) person-years for females (age-standardized RR = 3.7, p=0.02). The adjusted RR changed minimally from the unadjusted RR, suggesting that earlier age of infection alone is unlikely the explanation for the male predominance in ATL. Based on the small number of cases available for analysis, aspects of gender itself appear to play a role in the development of this malignancy.

Advances in interleukin 2 receptor targeted treatment

T cell activation and cellular immune responses are modulated by interleukin 2 (IL2) through binding to its corresponding cell surface receptor. Three forms of the receptor are recognised based on IL2 binding affinity. The high affinity receptor is a heterotrimer composed of alpha, beta, and gamma(c)-polypeptide chains. The 55 kDa alpha-chain also known as the Tac (T cell activation) antigen or CD-25 is a unique subunit of the high affinity IL2 receptor (IL2Ralpha). Resting T cells express few IL2Ralpha, however, when activated, the expression of ILR2alpha rapidly increases. The IL2Ralpha is shed from the cell surface and is measurable in the serum as a 45 kDa soluble form (s-Tac or s-IL2Ralpha). Serum concentrations of s-Tac can be used as a surrogate marker for T cell activation and IL2Ralpha expression. IL2Ralpha is over expressed by T cells in a number of autoimmune diseases, allograft rejection and a variety of lymphoid neoplasms. IL2 induced proliferation of T cells can be inhibited by the murine monoclonal antibody (anti-Tac) directed against the alpha-chain of the IL2R. Through molecular engineering, murine anti-Tac has been humanised reducing its immunogenicity without changing its specificity. Humanised anti-Tac (HAT) has been shown to reduce the incidence of renal and cardiac allograft rejection as well as decrease the severity of graft versus host disease in patients undergoing HLA matched allogeneic bone marrow transplantation. IL2Ralpha targeted treatment with radioimmunoconjugates of anti-Tac and immunotoxins has shown promise in the treatment of CD25 expressing lymphomas.

High circulating proviral load with oligoclonal expansion of HTLV-1 bearing T cells in HTLV-1 carriers with strongyloidiasis

Adult T cell leukemia (ATLL) develops in 3 - 5% of HTLV-1 carriers after a long period of latency during which a persistent polyclonal expansion of HTLV-1 infected lymphocytes is observed in all individuals. This incubation period is significantly shortened in HTLV-1 carrier with Strongyloides stercoralis (Ss) infection, suggesting that Ss could be a cofactor of ATLL. As an increased T cell proliferation at the asymptomatic stage of HTLV-1 infection could increase the risk of malignant transformation, the effect of Ss infection on infected T lymphocytes was assessed in vivo in HTLV-1 asymptomatic carriers. After real-time quantitative PCR, the mean circulating HTLV-1 proviral load was more than five times higher in HTLV-1 carriers with strongyloidiasis than in HTLV-1+ individuals without Ss infection (P<0.009). This increased proviral load was found to result from the extensive proliferation of a restricted number of infected clones, i.e. from oligoclonal expansion, as evidenced by the semiquantitative amplification of HTLV-1 flanking sequences. The positive effect of Ss on clonal expansion was reversible under effective treatment of strongyloidiasis in one patient with parasitological cure whereas no significant modification of the HTLV-1 replication pattern was observed in an additional case with strongyloidiasis treatment failure. Therefore, Ss stimulates the oligoclonal proliferation of HTLV-1 infected cells in HTLV-1 asymptomatic carriers in vivo. This is thought to account for the shortened period of latency observed in ATLL patients with strongyloidiasis. Oncogene (2000) 19, 4954 - 4960

Cancer surveillance series: non-Hodgkin's lymphoma incidence by histologic subtype in the United States from 1978 through 1995

BACKGROUND

Clinical investigations have shown prognostic heterogeneity within the non-Hodgkin's lymphomas (NHLs) according to histology, but few descriptive studies have considered NHLs by subgroup. Our purpose is to assess the demographic patterns and any notable increases in population-based rates of different histologic subgroups of NHL.

METHODS

Using data collected by the Surveillance, Epidemiology, and End Results Program of the National Cancer Institute, we calculated incidence rates for the major clinicopathologic categories of NHL by age, race, sex, geographic area, and time period.

RESULTS

Among the 60 057 NHL cases diagnosed during the period from 1978 through 1995, total incidence (per 100 000 person-years) was 17.1 and 11.5 among white males and females, respectively, and 12.6 and 7.4 among black males and females, respectively. However, rates for follicular NHLs were two to three times greater among whites than among blacks, with little sex variation. Blacks demonstrated much higher incidence than whites for peripheral T-cell NHL, with the incidence rates higher in males than in females. For other NHL subgroups, the incidence rates for persons less than 60 years of age were generally higher among males than among females, with little racial difference; at older ages, the rates were higher among whites than among blacks, with little sex difference. High-grade NHL was the most rapidly rising subtype, particularly among males. Follicular NHL increased more rapidly in black males than in the other three race/sex groups. Overall, the broad categories of small lymphocytic, follicular, diffuse, high-grade, and peripheral T-cell NHL emerged as distinct entities with specific age, sex, racial, temporal, and geographic variations in rates.

CONCLUSIONS

Findings from our large, population-based study reveal differing demographic patterns and incidence trends according to histologic group. Future descriptive and analytic investigations should evaluate NHL risks according to subtype, as defined by histology and new classification criteria.

HTLV-1 infections

Human T lymphotropic virus type 1 (HTLV-1) causes disabling and fatal diseases, yet there is no vaccine, no satisfactory treatment, and no means of assessing the risk of disease or prognosis in infected people. Recent research on the molecular virology and immunology of HTLV-1 shows the importance of the host's immune response in reducing the risk of these diseases, and is beginning to explain why some HTLV-1 infected people develop serious illnesses whereas most remain healthy life long carriers of the virus. These findings might be applicable to other persistent virus infections such as human immunodeficiency virus, hepatitis B, and hepatitis C.

HTLV type I/II in British Columbia Amerindians: a seroprevalence study and sequence characterization of an HTLV type IIa isolate

It has been established that the human T cell lymphotropic viruses type I and II (HTLV-I and HTLV-II) are both present in some indigenous peoples of the Americas. While HTLV-I has been identified in coastal British Columbia Indians (BCIs), HTLV-II has not been previously reported in the BCIs or other Canadian Amerindians. The prevalence of HTLV-I and HTLV-II in these populations has not been extensively studied. In this article, we examine a group of BCIs from Vancouver Island who belong to the Nuu-Chah-Nulth and are known to have an increased incidence of rheumatic disease. In 494 serum samples from this tribe, the levels of prevalence of HTLV-I and HTLV-II were 2.8 and 1.6%, respectively. No association could be made between arthropathy and HTLV-I infection. In addition, we characterized an HTLV-II isolate of a BCI from the coastal mainland of British Columbia and with a history of intravenous drug abuse. This case represents the first molecular characterization of a Canadian Amerindian HTLV-II isolate: a subtype IIa virus with phylogenetic affinity for intravenous drug user isolates and containing an extended form of the Tax protein. These results are consistent either with this strain having been sampled from a polymorphic ancestral pool of HTLV-II that gave rise to the current epidemic spread of this virus by intravenous drug use and sexual transmission, or with its being "back-transmitted" into the BC Amerindian population in association with intravenous drug use.

Cost-effectiveness of epoetin and autologous blood donationin reducing allogeneic blood transfusions incoronary artery bypass graft surgery

BACKGROUND

Coronary artery bypass graft (CABG) surgery accounts for a substantial portion of all allogeneic units of blood transfused. Drugs and autologous blood donation (ABD) are alternative or adjunctive methods for reducing complications and costs induced by allogeneic blood transfusions. Recombinant human erythropoietin (epoetin) has the potential to decrease perioperative need for allogeneic blood during CABG, but its high cost calls for a careful economic evaluation before it can be recommended for widespread use.

STUDY DESIGN AND METHODS

A decision tree was used to compare a hypothetical strategy of no epoetin with one in which epoetin was utilized to control blood transfusion needs in CABG; each strategy was tested with and without ABD. The impact of these strategies on both the quality-adjusted life years (QALYs) and costs ($US) was calculated.

RESULTS

Using epoetin alone and with ABD, respectively, avoided the transfusion of 0.61 and 1.35 units of allogeneic blood per patient and saved 0.000086 and 0.000146 QALYs per patient. This made cost-effectiveness (CE) higher than $7 million and $5 million for each QALY saved, respectively. ABD alone cost more than $1 million per QALY saved. If the risk of bacterial infections following allogeneic transfusions was included in the model, epoetin alone cost $6288 per QALY saved, while ABD, both alone and with epoetin, saved money.

CONCLUSION

On the basis of the existing evidence, neither of the blood-saving strategies modeled was a cost-effective means of avoiding the deleterious health effects of perioperative blood transfusions in CABG. However, if allogeneic blood-related infections were to be considered, both ABD and epoetin would be acceptable interventions.