Screening for human T cell leukaemia/lymphoma virus among blood donors in Sweden: cost effectiveness analysis

Cost-effectiveness of human T-cell leukemia virus type 1 (HTLV-1) antenatal screening for prevention of mother-to-child transmission

BACKGROUND

Human T-cell leukemia virus type 1 (HTLV-1) causes adult T-cell leukemia-lymphoma (ATL) and HTLV-1-associated myelopathy-tropical spastic paraparesis (HAM/TSP) with a poor prognosis. This study aimed to evaluate the cost-effectiveness and health impact of HTLV-1 antenatal screening.

METHODOLOGY/PRINCIPAL FINDINGS

A state-transition model was developed for HTLV-1 antenatal screening and no screening over a lifetime horizon from a healthcare payer perspective. A hypothetical cohort of 30-year-old individuals was targeted. The main outcomes were costs, quality-adjusted life-years (QALYs), life expectancy life-years (LYs), incremental cost-effectiveness ratios (ICERs), HTLV-1 carriers, ATL cases, HAM/TSP cases, ATL-associated deaths, and HAM/TSP-associated deaths. The willingness-to-pay (WTP) threshold was set at US$50,000 per QALY gained. In the base-case analysis, HTLV-1 antenatal screening (US$76.85, 24.94766 QALYs, 24.94813 LYs, ICER; US$40,100 per QALY gained) was cost-effective compared with no screening (US$2.18, 24.94580 QALYs, 24.94807 LYs). Cost-effectiveness was sensitive to the maternal HTLV-1 seropositivity rate, HTLV-1 transmission rate with long-term breastfeeding from HTLV-1 seropositive mothers to children, and the cost of the HTLV-1 antibody test. HTLV-1 antenatal screening was cost-effective when the maternal HTLV-1 seropositivity rate was greater than 0.0022 and the cost of the HTLV-1 antibody test was lower than US$94.8. Probabilistic sensitivity analysis using a second-order Monte-Carlo simulation showed that HTLV-1 antenatal screening was 81.1% cost-effective at a WTP threshold of US$50,000 per QALY gained. For 10,517,942 individuals born between 2011 and 2021, HTLV-1 antenatal screening costs US$785 million, increases19,586 QALYs and 631 LYs, and prevents 125,421 HTLV-1 carriers, 4,405 ATL cases, 3,035 ATL-associated deaths, 67 HAM/TSP cases, and 60 HAM/TSP-associated deaths, compared with no screening over a lifetime.

CONCLUSION/SIGNIFICANCE

HTLV-1 antenatal screening is cost-effective and has the potential to reduce ATL and HAM/TSP morbidity and mortality in Japan. The findings strongly support the recommendation for HTLV-1 antenatal screening as a national infection control policy in HTLV-1 high-prevalence countries.

Prevalence of human T-cell lymphotropic virus type-1 infection among blood donors in mainland China: a systematic review and meta-analysis of the last 20 years

Background: The southeastern coastal area of China has a high prevalence of HTLV-1 infection among blood donors. However, the estimation of HTLV-1 prevalence on a national and regional level is little known. The aim of this study is to understand and explore the estimation of HTLV-1 infection prevalence among blood donors on a national and regional level in mainland China by using a systematic review and meta-analysis. Study design and methods: All relevant publications of the past two decades (1998-2017), which were reported in both English and Chinese languages, were adopted and systematically assessed. The estimation of prevalence and its 95% confidence interval (CI) at the level of provinces/municipalities and overall were estimated using meta-analysis method. Results: From the 327 studies searched, 60 met the inclusion criteria. These were from 18 provinces and four municipalities and included 1,420,079 blood donors. The overall estimation of the HTLV-1 prevalence in blood donors was 0.169‰, and its 95% CI was 0.121‰-0.240‰. Conclusion: A disproportionate distribution of HTLV-1 infection among blood donors in different provinces/municipalities regarding its prevalence has been reported. This study recommends developing appropriate HTLV-1 screening strategies of blood donors in various regions of China considering regional prevalence, and cost-effectiveness.

Reconsideration of blood donation testing strategy for human T-cell lymphotropic virus in Australia

BACKGROUND AND OBJECTIVES

Universal testing of blood donations for human T-cell lymphotropic virus (HTLV) in Australia may no longer be appropriate given the low prevalence of HTLV infection and the mitigating effect of universal leucodepletion for cellular components. This study aimed to determine the most appropriate HTLV testing strategy using the Risk-Based Decision-Making Framework for Blood Safety.

MATERIALS AND METHODS

The risk of HTLV transfusion-transmission using three testing strategies (universal, new-donor and no testing) and cost-effectiveness of the first two strategies were assessed using adaptations of published mathematical models.

RESULTS

The overall prevalence for 2004-2014 was three HTLV-positives per million donations. It was estimated that annually, universal testing incurred a cost of approximately AUD $3 million and prevented 83 HTLV-positive cellular components from being issued, and new-donor testing cost approximately $225 000 and prevented 81 components. The number of cases of transfusion-transmitted HTLV and HTLV-associated disease prevented per year by universal and new-donor testing was essentially equivalent. According to preset risk thresholds, the risk of transfusion-transmission was negligible for universal and new-donor testing, and minimal without testing.

CONCLUSION

Transfusion-transmission of HTLV is a minimal risk in Australia even without testing. However, any revision of testing strategy must consider not only risk and cost-effectiveness, but also stakeholder, ethical and regulatory perspectives. Considering all relevant criteria, new-donor testing is judged the optimal strategy because it is able to achieve almost the same outcomes as universal testing, at a fraction of the cost.

Seroprevalence and geographical distribution of human T-lymphotropic virus type 1 among volunteer blood donors in endemic areas of Iran

Background

Human T-cell lymphotrophic virus type 1 (HTLV-1) has a worldwide distribution and it is endemic in some regions of Iran. One of the most important routes of HTLV-1 transmission is via transfusion of contaminated blood components. The risk of transmission through asymptomatic blood donors, particularly in endemic areas should be considered and appropriately managed. The main objective of this study was to determine the seroprevalence and description the geographic distribution of HTLV-1 among voluntary blood donors in Iran.

Methods

This retrospective study carried out using the data obtained from the main database of the seven blood transfusion centers of Iranian Blood Transfusion Organization between 2009 and 2013. The presence of anti-HTLV-1/2 antibodies were primarily assessed using Enzyme-linked Immunosorbent Assay. The Ab Kit assay, contain antigens for the screening of antibodies to HTLV type 1 and 2. So, it is expressed as HTLV 1/2 assay. Samples that were positive by the western blot confirmatory test were considered as definite positive HTLV-1 or HTLV-2 cases. The main socio-demographic variables were; age, gender, donation history and marital status. Descriptive and analytical statistics were used to summarize the gathered data. The chi-Square Statistical test was used to test the association between groups, P-value of less than 0.05 was considered significant.

Results

A total of 1864489 blood donations were evaluated. There were 1840 confirmed HTLV-1 positive donations (0.098%). None were positive for anti-HTLV-2. The overall HTLV-1 prevalence was 98.7 per 100,000 donations during the 5 year period. Seroprevalence was higher among females, married and older blood donors. The overall seropositivity among first time, regular and lapsed donors was, 0.29% (290/100000), 0.001% (1/100000) and 0.02% (20/100000) respectively. A significant difference was observed between regular and the first time (p <0.0001) and also between lapsed and regular blood donors (p <0.0001). Most of the HTLV-1 seropositive blood donors (175 per 100,000) were from northeastern regions. We observed a gradual decline in overall HTLV-1 prevalence during the course of the study, the prevalence rate decreased from 0.13% (130/100000) in 2009 to 0.07% (70/100000) in 2013.

Conclusions

The Seroprevalence of HTLV-1 among Iranian blood donors in the regions of our study still is considerable, but there is an obvious declining prevalence over the course of present study. Blood transfusion centers should continually evaluate the residual risk of infection in the country, especially in endemic areas.

Human T-Cell Lymphotropic Virus Types 1 and 2 Seropositivity among Blood Donors at Mbarara Regional Blood Bank, South Western Uganda

Background. The human T-cell lymphotropic virus types 1 and 2 (HTLV 1/2) are retroviruses associated with different pathologies. HTLV-1 causes adult T-cell leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP); HTLV-2 is not clearly associated with a known clinical disease. Both viruses may be transmitted by whole blood transfusion, from mother to child predominantly through breastfeeding, and by sexual contact. Presently, none of the regional blood banks in Uganda perform routine pretransfusion screening for HTLV. The aim of this study was to determine the prevalence of anti-human T-cell lymphotropic virus types 1/2 (HTLV-1/2) antibodies among blood donors at Mbarara Regional Blood Bank in South Western Uganda. A cross-sectional study was conducted between June 2014 and September 2014. Methodology. Consecutive blood samples of 368 blood donors were screened for anti-HTLV-1/2 antibodies using an enzyme linked immunosorbent assay (ELISA). Samples reactive on a first HTLV-1/2 ELISA were further retested in duplicate using the same ELISA. Of the three hundred and sixty-eight blood donors (229 (62.2%) males and 139 (37.8%) females), only two male donors aged 20 and 21 years were HTLV-1/2 seropositive, representing a prevalence of 0.54%. Conclusion. HTLV-1/2 prevalence is low among blood donors at Mbarara Regional Blood Bank. Studies among other categories of people at risk for HTLV 1/2 infection should be carried out.

Human T-lymphotropic virus and transfusion safety: does one size fit all?

Human T-cell leukemia viruses (HTLV-1 and HTLV-2) are associated with a variety of human diseases, including some severe ones. Transfusion transmission of HTLV through cellular blood components is undeniable. HTLV screening of blood donations became mandatory in different countries to improve the safety of blood supplies. In Japan and Europe, most HTLV-infected donors are HTLV-1 positive, whereas in the United States a higher prevalence of HTLV-2 is reported. Many industrialized countries have also introduced universal leukoreduction of blood components, and pathogen inactivation technologies might be another effective preventive strategy, especially if and when generalized to all blood cellular products. Considering all measures available to minimize HTLV blood transmission, the question is what would be the most suitable and cost-effective strategy to ensure a high level of blood safety regarding these viruses, considering that there is no solution that can be deemed optimal for all countries.

Seroepidemiology of human T-cell lymphotropic virus type-1 (HTLV1) in Mashhad

INTRODUCTION

Human T-cell lymphotropic virus (HTLV-I) is associated with adult T cell leukemia/lymphoma (ATL) and HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The major routes of HTLV-I transmission are mother-to-child, sexual contact, and blood transfusion. Mashhad is one of the main endemic areas in the world for HTLV-I, and minimizing the risk of HTLV-I transmission through blood transfusion is one of the main duties of the Blood Transfusion Center in Mashhad. The aim of this study was to determine the prevalence of HTLV-I in the blood donor population in Mashhad during 2011-2013.

METHODS

All the blood donors in Mashhad from March 2011 to April 2013 who were diagnosed with HTLV-I on the ELISA screening test and the Western blot confirmatory test were included in this seroepidemiological study.

RESULTS

From 174,662 blood donors, 327 donors were confirmed to be infected with HTLV-I according to Western blot assay. The seropositive donors ranged in age from 17 to 59, and their mean age was 39.88±10.49 years. The overall prevalence rates of HTLV-I infection were calculated as 0.18% and 0.19%, respectively.

CONCLUSION

Due to the lower frequency of infection in regular blood donors, younger individuals, and people with higher education levels, the selection of blood donors from these populations should be further considered.

Emerging infectious threats to the blood supply: seroepidemiological studies in iran - a review

SUMMARY

The risk of transfusion-transmitted infections has been greatly reduced by improvements in donor screening and testing. However, newly recognized blood-borne infectious agents can be threats to blood safety. In order to evaluate the prevalence some of these agents in blood donors, a systematic review was conducted. Data were obtained from published papers related to HGV, Torque Teno virus (TTV), HTLV, West Nile virus (WNV) and SEN virus (SEN-V). Based on these studies, the prevalence of HGV varied from 1 to 8.6% for anti-E2 and from 0 to 4.8% for HGV RNA. The prevalence of TTV DNA and HTLV-I varied from 2.7 to 79.5% and from 0.013 to 2.3%, respectively. The WNV-specific IgM antibody and WNV RNA are negative in blood donors. Prevalence rates of SEN-V in Iranian blood donors range from 23 to 90.8%. Consequences of these infectious agents for blood safety are different. Thus, the need to perform laboratory screening as well as effectiveness and efficiency of laboratory tests depend on pathogenicity level and epidemiological conditions of emerging infections. However, being prepared based on the current level of risk and interventions to reduce the risk can be effective in reducing the potential threat for blood supply.

Human T-lymphotropic virus lookback in NHS Blood and Transplant (England) reveals the efficacy of leukoreduction

BACKGROUND

Leukoreduction of blood components was introduced in the United Kingdom during 1998. Human T-lymphotropic virus (HTLV) screening of blood donations was introduced in 2002. NHS Blood and Transplant conducted an HTLV lookback on blood components issued before 2002. A proportion of included components were nonleukoreduced, although the majority were subject to white blood cell reduction measures.

STUDY DESIGN AND METHODS

A standard lookback was conducted on untested cellular blood components from donors later confirmed to be HTLV positive, for the 4 to 5 years before 2002, and on the last tested negative donation from donors who had seroconverted.

RESULTS

A total of 437 red blood cell and platelet components were included and an outcome was reported for 84% of these. Just over half of identified recipients were dead at the time of lookback; blood samples for testing were obtained from 77% of identified living recipients. HTLV infection was confirmed in seven recipients, but one was discounted as not transfusion transmitted.

CONCLUSION

Although numbers are small, our results provide evidence of the efficacy of leukoreduction in reducing the likelihood of HTLV transmission through transfusion of cellular blood components. The HTLV-positive rate in recipients of leukoreduced components was 3.7%, a reduction of 93% compared with nonleukoreduced components. Importantly, the one infected recipient of a leukoreduced component had existing risk factors for HTLV infection. HTLV lookback was much less efficient in identifying infected recipients than was hepatitis virus C lookback.

Epidemiology, treatment, and prevention of human T-cell leukemia virus type 1-associated diseases

Human T-cell leukemia virus type 1 (HTLV-1), the first human retrovirus to be discovered, is present in diverse regions of the world, where its infection is usually neglected in health care settings and by public health authorities. Since it is usually asymptomatic in the beginning of the infection and disease typically manifests later in life, silent transmission occurs, which is associated with sexual relations, breastfeeding, and blood transfusions. There are no prospects of vaccines, and screening of blood banks and in prenatal care settings is not universal. Therefore, its transmission is active in many areas such as parts of Africa, South and Central America, the Caribbean region, Asia, and Melanesia. It causes serious diseases in humans, including adult T-cell leukemia/lymphoma (ATL) and an incapacitating neurological disease (HTLV-associated myelopathy/tropical spastic paraparesis [HAM/TSP]) besides other afflictions such as uveitis, rheumatic syndromes, and predisposition to helminthic and bacterial infections, among others. These diseases are not curable as yet, and current treatments as well as new perspectives are discussed in the present review.

HTLV infection and its implication in gynaecology and obstetrics

INTRODUCTION

Worldwide, 20-30 million people are estimated to be infected with HTLV. HTLV-1 is endemic in Western Africa and Southern Japan, whereas HTLV-2 is considered to be spread among native American people.

MATERIALS AND METHODS

The impact of HTLV in gynaecology and obstetrics is being reviewed. Search strategy and selection criteria for identifying relevant data were performed by searching Medline, Current Contents, Web of Science, Embase and references from relevant articles. English and German gynaecological and infectious diseases textbooks as well as national and international guidelines and recommendations were also reviewed.

RESULTS

Transmission may occur by sexual intercourse or cellular blood products. Although materno-fetal transmission is debated, transmission through maternal breast milk has been confirmed. An HTLV-infection can lead to adult T-cell leukaemia (ATL) or cumulative opportunistic and neurological disorders that can occur with varying degrees of severity. Diagnosis can be done by antibody detection via the use of ELISA and western blot analysis as well as PCR diagnosis.

CONCLUSION

Due to inadequate treatment options and the lack of an effective vaccination, prevention is currently only possible by restricting transmission, including the usage of condoms during sexual intercourse or avoiding breastfeeding in HTLV-seropositive mothers. If, due to socio-economic reasons, breastfeeding cannot be avoided, short-term breastfeeding for a maximum of up to 6 months is suggested.

Blood safety strategies for human T-cell lymphotropic virus in Europe

BACKGROUND

To prevent the blood transmission of human T-cell lymphotropic virus (HTLV), different countries have introduced anti-HTLV blood screening. Furthermore, leucoreduction of blood components has been implemented to preclude the transmission of infectious agents present in white blood cells.

STUDY DESIGN AND METHODS

To evaluate the current European strategies adopted to ensure the blood safety for HTLV, a European investigation spanning a period from 2003 to 2008 was carried out.

RESULTS

In 2003, of the 23 included countries, 11 performed anti-HTLV screening, four of which (Scandinavian countries) only did it on first-time donors. Norway and Finland stopped it in 2007 and 2008, respectively. Two groups may be defined according to increasing prevalence rates per 10 000 donations in first-time donors: Scandinavia and Ireland (0 to 0.17), France, the Netherlands and UK (0.45 to 0.48); Romania was clearly apart from all other participating countries (5.33). HTLV-positive donors (88.6%) either come from endemic areas (82.3%) or declare to have a sexual partner coming from endemic areas (6.3%). Of the 283 HTLV-positive donations that could be characterized, 6.6% were HTLV-II. Fourteen of 22 countries currently use systematic leucoreduction, at least in cellular blood components. Six countries perform both universal anti-HTLV screening and blood cell leucoreduction.

CONCLUSION

The implementation of leucoreduction did not modify the blood HTLVscreening policy, except for Norway and Finland. Several screening strategies in low endemic countries performing leucoreduction were discussed. However, the withdrawal of anti-HTLV screening should be decided after assessing the remaining HTLV transfusion risk.

Seroprevalence of human T-lymphotropic virus type 1 and 2 in Korean blood donors

The seroprevalence rate of human T-lymphotropic virus (HTLV) among the Korean blood donor population was studied to determine whether screening for HTLV should be implemented. A total of 15,173 serum samples collected from June to July 2006 at five Blood Centers which are located closely to Japan geographically, where the prevalence of HTLV is known to be high, were tested. Serological screening was done by a chemiluminescence method. Samples reactive repeatedly on serological screening were confirmed further by Western blot, line immunoassay, nested polymerase chain reaction and sequencing of proviral DNA. Six samples tested reactive with the serological assay showing a reactive rate of 0.004%. Among the six samples, one sample was confirmed as HTLV-1 positive, giving a confirmed reactive rate of 0.007%. Based on the results of this study, an extended study will be conducted to evaluate whether introduction of HTLV screening is necessary in Korea.

Survival after blood transfusion

BACKGROUND

Long-term survival of transfusion recipients has rarely been studied. This study examines short- and long-term mortality among transfusion recipients and reports these as absolute rates and rates relative to the general population.

STUDY DESIGN AND METHODS

Population-based cohort study of transfusion recipients in Denmark and Sweden followed for up to 20 years after their first blood transfusion. Main outcome measure was all-cause mortality.

RESULTS

A total of 1,118,261 transfusion recipients were identified, of whom 62.0 percent were aged 65 years or older at the time of their first registered transfusion. Three months after the first transfusion, 84.3 percent of recipients were alive. One-, 5-, and 20-year posttransfusion survival was 73.7, 53.4, and 27.0 percent, respectively. Survival was slightly poorer in men than in women, decreased with increasing age, and was worst for recipients transfused at departments of internal medicine. The first 3 months after the first transfusion, the standardized mortality ratio (SMR) was 17.6 times higher in transfusion recipients than in the general population. One to 4 years after first transfusion, the SMR was 2.1 and even after 17 years the SMR remained significantly 1.3-fold increased.

CONCLUSION

The survival and relative mortality patterns among blood transfusion recipients were characterized with unprecedented detail and precision. Our results are relevant to assessments of the consequences of possible transfusion-transmitted disease as well as for cost-benefit estimation of new blood safety interventions.

False-reactive microbiologic screening test results in Swedish blood donors?how big is the problem? A survey among blood centers and deferred donors

BACKGROUND

Screening of blood donors for markers of transfusion-transmissible infectious agents leads to a varying number of false-reactive test results and sometimes thereby temporary or permanent deferral of donors and also to loss of collected units.

STUDY DESIGN AND METHODS

Data on false-reactive screening test results in 2002 and 2003 were collected from 19 blood centers in Sweden. A questionnaire was sent to donors deferred because of false-reactive screening test results to investigate their perception of the information and their reaction to the deferral.

RESULTS

Testing of 21,189 samples from new donors and 423,543 donations from regular and/or repeat donors produced 1,059 false-reactive test results, mostly from hepatitis C virus antibody testing, and 299 deferrals. Six different human immunodeficiency virus tests led to between 0.02 and 0.2 percent false-reactive results. The deferral rate varied considerably between different counties. Of 204 deferred donors contacted, 180 (88%) answered the questionnaire. More than 80 percent were worried about their test results and worry was more common among those who did not feel sufficiently informed.

CONCLUSION

The results imply that there is a need for a more standardized approach to the screening of blood donors and donations with the aim of minimizing the number of false-reactive screening test results. They also emphasize the importance of appropriate information and support to deferred donors.

Economic assessment on the management of chronic lymphocytic leukaemia

In the last decade, several new promising treatments for chronic lymphocytic leukaemia (CLL) have been developed. Healthcare costs are increasing and new treatments tend to be very expensive; therefore, information about the cost effectiveness in treatments for CLL is urgently needed. The authors performed a literature review on the currently available economic evaluations on CLL treatments. A total of 65 articles were found, of which 11 could be included. These articles were evaluated on the basis of six methodological requirements for economic evaluations, enabling readers to judge the value of the studies. Only a small amount of information was available on the costs of CLL treatments. Future economic evaluations should be performed according to the methodological requirements for these studies, which should also be properly documented.

Uses and sources of data on long-term survival after blood transfusion

Several public policy decisions in transfusion medicine require information on the long-term (> or =10-year) survival of transfused patients. This information is needed (1) to estimate the number of surviving transfusion recipients who have contracted a particular infection through transfusion, (2) to assess the cost-effectiveness of measures introduced to further improve the safety of the allogeneic blood supply, (3) to estimate the total anticipated number of transfusion-transmitted cases of disease when a novel transfusion-transmitted infection with a long incubation period emerges, and (4) determine the scope of any proposed lookback investigation in terms of the length of time that should be covered retrospectively by the lookback effort. Although the probabilities of survival of Olmsted County, MN, residents transfused in 1981 were often used previously when input data on long-term posttransfusion survival were needed in the United States, these data most likely do not reflect the survival of patients transfused in the 1990s. Recent data from Sweden, Northern England, and New York City suggest that the short-term (up to 5 years posttransfusion) probabilities of survival reported from Olmsted County may have to be reduced by up to 20% before they can be used for making public policy decisions in the future, and that probabilities of survival of 66%, 60%, and 47%, respectively, at 1, 2, and 5 years posttransfusion may reflect the life expectancy of subjects transfused in the 1990s. No empirical data on the 10-year probability of survival of such patients are currently available from population-based studies, but some data suggest that the 10-year survival of an unselected population transfused in 1988 to 1990 may be 40%. A population-based study that includes several US counties has to be undertaken to generate the information needed for public policy decisions in the future.

Pharmaco-economics of blood transfusion safety: review of the available evidence

BACKGROUND AND OBJECTIVES

Pharmaco-economics provides a standardized methodology for valid comparisons of interventions in different fields of health care. The role of pharmaco-economics in the safety of blood and blood products has, however, been very limited to date. This review discusses the pharmaco-economic evaluations of strategies to enhance blood product safety that have been published in the scientific literature.

MATERIALS AND METHODS

We reviewed pharmaco-economic methodology with special reference to cost-effectiveness analysis. We searched the literature for cost-effectiveness in blood product safety.

RESULT

Net costs per quality adjusted life-year (QALY) gained varied from cost-saving for human immunodeficiency virus (HIV)- and hepatitis C virus (HCV) antibody screening and leucoreduction to several million US dollars per QALY gained for solvent-detergent treatment of plasma, nucleic acid amplification testing and HIV p24 antigen testing.

CONCLUSIONS

To date the safety of blood transfusion has been largely determined by available technology, irrespective of pharmaco-economics. Net costs up to several million US dollars per QALY gained were found for interventions implemented.

Malignancy: Human T-Cell Lymphotropic Virus Type I and Adult T-Cell Leukaemia/Lymphoma

Adult T-cell leukaemia/lymphoma (ATLL) was first identified in Japan in 1977 [1,2]. The causative agent, the human T-lymphotropic virus type I (HTLV-I), was isolated 3 years later by Gallo's group from a patient initially diagnosed as having mycosis fungoides but subsequently reclassified as a case of ATLL [3]. Since this time, much has been discovered about the molecular pathogenesis of the disease. Despite this, treatment of ATLL remains disappointing and the prognosis of acute and lymphoma types poor. In the United Kingdom, cases of ATLL are mainly restricted to people of Afro-Caribbean descent but the disease is of general importance because ATLL has also been reported in non-endemic areas and may possibly spread into other populations via blood transfusion as blood donors in the UK are currently not screened for HTLV-I.

Human T-cell leukaemia/lymphoma virus risk may be enhanced in some selected donor populations

BACKGROUND AND OBJECTIVES

Certain patient ethnic groups may require blood components from donors under-represented in the UK donor population. Selective recruitment of Afro-Caribbean donors is therefore necessary but was considered to pose an increased risk of human T-cell leukaemia/lymphoma virus (HTLV) infection. To assess this a seroprevalence study of HTLV was undertaken in Afro-Caribbean and Caucasian donors.

MATERIALS AND METHODS

Sera from 1100 Afro-Caribbean and 1100 Caucasian donors were tested for antibody to HTLV. Reactive samples were confirmed for specificity using an algorithm comprising two additional assays and polymerase chain reaction (PCR) where possible.

RESULTS

Six Afro-Caribbean donors (0.55%) were considered to be infected with HTLV I.

CONCLUSION

Donor selection in this case caused a significantly elevated prevalence of HTLV infection and serves as a warning of the need for care in the design of policies for selective donor recruitment.

Long-term survival in transfusion recipients in Sweden, 1993

BACKGROUND

Survival and characteristics of transfusion recipients have not been studied enough, although they represent key measures in cost-effectiveness analyses of various donor screening procedures.

STUDY DESIGN AND METHODS

Hospital and blood bank records were collected on all patients in Orebro County, Sweden, from March through May 1993 (1111 transfusion episodes) and a random sample from Stockholm County during April 1993 (793 transfusion episodes). All patients were then matched with the national register of deaths in Sweden during a follow-up period of 40 months.

RESULTS

The median patient age was 71 years and the median transfusion total was 2 units. Only 35 percent of the patients were under the age of 65, 9 percent under 40, and 1.6 percent under 1 year. About half (56%) were women. Among the Orebro patients, 47 percent were surgical and 29 percent internal medicine patients. Of 1720 patients whose survival could be investigated, 66 percent were alive after 1 year and 51 percent after 40 months. The survival rates were rather similar in patients receiving RBCs and plasma but lower in those receiving platelets.

CONCLUSION

The survival of patients transfused in Sweden in 1993 differered significantly from estimations based on studies from the 1980s. This difference has major implications for the estimations of cost-effectiveness of blood donor screening for infectious agents.

Human T-cell lymphotropic virus testing of blood donors in Norway: a cost-effect model

BACKGROUND

Human T-cell lymphotropic virus type I and II (HTLV-I and II) are human retroviruses that can be transmitted by transfusion of whole blood. An HTLV-I infection is associated with adult T-cell leukaemia (ATL) and with tropical spastic paraparesis (TSP). Antibody tests from 5.5 million European blood donors have shown that the HTLV prevalence is low, ranging from 0 to 0.02%. This paper examines costs and effects associated with the intervention of testing all new blood donors for HTLV.

METHODS

A mathematical model was used to calculate the number of cases prevented by the intervention. For a given prevalence of HTLV in the blood donor population, the model calculates the number of recipients infected by transfusion, and the number of partners and offspring that will in turn be infected. The model then calculates the number of subjects with disease due to HTLV-I infection and the number of deaths from disease. From these numbers the measures of cost and effect are calculated.

RESULTS

Testing all new blood donors for HTLV is calculated to cost US$ 9.2 million per life saved, or US$ 420,000 per quality adjusted life year gained by the intervention, when the HTLV prevalence among donors is 1 per 100,000. When the prevalence among donors is 10 per 100,000 the intervention will cost US$ 0.9 million per life saved, or US$ 41,000 per quality adjusted life year gained. The same analysis shows that testing blood donors for human immunodeficiency virus (HIV) saves money when the HIV prevalence among donors is above 0.7 per 100,000.

CONCLUSION

For Norway, studies suggest a willingness to pay to save a statistical life of approximately US$ 1.2 million. The costs fall under this value when the number of infected persons is > or = 8 per 100,000 donors. The results are uncertain because of the uncertainty in HTLV infection and disease parameters.

Human T cell leukaemia/lymphoma virus infection in pregnant women in the United Kingdom: population study

OBJECTIVE

To assess the prevalence of human T cell leukaemia/lymphoma virus (HTLV) infection in pregnant women in the United Kingdom.

DESIGN

Population study.

SUBJECTS

Guthrie card samples from babies born in 1997-8. Samples were linked to data on mother's age and ethnic status and parents' country of birth and then anonymised.

SETTING

North Thames Regional Health Authority.

MAIN OUTCOME MEASURES

Presence of antibodies against HTLV in eluates tested by gelatin particle agglutination assay and results confirmed by immunoblot.

RESULTS

Of 126 010 samples tested, 67 had confirmed antibodies to HTLV (59 HTLV-I, 2 HTLV-II, 6 untyped) and six had indeterminate results. Seroprevalence was 17.0 per 1000 (95% confidence interval 9.2 to 28.3) in infants whose mothers were born in the Caribbean, 3.2/1000 (1.5 to 5.9) with mothers born in west and central Africa, and 6.8/1000 (3.1 to 12.9) in infants of black Caribbean mothers born in non-endemic regions. In infants with no known risk (both parents born in non-endemic regions and mother not black Caribbean) seroprevalence was 0.06-0.12 per 1000. Mother's country of birth, father's country of birth, and mother's ethnic status were all independently associated with neonatal seroprevalence. An estimated 223 (95% confidence interval 110 to 350) of the 720 000 pregnant women each year in the United Kingdom are infected with HTLV.

CONCLUSIONS

The prevalence of HTLV and HIV infections in pregnant women in the United Kingdom are comparable. The cost effectiveness of antenatal HTLV screening should be evaluated, and screening of blood donations should be considered.

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.

Comparative evaluation of 14 immunoassays for detection of antibodies to the human T-lymphotropic virus types I and II using panels of sera from Sweden and West Africa

BACKGROUND

A new generation of assays for the detection of human T-lymphotropic virus types I and II (HTLV-I/II) antibodies has been released. These assays incorporate HTLV-I- and HTLV-II-specific antigens, and some are based on new assay principles. Comparative evaluation data that include these new as well as previous assays are limited.

STUDY DESIGN AND METHODS

Fourteen HTLV antibody assays were evaluated by using well-characterized panels of sera from Guinea-Bissau, West Africa, and Sweden. The sera included 127 HTLV-I-positive and 62 HTLV-II-positive specimens, as well as 919 consecutive negative samples.

RESULTS

The sensitivity for HTLV-I was 100 percent for all assays, except one, which repeatedly missed one sample. The sensitivity for HTLV-II varied between 86 percent and 100 percent. In general, new-generation assays incorporating HTLV-II-specific antigens, and some of which are based on new assay principles, had a higher sensitivity for HTLV-II than previous assays, which mainly are based on HTLV-I antigens. The specificity was generally higher for new assays than for the previous versions. Testing of Swedish blood donor sera gave higher specificities (94-100%) than did that of African specimens (90-99.7%). Most assays had low delta values (DVs), although there was a tendency toward increased DVs for the new generation of assays. Only two of the new generation of assays came close to a combination of high sensitivity for both HTLV-I and HTLV-II, high specificity, positive and negative predictive values, and high DVs.

CONCLUSION

The sensitivity for HTLV-I was generally high and appears to have improved for HTLV-II with the introduction of a new generation of assays incorporating HTLV-II-specific antigens. However, some assays still give false-negative results on HTLV-II-positive specimens. The specificities and the DVs were generally higher for the new assays than for the previous versions.