Infección experimental en ovinos con el virus de leucosis bovina: dosis mínima de células BLV-FLK y virus libre de células, y actividad neutralizante de anticuerpos naturales / Experimental infection of sheep with Bovine leukemia virus (BLV): Minimum dose of BLV-FLK cells and cell-free BLV and neutralization activity of natural antibodies

Abstract Bovine leukemia virus (BLV) is an important cattle pathogen that causes major economic losses worldwide, especially in dairy farms. The use of animal models provides valuable insight into the pathogenesis of viral infections. Experimental infections of sheep have been conducted using blood from BLV-infected cattle, infectious BLV molecular clones or tumor-derived cells. The Fetal Lamb Kidney cell line, persistently infected with BLV (FLK-BLV), is one of the most commonly used long-term culture available for the permanent production of virus. FLK-BLV cells or the viral particles obtained from the cell-free culture supernatant could be used as a source of provirus or virus to experimentally infect sheep. In this report, we aimed to determine the minimum amount of FLK-BLV cells or cell-free supernatant containing BLV needed to produce infection in sheep. We also evaluated the amount of antibodies obtained from a naturally-infected cow required to neutralize this infection. We observed that both sheep experimentally inoculated with 5000 FLK-BLV cells became infected, as well as one of the sheep receiving 500 FLK-BLV cells. None of the animals inoculated with 50 FLK-BLV cells showed evidence of infection. The cell-free FLK-BLV supernatant proved to be infective in sheep up to a 1:1000 dilution. Specific BLV antibodies showed neutralizing activity as none of the sheep became infected. Conversely, the animals receiving a BLV-negative serum showed signs of BLV infection. These results contribute to the optimization of a sheep bioassay which could be useful to further characterize BLV infection.

Resumen El virus de la leucosis bovina (bovine leukemia virus [BLV]) es un importante agente patógeno del ganado que causa importantes pérdidas económicas en todo el mundo, especialmente en los rodeos lecheros. El uso de modelos animales proporciona información valiosa sobre la patogénesis de las infecciones virales. Se realizaron infecciones experimentales en ovejas usando sangre de bovinos infectados con BLV, clones moleculares de BLV infecciosos o células derivadas de tumores. La línea celular Fetal Lamb Kidney, persistentemente infectada con el BLV (FLK-BLV), es uno de los cultivos a largo plazo más utilizados para la producción permanente de virus. Las células FLK-BLV o las partículas virales obtenidas del sobrenadante del cultivo libre de células podrían usarse como fuente de provirus o de virus para infectar experimentalmente ovejas. En este trabajo, nuestro objetivo fue determinar la cantidad mínima de células FLK-BLV o de sobrenadante libre de células que contiene BLV necesaria para producir infección en ovejas. También evaluamos la cantidad de anticuerpos bovinos anti-BLV necesaria para neutralizar la infección. Observamos que las dos ovejas inoculadas experimentalmente con 5000 células FLK-BLV se infectaron, y que una de las dos ovejas que recibieron 500 células FLK-BLV se infectó. Ninguno de los animales inoculados con 50 células FLK-BLV mostró evidencia de infección. El sobrenadante FLK-BLV libre de células demostró ser infectivo en ovejas hasta la dilución 1:1000. Los anticuerpos BLV específicos mostraron actividad neutralizante, ya que ninguna de las ovejas se infectó. Por el contrario, los animales que recibieron un suero BLV negativo mostraron signos de infección por BLV. Estos resultados contribuyen a la optimización de un bioensayo en ovejas útil para caracterizar la infección por BLV.

High CD8 T cell percentage and HCV replication control are common features in HIV-1 controllers and HTLV-2-co-infected patients with a history of injection drug use.

HTLV-2/HIV-1-coinfected patients and HIV-infected patients with natural HIV-1 control show an immune capacity that allows some control of viral infections. These two groups of patients have showed an immune capacity that allows them to have some control over viral infections, very strong control of HIV-1 replication in the case of HIV-1 controllers. The purpose of this retrospective cross-sectional study was to compare viral and immunologic parameters between three cohorts of Caucasian adult HIV-1-infected patients, including HIV-1 controllers (29 patients), HTLV-2/HIV-1 chronic progressors (56 patients), and HIV-1 chronic progressors (101 patients), followed in two different tertiary University Hospitals in Spain. Demographic parameters, nadir CD4 T cell count, CD4 and CD8 T cell counts and percentage, anti-HCV antibodies, HCV RNA load, HCV genotype, HIV-1 RNA loads, and anti-HTLV-2 antibodies were analyzed. HIV-1 controllers and HTLV-2/HIV-1 chronic progressors were younger and with shorter time since HIV-1 diagnosis compared to HIV-1 chronic progressors. HIV-1 controllers and HTLV-2/HIV-1 chronic progressors had significantly higher CD8 T cell percentage (p = 0.002 and p = 0.016, respectively) and lower levels of HCV RNA loads (0.015 and 0.007, respectively) compared to that of HIV-1 chronic progressors. Multivariate analyses showed that gender and HTLV-2 infection were independently associated to HCV RNA load, while only HTLV-2 infection was independently associated to CD8 T cell percentage. The implication of HTLV-2 infection in the control of HIV-1 and HCV infections is worth being further analyze.

Phylogeny of human T-lymphotropic virus-1 subtypes in Guinea-Bissau.

Background: Human T-cell leukaemia/lymphoma virus type 1 (HTLV-1) was the first human retrovirus discovered and there is an estimate of 15-20 million infected worldwide. Endemic areas are Japan, West Africa, Central Africa, South America, the Caribbean, Middle East, Australia and the Pacific Islands. In Guinea-Bissau, adult HTLV-1 prevalence is 2-3%, and higher among HIV-infected patients. Materials and methods: Blood samples were collected in a recent HIV/HTLV survey in Bissau, the capital of Guinea-Bissau. Initially, participants were tested for HTLV serologically. The p24 and LTR regions of the proviral genome were then attempted sequenced. Sequences were analysed phylogenetically and compared with reference sequences for HTLV-1. Results: A total of 3% (78/2583) participants were positive on chemiluminesent assay, six additional samples came from another study. Of the 84 seropositive participants we successfully performed sequencing on samples, from 66 participants, 17 were positive for LTR only, one for p24 only and 48 for both. Sequences were in subgroup D of HTLV-1a cosmopolitan, while HTLV-1g was present in one participant. Conclusion: HTLV-1a subgroup D and, to a lesser extent HTLV-1g, is present in Guinea-Bissau and sequences are very similar, especially within households. Presence of HTLV-1g indicates monkey-to-man zoonotic events and at least two circulating HTLV strains in Guinea-Bissau. New sequences accession numbers: MG387979-MG388043 for LTR and MG388044-MG388092 for p24.

[Advances in application of Jurkat cell model in research on infectious diseases].

Infectious diseases can be caused by multiple pathogens, which can produce specific immune response in human body. The immune response produced by T cells is cellular immunity, which plays an important role in the anti-infection process of human body, and can participate in immunological protection and cause immunopathology. The outcome of various infectious diseases is closely related to cellular immune function, especially the function of T cells. Jurkat cells belong to the human acute T lymphocyte leukemia cell line. Jurkat cell model can simulate the function T lymphocytes, so it is widely used in the in vitro studies of T cell signal transduction, cytokines, and receptor expression, and can provide reference and guidance for the treatment of various infectious diseases and the research on their pathogenesis. The Jurkat cell model has been widely used in the in vitro studies of viral diseases and atypical pathogens, but parasitic infection studies using the Jurkat cell model are still rare. This article reviews advances in the application of Jurkat cell model in the research on infectious diseases.

Cellular Immune Responses against Simian T-Lymphotropic Virus Type 1 Target Tax in Infected Baboons.

UNLABELLED: There are currently 5 million to 10 million human T-lymphotropic virus type 1 (HTLV-1)-infected people, and many of them will develop severe complications resulting from this infection. A vaccine is urgently needed in areas where HTLV-1 is endemic. Many vaccines are best tested in nonhuman primate animal models. As a first step in designing an effective HTLV-1 vaccine, we defined the CD8(+) and CD4(+) T cell response against simian T-lymphotropic virus type 1 (STLV-1), a virus closely related to HTLV-1, in olive baboons (Papio anubis). Consistent with persistent antigenic exposure, we observed that STLV-1-specific CD8(+) T cells displayed an effector memory phenotype and usually expressed CD107a, gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α). To assess the viral targets of the cellular immune response in STLV-1-infected animals, we used intracellular cytokine staining to detect responses against overlapping peptides covering the entire STLV-1 proteome. Our results show that, similarly to humans, the baboon CD8(+) T cell response narrowly targeted the Tax protein. Our findings suggest that the STLV-1-infected baboon model may recapitulate some of the important aspects of the human response against HTLV-1 and could be an important tool for the development of immune-based therapy and prophylaxis. IMPORTANCE: HTLV-1 infection can lead to many different and often fatal conditions. A vaccine deployed in areas of high prevalence might reduce the incidence of HTLV-1-induced disease. Unfortunately, there are very few animal models of HTLV-1 infection useful for testing vaccine approaches. Here we describe cellular immune responses in baboons against a closely related virus, STLV-1. We show for the first time that the immune response against STLV-1 in naturally infected baboons is largely directed against the Tax protein. Similar findings in humans and the sequence similarity between the human and baboon viruses suggest that the STLV-1-infected baboon model might be useful for developing a vaccine against HTLV-1.

Thymosin α 1 potentiates the release by CD8(+) cells of soluble factors able to inhibit HIV-1 and human T lymphotropic virus 1 infection in vitro.

BACKGROUND: Thymosin α-1 (Tα1) exploits a specific action on lymphoid cells and is able to induce in peripheral blood mononuclear cells (PBMCs) a strong transcriptional response. CD8 antiviral factor activity plays a role in the control or prevention of HIV-1 infection by a non-cytolytic mechanism. The ability of Tα1 to modulate the release of antiretroviral soluble factors by CD8(+) cells was investigated. METHODS: Supernatants from lipopolysaccharide (LPS) stimulated CD8(+)-isolated cells treated with Tα1 were screened on in vitro infection of human monocyte-derived macrophages (MDMs) and PBMCs with HIV-1, and of PBMCs with human T lymphotropic virus 1 (HTLV-1). In CD8(+) cells, as well as in PBMCs of healthy donors as from HIV(+) individuals, a microarray analysis to assess the transcriptional response after treatment was performed. RESULTS: Tα1 potentiates the release, in LPS-stimulated CD8(+) cells, of soluble factors able to inhibit both in vitro HIV-1 infection of MDMs and PBMCs and in vitro HTLV-1 infection of PBMCs. A distinctive transcriptional profile was induced by Tα1 in PBMCs from HIV(+) donors. CONCLUSIONS: These findings suggest that Tα1 would represent a re-evaluated approach to antiretroviral therapy in combination with innovative treatments and with vaccine administration.

Immunological alterations and associated diseases in mandrills (Mandrillus sphinx) naturally co-infected with SIV and STLV.

Mandrills are naturally infected with simian T-cell leukaemia virus type 1 (STLV-1) and simian immunodeficiency virus (SIV)mnd. In humans, dual infection with human immunodeficiency virus (HIV) and human T-cell lymphotropic virus type 1 (HTLV-1) may worsen their clinical outcome. We evaluated the effect of co-infection in mandrills on viral burden, changes in T-cell subsets and clinical outcome. The SIV viral load was higher in SIV-infected mandrills than in co-infected animals, whereas the STLV-1 proviral load was higher in co-infected than in mono-infected groups. Dually infected mandrills had a statistically significantly lower CD4+ T-cell count, a lower proportion of naive CD8+ T cells and a higher proportion of central memory cells. CD4(+) and CD8(+) T cells from SIV-infected animals had a lower percentage of Ki67 than those from the other groups. Co-infected monkeys had higher percentages of activated CD4(+) and CD8(+) T cells. Two co-infected mandrills with high immune activation and clonal integration of STLV provirus showed pathological manifestations (infective dermatitis and generalised scabies) rarely encountered in nonhuman primates.

HTLV em gestantes de dois municípios da região sul da Bahia e avaliação da transmissão materno-infantil / HTLV in pregnant women in two cities of southern Bahia and evaluation of maternal-infant transmission

A prevalência de HTLV- 1 no Brasil é diversa, dependendo tanto da região geográfica quanto do grupo analisado. Um estudo populacional realizado em Salvador detectou prevalência de 1,76%, além de maior prevalência em mulheres e associação com menores níveis de escolaridade e renda. Como a via mais frequente de transmissão vertical do HTLV-1 é a amamentação e considerando a maior prevalência nas mulheres, é muito importante a realização de exames de triagem para HTLV-1 como parte do prénatal. Até o momento, não existem estudos publicados sobre a soroprevalência do HTLV-1 em gestantes na região sul da Bahia. No presente estudo, as gestantes foram selecionadas em dois centros de referência regionais de saúde do sul da Bahia. Um total de 2.766 gestantes atendidas na sala de pré-parto entre novembro de 2008 e maio de 2010 foram analisados. Um questionário foi aplicado, e todas as amostras de plasma reagentes foram testadas em duplicata e confirmadas por Western blot e PCR. Além disso, mulheres positivas foram contactadas e visitadas. Os membros da família que estavam presentes durante a visita foram convidados a serem testados para o HTLV...

The prevalence of HTLV-1 in Brazil is diverse, depending on both the geographic region and the group analyzed. A study conducted on general population revealed that the prevalence in Salvador was 1.76%. Besides, it was also found that the prevalence was higher amongst women and that the virus was associated with lower education and lower income. As the most frequent pathway of vertical transmission of HTLV-1 is breast-feeding, and considering the higher prevalence in women, it is very important to perform screening examinations for anti-HTLV-1...

Schistosoma antigens downmodulate the in vitro inflammatory response in individuals infected with human T cell lymphotropic virus type 1.

UNLABELLED: Human T cell lymphotropic virus type 1 (HTLV-1) is the causal agent of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). While the immune response to HTLV-1 infection is polarized to the Th1-type, chronic helminth infections drive the Th2- and T regulatory-type, and are able to downregulate the inflammatory response in some autoimmune diseases. OBJECTIVE: To evaluate whether Schistosoma spp. antigens alter the in vitro cytokine response in HTLV-1 infection. METHODS: The recombinant Schistosoma antigens Sm29 and ShTSP2 (tetraspanin) and PIII, a fraction of the Schistosoma mansoni adult worm antigen were added to peripheral blood mononuclear cell (PBMC) cultures of HTLV-1-infected individuals and the levels of interferon (IFN)-γ and interleukin (IL)-10 in the supernatants were measured using the ELISA sandwich technique. RESULTS: Compared to the levels of cytokine in nonstimulated cultures, the levels of IFN-γ were reduced in 50, 47 and 50% of patients by the presence of Sm29, ShTsp2 and PIII, respectively. The downregulation of IFN-γ production in the presence of Sm29 antigen was observed mainly in subjects who had lower basal levels of this cytokine. The levels of IL-10, however, increased by the addition of the three antigens in the cultures in 74, 62 and 44% of individuals, respectively. In addition, there was a decrease in the ratio of IFN-γ/IL-10 levels in cultures stimulated with Sm29 and ShTSP2 when compared to nonstimulated ones. CONCLUSIONS: The Schistosoma spp. antigens used in this study were able to downmodulate IFN-γ production in vitro in HTLV-1 infection. This may be associated with the increased levels of IL-10 induced by the antigens.

Simian T-cell lymphotropic virus type I alters the proviral load and biodistribution of simian retrovirus type 2 in co-infected macaques, supporting advancement of immunosuppressive pathology.

The infection dynamics and pathology of a retrovirus may be altered by one or more additional viruses. To investigate this further, this study characterized proviral load, biodistribution and the immune response in Macaca fascicularis naturally infected with combinations of simian retrovirus type 2 (SRV-2) and simian T-cell lymphotropic virus type I (STLV-I). As the mesenteric lymph node (MLN) and the spleen have been implicated previously in response to retroviral infection, the morphology and immunopathology of these tissues were assessed. The data revealed a significant change in SRV-2 biodistribution in macaques infected with STLV-I. Pathological changes were greater in the MLN and spleen of STLV-I-infected and co-infected macaques compared with the other groups. Immune-cell populations in co-infected macaque spleens were increased and there was an atypical distribution of B-cells. These findings suggest that the infection dynamics of each virus in a co-infected individual may be affected to a different extent and that STLV-I appears to be responsible for enhancing the biodistribution and associated pathological changes in SRV-2 in macaques.

HTLV-3/STLV-3 and HTLV-4 viruses: discovery, epidemiology, serology and molecular aspects.

Human T cell leukemia/lymphoma virus Type 1 and 2 (HTLV-1 and HTLV-2), together with their simian counterparts (STLV-1, STLV-2), belong to the Primate T lymphotropic viruses group (PTLV). The high percentage of homologies between HTLV-1 and STLV-1 strains, led to the demonstration that most HTLV-1 subtypes arose from interspecies transmission between monkeys and humans. STLV-3 viruses belong to the third PTLV type and are equally divergent from both HTLV-1 and HTLV-2. They are endemic in several monkey species that live in West, Central and East Africa. In 2005, we, and others reported the discovery of the human homolog (HTLV-3) of STLV-3 in two asymptomatic inhabitants from South Cameroon whose sera exhibited HTLV indeterminate serologies. More recently, two other cases of HTLV-3 infection in persons living in Cameroon were reported suggesting that this virus is not extremely rare in the human population living in Central Africa. Together with STLV-3, these human viral strains belong to the PTLV-3 group. A fourth HTLV type (HTLV-4) was also discovered in the same geographical area. The overall PTLV-3 and PTLV-4 genomic organization is similar to that of HTLV-1 and HTLV-2 with the exception of their long terminal repeats (LTRs) that contain only two 21 bp repeats. As in HTLV-1, HTLV-3 Tax contains a PDZ binding motif while HTLV-4 does not. An antisense transcript was also described in HTLV-3 transfected cells. PTLV-3 molecular clones are now available and will allow scientists to study the viral cycle, the tropism and the possible pathogenicity in vivo. Current studies are also aimed at determining the prevalence, distribution, and modes of transmission of these viruses, as well as their possible association with human diseases. Here we will review the characteristics of these new simian and human retroviruses, whose discovery has opened new avenues of research in the retrovirology field.

Monocytes from HTLV-1-infected patients are unable to fully mature into dendritic cells.

Human T-cell lymphotropic virus type 1 (HTLV-1) is a causative agent of adult T-cell leukemia and HTLV-1-associated myelopathy/tropical spastic paraparesis. HTLV-1-associated myelopathy/tropical spastic paraparesis is a chronic inflammatory disease characterized by loss of motor movement in response to spinal marrow cell destruction by T lymphocytes. To perform their cellular function, T cells need to be activated by antigen-presenting cells, such as dendritic cells (DCs). The aim of this work was to analyze DC differentiation and activation from monocytes of HTLV-1-infected individuals. We demonstrated that monocytes from HTLV-1-infected patients who had been stimulated to differentiate had an impaired loss of CD14 expression, expressed low levels of CD1a, and maintained secretion of tumor necrosis factor-α compared with monocytes from noninfected donors. We further evaluated DC activation by tumor necrosis factor-α. We observed that in response to activation, DCs that were derived from noninfected donors had an increase in the percentage of CD83(+), CD86(+), and human leukocyte antigen-DR(+) cells, whereas in DCs derived from HTLV-1-infected patients, the percentage of CD83(+), CD86(+), and human leukocyte antigen-DR(+) cells remained similar to that of nonactivated cells. Moreover, these cells had an impaired capacity to stimulate allogeneic T lymphocytes. We demonstrated that DC maturation was altered in HTLV-1-infected patients, which could contribute to the development of HTLV-1-associated diseases.

Highly active antiretroviral treatment against STLV-1 infection combining reverse transcriptase and HDAC inhibitors.

Approximately 3% of all human T-lymphotropic virus type 1 (HTLV-1)-infected persons will develop a disabling inflammatory disease of the central nervous system known as HTLV-1-associated myelopathy/tropical spastic paraparesis, against which there is currently no efficient treatment. As correlation exists between the proviral load (PVL) and the clinical status of the carrier, it is thought that diminishing the PVL could prevent later occurrence of the disease. We have conducted a study combining valproate, an inhibitor of histone deacetylases, and azidothymidine, an inhibitor of reverse transcriptase, in a series of baboons naturally infected with simian T-lymphotropic virus type 1 (STLV-1), whose PVL was equivalent to that of HTLV-1 asymptomatic carriers. We show that the combination of drugs caused a strong decrease in the PVL and prevented the transient rise in PVL that is seen after treatment with histone deacetylases alone. We then demonstrate that the PVL decline was associated with an increase in the STLV-1-specific cytotoxic T-cell population. We conclude that combined treatment with valproate to induce viral expression and azidothymidine to prevent viral propagation is a safe and effective means to decrease PVL in vivo. Such treatments may be useful to reduce the risk of HAM/TSP in asymptomatic carriers with a high PVL.

The 14th International Conference on Human Retrovirology: HTLV and related retroviruses (July 1-4, 2009; Salvador, Brazil).

The "14th International Conference on Human Retrovirology: HTLV and Related Retroviruses" was held in Salvador, Bahia, from July 1st to July 4th 2009. The aim of this biennial meeting is to promote discussion and share new findings between researchers and clinicians for the benefit of patients infected by human T-lymphotropic virus (HTLV). HTLV infects approximately 15-20 million individuals worldwide and causes a broad spectrum of diseases including neurodegeneration and leukemia. The scientific program included a breadth of HTLV research topics: epidemiology, host immune response, basic mechanisms of protein function, virology, pathogenesis, clinical aspects and treatment. Exciting new findings were presented in these different fields, and the new advances have led to novel clinical trials. Here, highlights from this conference are summarized.

Presentation of human T cell leukemia virus type 1 (HTLV-1) Tax protein by dendritic cells: the underlying mechanism of HTLV-1-associated neuroinflammatory disease.

HTLV-1 is the etiologic agent of a debilitating neurologic disorder, HAM/TSP. This disease features a robust immune response including the oligoclonal expansion of CD8+ CTLs specific for the viral oncoprotein Tax. The key pathogenic process resulting in the proliferation of CTLs and the presentation of Tax peptide remains uncharacterized. We have investigated the role of APCs, particularly DCs, in priming of the anti-Tax CTL response under in vitro and in vivo conditions. We investigated two routes (direct vs. indirect) of Tax presentation using live virus, infected primary CD4+/CD25+ T cells, and the CD4+ T cell line (C8166, a HTLV-1-mutated line that only expresses Tax). Our results indicated that DCs are capable of priming a pronounced Tax-specific CTL response in cell cultures consisting of naïve PBLs as well as in HLA-A*0201 transgenic mice (line HHD II). DCs were able to direct the presentation of Tax successfully through infected T cells, live virus, and cell-free Tax. These observations were comparable with those made with a known stimulant of DC maturation, a combination of CD40L and IFN-gamma. Our studies clearly establish a role for this important immune cell component in HTLV-1 immuno/neuropathogenesis and suggest that modulation of DC functions could be an important tool for therapeutic interventions.

Long-term serologic follow-up of blood donors with biologic false reactivity on an anti-human T-cell lymphotropic virus Types I and II chemiluminescent immunoassay and implications for donor management.

BACKGROUND: This study reports the results of the long-term serologic follow-up of blood donors who gave an index biologic false-reactive (BFR) result on an anti-human T-lymphotropic virus Types I and II (HTLV-I and -II) chemiluminescent immunoassay (ChLIA). STUDY DESIGN AND METHODS: All allogeneic whole-blood and apheresis donors who gave an index BFR result on a HTLV-I and -II ChLIA between May 10, 1997, and December 31, 2004, were included in the study. Donors were followed up for an additional 2 years until December 31, 2006. RESULTS: A total of 332 donors gave an index BFR donation during the study period. Donors were divided into five groups based on results of donations subsequent to the index BFR donation: 89 (26.8%) donors gave only nonreactive donations subsequent to the index BFR result, 56 (16.9%) donors gave only BFR donations, 43 (13.0%) gave one or more subsequent BFR donations before giving only nonreactive donations, 59 (17.8%) donors gave intermittent BFR and nonreactive donations, and 85 (25.6%) donors gave no further donations during the study period. The estimated mean duration of biologic false reactivity from the time of the index BFR donation in donors who gave only a single BFR result was 7.0 (1.4-42.75) months and 23.3 (4.1-92.25) months in those donors who gave several BFR results before giving nonreactive donations. Modeling of the data indicated that notification and deferral of donors after two consecutive BFR donations would result in the deferral of 143 of 332 (43.1%) of donors with an index BFR result while allowing donors to give three BFR results would reduce the number of deferred donors to 74 of 332 (22.3%). CONCLUSION: The results of this study indicate that although biologic false reactivity is usually transient, the time for resolution is variable. Allowing donors to give two or three BFR results before notification and deferral is one strategy that would substantially reduce the number of donors requiring deferral.

Correlação de polimorfismos na região promotora dos genes de IL-6 e IL-10 com o desenvolvimento de doenças em indivíduos infectados pelo HTLV-I e análise da distribuição destes polimorfismos em diferentes grupos populacionais brasileiros / Correlation of polymorphisms in the promoter region of genes of IL-6 and IL-10 with the development of diseases in individuals infected with HTLV-I and analysis of the distribution of these polymorphisms in different population groups Brazilians

Polimorfismos localizados em regiões promotoras ou em outras regiões regulatórias dos genes podem estar relacionados à produção diferenciada de citocinas, podendo, conseqüentemente, alterar a intensidade ou a qualidade da resposta imune. Neste trabalho, investigamos a associação entre polimorfismos nos promotores de IL-6 e IL-IO com o desenvolvimento de TSP/HAM, e com osteopenia, em pacientes infectados pelo HTLV-l de Salvador. Para avaliar a correlação com TSP/HAM, nós analisamos 133 indivíduos infectados pelo HTLV-1 (84 assintomáticos, 26 com TSP/HAM e 23 oligosintomáticos) e 100 soronegativos da população geral de Salvador. Para avaliar a possível correlação com osteopenia, os polimorfismos foram analisados em 43 indivíduos, jovens (20-45 anos), assintomáticos, a fim de identificar fatores de risco que poderiam estar relacionados com alterações no metabolismo ósseo. Vale ressaltar, que a freqüência de SNP e de seus haplótipos podem diferir em populações com diferentes backgrounds genéticos, explicando em parte por que algumas populações são mais susceptíveis a determinadas patologias. Desta forma, inicialmente, analisamos o padrão dos polimorfismos nos promotores de IL-6 e IL-IO na população de Salvador e em duas outras populações brasileiras: 99 ameríndios (tribo Tiriyó) e 94 indivíduos de Joinville (descendentes de alemães). Os polimorfismos foram investigados por RFLP (-634G/C e-592C/A) e por Real Time PCR (-572G/C, -597G/ e -174G/C). A freqüência do SNP -174G/C na região promotora do gene da IL-6 foi altamente heterogênea em todas as populações estudadas, sendo os resultados consistentes com dados de outras populações de mesmo background étnico. Descrevemos pela primeira vez a prevalência do polimorfismo -634C/G nesses grupos étnicos. Observamos uma diferença significante na freqüência alélica do SNP -592C/A IL-10 entre os indivíduos de Tiriyó e as duas outras populações, mas não entre Salvador e Joinville. O alelo A na posição -592A foi significativamente mais prevalente nos Tiriyós, sendo sua freqüência similar àquela relatada em populações da Ásia e Índia. Nos indivíduos infectados, detectamos uma maior freqüência do alelo -634C no grupo TSP/HAM (21.2%), quando comparado aos oligosintomáticos (6.5%; p=0.038) e assintomáticos (9.5%; p=O.025). Similarmente, a freqüência do alelo -174G alelo foi maior em TSP/HAM, quando comparado aos oligosintomáticos (p=O.02). Além disso, a combinação -634GC/-174GG foi mais freqüente nos pacientes com TSP/HAM (38.5%) que nos outros grupos (8.7%; p=O.016 para oligosintomáticos e 15.5%, p=O.012 para assintomáticos), sugerindo que esta combinação poderia estar relacionada ao desenvolvimento de TSP/HAM. Em relação à identificação de possíveis fatores de risco para o desenvolvimento de osteopenia em indivíduos jovens assintomáticos, embora não tenhamos encontrado associação com os polimorfismos em IL-6, todos os indivíduos -174GC apresentaram níveis de osteoclacina menores que os valores normais (3.1mg/dL) (p=O.029) e este polimorfismo foi associado ainda a maior carga proviral (p=O.OO5). Juntos, esses resultados sugerem que polimorfismos em genes de IL-6 podem ser importantes no desenvolvimento de doença em indivíduos infectados pelo HTLV-1 e que o background genético deve ser considerados. Esses estudos podem contribuir para a melhor compreensão da complexa associação entre a variabilidade região promotora da de IL-6 e susceptibilidade à doença, bem como podem ajudar na compreensão da interação: hospedeiro X vírus na patogênese do HTLV-1.