Leucemia asociada al virus linfotrópico T humano tipo 1 (HTLV-1) y transmisión intrafamiliar de la infección en Santiago del Estero / Leukemia associated to human T cell lymphotropic virus type 1 (HTLV-1) infection and intrafamily transmission in Santiago del Estero

Resumen La leucemia/linfoma a células T del adulto (ATLL) es una enfermedad hematológica causada por el virus linfotrópico T humano tipo 1 (HTLV-1) que se desarrolla luego de 20 años de incubación, preferencialmente cuando la infección se adquiere por transmisión vertical. Este tiempo se reduce de 3 meses a 3 años cuando la transmisión del virus es por transfusión o trasplante de órganos. La ATLL aguda es de difícil diagnóstico por ser inusual y tener una rápida progresión a la muerte. En el Noroeste argentino, donde el virus es endémico, la ATLL es más frecuente, sin embargo, también se la detecta continuamente en el resto del país. El tratamiento de elección, en primera instancia, es el uso combinado de antivirales. Presentamos un caso de ATLL aguda desarrollada en un hombre de 59 años de Santiago del Estero a partir del cual se identificó transmisión intrafamiliar de la infección por HTLV-1.

Abstract Adult T-cell leukemia/lymphoma (ATLL) is an hematological disease caused by human T-cell lymphotropic virus type 1 (HTLV-1) that develops after 20 years of incubation preferentially when the infection is acquired by vertical transmission. In cases of transmission by transfusion or organ transplant, this time is reduced from 3 months to 3 years. Acute ATLL is difficult to diagnose because it is unusual and has a rapid progression to death. In the Argentine Northwest, where the virus is endemic, ATLL is more frequent, however it is also detected continuously in the rest of the country. The treatment of choice, in the first instance, is the combined use of antivirals. We present a case of acute ATLL developed in a 59-year-old man from Santiago del Estero from which intrafamilial transmission of HTLV-1 infection was identified.

HTLV-2 infection in Manaus, Brazil: first description of HTLV-2c subtype in an urban area of the Western Amazon region

Abstract INTRODUCTION: We investigated the prevalence of human T-cell lymphotropic virus types 1 and 2 (HTLV-1/2) infection in patients with hematological diseases from the western Amazon region of Brazil. METHODS: Samples from 306 patients were submitted for the molecular diagnosis of HTLV-1/2 infection by real time PCR (qPCR), with amplification, sequencing, and phylogenetic analysis of the long terminal repeat (LTR) region. RESULTS: A 29-year-old male carrier of sickle cell anemia with a history of multiple blood transfusions was diagnosed with the HTLV-2c subtype. CONCLUSIONS: This study describes the first known occurrence of HTLV-2c in the urban area of Brazil's western Amazon region.

Laboratory diagnosis of human T-lymphotropic virus in Brazil: assays, flowcharts, challenges, and perspectives

Abstract INTRODUCTION We present a data analysis and review of recent studies regarding the laboratory diagnosis of human T-lymphotropic virus 1 and 2 (HTLV-1/2) infections in Brazil. METHODS Target populations, available diagnostic serological assays (screening and complementary tests), molecular assays (in-house), causes of false-positive and false-negative results, and flowcharts were analyzed. RESULTS A table presents the target populations, two diagnostic flowcharts (depending on laboratory infrastructure and study population), and recent research that may improve how HTLV-1/2 is diagnosed in Brazil. CONCLUSIONS: Our results support the implementation of public policies to reduce HTLV-1/2 transmission and its associated diseases.

Brazilian protocol for sexually transmitted infections 2020: human T-cell lymphotropic virus (HTLV) infection

Abstract This article addresses the Human T-lymphotropic virus (HTLV). This subject comprises the Clinical Protocol and Therapeutic Guidelines for Comprehensive Care for People with Sexually Transmitted Infections, published by the Brazilian Ministry of Health. HTLV-1/2 infection is a public health problem globally, and Brazil has the largest number of individuals living with the virus. HTLV-1 causes several clinical manifestations of neoplasm (adult T-cell leukemia/lymphoma) and inflammatory nature, such as HTLV-1-associated myelopathy and other manifestations such as uveitis, arthritis, and infective dermatitis. These pathologies have high morbidity and mortality and negatively impact the quality of life of infected individuals. This review includes relevant information for health authorities professionals regarding viral transmission, diagnosis, treatment, and monitoring of individuals living with HTLV-1 and 2 in Brazil.

Specificity of HTLV screening tests and its impact on health care program costs: The perspective of antenatal screening in Brazil

Abstract INTRODUCTION: Brazil ranks first in the number of HTLV-1/-2-infected individuals worldwide. The high morbidity and mortality of HTLV-1-associated diseases, especially following infection in infancy, requires strong action to reduce vertical transmission. METHODS: To facilitate the appraisal of the implementation of the HTLV antenatal screening program by the Brazilian Ministry of Health, we determined the costs in distinct scenarios according to HTLV seroprevalence, specificity of the screening test, and type of confirmatory test. RESULTS: HTLV antenatal screening would cost R$ 55,777,012-R$ 77,082,123/year. Screening assays with high specificity reduce the need and cost of confirmatory assays by up to 25%. CONCLUSIONS: Careful selection of the screening assay is required to optimize the program.

Evaluación de dos marcas comerciales de pruebas de ELISA para el diagnóstico de HTLV-1 frente a muestras peruanas

Resumen Por ser el Perú un país endémico de HTLV-1, es importante conocer la confiabilidad de las marcas comerciales para el diagnóstico más usadas en nuestro país. En el presente estudio, evaluamos dos marcas comerciales de pruebas de ELISA (Biokit y Wantai) para la detección de anticuerpos contra HTLV-1 frente a muestras peruanas. Ambas marcas comerciales fueron evaluadas frente a 242 sueros: 123 positivos a HTLV-1 y 119 negativos a HTLV-1 (referencia: inmunoblot). Se estimaron los parámetros de precisión diagnóstica. La sensibilidad, especificidad, VPP, VPN e índice de validez de Biokit fueron: 100%, 93,2%, 93,8%, 100%, 96,6%; respectivamente y de Wantai fue de 99,1% para todos los parámetros. Concluimos, que la marca Biokit fue la más adecuada para ser usada en el Laboratorio de Referencia Nacional de Virus de Transmisión Sexual, VIH/SIDA de Perú.

Abstract As Peru is endemic to HTLV-1, it is important to know the reliability of the most used screening trademarks in our country. In the present study, we evaluated two brands of ELISA (Biokit and Wantai) for the detection of antibodies against HTLV-1/2 against Peruvian samples. Both brands were evaluated against 242 sera: 123 positive for HTLV-1 and 119 negative for HTLV-1 (Reference: Immunoblot). We estimated diagnostic accuracy parameters. The sensitivity, specificity, PPV, NPV and validity index of Biokit were: 100%, 93.2%, 93.8%, 100%, 96.6%; respectively and Wantai were 99.1% for all parameters. We conclude that the Biokit brand is the most suitable for use in the National Reference Laboratory of Sexually Transmitted Viruses HIV/AIDS, Peru.

Association of TLR3 single nucleotide polymorphisms with susceptibility to HTLV-1 infection in Iranian asymptomatic blood donors

Abstract INTRODUCTION: The human T-lymphotropic virus type 1 (HTLV-1) has a single-stranded RNA genome and expresses specific proteins that have oncogenic potential. Approximately 15 to 20 million people worldwide have been infected by this virus. Changes in protein or gene expression are the effects of single nucleotide polymorphisms (SNPs) within the Toll-like receptor 3 (TLR3) gene. The function and efficacy of signal transduction also lead to modified immune responses. The present study aimed to investigate the association of SNPs within TLR3 (rs3775291 and rs3775296) with susceptibility to HTLV-1 infection in Iranian asymptomatic blood donors. METHODS: This study was performed on 100 HTLV-1-infected asymptomatic blood donors and 118 healthy blood donors. Genomic DNA from all participants was purified and then amplified using specific PCR primers. SNPs within TLR3 were evaluated using the restriction fragmentation length polymorphism technique, and the results were analyzed using SPSS software (version 22). RESULTS: The frequencies of the TLR3 (rs3775296) CC, CA, AA genotypes were 70%, 24%, and 6% in the patient group, and 50.8%, 44.9%, and 4.2% in the control group, respectively. There was a significant difference in the frequency distribution of TLR3 (rs3775296) genotypes and alleles, but not in the frequency distribution of TLR3 (rs3775291) genotypes between the patient and control groups. CONCLUSIONS: The TLR3 SNP rs3775296 was significantly associated with HTLV-1 infection and may be a protective factor against this viral infection.

Line immunoassay for confirmation and discrimination of human t-cell lymphotropic virus infections in inconclusive western blot serum samples from Brazil

Difficulties in confirming and discriminating human T-cell lymphotropic virus type 1 (HTLV-1) and HTLV-2 infections by serological Western blot (WB) assays (HTLV Blot 2.4; MP Biomedicals) have been reported in Brazil, mainly in HIV/AIDS patients, with a large number of WB-indeterminate and WB-positive but HTLV-untypeable results. Nonetheless, a line immunoassay (LIA) (INNO-LIA HTLV-I/II; Fujirebio) provided enhanced specificity and sensitivity for confirming HTLV-1/2 infections. To add information concerning the improved ability of the LIA in relation to WB when applied to samples of individuals from different risk groups from Brazil, we performed the present study. Three groups were analyzed group 1 (G1), with 62 samples from HIV/AIDS patients from São Paulo, SP (48 WB indeterminate and 14 HTLV untypeable); group 2 (G2), with 24 samples from patients with hepatitis B or hepatitis C from São Paulo (21 WB indeterminate and 3 HTLV untypeable; 17 HIV seropositive); and group 3 (G3), with 25 samples from an HTLV outpatient clinic in Salvador, Bahia (16 WB indeterminate and 9 HTLV untypeable; all HIV seronegative). Overall, the LIA confirmed HTLV-1/2 infection (HTLV-1, HTLV-2, or HTLV) in 66.1% (G1), 83.3% (G2), and 76.0% (G3) of samples. Interestingly, the majority of WB-indeterminate results were confirmed by the LIA as being HTLV-2 positive in G1 and G2 but not in G3, in which the samples were defined as being HTLV-1 or HTLV positive. These results agree with the virus types that circulate in such patients of different regions in Brazil and emphasize that the LIA is the bes

Neurologic complications of HTLV-1: a review / Complicações neurológicas do HTLV: uma revisão HTLV-1

The human T-cell lymphotropic virus type 1 (HTLV-1) is a retrovirus that infects about 20 million people worldwide and causes immune-mediated diseases of the nervous system. The classical neurological presentation of HTLV-1 infection is the so-called HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). However, HAM/ TSP is not the only neurological outcome that can result from HTLV-1 infection. In this Review it is made an update on the many aspects of this important neurological condition, the HTLV-1 neurological complex.

O vírus linfotrópico de células T humanas tipo 1 (HTLV-1) é um retrovírus que infecta cerca de 20 milhões de pessoas em todo o mundo e causa doenças imunomediadas do sistema nervoso. A apresentação neurológica clássica da infecção pelo HTLV-1 é a chamada paraparesia espástica tropical / mielopatia associada ao HTLV-1 (HAM/TSP). HAM / TSP,no entanto, não é o único desfecho neurológico que pode resultar da infecção pelo HTLV-1. Nesta revisão, é feita uma atualização sobre vários aspectos desta importante condição neurológica, o complexo neurológico do HTLV-1.

Human T cell lymphotropic virus type 1 infection among men who have sex with men in Central Brazil

ABSTRACT Human T cell lymphotropic virus type 1 (HTLV-1) was the first retrovirus discovered in humans and is endemic in several parts of the world. Because of risk behaviors, mainly sexual, men who have sex with men (MSM) are at high risk of acquiring HTLV-1 infection. A cross-sectional study was performed to estimate the prevalence of HTLV-1 infection, to characterize genetically HTLV-1 sequences and to identify risk behaviors associated with this infection among MSM in Central Brazil. A total of 430 MSM were enrolled in this study and three were shown to be HTLV-1 infected, prevalence of 0.7% (95% confidence interval: 0.4-0.9). Phylogenetic analysis showed that all HTLV-1 positive samples belonged to Cosmopolitan subtype Transcontinental subgroup A. Although the prevalence rate of HTLV-1 infection found in this study was similar to that observed among Brazilian blood donors, additional HTLV-1 preventive interventions need to be further implemented because this population is engaged in high-risk sexual behavior.

Rendimiento diagnóstico de la prueba de inmunofluorescencia indirecta para la detección de anticuerpos contra HTLV-1 / Diagnostic performance of the indirect immunofluorescence test for the detection of antibodies against HTLV-1

RESUMEN El objetivo del estudio fue determinar el rendimiento diagnóstico de la prueba de inmunofluorescencia indirecta (IFI) para la detección de anticuerpos contra HTLV-1. Se realizó un estudio de evaluación de prueba diagnóstica. Se usaron cultivos celulares MT2 infectados con HTLV-1 y K-562 sin infección, luego fueron sembrados, fijados en láminas para inmunofluorescencia y enfrentados a sueros. Se usaron 155 sueros (80 positivos para HTLV-1 y 75 positivos para otras enfermedades) procedentes de la seroteca del Instituto Nacional de Salud del Perú. Adicionalmente, se evaluó la repetibilidad (en el laboratorio) y reproducibilidad (en laboratorios de costa, sierra y selva) de la prueba. La prueba IFI para la detección de anticuerpos contra HTLV-1 tuvo una sensibilidad de 98,75% (IC 95%: 95,69-100%), una especificidad de 98,67% (IC 95%: 95,40-100%) y el índice de kappa de 0,975. No hubo falsos positivos ni falsos negativos; sin embargo, sí se obtuvo un resultado indeterminado y uno inespecífico. La prueba mostró 100% de concordancia en la repetibilidad y reproductibilidad. Concluimos que los resultados obtenidos son comparables a la prueba de referencia. La prueba de IFI presenta un buen rendimiento diagnóstico y sería de utilidad para la confirmación de HTLV-1.

ABSTRACT The objective of the study was to determine the diagnostic yield of the indirect immunofluorescence (IFI) test for the detection of antibodies against HTLV-1. A diagnostic test evaluation study was performed. HTLV-1-infected MT2 cells and HTLV-1-uninfected K-562 cells were cultured; then these cells were impregnated and fixed in sheets for immunofluorescence and faced to Peruvian sera. A total of 155 sera (80 HTLV-1-positive sera and 75 sera positive for other diseases) from the Peruvian Instituto Nacional de Salud were used. In addition, the parameters of repeatability (intra-laboratory) and reproducibility (in laboratories of the Peruvian coast, mountains and jungle) of the test were evaluated. The IFI test detected the presence of antibodies against HTLV-1 reaching a sensitivity of 98.75% (95% CI: 95.69 - 100.00%), a specificity of 98.67% (95% CI: 95.40 - 100.00%) and the Kappa index was 0.975. There were no false positives or false negatives; however, one undetermined result and one non-specific result were obtained. The test showed 100% qualitative agreement when performing the repeatability and reproducibility. The results obtained are comparable to the reference test. Therefore, the IFI test had a good diagnostic performance and would be useful for the confirmation of HTLV-1.

Case for diagnosis. Infective dermatitis associated with HTLV-1: differential diagnosis of atopic dermatitis

Abstract: Infective dermatitis associated with HTLV-1 (IDH) is the main cutaneous marker of HTLV-1 infection. This disease occurs primarily in children and should be differentiated from other eczemas, especially from atopic dermatitis. The largest series of IDH are from Jamaica and Brazil. There are an estimated 15 to 20 million infected people in the world, and Brazil is one of the endemic regions. Studies suggest that IDH in children may be a marker for the development of T-cell leukemia/lymphoma (ATL) or myelopathy associated with HTLV-1/tropical spastic paraparesis (HAM / TSP) in adulthood.

Comparative performances of serologic and molecular assays for detecting human T lymphotropic virus type 1 and type 2 (HTLV-1 and HTLV-2) in patients infected with human immunodeficiency virus type 1 (HIV-1)

ABSTRACT The present study evaluated several techniques currently available (commercial kits and in-house assays) for diagnosing human T lymphotropic viruses types 1 and 2 in two groups of patients enrolled at HIV/AIDS specialized care services in São Paulo: Group 1 (G1), n = 1608, 1237 male/371 female, median age 44.3 years old, majority using highly active antiretroviral therapy (HAART); G2, n = 1383, 930 male/453 female, median age of 35.6 years old, majority HAART naïve. Enzyme immunoassays [(EIA) Murex and Gold ELISA] were employed for human T lymphotropic viruses types 1 and 2 screening; Western blotting (WB), INNO-LIA (LIA), real-time PCR pol (qPCR), and nested-PCR-RFLP (tax) were used to confirm infection. Samples were considered human T lymphotropic viruses types 1 and 2 positive when there was reactivity using at least one of the four confirmatory assays. By serological screening, 127/2991 samples were positive or borderline, and human T lymphotropic virus infection was confirmed in 108 samples (three EIA-borderline): 56 human T lymphotropic virus type 1 [G1 (27) + G2 (29)]; 45 human T lymphotropic virus type 2 [G1 (21) + G2 (24)]; one human T lymphotropic virus type 1 + human T lymphotropic virus type 2 (G2); six human T lymphotropic virus [G1 (2) + G2 (4)]. Although there were differences in group characteristics, human T lymphotropic viruses types 1 and 2 prevalence was similar [3.1% (G1) and 4.2% (G2), p = 0.113]. The overall sensitivities of LIA, WB, qPCR, and PCR-RFLP were 97.2%, 82.4%, 68.9%, and 68.4%, respectively, with some differences among groups, likely due to the stage of human T lymphotropic virus infection and/or HAART duration. Indeterminate immunoblotting results were detected in G2, possibly due to the seroconversion period. Negative results in molecular assays could be explained by the use of HAART, the occurrence of defective provirus and/or the low circulating proviral load. In conclusion, when determining the human T lymphotropic virus infection, the findings highlight that there is a need to consider the blood samples with borderline results in screening assays. Of all the tested assays, LIA was the assay of choice for detecting human T lymphotropic virus type 1 and human T lymphotropic virus type 2 in human immunodeficiency virus type 1-infected patients.

Linfoma duodenal asociado a infección por Strongyloides stercoralis. Dos manifestaciones de la infección por HTLV-1 / Duodenal Lynphoma associated to Strongyloides stercoralis infection. Two types of HTLV-1 infection

La infección por el virus linfotrópico de células T humanas tipo 1 (HTLV-1), es causante de la leucemia/linfoma de células T del Adulto (ATLL), siendo la afectación duodenal poco usual. La coinfección de HTLV-1 con Strongyloides stercolaris es común en los pacientes con HTLV- 1 debido a la inadecuada respuesta TH2 que presentan estos sujetos. Describimos a una paciente mujer de 48 años de edad, natural y procedente de la selva del Perú con historia familiar de infección por HTLV- 1 quien acude con diarrea crónica y baja de peso. Se le diagnosticó infección por HTLV-1 así como ATLL duodenal y estrongiloidiasis. Se inició tratamiento con ivermectina y quimioterapia, siendo estabilizada y dada de alta. Reportamos el presente caso debido a la poca frecuencia de coexistencia en duodeno de ATLL y estrongiloidiasis.

Infection by the Human T- Lymphotropic virus I (HTLV-1) causes Adult T cell Leukemia-lymphoma (ATLL), being the duodenal involvement rare. Commonly, patients co-infected with HTLV-1 and Strongyloides stercoralis are seen due to the lack of TH2 response found on these patients. We describe a 48-year-old woman, from the jungle of Peru, with a family history of HTLV-1 infection, who presented with a History of chronic diarrhea and weight loss. HTLV-1 infection with ATLL and strongyloidiasis were diagnosed. Ivermectin treatment and chemotherapy were initiated, being stabilized, and discharged. We report this case because of the unusual coexistence in the duodenum of ATLL and strongyloidiasis.

Short communication: failures in detecting HTLV-1 and HTLV-2 in patients infected with HIV-1

Changes in retrovirus acquisition/transmission behaviors have been reported in Brazil, with a concerning increase in HIV-1-infected individuals aged 15-39 years. In São Paulo, HIV-1/HTLV-1 and HIV-1/HTLV-2 coinfections have been associated with intravenous drug use and failure to detect HTLV-1/2 (human T cell lymphotropic virus types 1 and 2) with immunosuppression and the use of highly active antiretroviral therapy (HAART). Negative results for HTLV serologic [western blotting (WB)] and molecular [real-time PCR pol (qPCR)] confirmatory assays have been reported, whereas the best sensitivity has been found for INNO-LIA (LIA). In this study, we expand our previous data by analyzing a group of young patients (n = 1,383; median age 35.6 years) who recently acquired HIV by sexual contact, the majority of whom were HAART naïve, and comparing the performances of four HTLV confirmatory assays LIA, WB, qPCR, and PCR-RFLP (tax). We confirmed HTLV infection in 58 (4.2%) blood samples 29 HTLV-1, 24 HTLV-2, 1 HTLV-1+HTLV-2, and 4 HTLV. LIA, WB, qPCR, and PCR-RFLP sensitivities were 94.8%, 82.8%, 79.2%, and 74.5%, respectively. Associations of HTLV infection with female gender (OR = 2.28, 1.31-4.00) and age >40 years (p < .0001) were detected. The results confirm the low sensitivities of molecular assays and the best performance of LIA in detecting HTLV-1/2 in such patients. We hypothesize that the negative PCR results are due to the presence of defective provirus and/or low proviral load circulating in such patients, with inconclusive WB coinciding with the seroconversion period. Corroborating the associations obtained, repeated exposure is required for HTLV sexual transmission/acquisition, which is more efficient from male to female

Comparação de testes laboratoriais para o diagnóstico de infecção por vírus linfotrópicos de células T humanas do tipo 1 (HTLV-1)e tipo 2 (HTLV-2) em pacientes infectados por HIV-1 / Comparison of laboratorial tests for the diagnosis of human T-lymphotropic virus type 1 (HTLV-1) and type 2 (HTLV-2) in HIV-1 infected patients

O presente estudo pesquisou o melhor algoritmo de testes laboratoriais para efetuar o diagnóstico de infecção por vírus linfotrópicos de células T humanas dos tipos 1 (HTLV-1) e 2 (HTLV-2) em pacientes HIV-1 positivos. Amostras de sangue de 1.608 pacientes do CRT DST/Aids-SP foram analisadas quanto à presença de anticorpos específicos usando-se dois ensaios de triagem (EIA Murex HTLV-I+II e Gold ELISA HTLV-I/II), dois confirmatórios [HTLV Blot 2.4 (Western Blot – WB) e INNO-LIA HTLV I/II (Line ImmunoAssay - LIA)] e um molecular (PCR em tempo real pol). Na triagem foram detectados 51(Murex) e 49 (Gold ELISA) soros reagentes. Pelo WB, 23 soros confirmaram infecção por HTLV-1, 12 HTLV-2, seis HTLV e nove apresentaram perfis indeterminados. O LIA detectou 24 soros HTLV-1 positivos, 20 HTLV-2 e seis HTLV. A PCR evidenciou segmento pol de HTLV-1 em 18 e HTLV-2 em 12 amostras de sangue. Pelos testes confirmatórios, em 50 pacientes foi confirmada a infecção por HTLV: 25 HTLV-1 (1,55 %), 21 HTLV-2 (1,31 %) e quatro HTLV (0,25 %). As sensibilidades do LIA, WB e PCR foram de 96 %, 76 % e 60 %, respectivamente. Considerando-se apenas o custo, o melhor algoritmo diagnóstico para população infectada pelo HIV-1 foi o uso da PCR seguida do LIA...

Dried blood spot testing for the antenatal screening of HTLV, HIV, syphilis, toxoplasmosis and hepatitis B and C: prevalence, accuracy and operational aspects

Introduction: Screening for vertically transmitted infection is mandatory and must be conducted at the first prenatal consultation. The most vulnerable women's groups are those at the lowest socio-economic level. Dried blood spot testing on filter paper could represent a secure way to screen pregnant women in the prenatal period. Methods: A cross-sectional study was conducted between November 2009 and March 2010, in the Metropolitan Region of Salvador, Bahia, Brazil, to compare the accuracy of the dried blood spot in filter paper and venipuncture serological as screening methods for HIV, HTLV, VHB, VHC, Treponema pallidum, and Toxoplasma gondii during prenatal period. Results of the venous blood sample collected in tubes were considered the gold standard. Results: Serum samples and dried blood spot were obtained from 692 pregnant women aged between 14 and 42 years, with a median age of 26. Thirteen women were seropositive for T. gondii (1.88%; 95% CI: 0.60–2.71%), five for T. pallidum (0.72%; 95% CI: 0.15–1.61%), two for HBV (0.29%; 95% CI: 0.050.95%) and one for HTLV-1 (0.14%; 95% CI: 0.01–0.71%). No one was positive for HCV and HIV. The dried blood spot accuracy for syphilis and HTLV were 100% (95% CI: 99.25–100) and 100% (95% CI: 99.45–100%), respectively. The average time between blood collection and recording of the sample in the reference laboratory was 4.93 (3.82) days and between dried blood spot processing and active search for pregnant women was 3.44 (4.27) days. Conclusions: The use of dried blood spot may represent a secure way to expedite access to results of vertically transmitted diseases in the prenatal period, particularly in regions with scarce healthcare resources. .

Diagnóstico serológico de HTLV-1/2: combinación de técnicas de tamizaje para definir el estatus serológico en donantes de sangre / [Serological diagnosis of HTLV-1/2: combination of screening assays to define the serological status in blood donors].

Alternative algorithms were evaluated in order to reduce the number of false reactive results for antibodies against HTLV-1/2. From 20,210 samples tested, 0.37

(74/20,210) was reactive by ELISA Murex. Of these, 23 were confirmed as positive by the indirect immunofluorescence assay whereas 51 were negative, being the positive predictive value (PPV) 31.08

. From a combination of the ELISA Murex assay with the particle agglutination assay (PA) and ELISA MP, the following results were obtained: 26/74 were reactive by ELISA Murex and PA, PPV 88.5

and 32/74 were reactive by ELISA Murex and ELISA MP, PPV 71.8

. The ROC curve analysis determined that for an RP 4.74, the values for sensitivity, specificity, PPV and NPV by ELISA Murex were 100

, respectively. We propose that reactive samples by ELISA Murex with an RP d 4.74 should be retested in duplicate by PA, and the resulting concordantly nonreactive samples should be defined as negative for HTLV-1/2.