Increased prevalence of human herpesvirus type 8 (HHV-8) genome among blood donors from North-Western Argentina.

The prevalence of HHV-8 infection varies widely in South American populations, displaying geographical variations in its distribution. The heterogeneous genetic contributions provided by the transatlantic parental populations that modified the Native American genomes may explain this epidemiological observation. Aiming to determine the prevalence of HHV-8 genome among healthy South American blood donors and its potential association with genetic ancestry, 772 individuals were screened by a highly sensitive PCR protocol and ancestry was assessed in 414 samples. HHV-8 DNA was significantly more prevalent among North-western Argentines than among those from the metropolitan region (P = 0.001) and Bolivians (P = 0.0008), but no differences were found when compared with Peruvians and Paraguayans. Although significant differences were observed in the ancestry components of the studied populations, no association was found in the genetic admixture between HHV-8 [+] and HHV-8 [-] samples from the same place. These results support the hypothesis of the existence of geographical factors related to HHV-8 prevalence which could be explained by the presence of specific risk factors, cultural characteristics or behaviors, probably related to contaminated saliva and/or sexual transmission. The presence of HHV-8 in South American blood units available for transfusion and an increased risk of infection in some provinces of North-western Argentina represent a hazard for immunosuppressed recipients. J. Med. Virol. 89:518-527, 2017. © 2016 Wiley Periodicals, Inc.

Role of HLA-DP and HLA-DQ on the clearance of hepatitis B virus and the risk of chronic infection in a multiethnic population.

BACKGROUND & AIMS: HBV infection exhibits geographical variation in its distribution in South America. While HBV rates are low in central Argentina, the north-western region exhibits intermediate HBV rates. Unfortunately, the reasons that could explain this difference are still unknown. METHODS: A total of 1440 Argentines were recruited and grouped into HBV patients, HBV-resolved individuals and healthy controls. Genetic ancestry was assessed by analysis of biparental lineages and ancestry autosomal typing. SNPs of HLA-DPA1 (rs3077), HLA-DPB1 (rs9277542), HLA-DQB1 (rs2856718) and HLA-DQB2 (rs7453920) were determined, and HBV genotyping was performed by phylogenetic analysis in HBV patients. RESULTS: Native American ancestry prevailed in the north-western region when compared with central Argentina (P<.0001). However, no differences were observed among the three groups of each region. The distribution of HBV genotypes revealed significant differences (P<.0001). Three SNPs (rs3077, rs9277542 and rs7453920) showed a significant association with protection against chronic HBV and viral clearance in both regions. The remaining SNP showed a significant association with susceptibility to chronic HBV. The frequency rates of rs3077-T, related to protection against chronic HBV and viral clearance, were lower in north-western Argentina when compared with central Argentina. The same uneven frequency rates were observed for SNP rs9277542. CONCLUSIONS: This is the first study addressing the associations between the HLA-DP and HLA-DQ loci and the protection against chronic HBV and viral clearance in a multiethnic South American population. The uneven distribution of HLA-DP and HLA-DQ supports the HBV epidemiological differences observed in these two regions of Argentina with dissimilar ancestry genetic background.

Prevalence and trends of markers of hepatitis B virus, hepatitis C virus and human Immunodeficiency virus in Argentine blood donors.

BACKGROUND: Transfusion-transmitted infections are a major problem associated with blood transfusion. The aim of this study was to determine prevalence and trends of HBV, HCV and HIV in blood donors in Argentina. METHODS: A retrospective study was carried out in blood donors of 27 transfusion centers covering the whole country over a period of eight years (2004-2011). Serologic screening assays for HBsAg, anti-HBc, anti-HCV, and anti-HIV were performed in all centers and nucleic acid amplification testing (NAT) was performed in 2 out of the 27 centers. RESULTS: The 2,595,852 samples tested nationwide from 2004 to 2011 showed that the prevalence of HBsAg decreased from 0.336% to 0.198% (p < 0.0001), that of anti-HBc from 2.391% to 2.007% (p < 0.0001), that of anti-HCV from 0.721% to 0.460%, (p < 0.0001) and that of anti-HIV from 0.208% to 0.200 (p = 0.075). The prevalence of HBV, HCV and HIV was unevenly distributed among the different regions of the country. Two out of 74,838 screening- negative samples were positive in NAT assays (1 HIV-RNA and 1 HCV-RNA); moreover, HBV-DNA, HCV-RNA and HIV-RNA were detected in 60.29, 24.54 and 66.67% of screening-positive samples of the corresponding assays. As regards donors age, positive HBV-DNA and HCV-RNA donors were significantly older than healthy donors (46.6, 50.5 and 39.5 y respectively, p < 0.001). CONCLUSIONS: Argentina has a low prevalence of HBsAg, anti-HCV and anti-HIV in blood donors, with a decreasing trend for HBsAg, anti-HBc and anti-HCV but not for anti-HIV over the last 8 years. The uneven distribution of transfusion-transmitted infections prevalence among the different regions of the country highlights the need to implement regional awareness campaigns and prevention. The discrepancy between samples testing positive for screening assays and negative for NAT assays highlights the problem of blood donors who test repeatedly reactive in screening assays but are not confirmed as positive upon further testing. The uneven distribution of age between healthy donors and NAT-positive donors could be related to changes in risks of these pathogens in the general population and might be attributed to a longer exposure to transmission risk factors in elderly people.

[Risk of transfusional-transmitted infections]. / Riesgo de transmisión de infecciones por vía transfusional.

Although each donated unit of blood is tested for evidence of infection by specific agents, there are at least four potential reasons why transmission of these agents may still occur: a) the donor has negative laboratory test results during the early stages of infection, known as the window period, b) the existence of a chronic carrier state in which a clinically asymptomatic donor will persistently test negative on a screening assay, c) donors harbouring a mutant or atypical variant and d) laboratory errors when performing the screening tests. Measures to assure the safety of blood and blood components include use of voluntary donors, donor selection and questioning, laboratory testing for serological markers of infections, maintenance of registries of disqualified donors and, more recently, the introduction of direct testing for viral nucleic acids. All these measures must be accompanied by rigorous quality control systems. The potential risk of transfusion-transmitted infectious diseases can be estimated by reviewing the records of blood donations, the screening procedures and determining the prevalence of the serologic markers of infectious diseases. Accurate estimates of the risk of transfusion-transmitted infections are needed in order to monitor the safety of the blood supply and evaluate the yield and cost effectiveness of alternatives to allogeneic transfusion. Genomic screening for infectious agents, especially viruses, became possible with the development of various nucleic acid amplification techniques. They combine the advantages of direct detection of the organism with a sensitivity several orders of magnitude higher than that of traditional methods.

Virus de West Nile. Nuevo virus emergente en medicina transfusional / West Nile Virus. A new emergent virus in transfusional medicine

West Nile virus is a member of the Flaviviridae family. It was first isolated in Uganda and is indigenous to Africa, Asia, Australia and southern Europe. In recent years, local epidemics have been reported in Romania, Russia and Israel. In 1999 the virus presented a rapid emergence in North America and until November 2002 it has caused over 4,100 symptomatic infections in humans, of whom more than 240 have died. The life cycle of the virus includes mosquitoes as vectors with birds as amplifying viremic vertebrate hosts. Human, horses and other animals serve as dead-end hosts. Most infections are mild, with symptoms primarily being fever, headache, and myalgias. People older than 50 years are at highest risk of severe disease, which include encephalomyelitis. In 2002, 5 new modes of transmission were recognized: blood transfusion, organ transplantation, breast-feeding, transplacental transmission and occupational exposure in laboratory workers. Regarding blood transfusion, during the 2002 West Nile virus epidemic in the United States, 23 patients were confirmed to have acquired West Nile virus through transfused red cells, platelets or fresh-frozen plasma. Currently, there is no specific drug treatment or vaccine against the infection, and avoiding mosquito bites is the best way to protect against the disease.

Virus TT (TTV) ¿Es un verdadero causante de hepatis? / Is TT virus (TTV) a true hepatitis virus cause?

El virus TT (TTV), se detectó en sangre de tres pacientes con hepatitis postransfusional que eran negativos para todos los marcadores de virus de hepatitis conocidos. Los títulos de ADN viral estaban correlacionados con los niveles de aminotransferas séricas (ALT). Además se aisló el virus de hígado con títulos iguales o mayores a los sueros correspondientes. Posteriormente se comprobó que la mayoría de las personas TTV positivas no presentan evidencias bioquímicas o histológicas de enfermedad hepática. TTV tiene una distribución mundial, con una alta prevalencia en la población general, y existen evidencias de que es transmisible a través de transfusiones sanguíneas, por vía entérica y de madre a hijo. Existe una importante cantidad de estudios que sugieren que este virus no es una causa significativa de enfermedad hepática crónica o aguda y hasta ahora no se ha descripto ninguna asociación de la infección con otras enfermedades.

Riesgo de transmision de infecciones por via transfusional / Risk of transfusional-transmitted infections

Although each donated unit of blood is tested for evidence of infection by specific agents, there are at least four potential reasons why transmission of these agents may still occur: a) the donor has negative laboratory test results during the early stages of infection, known as the window period, b) the existence of a chronic carrier state in which a clinically asymptomatic donor will persistently test negative on a screening assay, c) donors harbouring a mutant or atypical variant and d) laboratory errors when performing the screening tests. Measures to assure the safety of blood and blood components include use of voluntary donors, donor selection and questioning, laboratory testing for serological markers of infections, maintenance of registries of disqualified donors and, more recently, the introduction of direct testing for viral nucleic acids. All these measures must be accompanied by rigorous quality control systems. The potential risk of transfusion-transmitted infectious diseases can be estimated by reviewing the records of blood donations, the screening procedures and determining the prevalence of the serologic markers of infectious diseases. Accurate estimates of the risk of transfusion-transmitted infections are needed in order to monitor the safety of the blood supply and evaluate the yield and cost effectiveness of alternatives to allogeneic transfusion. Genomic screening for infectious agents, especially viruses, became possible with the development of various nucleic acid amplification techniques. They combine the advantages of direct detection of the organism with a sensitivity several orders of magnitude higher than that of traditional methods (AU)#S

Anticuerpos anti-Trypanosoma cruzi en donantes de sangre / Serological screening of antibodies to Trypanosoma cruzi

La vía transfusional es la segunda ruta más común de infección de la enfermedad de Chagas en regiones endémicas. Para el tamizaje de donantes de sangre, la OMS recomienda el uso de al menos dos ensayos. Las pruebas convencionales, Enzimoinmunoensayo (ELISA) y hemo-aglutinación indirecta (HAI), no son suficientemente sensibles y específicas. El objetivo de este trabajo fue estudiar la prevalencia de anti-T.cruzi en nuestra población de donantes de sangre, y comparar las sensibilidades y especificidades relativas de diferentes ensayos. Evaluamos 12479 donantes consecutivos con HAI y ELISA y de ellos, seleccionamos un panel de 138 muestras para estudiar sensibilidad y 784 para especificidad. La seroprevalencia fue 1,89 por ciento (ES: 0,122; IC: 1,65-2,14; p<0,05) y 1,10 por ciento (ES: 0,094; IC: 0,91-1,29; p<0,05) se confirmaron positivos. De los ELISAs, el recombinante presentó la mayor especificidad relativa y se observó una muy buena performance en cuanto a la sensibilidad, con valores de densidad óptica más elevados. Este ensayo es útil para tamizaje o como un tercer método para confirmar resultados discordantes en donantes de sangre.

Transfusión autóloga / Autologous transfusion

La transfusión autóloga surge como necesidad de contar con garantías en cuanto a evitar los posibles efectos secundarios de las transfusiones. En este artículo se presentan los conceptos básicos de esta técnica utilizada en algunos de los períodos perioperatorios

Transfusión autóloga / Autologous transfusion

La transfusión autóloga surge como necesidad de contar con garantías en cuanto a evitar los posibles efectos secundarios de las transfusiones. En este artículo se presentan los conceptos básicos de esta técnica utilizada en algunos de los períodos perioperatorios

Evaluación de una técnica de enzimoinmunoensayo para detección de anticuerpos anti-HTLV-I / Anti HTLV-EIA screening test assessment

El HTLV-I y el HTLV-II son virus cuya transmisión ocurre de madre a hijo, por contacto sexual y por transfusiones de sangre o por compartir agujas contaminadas. El HTLV-I está asociado al menos con dos enfermedades, la leucemia-linfoma T del adulto y la parapesia espástica tropical. Con el fin de prevenir la transmisión por vía transfusional en varios países se testean las donaciones de sangre para Ac anti-HTLV-I. El presente estudio tuvo como objetivo la evaluación de un nuevo test de enzimoinmunoensayo para detección de Ac anti HTLV-I (Abbott HTLV-I 2.0 EIA, USA) utilizando muestras repetidamente reactivas por la prueba de AP y positivas, indeterminadas o negativas por WB. Se utilizaron 63 sueros obtenidos de donantes voluntarios vinculares de sangre. Treinta fueron negativos por WB, 13 reactivos para HTLV-I, 2 reactivos para HTLV-II, uno para HTLV-I/II y 17 indeterminados. Todas las muestras positivas por WB también lo fueron por EIE; en cuanto a las negativas por la técnica confirmatoria, el 13 por ciento fue reactivo por EIE. Por último, de los sueros indeterminados, el 53 por ciento fue positivo por EIE. La técnica del EIE resultó tener muy buena sensibilidad y podría constituir una alternativa útil en el caso de no disponer momentáneamente de reactivos para realizar la confirmación. Según lo observado en nuestra experiencia, un resultado positivo por EIE para una muestra repetidamente reactiva por AP indica con alta probabilidad que están presentes Ac anti-HTLV y viceversa.

Prevalencia de anticuerpos anti-Trypanosoma cruzi en donantes de sangre / Prevalence of anti-Trypanosoma cruzi antibodies in blood donors

La transmisión de la enfermedad de Chagas por vía transfusional es la segunda causa en importancia de infección en áreas endémicas. Existen discrepancias en los resultados obtenidos con los equipos disponibles para el estudio de la presencia de marcadores serológicos anti-Trypanosoma cruzi. El objetivo del presente trabajo fue determinar la seroprevalencia de marcadores anti-T. cruzi, comparar la sensibilidad y especificidad relativas de las dos técnicas de tamizaje que utilizamos en nuestra División y confirmar los resultados con un tercer ensayo. Se estudiaron un total de 20 860 donantes voluntarios por hemoaglutinación indirecta (HAI) y enzimoinmunoensayo (EIE). Las muestras repetidamente reactivas fueron ensayadas por un EIE llevado a cabo en tiras de nitrocelulosa (DB). Los sueros que resultaron reactivos en al menos dos de las pruebas se consideraron positivos. La prevalencia de marcadores anti-T. cruzi, fue de 2.76 por ciento (576 muestras). De todas las muestras estudiadas, el 1.87 por ciento fueron confirmadas positivas. No se registraron flasos negativos para la prueba de EIE, mientras que 98 muestras (0.47 por ciento) fueron falsos negativos para el HAI. La especificidad relativa fue del 99.3 por ciento y 99.8 por ciento para EIE y HAI respectivamente. En nuestro caso, el descarte de unidades falsamente reactivas corresponde a casi el 0.9 por ciento del total de donaciones, de las cuales dos tercios corresponden a falsos EIE y un tercio a falsos HAI. Es importante destacar que en la población estudiada no se han resgistrado falsos negativos para EIE pero sí para HAI, lo que indicaría, que a pesar de que el primer método es menos específico, resulta mucho más sensible. Resulta de importancia la confirmación de los resultados obtenidos en las pruebas tamiz para evitar al aviso innecesario a los donantes falsamente reactivos y permitir eventualmente futuras donaciones. El DB empleado en el presente estudio resulta una alternativa útil para este propósito.

Quienes pueden ser donantes de sangre? / Who can be blood donors?

La seguridad del donante y del receptor en el proceso de las transfusiones sanguíneas es el eje del presente artículo en el cual se detallan los pasos a seguir en cuanto a los criterios para la recepción, examen físico, recuperación y posibles reacciones adversas del donante, así como la extracción de sangre

Efectos adversos inmunológicos de la terapia transfusional / Immunological adverse reactions to transfusion therapy

En este artículo se explican diversos cuadros clínicos que se observan al desencadenarse reacciones adversas a la terapia transfusional en pacientes que reciben transfusiones de sangre o hemoderivados, y se detallan las formas de tratarlas y prevenirlas

Prevención de la enfermedad hemolítica feto-neonatal por Rho (D) / Prevention of the fetal-neonatal haemolytic disease by Rho (D)

El presente artículo explica la enfermedad hemolítica feto-neonatal; el concepto y la fisiopatología, como así también la prevención de la misma