Sensitivity and specificity of the new Bio-Rad HIV screening test, Access HIV combo V2.

Diagnosing of human immunodeficiency virus (HIV) types 1 and 2 requires a screening with a highly sensitive and specific enzyme immunoassay and a low detection limit for the HIV-1 p24 antigen to minimize the diagnostic window. The objective of the study was to determine the sensitivity, specificity, and p24 limit of detection of the Access HIV combo V2 assay. Retrospective part of sensitivity: 452 HIV-1 positive samples from 403 chronic (9 different HIV-1 group M subtypes, 22 different HIV-1 group M CRFs, and 3 HIV-1 group O), 49 primary HIV-1 infections, 103 HIV-2 positive samples assessed at Pitié-Salpêtrière Hospital, 600 untyped HIV-1, 10 subtype-D, and 159 untyped HIV-2 samples assessed in Bio-Rad Laboratories. Prospective part of clinical specificity: all consecutive samples in two blood donor facilities and Pitié-Salpêtrière (6,570 patients) tested with Access HIV combo V2 and respectively Prism HIV O Plus (Abbott) or Architect HIV Ag/Ab Combo (Abbott) for Ag/Ab screening, and Procleix Ultrio (Gen Probe) for HIV RNA screening. Limit of detection for p24 antigen was assessed on recombinant virus-like particles (10 HIV-1 group M subtypes/CRFs, HIV-1 group O). Sensitivity [95% confidence interval (CI)] of Access HIV combo V2 was 100% (99.63-100) for HIV-1 chronic infection, 100% (98.55-100) for HIV-2 chronic infection, and 100% (93.00-100) for HIV-1 primary infection. Specificity (95% CI) was 99.98 (99.91-100). Limit of detection for p24 antigen was around 0.43 IU/mL [interquartile range (0.38-0.56)], and consistent across the 11 analyzed subtypes/CRFs. Hence, with both high sensitivity and specificity, Access HIV combo V2 is a suitable screening assay for HIV-1/2 infection. IMPORTANCE: Bio-Rad is one of the leading human immunodeficiency virus (HIV) screening test manufacturers. This laboratory released in 2021 their new version of the Access combo HIV test. However, to date, there have been no studies regarding its performance, especially its limit of detection of the diverse p24 antigen. We present the sensitivity (chronic and primary HIV-1 infection and HIV-2 chronic infection), specificity (blood donors and hospitalized patients), and raw data for the p24/seroconversion panels the manufacturer gave to the European agencies.

Outcomes of discordant HIV screening test results at a southern academic medical center.

OBJECTIVE: The aim of this study was to examine outcomes of follow-up for persons with discordant fourth-generation HIV screening test results. DESIGN: A retrospective chart review. METHODS: We analyzed the electronic health record at the Medical University of South Carolina for a 10-year period spanning 2012-2022 to identify instances of discordant HIV screening test results, wherein initial antigen/antibody screening was positive, but reflex confirmatory testing for HIV-1 and HIV-2 antibodies was negative. We reviewed individual records to evaluate clinical follow-up and determine if the discordant test represented an acute HIV infection, a false-positive result, or was unresolved. RESULTS: We identified 199 testing instances with discordant results. Most discordant results ( n  = 115) were subsequently determined to reflect a false-positive test, while 56 were unresolved without documented follow-up testing. Twenty-eight cases of acute HIV infection were identified of which 26 were linked to care within a month of initial testing. Two acute HIV cases were not identified in real time leading to delay in diagnosis and care. Testing done in the context of infectious symptoms and testing performed in the emergency department were associated with increased odds of a discordant test ultimately reflecting acute HIV infection. CONCLUSION: These results demonstrate the importance of appropriate and timely follow-up for discordant HIV screening test results.

Evaluación de la estabilidad del sistema de diagnóstico inmunoenzimático DAVIH VIH-2 / Evaluation of the stability of the immunoenzymatic diagnostic system DAVIH VIH-2

Introducción: el estudio de la estabilidad de los componentes y el producto terminado constituye un importante requisito regulatorio en los diagnosticadores. Objetivo: realizar un estudio de estabilidad en tiempo real durante doce meses del sistema inmunoenzimático (ELISA) DAVIH VIH-2. Métodos: se realizó un estudio de estabilidad en tiempo real durante doce meses en tres lotes del diagnosticador DAVIH VIH-2, ELISA indirecto diseñado para la detección de anticuerpos contra el virus de inmunodeficiencia humana tipo 2 en suero o plasma humano. Se controlaron los requisitos de calidad de los componentes de acuerdo a sus especificaciones. Se estudió la normalidad de valores de densidad óptica/valor límite y la homogeneidad de las medias y varianzas mediante las dócimas de Grubbs y Cochran. Se estimó la precisión en los controles positivo y negativo del sistema y en seis muestras con diferente reactividad al virus de inmunodeficiencia humana tipo 2 mediante el cálculo del coeficiente de variación y se confeccionaron las cartas de control de los valores de las medias de densidad óptica respecto al tiempo. Resultados: los requisitos de calidad de cada componente se cumplieron durante 12 meses, excepto las características funcionales del conjugado a partir de los seis meses. Los valores en las dócimas de Grubbs y Cochran fueron menores que los valores críticos tabulados para α del 1 y 5 por ciento por lo que existió homogeneidad en las medias y las varianzas en todo el periodo. El coeficiente de variación se mantuvo inferior al 10 por ciento excepto en las muestras con reactividad media y baja, mientras que en las cartas de control, los valores de densidad óptica se mantuvieron en el límite de la media ±2 desviaciones estándar hasta el noveno mes(AU)

Fourth-generation enzyme-linked immunosorbent assay for the simultaneous detection of human immunodeficiency virus antigen and antibody

The VIDAS HIV DUO Ultra, a fourth-generation immunoassay under development for the simultaneous detection of human immunodeficiency virus type 1 (HIV-1) p24 antigen and antibodies to HIV-1 and HIV-2, was evaluated. The enzyme-linked fluorescence immunoassay, performed on the automated VIDAS instrument, is claimed to detect early and established HIV infection. The assay was challenged with a total of 2,847 samples that included 74 members of 10 seroconversion panels, 9 p24 antigen-only-reactive members of a panel of group M clades, 503 consecutively collected samples from individuals seeking care in the University of Maryland Medical System, 1,010 samples from U.S. blood donors, 1,141 samples from patients in a high-incidence population in Trinidad, 83 samples from a clinic for sexually transmitted diseases in the Bahamas, 10 confirmed HIV-1 group O samples, and 16 confirmed HIV-2 samples from the Cote d'Ivoire. Reference tests were U.S. Food and Drug Administration-licensed HIV antibody screening, p24 antigen tests, HIV confirmatory assays, and the Roche Diagnostics Amplicor HIV-1 Monitor. The VIDAS HIV DUO Ultra demonstrated 100% sensitivity and 99.5% specificity overall, with a 99.7% specificity in low-risk individuals. The analytical sensitivity, as assessed by seroconversion panels and p24 antigen in samples, was equivalent to the sensitivity of the reference assays used to characterize these panels. The VIDAS HIV DUO Ultra is accurate, offers potential advantages over conventional HIV testing for time and cost savings, has walk-away capability, and correctly identifies both early and established HIV infections.

Respuesta inmune humoral hacia VIH-2 en México / Humoral immune response to HIV-2 in Mexico

Objetivo. Estudiar las reacciones hacia antígenos de VIH-2 de sueros mexicanos VIH-1 positivos, en relación con la vía de transmisión y el estado clínico de los individuos infectados. Material y métodos. Se estudiaron 654 sueros (492 VIH-1 positivos y como controles 162 VIH-1 negativos). Se preparon Inmuno blots (IB) con antígenos semipurificados de MS-VIH-2 y de IIIb/LAV-VIH-1 y se corrieron en ambos todas las muestras de suero. Resultados. En el análisis de los IB de los sueros VIH-1 positivios se encontró que 79 por ciento (388/492) presentaron reactividad con, por lo menos, una proteína VIH-2; 71 por ciento (352/492) de los sueros reconocen la proteína de cápside p24; la glicoproteína transmembranal de VIH-2 es reconocida por 24 por ciento (119/492) de los sueros y 9 por ciento (44/492) reconocieron la glicoproteína externa de este retrovirus. La reactividad con VIH-2 de sueros VIH-1 positivos está significativamente asociada a la vía de adquisición de la infección (81 por ciento en vía sexual contra 39 por ciento en vía sanguínea) y al estado clínico (84 por ciento en pacientes asintomáticos o con linfadenopatía contra 31 por ciento en pacientes con SIDA). Se descartó la posible infección con los dos tipos de VIH por medio del ensayo comercial Liatek (Organon Teknica). Conclusiones. Se propone como hipótesis que las cepas introducidas originalmente en nuestro país a través de las dos vías principales de transmisión son de orígenes diferentes

Objective. To study the reactions of Mexican HIV-1 positive sera to HIV-2 antigens, and their relation to the mode of ransmission and the clinical status of infected individuals. Material and Methods. Six-hundred and fifty-four sera samples collected in Mexico were tested using HIV-2 immunoblot (IB) techniques; 492 samples were from HIV-1 positive cases and 162 from HIV-1 negative controls. Results. Seventy-nine percent (388/492) of the HIV-1 reactive sera showed reactivity with at least one HIV-2 protein: 71% (352/492) recognized the capsid protein p24, 24% (119/492) the transmembrane glycoprotein and 9% (44/492) the external glycoprotein of HIV-2. Considering the transmission mechanism, HIV-2 reactivity occurred in 81% (324/401) of the sexually infected patients, and only in 39% (16/41) of people infected through blood products. Ten highly reactive gp32 HIV-2 sera samples were titrated and results showed that reactivity with HIV-1 gp41 was always higher than that to HIV-2 gp32. HIV-1-HIV-2 dual infection was discarded by negative results with the commercial assay Liatek HIV 1+2. Conclusions. We propose that the serological cross-reactivity found can be due to a possible initial introduction in Mexico of two different viral strains through the two main ransmission routes and that the strains circulating in sexually infected individuals are more similar to the HIV-2 strains, at least with respect to their glycoproteins, than the HIV-1 strains predominant in other countries.

Routine HIV screening among blood donors in Buenos Aires (Argentina): Results from six years' experience and report of a single window-period donation

Antecedentes. En Argentina, la detección de anticuerpos anti-VIH (virus de la inmunodeficiencia humana) es obligatorio desde 1991 y desde 1997 se recomienda el tamizaje del antígeno p24. MÉTODOS. Se tamizaron un total de 30.132 donaciones sucesivas. A las muestras repetidamente reactivas se les realizó otra reacción de tamizaje y/o Western blot (WB), para anticuerpos anti-VIH, o ensayo de neutralización para el antígeno p24. RESULTADOS. Se obtuvieron el 0,3623% de muestras repetidamente reactivas y el 0,2084% de donantes verdaderamente infectados con VIH. Sólo un donante resultó no reactivo para anti-VIH, repetidamente reactivo para antígeno p24 y positivo por neutralización con posterior seroconversión. Las muestras con razón (..) (AU)

Background. Blood donor HIV antibody detection has been mandatory in Argentina since 1991, and p24 antigen screening was recommended in 1997. Methods. A total of 30,132 consecutive donations were screened. Repeatedly reactive samples were tested by another screening test and/or by Western blot (WB) for HIV Ab, or by a neutralization assay for p24 Ag. Results. Among the total, 0.3623% of samples were repeatedly reactive and 0.2084% were true HIV-infected donors. Only one donor tested nonreactive for HIV Ab, repeatedly reactive for p24 Ag, positive by neutralization assay, and seroconverted later. Samples with a signal-to-cutoff (S/CO) ratio ¡Ý 3.00 on routine HIV Ab testing were 100.0% positive by WB and/or repeatedly reactive by the second test. In samples with a S/CO ratio < 3.00, 11.1% were positive by WB and/or the majority were nonreactive by the second test. Among HIV-infected donors, 89.5% possessed risk factors (which had been denied previously), 56.5% were repeatedly reactive by other screening procedures and 88.6% were coinfected with other blood-transmissible viruses. Conclusions. When the EIA S/CO ratio is ¡Ý 3.00, WB can be replaced by a second screening test. The pre-donation questionnaire should be improved to detect risk behavior in prospective donors. There was a high association between HIV and other blood-transmissible viruses (AU)

Enfermedades marcadoras de sida en un grupo de pacientes africanos con infección por VIH/sida / Infections and other opportunistic processes in a group of African patients with HIV infection/AIDS

No disponible

Risco atual de transmissao de AIDS por transfusao / Actual risk of AIDS transmission by transfusion

Desde 1982 e sabida a possibilidade de transmissao da infeccao pelo HIV atraves da transfusao de sangue. Este risco hoje e muito menor, mas nao e ausente, quando as unidades a serem trasnfundidas sao testadas: uma em 60.000, testada negativa, transmite a infeccao nos Estados Unidos. No Brasil a prevalencia de doadores de sangue soropositivos para o anti HIV e 15 vezes maior: admitindo que as falhas de diagnostico da infeccao pelo individuo estar na "janela" sorologica serem iguais nos dois paises, o risco de pegar uma infeccao pelo HIV tomando unidade que testou negativa no Brasil vai de 1/2533 a 1/5000 e nao adianta fazer mais e mais testes para evitar isto. A unica maneira de melhorar esta situacao e mudar o perfil dos doadores, afastando da doacao os que realmente nao querem doar, e sim obter um teste anti HIV rapidamente e de graca - e para isto a melhor solucao e fazer sistemas de execucao rapidos e gratuitos deste exame disponiveis para a populacao, longe dos servicos de Hemoterapia e colheita de sangue.

Production of monoclonal antibodies to human immunodeficiency virus type-2

The ROD strain of the human immunodeficiency virus type 2 (HIV-2) was used to produce monoclonal antibodies. Virus grown in CEM cells was partially purified by ultracentrifugation and solubilized in a buffer containing Triton X-100. BALB/c mice were inoculated intraperitoneally with 50 micrograms of solubilized virus preparations mixed 1:1 with complete Freund's adjuvant. Animals were boosted on day 28 and sacrificed on day 31. Spleen cells from the immunized animals were fused with SP20/Ag 14 myeloma cells and cultured in HAT medium. Following selection of the hybrids of interest by an HIV-2 ELISA procedure, hybridomas were cloned twice by limiting dilution. Six clones were found to produce antibodies that reacted with HIV-2 antigens as judged by ELISA. These antibodies were concentrated by ammonium sulfate precipitation, and analyzed by the Western blot procedure. Monoclonal antibodies specifically reactive to an HIV protein of 68 KD were obtained. These antibodies did not react with an HIV-2 band of 55 KD. These data showed that the monoclonal antibodies recognized the carboxy terminal region (the RNAse H domain) of the HIV-2 retrotranscriptase enzyme

The seroprevalence of hepatitis and retroviral infection in Jamaican haemodialysis patients

63 haemodialysis (HD) patients and 63 age and gender matched controls were investigated for hepatitis B surface antigen (HbsAg) and antibodies to hepatitis B virus (anti-HBV), hepatitis C virus (anti-HCV), hepatitis D virus (anti-HDV), human immunodeficiency virus types 1 and 2 (anti-HIV-1 and 2) and human T-cell lymphotropic virus type-1 (anti-HTLV-1). The notable finding was an increase in hepatitis B markers, 34.9 percent in HD patients compared to 19.0 percent in controls (p < 0.02). The seroprevalence of anti-HCV (7.9 percent, p < 0.03) and anti-HTLV-1 (9.5 percent; p < 0.006) was also increased in the patients. Four of the five patients positive for anti-HCV were also seropositive for HBV. Anti-HIV and anti-HDV were not detectable in the HD patients in this study. The possibility of HTLV-1 being transmitted by organ transplantation is raised. The seropositivity rate for hepatitis B and C increased with duration on dialysis, but it is likely that it was related to the number of blood transfusions since 50 percent with no transfusion were HBV seropositive.(AU)

Avaliaçäo do desempenho de uma prova rápida para diagnóstico da infecçäo pelo HIV / Diagnosis of HIV infection. Performance evaluation of a rapid HIV test

Avaliamos o desempenho do teste denominado "Simplex HIV & II Rapid Test", proposto para diagnosticar, de maneira muito simples e rápida, a infecçäo por HIV-1/2. A fim de realizar a prova imunogromatográfica, usamos saliva. O complexo antígeno-anticorpo formando é revelado por sistema indicador. Verificamos resultados decepcionantes, tendo sido expressivas as porcentagens de falso-negativos e de falsos-positivos, imunocompatíveis com o que se deseja em tarefas assistenciais e epidemiológicas. Alertamos para a necessidade de näo adotar procedimentos qualificados como rápidos e singelos sem antes analisar as qualidades deles, sobretudo quanto às sensibilidades e especificidades. Julgamos também indispensável estipular oficialmente as situaçöes nas quais poderäo ser utilizados.

Seropositividad para VIH-1 y VIH-2 en donadores de sangre en el Hospital General de Ticomán S.S / Prevalence of HIV-1 and HIV-2 in voluntary blood donnors at the Ticoman General Hospital

En un estudio observacional, longitudinal y abierto, se valoró la seroprevalencia a los virus de la inmunodeficiencia humana 1 y 2 en 76 donadores voluntarios de sangre en el Hospital General de Ticomán S.S. De los 76 sujetos estudiados, 1 heterosexual promiscuo fue positivo al VIH-1, todos los donadores fueron seronegativos al VIH-2. Nuestros resultados apoyan la baja prevalencia del VIH-1 en la población fuera de los grupos de riesgo, y aunque no hubo seropositividad al VIH-2, debe tenerse en mente la aparición de dicho virus en nuestro país en cualquier momento