Mimotopes selected by biopanning with high-titer HIV-neutralizing antibodies in plasma from Chinese slow progressors

OBJECTIVE: One approach to identifying HIV-1 vaccine candidates is to dissect the natural antiviral immune response in treatment-naïve individuals infected for over ten years, considered slow progressor patients (SPs). It is suspected that SP plasma has strongly neutralizing antibodies (NAb) targeting specific HIV viral epitopes. METHODS: NAbs levels of 11 HIV-1-infected SPs were detected by PBMC-based neutralization assays. To investigate SP NAb epitope, this study used a biopanning approach to obtain mimotopes of HIV-1 that were recognized by SP plasma NAbs. IgG was purified from hightiter NAb SP plasma, and used as the ligand for three rounds of biopanning to select HIV-specific mimotopes from a phage-displayed random peptide library. Double-antibody sandwich ELISA, competitive inhibition assays, and peptide sequence analysis were used to evaluate the characteristics of phage-borne mimotopes. RESULTS: SPs had significantly more plasma neutralizing activity than typical progressors (TPs) (p = 0.04). P2 and P9 plasma, which have highest-titer HIV-NAb, were selected as ligands for biopanning. After three rounds of biopanning, 48 phage clones were obtained, of which 22 clones were consistent with requirement, binding with HIV-1 positive plasma and unbinding with HIV-1 negative plasma. Compared with linear HIV-1 protein sequence and HIV-1 protein structure files, only 12 clones were possible linear mimotopes of NAbs. In addition, the C40 clone located in gp41 CHR was found to be a neutralizing epitope, which could inhibit pooled HIV-1 positive plasma reaction. CONCLUSION: Biopanning of serum IgG can yield mimotopes of HIV-1-related antigen epitopes. This methodology provides a basis for exploration into HIV-1-related antigen-antibody interactions and furthers NAb immunotherapy and vaccine design.

Prevalence of HIV, syphilis, hepatitis B and C among adults with mental illness: a multicenter study in Brazil / Prevalência de HIV, sífilis, hepatites B e C entre adultos com transtornos mentais: um estudo multicêntrico no Brasil

OBJECTIVE: There is evidence that patients with mental illness have increased prevalence of sexually transmitted infections, but data in Brazil are scarce. The objective of this study was to determine the prevalence of HIV, hepatitis C and B, and syphilis among patients with mental illness in Brazil. METHOD: A multicenter representative sample of adults with mental illness was randomly selected from 26 mental health institutions throughout Brazil. Sociodemographic, sexual behavior and clinical data were obtained from person-to-person interviews and blood was collected for serology testing. Seroprevalence with 95 percent confidence limits were obtained correcting for sampling scheme. RESULTS: Of the 2,475 patients interviewed, 2,238 had blood collected. Most participants were sexually active ever (88.8 percent) or in the last 6 months (61.6 percent), female (51.9 percent), and single (66.6 percent). Half of the sample had less than 5 years of schooling and the mean monthly individual income was low (US$ 210.00). Condom use was very low either during lifetime (8 percent) or in the last 6 months (16 percent). Overall seroprevalence were 1.12 percent, 0.80 percent, 1.64 percent, 14.7 percent and 2.63 percent for, respectively, syphilis, HIV, HBsAg, anti-HBc and anti-HCV. CONCLUSIONS: Seroprevalences found were higher than other populations with representative studies in Brazil, with high rates of sexual risk behavior. This is of public health concern, and prevention and care strategies for sexually transmitted infections among psychiatric patients should urgently be implemented by health authorities.

OBJETIVO: Evidências indicam que pacientes com transtornos mentais têm elevada prevalência de infecções sexualmente transmissíveis, mas dados brasileiros são escassos. O objetivo deste estudo foi determinar a prevalência do HIV, hepatites C e B, e sífilis entre pacientes com transtornos mentais no Brasil. MÉTODO: Uma amostra representativa de pacientes adultos com transtornos mentais foi aleatoriamente selecionada de instituições públicas de saúde mental no Brasil. Dados sociodemográficos, comportamentais e clínicos foram obtidos por entrevista face-a-face e sangue foi coletado para exames sorológicos. Soroprevalências com intervalo de 95 por cento de confiança foram obtidas com correção para o esquema amostral. RESULTADOS: Dos 2.475 pacientes entrevistados, 2.238 tiveram sangue coletado. A maioria era sexualmente ativa ao longo da vida (88,8 por cento) ou nos últimos seis meses (61,4 por cento), do gênero feminino (51,9 por cento), solteira (66,6 por cento), com metade dos participantes com menos de cinco anos de escolaridade e renda média mensal baixa individual (US$210). Uso de preservativo foi baixo em toda a vida (8 por cento) ou nos últimos seis (16 por cento). As soroprevalências gerais foram 1,12 por cento, 0,80 por cento, 1,64 por cento, 14,7 por cento e 2,63 por cento para, respectivamente, sífilis, HIV, HBsAg, anti-HBc e anti-HCV. CONCLUSÕES: As soroprevalências encontradas são maiores do que outros estudos com populações representativas no Brasil, com altos índices de comportamento sexual de risco. Isto é preocupante e estratégias de prevenção e cuidado para as infecções sexualmente transmissíveis entre pacientes psiquiátricos devem ser urgentemente implementadas pelos serviços de saúde.

Introduction and immunopathogenesis of acquired immune deficiency syndrome.

India has a large number of patients with acquired immune deficiency syndrome (AIDS), the third largest population of this group in the world. This disease was first described in patients with Pneumocystis pneumonia in 1981. Ocular lesions can occur at any stage of the disease but are more commonly seen at the late stages. Human immunodeficiency virus (HIV), the causative agent of AIDS is a retrovirus with RNA genome and a unique 'Reverse transcriptase enzyme' and is of two types, HIV-1 and 2. Most human diseases are caused by HIV-1. The HIV-1 subtypes prevalent in India are A, B and C. They act predominantly by reducing the CD4+ cells and thus the patient becomes susceptible to opportunistic infections. High viral titers in the peripheral blood during primary infection lead to decrease in the number of CD4+ T lymphocytes. Onset of HIV-1-specific cellular immune response with synthesis of HIV-1 specific antibodies leads to the decline of plasma viral load and chronification of HIV-1 infection. However, the asymptomatic stage of infection may lead to persistent viral replication and a rapid turnover of plasma virions which is the clinical latency. During this period, there is further decrease in the CD4+ counts which makes the patient's immune system incapable of controlling opportunistic pathogens and thus life-threatening AIDS-defining diseases emerge. Advent of highly active antiretroviral treatment (HAART) has revolutionized the management of AIDS though there is associated increased development of immune recovery uveitis in a few of these patients.

Anti-human immunodeficiency virus type 1 humoral immune response and highly active antiretroviral treatment

Highly active antiretroviral treatment (HAART) of human immunodeficiency type 1 (HIV-1) infection is very effective in controlling infection, but elimination of viral infection has not been achieved as yet, and upon treatment interruption an immediate rebound of viremia is observed. A combination of HAART with an immune stimulation might allow treatment interruption without this rebounding viremia, as the very low viremias observed with successful HAART may be insufficient to permit maintenance of a specific anti-HIV-1 immune response. The objective of this study was to compare the humoral immune response of individuals undergoing successful HAART (NF=no failure) with that of individuals with evidence of failure of therapy (FT) and to verify if the viremia peaks observed in individuals with therapy failure would act as a specific stimulus for the humoral anti-HIV-1 immune response. Antibodies binding to gp120 V3 genotype consensus peptides were more frequently observed for FT, mainly against peptides corresponding to sequences of genotypes prevalent in the Rio de Janeiro city area, B and F. HIV-1 neutralization of HIV-1 IIIB and of four primary isolates from Rio de Janeiro was less frequently observed for plasma from the NF than the FT group, but this difference was more expressive when plasma from individuals with detectable viremia were compared to that of individuals with undetectable viral loads in the year before sample collection. Although statistically significant differences were observed only in some specific comparisons, the study indicates that presence of detectable viremia may contribute to the maintenance of a specific anti-HIV-1 humoral immune response.

Evaluation of a new dot blot assay for confirmation of human immunodeficiency virus type 1 and 2 infection using recombinant p24, gp41, gp 120 and gp36 antigens

Objectives:A sensitive and accurate dot blot assay using recombinant p24 [gag], gp41 and gp120 [env] proteins of HIV-1 and also recombinant gp36, the specific HIV-2 antigen was developed to confirm the presence of antibodies in sera reactive in screening enzyme-linked immunosorbent assays.Methods:We collected sera from Iranian 125 confirmed HIV positive Iranian samples [seropositive group] from AIDS patients, asymptomatic HIV-infected subjects, HIV-infected intravenous drug users and also hemophilic infected subjects. The samples were obtained from the AIDS Specimen Bank, Pasture Institute, Iran during 2002 to 2003. We also obtained 180 samples [seronegative group] from healthy blood donors. Recombinant antigens were expressed in Escherichia coli. By use of highly purified antigens, the dot blot procedure was developed. Analysis of the results was accomplished by capturing the dot blot images.Results:We established and interpreted the results using Centers for Disease Control criteria. We defined the positive test result as the presence of antibody against at least 2 different HIV gene products, one of which had to be an env gene product while a negative test result was defined as no antibodies against any of the HIV gene products and an indeterminate result was defined as antibodies reacting with only one HIV env gene product or against gag gene product only.Conclusion:The recombinant HIV dot blotting assay identified seropositive individuals with a high degree of accuracy; none of the HIV-seropositive subjects had a negative test result. Reactivity with these antigens, demonstrated 100% sensitivity and specificity in distinguishing seronegative from seropositive sera. The different sets of Western blot interpretative accepted criteria did not make a difference in interpretation of the seronegative and seropositive samples

HIV-1 binding and neutralizing antibodies of injecting drug users

Previous studies have demonstrated a stronger seroreactivity against some synthetic peptides responsible for inducing neutralizing antibodies in injecting drug users (IDU) compared to that of individuals sexually infected with HIV-1 (S), but the effectiveness in terms of the neutralizing ability of these antibodies has not been evaluated. Our objective was to study the humoral immune response of IDU by determining the specificity of their antibodies and the presence of neutralizing antibodies. The neutralization capacity against the HIV-1 isolate MN (genotype B), the primary HIV-1 isolate 95BRRJ021 (genotype F), and the seroreactivity with peptides known to induce neutralizing antibodies, from the V2 and V3 loops of different HIV-1 subtypes, were analyzed. Seroreactivity indicates that IDU plasma are more likely to recognize a broader range of peptides than S plasma, with significantly higher titers, especially of V3 peptides. Similar neutralization frequencies of the MN isolate were observed in plasma of the IDU (16/47) and S (20/60) groups in the 1:10 dilution. The neutralization of the 95BRRJ021 isolate was more frequently observed for plasma from the S group (15/23) than from the IDU group (15/47, P = 0.0108). No correlation between neutralization and seroreactivity with the peptides tested was observed. These results suggest that an important factor responsible for the extensive and broad humoral immune response observed in IDU is their infection route. There was very little difference in neutralizing antibody response between the IDU and S groups despite their differences in seroreactivity and health status.

Human immunodeficiency virus type 1 neutralization by plasma from B or F genotype infected individuals

Anti-human immunodeficiency virus type 1 (HIV-1) "binding antibodies" (antibodies capable of binding to synthetic peptides or proteins) occur throughout HIV-1 infection, are high-titered and highly cross-reactive, as confirmed in this study by analyzing plasma from B and F genotype HIV-1 infected individuals. Plasma from individuals infected with clade F HIV-1 displayed the most frequent cross-reactivity, in high titers, while Bbr plasma showed much higher specificity. Similarly, neutralization of a reference HIV-1 isolate (HIV-1 MN) was more frequently observed by plasma from F than B genotype infected individuals. No significant difference was seen in neutralization susceptibility of primary B, Bbr or F clade HIV-1 by plasma from individuals infected with the classical B (GPGR) or F HIV-1, but Bbr (GWGR) plasma were less likely to neutralize the F genotype primary HIV-1 isolates. The data indicate that both B and F genotype derived vaccines would be equally effective against B and F HIV-1 infection, with a slightly more probable effectiveness for F than B genotype. Although the Bbr variant appears to induce a much more specific humoral immune response, the susceptibility in neutralizing the Brazilian HIV-1 B genotype Bbr variant is similar to that observed with the classical B genotype HIV-1.

Antibody recognition of synthetic peptides mimicking immunodominant regions of HIV-1 p24 and p17 proteins / Reconocimiento por anticuerpos de péptidos sintéticos que imitan regiones inmunodominantes de las proteínas p24 y p17 de VIH-1

The gag gene of HIV-1 encodes a single open reading frame of 55 kDa that contains three subdomains: the matrix domain (p17), the capsid domain (p24) and the nucleocapsid domain (p15). The p24 and p17 proteins have a predominant a-helical structure and perform important functions throughout thevirallife-cycle. The determination of gag-specific antibodies is important because declining titers of these antibodies herald clinical deterioration.In this work we present the results obtained on immunoreactiviy of synthetic peptides that mimic immunogenic a-helical regions of p24 and p17. The influence on the immunoreactivity of structural modifications in native sequences, including the addition of non immunogenic side chains: AAAC- and -CAAA on both side of minimal epitopes was evaluated in indirect and competitive enzymeimmunoassays. The conformational characteristcs to the peptides were analysed by circular dichroism and these results were correlated with that obtained in the immunoassays. It was shown that the reactivity of peptides mimicking short a-helical regions of p24 and p17 is improved by adding short non immunogenic chains on both N- and C- terminus. These modifications enhanced the immobilization of the peptides onto the solid support and allowed more accesibility to the minimal epitopes byspecific antibodies, in solution.

El gen gag del VIH-1 codifica una región de 55kDA que contiene tres subdominios: matriz (p17), cápside (p24) y nucleocápside (p15). Las proteínas p24 y p17 tienen una estructura predominante helicoidal y cumplen un rol importante en el ciclo de vida del virus. En este trabajo presentamos los resultados de inmunorreactividad de péptidos sintéticos que imitan regiones helicoidales de p24 y p17. Utilizando enzimoinmunoensayos se evaluó la influencia de modificaciones en las secuencias nativas sobre la capacidad de reconocimiento de anticuerpos específicos en solución y en fase sólida, incluyendo el agregado de cadenas no inmunogénicas en ambos extremos de los epitopes mínimos. La conformación de los péptidos se determinó por dicroísmo circular y los resultados se correlacionaron con los de inmunorreactividad. Se observó que la capacidad de reconocimiento de anticuerpos por péptidos pequeños que imitan estructuras helicoidales de p24 y p17 mejoró con el agregado de cadenas no inmunogénicas en ambos extremos de los epitopes. Estas modificaciones mejoran la inmovilización sobre las superficies sólidas y permiten una mayor accesibilidad de los anticuerpos a los epitopes mínimos en solución.

Who is at high risk? A comparison of the seroprevalence of human immunodeficiency virus in pregnant women and a high risk group

To compare the seroprevalence of HIV in Jamaican pregnant women with that in substance abusers, two groups of antenatal patients were studied, one (A) attending a public hospital clinic and the other (B) attending private clinics. The HIV seroprevalence in the antenatal patients was compared with that in the substance abusers, group C, in 1996 and five years later in 2001. HIV antibody was determined by enzyme immunoassay. The HIV seroprevalence in group A more than doubled (1.6-3.8) in five-years, 1996-2001. There were no seropositives in group B. In group C, the seroprevalence rose from 2.08 in 1996 to 5.76 in 2001. There was indication that group A might no longer be considered [quot ]low risk[quot ], as there was no significant difference from group C in HIV seroprevalence in 1996 and 2001. The trend seen in this study is worthy of further investigation

Vertical human immunodeficiency virus type 1 - HIV-1 -transmission - a review

Several factors appear to affect vertical HIV-1 transmission, dependent mainly on characteristics of the mother (extent of immunodeficiency, co-infections, risk behaviour, nutritional status, immune response, genetical make-up), but also of the virus (phenotype, tropism) and, possibly, of the child (genetical make-up). This complex situation is compounded by the fact that the virus may have the whole gestation period, apart from variable periods between membrane rupture and birth and the breast-feeding period, to pass from the mother to the infant. It seems probable that an extensive interplay of all factors occurs, and that some factors may be more important during specific periods and other factors in other periods. Factors predominant in protection against in utero transmission may be less important for peri-natal transmission, and probably quite different from those that predominantly affect transmission by mothers milk. For instance, cytotoxic T lymphocytes will probably be unable to exert any effect during breast-feeding, while neutralizing antibodies will be unable to protect transmission by HIV transmitted through infected cells. Furthermore, some responses may be capable of controlling transmission of determined virus types, while being inadequate for controlling others. As occurence of mixed infections and recombination of HIV-1 types is a known fact, it does not appear possible to prevent vertical HIV-1 transmission by reinforcing just one of the factors, and probably a general strategy including all known factors must be used. Recent reports have brought information on vertical HIV-1 transmission in a variety of research fields, which will have to be considered in conjunction as background for specific studies

Prevalencia de anticuerpos anti-VIH en pacientes del servicio de Biología de la Reproducción Humana del Centro Médico Nacional "20 de Noviembre" del I.S.S.S.T.E / Prevalence of antibodies anti-VIH in patients at the Biology of Human Reproduction Service, at Centro Medico Nacional \"20 de Noviembre\" ISSSTE

En el servicio de Biología de la Reproducción Humana del Centro Médico Nacional "20 de Noviembre" del I.S.S.S.T.E. de enero de 1994 a agosto de 1998 en la primera visita fueron tomadas en forma rutinaria muestras para detectar anticuerpos anti-VIH en la pareja. De 672 muestras 3 (0.44 por ciento) fueron positivas para anticuerpos anti-VIH con ELISA y dos de ellas confirmadas con el análisis de Western Blot

Anti-HIV-1/2 antibody detection by dot-ELISA in oral fluid of HIV positive/AIDS patients and voluntary blood donors

Serology is the primary means for identifying patients with HIV infection and Acquired Immunodeficiency Syndrome (AIDS). Testing of serum by serologic methods has been extensively used since 1985, not only for clinical diagnosis but also for epidemiological surveillance and donor screening in blood banks. Fast serological diagnostic techniques are now being developed, using urine and oral fluid, as an alternative for anti-HIV antibody screening, and many parallel studies are proving its accuracy. The purpose of this study was to evaluate the sensitivity, specificity,accuracy, positive predictive value (PPV) and negative predictive value(NPV) of the ImmunoComb II HIV 1&2 Saliva test from Orgenics(Dot-ELISA) compared to the routine exams (ELISA and Western Blot) of HIV positive/ AIDS patients, undergoing antiretroviral treatment or not, in different stages of the disease's evulution, and compared to serologic testing of known HIV negative patients by the use of serum ELISA (blood donors). To accomplish this, patients of the Immunogenic Deficiencies Control Center (CCDI) and voluntary blood donors of the Blood Bank Center of the Medical School of Säo Paulo/Federal University of Säo Paulo(EPM-UNIFESP) were evaluated. Sensitivity of Dot-ELISA in oral fluid was 100 percent, specificity 97.08 percent, PPV 96.66 percent and NPV 100 percent. The method used in this case study was shown to be highly sensitive and specific, being useful particularly epedemiological sur veillance and screening.

Deteccao sorologica de anticorpos anti-HIV 1 em pacientes com hanseniase / ?

Foi realizada a deteccao sorologica dos anticorpos anti-HIV 1 em um grupo de 59 pacientes com hanseniase multibacilar (Grupo A), 20 dos quais apresentaram surto reacional tipo II. Foi incluida tambem a analise retrospectiva da mesma sorologia correspondente a 104 pacientes (Grupo B) com formas multi e paucibacilares de hanseniase. As amostras de ambos os grupos foram testadas utilizando dois tipos de ELISA para o HIV 1. A prevalencia da infeccao pelo HIV 1 foi significativamente superior entre os pacientes com hanseniase (1,84 por cento) que entre os doadores de sangue (Grupo Controle - 0,28 por cento). Resultados falsamente positivos nao foram detectados nos testes de ELISA utilizados

Nodal radiotherapy in refractory tuberculosis in an AIDS patients

A 25-year-old female with transfusion-associated acquired immunodeficiency syndrome (AIDS) treated with zidovudine (AZT) developed cervical lymph node enlargement. The histological study disclosed granulomas and the culture revealed M. tuberculosis. The patient was treated with isoniazid, rifampicin and pirazynamide and the lymphadenomegaly resolved. Five years later, with a CD4 cell count of 245, the lymph node enlargement reappeared, the biopsy and special studies confirming tuberculosis (TB). She was then given cirpofloxacin, azithromicin, ethambutol, amikacin and pirazyn amide without success. In two instances the enlarged nodes were surgically removed. Facing progressive osbtruction of both the airway and the esophagus, localized radiotheraphy (1800 cGy in nine fractions) to the right aspect of the neck was delivered with dramatic resolution of the node elargement; however, dissemination of the infection leading to a severe lung infiltration and respiratory failure ended the life of the patient

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.

Nuevo método para la determinación del anticuerpo anti GP 41 / Annual reports 1993 / New method for the detection of anti GP 41 antibodies

Actualmente se emplean los métodos ELISA y Aglutinación de particículas de gelatina para la detección de anticuerpo anti HIV. Sin embargo, se hace necesario encontrar un método rápido, fácil y accesible al operador. El método de SimpliRed que fue desarrolladopor científicos australianos (Agen Biomedical Limited) para la determinación del anticuerpo anti HIV se basa en la aglutinación de glóbulos rojos, lo que se puede determinar por visualización directa utilizando 10 ul de sangre total. El método utiliza un anticuerpo monoclonal de doble especifidad en donde uno de los fragmentos Fab está dirigido exclusivamente contra la glicoforina (glicoproteina de membrana de los glóbulos rojos), lo cuál permite la unión al eritrocito sin producir aglutinación. El otro fragmento Fab. es conjugado a péptidos sintéticos correspondientes a epítopes de HIV cubiertos con proteínas gp41. El fragmento Fab. es reconocido por el anticuerpo anti gp41 si estuviese presente en la sangre o suero, ocurriendo en este caso aglutinación en dos minutos. Se han analizado 30 sueros y plasmas de portadores HIV provenientes del Japón por método de Aglutinación de partículas de gelatina (Serodia HIV Fujirebio), Western Blot (Lab Blot), (Diagnostic Pasteur) y el método SimpliRed cuyos resultados demostraron 78 por ciento de sensibilidad y una especifidad del 100 por ciento utilizando el método de SimpliRed. Este método ofrece muchas expectativas para futuros ensayos, puede ser empleado en los bancos de sangre juntamente con la tipificación sanguínea y en los centros de asistencias de urgencias

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.