IL-21 is associated with natural resistance to HIV-1 infection in a Colombian HIV exposed seronegative cohort.

Higher IL-21 levels were associated with natural resistance to HIV infection in an Italian cohort. Thus we wanted to confirm such association in HIV exposed seronegative individuals (HESN) from Colombia. Cells from HESN were less susceptible to infection and expressed higher IL-21 mRNA levels than healthy controls at both baseline and 7-days post-infection; similar results were observed for IL-6, perforin, and granzyme. These results suggest that IL-21/IL-6 increase may be a distinctive quality in the profile of HIV-1 resistance, at least during sexual exposure. However, further studies are necessary to confirm the specific protective mechanisms of these cytokines.

Presence of p24-antigen associated to erythrocyte in HIV-positive individuals even in patients with undetectable plasma viral load.

BACKGROUND: HIV adherence to erythrocytes has been demonstrated in vitro, and it has been suggested that erythrocytes may be carriers of the virus. However, the association between HIV particles or viral proteins and erythrocytes in HIV-infected individuals is still to be elucidated. METHODOLOGY/PRINCIPAL FINDINGS: HIV-positive participants (n =112) were classified into two groups according to values of three plasma viral loads (pVL) determined during the 12-month period prior to the study. The first group included 71 individuals with detectable pVL, whereas the second group included 41 individuals with undetectable pVL. Plasma viral load, erythrocyte-associated p24-antigen and p24-antigen in plasma were determined at the moment of the study. A total of 51 out of the 71 patients with detectable pVL showed erythrocyte-associated p24-antigen whereas 13 showed p24-antigen in plasma. Twenty-two out of the 51 patients with erythrocyte-associated p24-antigen showed pVL<10,000 copies/ml and undetectable p24-antigen in plasma. The data indicates that the amount of erythrocyte-associated p24-antigen was not related to p24-antigen in plasma or pVL levels in this group. Among the 41 patients with prior undetectable pVL, eight presented detectable pVL and erythrocyte-associated p24-antigen at the moment of the study. The other 33 showed undetectable pVL and five of these presented erythrocyte-associated p24-antigen. A positive relationship was found between the presence of erythrocyte-associated p24-antigen and the detectable pVL at the moment of the study (p<0.00001). Even more, in another series of assays, a detectable viral load associated to erythrocytes was determined and it was always accompanied by erythrocyte-associated p24-antigen detection. CONCLUSIONS/SIGNIFICANCE: This study demonstrates the presence of erythrocyte-associated p24-antigen in HIV-infected individuals. Since erythrocyte-associated p24-antigen is not always related to pVL or p24-antigen in plasma, erythrocyte-associated p24-antigen showed viral expression not represented in plasma. Therefore, the determination of erythrocyte-associated p24-antigen may contribute to better understand the kinetics and/or evolution of HIV infection.

Centrifugation improves the detection of HIV-1 p24 antigen in plasma from children born to mothers infected with HIV-1.

Detection of HIV proteins and/or nucleic acids is necessary for the diagnosis of perinatal HIV infection. Despite its low sensitivity, detection of p24 antigen in plasma is a simple and economic method for the diagnosis of HIV in exposed children. The aim of this study was to improve the sensitivity of detection of p24 using centrifugation of plasma. Forty-seven selected stored samples from 37 children (23 infected, 14 uninfected, median age of 137 days) were examined. Plasma samples (volume 0.3-1.5 ml) were defrosted, centrifuged at 23,500 x g at 4 degrees C for 60 min and determination of p24 was carried out in the resuspended pellet (0.12 ml). In 32 plasma samples from infected children, p24 was found originally in 6 (18.7%) and resulted positive in 24 (75%) pellets. When only one sample per child was considered, sensitivity was significantly higher in pellets, 3/23 uncentrifuged plasma samples and 15/23 pellets (McNemar Test, p<0.001). Specificity was 100%. The absorbance/cut-off ratio was always higher in the pellets from positive children (p=0.028). Plasma samples with volumes of 1 ml or more achieved a higher sensitivity (91.7% vs. 36.4%, p=0.009). Centrifugation of plasma samples prior to determination of p24 in pediatric patients resulted in a significant increase in sensitivity.

Replacement of HIV p24 Ag test by a multiplex RT-PCR method for primary screening of blood donors.

Nucleic Acid Testing (NAT) as a tool for primary screening of blood donors became a reality in the end of the 1990 decade. We report here the development of an "in-house" RT-PCR method that allows the simultaneous (multiplex) detection of HCV and HIV-RNA in addition to an artificial RNA employed as an external control. This method detects all HIV group M subtypes, plus group N and O, with a detection threshold of 500 IU/mL. After validation, the method replaced p24 Ag testing, in use for blood donation screening since 1996 at our services. From July 2001 to February 2006, 102,469 donations were tested and 41 (0.04%) were found HIV-RNA reactive. One NAT-only reactive donation (antibody non-reactive) was observed, with subsequent seroconversion of the implied donor, giving a yield of 1:102,469. This rate is in contrast to the international experience that reports a detection of approximately 1:600,000 - 1:3,100,000 of isolated HIV-RNA donations.

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

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 >/= 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 >/= 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.

Revisión actualizada de los metodos para el tamizaje de la transmision transfusional del virus de la inmunodeficiencia humana en donantes de sangre / Methodological review on screening of transfusional transmission of human immunodeficiency virus in blood donors

El objetivo de este trabajo es realizar una breve revisiøn de la metodología disponible para el tamizaje seroløgico del virus de inmunodeficiencia humana (VIH) en donantes de sangre, con especial énfasis en las pruebas de detecciøn de antígeno p24, su sensibilidad y especificidad comparativas y su aplicaciøn en los Bancos de Sangre de nuestro país. (AU)

[Screening of HIV in blood banks. Evaluation of fourth generation kits]. / Screening de HIV en bancos de sangre. Evaluación de los equipos de cuarta generación.

Use of detection tests for p24 HIV antigen (p24Ag) in blood banks in Argentina is recommended by the Argentinean Society of Hemotherapy and Immunohematology. In the blood bank of the National University of Cordoba (Argentina), the recent implementation of the p24Ag screening test has considerably increased the cost of the battery of screening tests and its use in all blood donations has not produced the benefits expected. A 4th generation EIA was evaluated for the screening of HIV in comparison with the currently used assays in the blood bank of National University of Cordoba (3rd generation EIA + p24Ag assay). For this comparison, 11 serum samples from subjects with early HIV infection (early seroconversion period) were tested, as well as 27 serum samples from asymptomatic HIV-infected subjects and other 39 from non-HIV infected subjects. The 3rd generation EIA and the 4th generation EIA showed the same sensitivity value (100%) but the specificity of the 3rd generation EIA was higher (97.5%) comparing with 4th generation (95.1%). Besides, the p24Ag test failed to detect 2 samples from subjects with early HIV infection. These results indicate a good performance of both 3rd and 4th generation assays for screening of HIV. However, due to the lowest cost of 4th generation EIA kit, it could replace the currently used assays for HIV screening in regional blood banks. This screening assay will lead to gain in effectiveness and reduced costs until the detection of HIV RNA can be implemented in blood banks.

Screening de HIV en bancos de sangre: evaluacion de los equinos de cuarta generacion / Screening of HIV in blood banks: evaluation of fourth generation kits

La determinación de Ag p24 del virus HIV es recomendada por la Asociación Argentina de Hemoterapiae Inmunohematología para el tamizaje de HIV en los bancos de sangre de Argentina. La implementación de dicha determinación en el banco de sangre de la Universidad Nacional de Córdoba (UNC) implicó un costo elevadopara el nulo beneficio obtenido. Se evaluó la eficiencia del ensayo combinado Ag/Ac ELISA de 4ta generaciónpara el screening de HIV, en comparación a la estrategia actualmente utilizada en el banco de sangre de la UNC(ELISA 3ra generación + ELISA Ag p24). Se utilizaron 11 muestras de suero de pacientes infectados con HIV enetapa temprana de seroconversión, 27 muestras de suero de individuos infectados en etapa asintomática de la infección y 39 muestras de suero de individuos no infectados. Se demostró igual sensibilidad (100%) y una especificidad menor para el equipo de 4ta generación (95.1%) frente al equipo de 3ra generación (97.5%). El ensayo de Ag p24 falló en la detección de 2 muestras HIV tempranas. La alta sensibilidad y especificidad demostradas por los equipos de 3ra y 4ta generación, indica que ambos son adecuados para el tamizaje de HIV en bancos de sangre. Sin embargo, el ELISA de 4ta generación podría ser implementado en los bancos de sangre regionales como una alternativa de menor costo a la estrategia actualmente utilizada. Esta alternativa resulta viable hasta tanto sea posible incorporar en los bancos de sangre la detección de ARN de HIV por técnicas moleculares.(AU)

A single window-period donation detected by human immunodeficiency virus p24 antigen after 5 years of routine screening in a group of Brazilian blood banks.

BACKGROUND AND OBJECTIVES: The purpose of this article was to describe the experience of screening for human immunodeficiency virus (HIV) p24 antigen (p24Ag) in blood donors, in four Brazilian Blood Banks, and to report the detection of the first window-period donation. MATERIALS AND METHODS: During 61 months (May 96 to June 01), 103 470 consecutive donations were screened for HIV p24Ag using commercially available enzyme-linked immunosorbent assay (ELISA) kits. Testing was carried out in accordance with the instructions supplied with the kits. RESULTS: Fifty-eight repeatedly reactive samples were identified [0.056% of the total; 95% confidence interval (95% CI): 0.042-0.070]. Ten of the 58 were confirmed as p24Ag positive after neutralization (0.010%; 95% CI: 0.004-0.016), nine of the 10 (0.009%; 95% CI: 0.003-0.014) were also HIV antibody positive and only one (0.001%; 95% CI: 0-0.003) was HIV antibody negative. CONCLUSIONS: In this setting the rate of sole p24Ag-positive donations was one in 103 740. This figure corresponds closely with the previously estimated yield of one in 87 796 donations. The yield of HIV p24Ag+ : Ab- has been previously estimated in our centres to be 1 : 87 796 donations, a value similar to that observed in actual practice.

[P-24 antigenemia: correlation with some clinical and epidemiological aspects in 100 HIV-infected Cuban subjects]. / Antigenemia P24: correlación con algunos aspectos clínicos y epidemiológicos en 100 individuos cubanos infectados por VIH-1.

A non-probabilistic selection of 100 Cuban patients at different stages of HIV infection, according to the revised classification of the Centers for Disease Control and Prevention of 1987, was made from a set of 130 persons with serologically-confirmed HIV infection. Clinical and epidemiological information about each case was collected and peripheral blood samples were taken to detect HIV-1 p24 antigen. The frequency of p24 antigenemia detection and concentration were correlated with available clinical and epidemiological data. P24 antigenemia was significantly more frequent in AIDS patients. No difference was found between the type of opportunistic diseases diagnosed in the group of patients with detectable p24 antigen and the group that was negative to antigen presence; although in the group with antigenemia concentrations over 100 pg/ml, more than one AIDS-related disease was often diagnosed simultaneously. A history of sexual intercourses with several persons who had been infected with HIV was much more frequent in patients with antigenemia, and it was associated with a shorter time elapsed from the probable date of infection to the date of their classification as AIDS patients. These results were compared with the literature review information.

Maternal antibodies to HIV-1 envelope domains: No correlation with HIV-1 vertical transmission in patients from Argentina.

The role of the maternal antibody response in relation to vertical human immunodeficiency virus type 1 (HIV-1) transmission was investigated in HIV-1-infected mothers from Argentina. Sera from 23 transmitting and 18 nontransmitting HIV-1-infected mothers were tested for the presence of antibodies to V3 loop gp120 peptides representing both Argentinian sequences and several well-characterized viral isolates from different geographic areas. Argentinian sera from transmitting mothers had significantly higher capacity to react with four of 14 V3 loop peptides tested than sera from nontransmitting mothers. Frequency of reactivity against the other peptides did not differ between the two maternal groups. Furthermore, no differences in antibody affinity were found between transmitting and nontransmitting mothers. Sera were also tested against overlapping peptides covering a neutralizing epitope of the HIV-1 MN gp41 (amino acids 648-677). Statistical analysis indicated that no correlation between anti-gp41 antibodies and vertical transmission exists. Although we used V3 loop peptides based on local HIV-1 sequences, our data showed that maternal antibodies to these peptides, as well as to gp41 peptides, are not correlated with protection against HIV-1 vertical transmission.

Surrogate markers of disease progression in HIV-infected children in Rio de Janeiro, Brazil.

In order to test the predictive value of immune complex-dissociated p24 antigenaemia (ICD-p24Ag), beta 2 microglobulin (beta 2-M), and neopterin as markers of disease progression, 53 HIV-1 infected children (mean age 68 months) and nine HIV-negative controls (mean age 65 months) were studied prospectively for 9 months. Five were classified in category E (CDC-1994) and seroreverted during the study, 14 in category A, nine in category B, and 25 in category C (CDC-1994). Blood samples were taken at medium intervals of 61 days and tested for ICD-p24Ag, beta 2 microglobulin, and neopterin. The results were correlated with clinical outcome and CD4-lymphocyte counts. All three groups (A, B, C) of symptomatic children had similar positivity in an ICD-p24Ag test (48.1, 58.8, and 51.0 per cent, respectively), and all in group E had negative p24 antigenaemia. beta 2 microglobulin and neopterin tests showed no correlation with clinical stages of HIV-1 infection. There was no significant correlation between these three tests with age-matched CD4 lymphocyte counts (p > 0.05). In contrast, the CD4 lymphocyte count correlated well with disease stages. These data suggest that the markers evaluated in the present study do not correlate well with clinical findings or with CD4 lymphocyte counts. Of all the markers tested, CD4 count was the best to predict prognosis of HIV disease in this cohort.

Quantitation of HIV-1 RNA viral load using nucleic acid sequence based amplification methodology and comparison with other surrogate markers for disease progression.

In this study, HIV-1 viral blood quantitation determined by Nucleic Acid Sequence Based Amplification (NASBA) was compared with other surrogate disease progression markers (antigen p24, CD4/CD8 cell counts and beta-2 microglobulin) in 540 patients followed up at São Paulo, SP, Brazil. HIV-1 RNA detection was statistically associated with the presence of antigen p24, but the viral RNA was also detected in 68% of the antigen p24 negative samples, confirming that NASBA is much more sensitive than the determination of antigen p24. Regarding other surrogate markers, no statistically significant association with the detection of viral RNA was found. The reproducibility of this viral load assay was assessed by 14 runs of the same sample, using different reagents batches. Viral load values in this sample ranged from 5.83 to 6.27 log (CV = 36%), less than the range (0.5 log) established to the determination of significant viral load changes.

IgE against HIV proteins in clinically healthy children with HIV disease.

Elevated serum Ige was detected in 26% (7 of 30) of children with HIV infection. The majority of children with elevated IgE were of one ethnic group (Puerto Rican) (4 of 7), compared with only 9% (2 of 23) in the normal to low IgE group (p = 0.02). Most of the children with elevated IgE had decreased circulating CD4+ T cells (5 of 7 or 71%); but none had opportunistic infections, and none failed to thrive. Although similar numbers of children with normal to low IgE had decreased circulating CD4+ T cells (19 of 23 or 83%), this group had opportunistic infections (6 of 23 or 26%) and failure to thrive (7 of 30 or 30%). There was no difference in incidence of allergic symptoms between groups. IgE antibody against HIV protein was detected by Western blot technique in the sera of three children with elevated serum IgE. Thus we have identified a group of children with HIV infection and elevated serum IgE of predominantly one ethnic group, who are without opportunistic infections or failure to thrive, some of whom produce HIV-specific IgE. This suggests that IgE may play a protective (perhaps late compensatory) role in HIV disease in genetically predisposed individuals.

Comparison of virus burden in blood and sequential lymph node biopsy specimens from children infected with human immunodeficiency virus.

BACKGROUND: Lymph nodes serve as reservoirs for the replication of human immunodeficiency virus (HIV) type 1. Comparison of serial measurements of virus burden in lymph nodes and peripheral blood after a change in antiretroviral therapy may provide insights into pathogenic mechanisms and permit a more accurate assessment of a therapeutic response. STUDY DESIGN: Nevirapine was added to the drug regiment of eight children with HIV infection treated with the combination of zidovudine and didanosine who had increasing levels of serum p24 antigen. Lymph node biopsies were performed at entry and after 12 weeks of therapy. RESULTS: Neither CD4 counts nor p24 antigen level correlated with the degree of viremia as measured by ribonucleic acid copy numbers in plasma. Correlations were found between HIV DNA copy number in peripheral blood mononuclear cells and HIV DNA copy number in lymph nodes (p = 0.02), as well as between peripheral blood CD4 counts and lymph node architecture. The HIV signals in the lymph nodes conformed to the anatomic organization of apical light zones in the germinal centers; however, in more advanced disease stages, organized germinal centers disappeared as evidence by a decline in the extent of the follicular dendritic network. CONCLUSIONS: Lymph node biopsies in this small number of HIV-infected children revealed a progressive loss of an organized architecture, especially of the follicular dendritic network. This correlated with a progressive loss of CD4+ cells but not with other measures of disease stage, including viral load, as measured by ribonucleic acid copy numbers.

The influence of CD4+ T cells, HIV disease stage and zidovudine on HIV isolation in Bahia, Brazil.

HIV-1 isolation was attempted on 72 individuals, including persons with known HIV infection and five without proven HIV infection but with indeterminate Western blot patterns, as well as on low-risk HIV seronegative persons. The ability to detect HIV-1 from culture supernatant by p24 antigen capture assay was evaluated by segregating patients by absolute CD4+ cell counts, clinical stage of disease, p24 antigenemia and zidovudine use. The likelihood of a p24 positive HIV culture was highest among patients with CD4+ T-cell counts below 200/ul and patients with advanced clinical disease. Use of zidovudine did not affect the rate of HIV positivity in cultures.

CD4+ T-lymphocyte measures in the treatment of individuals infected with human immunodeficiency virus type 1. A review for clinical practitioners.

The CD4+ lymphocyte is a major target of the human immunodeficiency virus type 1 (HIV-1). CD4+ T-lymphocyte measures have been used to predict the risk of HIV-1-related complications in diverse populations, to guide management decisions, and to define cases of the acquired immunodeficiency syndrome (AIDS). To examine the role of CD4+ measures in the management and epidemiologic monitoring of HIV-1 infection, we evaluated current literature regarding the accuracy and precision of CD4+ measures and the use of these and other prognostic measures in the care of HIV-1-infected persons. Several studies have reported wide intraindividual and interindividual variability in the absolute CD4+ count, which can detract from its clinical usefulness. Approaches to address this variability include the following: drawing specimens at a similar time of the day; monitoring CD4+ percent that has less variability; following a meticulous laboratory technique; using serial tests to guide management decisions; and retesting after efforts to eliminate transient treatment and clinical factors that can affect the CD4+ count. The expense and limited availability of CD4+ measures also present barriers to widespread use. Other laboratory and clinical factors offer additional prognostic information and have an evolving role in management decisions. CD4+ measures have an important role in HIV-1 clinical care, research, and disease surveillance, but strategies are required to address problems with variability, expense, and availability.

Coinfection with human T-cell lymphotropic virus type I and HIV in Brazil. Impact on markers of HIV disease progression.

OBJECTIVES: To study the effect of human T-cell lymph-tropic virus type I (HTLV-I) on markers of human immunodeficiency virus (HIV) disease progression. DESIGN: A retrospective, nested case-control study. SETTING: A university hospital outpatient HIV clinic in Rio de Janeiro, Brazil. PARTICIPANTS: Human immunodeficiency virus-seropositive adults participating in a prospective HIV cohort study. MAIN OUTCOME MEASURES: The HIV clinical stage, CD4+ lymphocyte counts, and other laboratory parameters in 27 individuals infected with HIV and HTLV-I (coinfection) and 99 age-matched, HIV-seropositive, HTLV-seronegative controls (single infection). RESULTS: Variables independently associated with coinfection included higher CD4+ lymphocyte count (odds ratio [OR], 2.3; 95% confidence limits [CL], 1.3, 4.1), higher CD4+ percentage (OR, 2.0; 95% CL, 1.3, 3.2), beta 2-microglobulin level of 254 nmol/L or more (OR, 6.8; 95% CL, 1.3, 35.4), World Health Organization stages 3 and 4 (OR, 4.4; 95% CL, 1.1, 18.0), and reporting a parenteral risk factor (OR, 7.4; 95% CL, 1.4, 38.9). When stratified by p24 antigenemia, coinfection was associated with an estimated 82% higher CD4+ lymphocyte count (P < .05). CONCLUSION: Coinfection was associated with higher CD4+ lymphocyte counts, more advanced clinical disease, and higher beta 2-microglobulin levels than HIV infection alone. The higher mean CD4+ lymphocyte count does not appear to offer immunologic benefit. Caution should be exercised when using CD4+ lymphocytes as a surrogate marker in studies of HIV infection in populations where HTLV-I is prevalent. Further studies are needed to address whether current CD4+ lymphocyte values for the initiation of antiretroviral therapy and chemoprophylaxis against opportunistic infections in HIV infection are appropriate in coinfection.

Development and significance of zidovudine resistance in children infected with human immunodeficiency virus.

Decreasing susceptibility to zidovudine (ZDV) has been described in persons infected with human immunodeficiency virus (HIV) type 1 who are receiving ZDV therapy. However, the clinical significance of decreased ZDV susceptibility remains unclear. In this study, HIV isolates obtained from children with symptomatic HIV infection treated with ZDV were monitored for their susceptibility to the antiretroviral agent and correlated with disease progression. Using a peripheral blood mononuclear cell-based assay to measure ZDV susceptibility, we evaluated HIV isolates from 19 children (mean age, 6.8 years; range, 5 months to 12 years) during ZDV therapy for susceptibility to ZDV. Of the 19 children studied, 10 continued to have susceptible HIV strains during ZDV treatment, and 9 acquired resistant viruses. All eight isolates from children without previous exposure to ZDV were initially susceptible. After a median of 11 months of ZDV therapy, three (38%) of these eight children had acquired resistant HIV strains (defined as ZDV susceptibility > or = 10 mumol/L). Children with resistant strains had worse clinical outcomes than children whose viruses remained susceptible, as determined by a 50% decline in absolute CD4+ cell counts after 1 year of treatment, failure to thrive, or death. Children with resistant viruses who were given alternative antiretroviral therapy frequently responded to the new treatment with improved growth and stabilization of their HIV-related disease. These data suggest that, in HIV-infected children, ZDV-resistant HIV strains are associated with diminished drug efficacy and more rapid disease progression.