HIV Enzyme-linked Immunosorbent Assay Research Articles

Training family practice residents in HIV care.

Although family physicians are likely to encounter patients at risk for or diagnosed with HIV, they rarely are trained in prevention and treatment techniques. From 1997 to 2000, the University of Minnesota developed and evaluated a longitudinal curriculum to train family practice residents in the prevention and comanagement of HIV disease. Five residency programs participated. The core curriculum was based on 18 teaching modules incorporated into the standard 3-year residency program and covers topics in prevention, diagnosis, and treatment of HIV disease. Residents were encouraged to participate in elective rotations of HIV clinical care, service, and research, as well as attend a Sexual Attitude Reassessment Seminar. Baseline and postcurriculum attitude and knowledge surveys were performed and scores were compared before and after completion of the curriculum, as well as between the participants and a historical control group of residents who graduated in 1997. During the 3 academic years from 1997 to 2000, 214 residents participated in the study. Entering classes did not differ in baseline knowledge. Residents' knowledge about HIV disease, attitudes, confidence, and intention to treat HIV-positive patients improved (p < 0.01). The yearly number of HIV enzyme-linked immunosorbent assay (ELISA) tests performed at the residency sites increased from 1145 to 1665 by the project's end. The HIV Curriculum Project provides a useful model of an interdisciplinary program for training family medicine residents in HIV/AIDS. The evaluation data provide an assessment of the curriculum itself and an important look at family practice residents' knowledge, attitudes, and performance related to HIV over time.

PROGRESSIVE OUTER RETINAL NECROSIS CAUSED BY VARICELLA-ZOSTER VIRUS IN CHILDREN WITH ACQUIRED IMMUNODEFICIENCY SYNDROME

We report three HIV-infected children with bilateral progressive outer retinal necrosis caused by varicella-zoster virus. All three lost vision in both eyes. Aggressive treatment strategies with combination intravenous antiviral therapy in addition to intravitreal antiviral therapy and appropriate surgical management may prevent blindness. Rapid recognition of this distinct clinical syndrome is essential to improve visual outcome.

IgA antibodies to human immunodeficiency virus in serum, saliva and urine for early diagnosis of human immunodeficiency virus infection in Ugandan infants

IgA antibodies to human immunodeficiency virus in serum, saliva and urine for early diagnosis of human immunodeficiency virus infection in Ugandan infants

Decline in prevalence of HIV-1 infection and syphilis among young women attending antenatal care clinics in Addis Ababa, Ethiopia: results from sentinel surveillance, 1995-2001.

From 1995 to 2001, five rounds of sentinel surveillance were carried out for young women attending antenatal care clinics at four health centers in Addis Ababa, the capital city of Ethiopia, to monitor trends in the prevalence of HIV infection and syphilis. Serum samples were tested for antibodies to HIV (enzyme-linked immunosorbent assay and Western blotting) and antibodies to Treponema pallidum (T. pallidum hemagglutination assay and rapid plasma reagin test). Prevalence ratios for an increase in one calendar year were estimated using log-binomial models. Between 1995 and 2001, the prevalence of HIV infection among young women (age range, 15-24 years) attending antenatal care clinics in inner city health centers declined from 24.2% to 15.1% (prevalence ratio for an increase in one calendar year, 0.91; 95% confidence interval, 0.87-0.95). No change was observed for older age groups or in outer city health centers. The decline in the prevalence of active syphilis (T. pallidum hemagglutination assay and rapid plasma reagin testing positive for antibodies to T. pallidum) was more pronounced among and also restricted to the young age groups (age range, 15-24 years) in the inner city (from 7.6% in 1995 to 1.3% in 2001; prevalence ratio, 0.69; 95% confidence interval, 0.59-0.80). The declining trends in the prevalence of HIV infection and syphilis among young women attending antenatal care clinics in the inner city are encouraging, but these findings require confirmation in future years and for other population groups.

Decline in Prevalence of HIV-1 Infection and Syphilis Among Young Women Attending Antenatal Care Clinics in Addis Ababa, Ethiopia: Results From Sentinel Surveillance, 1995–2001

From 1995 to 2001, five rounds of sentinel surveillance were carried out for young women attending antenatal care clinics at four health centers in Addis Ababa, the capital city of Ethiopia, to monitor trends in the prevalence of HIV infection and syphilis. Serum samples were tested for antibodies to HIV (enzyme-linked immunosorbent assay and Western blotting) and antibodies to Treponema pallidum (T. pallidum hemagglutination assay and rapid plasma reagin test). Prevalence ratios for an increase in one calendar year were estimated using log-binomial models. Between 1995 and 2001, the prevalence of HIV infection among young women (age range, 15-24 years) attending antenatal care clinics in inner city health centers declined from 24.2% to 15.1% (prevalence ratio for an increase in one calendar year, 0.91; 95% confidence interval, 0.87-0.95). No change was observed for older age groups or in outer city health centers. The decline in the prevalence of active syphilis (T. pallidum hemagglutination assay and rapid plasma reagin testing positive for antibodies to T. pallidum) was more pronounced among and also restricted to the young age groups (age range, 15-24 years) in the inner city (from 7.6% in 1995 to 1.3% in 2001; prevalence ratio, 0.69; 95% confidence interval, 0.59-0.80). The declining trends in the prevalence of HIV infection and syphilis among young women attending antenatal care clinics in the inner city are encouraging, but these findings require confirmation in future years and for other population groups.

Utility of clinically-directed selective screening to diagnose HIV infection in hospitalized children in Bombay, India.

The increasing prevalence of HIV infection in urban India together with limited financial resources necessitates judicious HIV testing. This prospective study was undertaken to determine the utility of selective screening for HIV infection based on five clinical risk factors reported in African children. The study was conducted at the Departments of Paediatrics and Microbiology, LTMG Hospital, Bombay, India between September 1998 and 2000. The children were enrolled after taking informed consent from their parents. The HIV seroprevalence rate was determined in children (aged 1 month to 12 years) consecutively admitted with severe malnutrition, serious pyogenic infections (pneumonia, pyogenic meningitis, septicaemia), disseminated tuberculosis, chronic diarrhoea and oral candidiasis, present either singly or in combination. Children above 18 months of age were diagnosed as being infected with HIV if they tested positive by two different HIV enzyme-linked immunosorbent assay (ELISA) tests. In children less than 18 months of age the diagnosis of HIV infection was made if they were ELISA positive and also fulfilled the WHO criteria for symptomatic HIV infection. Of a total 204 children (110 male, 94 female) screened, 24 (11.8 per cent) were diagnosed as HIV-infected. The HIV seropositive rate was highest in children having oral candidiasis (40.6 per cent), followed by chronic diarrhoea (18.2 per cent), disseminated tuberculosis (16.2 per cent), severe malnutrition (14.4 per cent), and serious pyogenic infections (11.2 per cent). Only the presence of oral candidiasis was a significant independent risk factor for predicting HIV infection (p < 0.0001). However, as the number of risk factors concomitantly present increased, the chances of the child being infected with HIV also increased significantly (p < 0.001). Our study shows that clinically-directed selective screening does have a practical role in diagnosing HIV infection in a resource-poor setting.

Myelomeningocele in a child with intrauterine exposure to efavirenz

The authors report a case of a full-term male neonate born to a 34-year-old woman with heterosexually acquired asymptomatic HIV infection, with a CD4 cell count of 390/mm3 (26%) and an HIV-RNA level of 7600, receiving zidovudine, stavudine and efavirenz therapy before pregnancy. She was counselled regarding the potential risks of this therapy and the necessity for adequate birth control. After a period of amenorrhoea she performed a pregnancy test, which was positive. For this reason antiretroviral therapy was switched to an alternative regimen with lamivudine, stavudine and nelfinavir at 24 weeks of pregnancy. Obstetric controls were performed regularly and no side-effects were reported. Before and during the whole pregnancy the patient was submitted to daily folic acid supplementation. Ultrasound surveillance performed at the second trimester of gestation showed regular fetal growth and the presence of a lumbar mass and a triventricular hydrocephalus. The baby was born at the 38th week of gestational age, weight 3450 g, length 49 cm and head circumference 34.5 cm, presenting with a lumbo-sacral mass compatible with a myelomeningocele of 13 cm diameter with full intact skin (Fig. 1). A cerebral ultrasound showed a triventricular hydrocephalus. Magnetic resonance imaging confirmed a large sacral myelomeningocele lesion (10 cm diameter). Laboratory evaluation showed hepatic, renal and metabolic assessment in the normal range. The serological test for HIV (enzyme-linked immunosorbent assay and Western blot) was positive. HIV-1 DNA polymerase chain reaction at birth on plasma and cerebrospinal fluid was negative. The newborn was submitted to surgical repair of the myelomeningocele lesion and ventriculo–peritoneal shunting. Prophylactic therapy with zidovudine 2 mg/kg a day trial was started.Fig. 1.: Myelomeningocele in efavirenz-exposed newborn.The aetiology of myelomeningocele and other neural-tube defects still remain to be completely understood, although genetics, race, socioeconomics and environmental factors are recognized [1]. The role of folic acid deficiency as the major cause of spina bifida has been recognized, but at least 30% of cases are not prevented by periconceptional multivitamins containing folic acid supplementation. Therefore other specific environmental causes have been involved; to date maternal diabetes and fetal exposure to some anti-epileptic drugs such as valproic acid have been identified [2]. Efavirenz is a potent non-nucleoside reverse transcriptase inhibitor that shows a durable suppression of HIV replication. In animal studies [3], efavirenz crosses the placenta and produces fetal blood concentrations similar to maternal blood concentrations. Teratogenic effects have been observed in three out of 20 fetuses from efavirenz-treated cynomolgus monkeys from the 20th to the 150th days of gestation in a developmental toxicity study. Drug-induced neural tube defects such as anencephaly and unilateral anophthalmia were observed in one fetus, microophthalmia was observed in another fetus, and cleft palate was observed in a third fetus. These effects were not noted on rats and rabbits probably because of different pharmacokinetics. The use of this drug is not allowed in pregnant women for two reasons: first, the teratogenic effects were observed in monkeys exposed at the same recommended dose as in humans; second, the drug follows the same metabolic pathway in humans and monkeys (the 8-OH conjugated glucuronide is the major metabolite in plasma and urine) [4]. To date, this case is the first report of neural tube defect in a human fetus accidentally exposed to efavirenz during the first month of pregnancy. This hypothesis is supported by strong evidence: (i) the extension of fetal exposure to efavirenz occurred within the first 28 days of gestation, exactly corresponding to the embryological period of neural tube closure [5]; (ii) the teratological effect observed in our neonate involved neural tube development, as did the anencephalia observed in fetuses from efavirenz-treated monkeys. In conclusion, this case suggests special considerations: the demonstration of a possible teratogenic effect in humans strengthens the recommendation that pregnancy should be avoided in women receiving efavirenz. Moreover, efavirenz-treated women should be carefully advised to shift to an alternative antiretroviral treatment before pregnancy. If our report is confirmed by further observations, we believe that the advisability of efavirenz proscription in women of reproductive age should be prudently considered. Carlo Fundarò Orazio Genovese Claudia Rendeli Enrica Tamburrini Elio Salvaggio

Multiplex analysis of heterophil antibodies in patients with indeterminate HIV immunoassay results.

We hypothesized that heterophil antibodies reactive with animal proteins used in blot preparation caused nonspecific staining (NSS) on HIV Western blot (WB) studies, causing indeterminate results. We analyzed samples showing NSS on HIV WB using a multiplexed immunoassay to simultaneously measure IgG antibodies to animal IgG (bovine, goat, sheep, mouse) and bovine serum albumin. Heterophil antibodies reactive with IgG from several animal species were detected in 23 (49%) of 47 samples showing NSS on HIV WB; 15 positive samples demonstrated antibodies to all 5 antigens. Similar IgG heterophil antibodies were detected in only 2 (8%) of 24 control samples. Of the HIV WB samples with a positive HIV-1 enzyme-linked immunosorbent assay (ELISA) result at the time of WB testing (11/47), heterophil antibodies were found in 8 (73%) of 11. Preabsorption with bovine, goat, and sheep IgG removed heterophil antibodies detected by the multiplexed assay and, in some cases, eliminated reactivity in ELISA and WB testing. Heterophil antibodies are associated with indeterminate HIV immunoassay results and are an important cause of false-positive HIV ELISA results. Multiplexed immunoassays provide a powerful tool for screening patients for heterophil antibodies and resolving possible false-positive results.

Diagnosis of human immunodeficiency virus infection in perinatally exposed orphaned infants in a resource-poor setting.

Diagnosis of human immunodeficiency virus infection in perinatally exposed orphaned infants in a resource-poor setting.

Variability of human immunodeficiency virus type 1 group O strains isolated from Cameroonian patients living in France

Human immunodeficiency virus type 1 (HIV-1) nucleotide sequences encoding p24Gag and the Env C2V3 region were obtained from seven patients who were selected on the basis of having paradoxical seronegativity on a subset of HIV enzyme-linked immunosorbent assay detection kits and having atypical Western blot (immunoblot) reactivity. Sequence analyses showed that all of these strains were more closely related to the recently described Cameroonian HIV isolates of group O (HIV-1 outlier) than to group M (HIV-1 major). All seven patients had Cameroonian origins but were living in France at the time the blood samples were taken. Characterization of a large number of group M strains has to date revealed eight distinct genetic subtypes (A to H). Genetic distances between sequences from available group O isolates were generally comparable to those observed in M intersubtype sequence comparisons, showing that the group O viruses are genetically very diverse. Analysis of sequences from these seven new viral strains, combined with the three previously characterized group O strains, revealed few discernable phylogenetic clustering patterns among the 10 patients' viral sequences. The level of diversity among group O sequences suggests that they may have a comparable (or greater) age than the M group sequences, although for unknown reasons, the latter group dispersed first and is the dominant lineage in the pandemic.

Reducing volunteer bias

To estimate the prevalence of HIV-1 infection among adult and young offenders admitted to remand facilities in the province of Ontario, Canada, by using a design that reduces volunteer bias. A study using a modified anonymous HIV-surveillance design was conducted with urine specimens routinely collected from male and female entrants to all Ontario jails, detention and youth centres between February and August 1993. Information on sex, age, and history of injecting drug use was also collected. Urine was screened using a modified commercial HIV enzyme-linked immunosorbent assay kit and confirmed using a modified in-house Western blot assay. Data were obtained on 10,530 adult men, 1518 adult women, 1480 young male offenders, and 92 young female offenders. Urine specimens were available for 88% of new entrants. Of the entrants, 1% (n = 163) refused to have their urine used for research. Refusals were not associated with history of injecting drug use. Overall rates of HIV-1 infection were 1% for adult men, 1.2% for adult women, and 0% for young offenders. Both the rates of infection and prevalence of injecting drug use varied across facilities and geographic regions. Overall, 13% of adult men, 20% of adult women, 3% of young male offenders, and 2% of young female offenders reported a history of injecting drug use. Rates of infection were highest among self-reported injecting drug users. Rates of HIV were 3.6% for adult men and 4.2% for adult women who injected compared with 0.6 and 0.5%, respectively, for non-injecting drug users. The use of unlinked left-over specimens is an important tool for measuring HIV-prevalence rates and should be encouraged. The results indicate that HIV rates are much higher among those entering prisons than in the general population. The pattern of HIV in Ontario prisons is similar to that reported in Europe and the United States. We are optimistic that these data will stimulate much needed efforts towards education and health promotion, and open the door to further research in Canadian prisons.

A novel enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to HIV-1 envelope glycoproteins based on immobilization of rival glycoproteins in microtiter wells coated with concanavalin A

We have developed a novel method that greatly simplifies the preparation of solid-phase HIV-1 envelope glycoproteins for use in an ELISA that detects serum antibodies to HIV envelope antigens. This method utilizes concanavalin A absorbed to wells of microtiter plates to affinity immobilize detergent-solubilized viral glycoproteins released in culture fluids of HIV-1 infected cell lines grown in serum free medium. Antibodies binding to ConA-immobilized viral antigens are detected by peroxidase-conjugated antibodies and appropriate enzyme substrates. Unlike most commercial HIV ELISAs, which utilize gp120 depleted-purified virus as the source of antigens and thus favor detection of antibodies of core antigens, the ConA envELISA is highly sensitive for detecting antibodies to native gp120, as evidenced by the strong reactivity of gp120-specific human monoclonal antibodies. Our results also suggest that representation of gp41 in the assay varies and depends on which virus infected cell lines are use for antigen production. Since this assay accurately identified 14 HIV-1 antibody positive patient sera and no false positives were detected among 16 HIV-1 negative sera, the ConA envELISA shows promise as an inexpensive assay for the serologic diagnosis of HIV infections.