Role of the laboratory in ensuring global access to ARV treatment for HIV-infected children: consensus statement on the performance of laboratory assays for early infant diagnosis

A two day meeting hosted by the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC) was held in May 2006 in Entebbe, Uganda to review the laboratory performance of virologic molecular methods, particularly the Roche Amplicor DNA PCR version 1.5 assay, in the diagnosis of HIV-1 infection in infants. The meeting was attended by approximately 60 participants from 17 countries. Data on the performance and limitations of the HIV-1 DNA PCR assay from 9 African countries with high-burdens of HIV/AIDS were shared with respect to different settings and HIV- subtypes. A consensus statement on the use of the assay for early infant diagnosis was developed and areas of needed operational research were identified. In addition, consensus was reached on the usefulness of dried blood spot (DBS) specimens in childhood as a means for ensuring greater accessibility to serologic and virologic HIV testing for the paediatric population.

Evaluation of a quantitative double ELISA strategy for confirmation and differentiation of HIV infection

The current HIV pandemic is complicated by the spread of distinct types and subtypes of HIV. The currently used conventional diagnostic tests have shown limitations in the detection of antibodies against all HIV-1 subtypes, as demonstrated by recent identification of HIV-1 subtype O. To evaluate quantitatively the diagnostic potential of a double ELISA strategy for the detection and partial differentiation of HIV-1, HIV-1 subtype O and HIV-2 infections blood samples were examined at five different test centers: Blantyre, Malawi; Abidjan and Daloa, Ivory Coast; Yaoundé, Cameroon; Munich, Germany. All tests results, including ELISA extinction values and Western blot profiles, were forwarded to Munich for final interpretation. An indirect anti-HIV-1/2 ELISA and a competitive anti-HIV-1 ELISA were used in combination for the initial screening of blood specimens. All anti-HIV positive and anti-HIV negative samples were subjected to immunoblot analysis. Independent of the diversity of the extinction profiles, and of the test manufacturer, the quantitative evaluation of the ELISA extinction values could define two extinction areas with a 100% predictive value for HIV-1 seropositivity and HIV seronegativity; extinction values > 2 by the indirect ELISA and < 0.2 by the competitive ELISA for an anti-HIV-1 subtype A to I positive result; extinction values < 0.2 by the indirect ELISA and > 1.0 by the competitive ELISA for an anti-HIV negative result. Additionally, the quantitative evaluation of the extinction profile provides partial information on the HIV-1 subtype as far as the distinction in group M and group O is concerned. In conclusion, the quantitative evaluation of this double ELISA strategy can reduce the number of blood specimens that require additional confirmatory testing in developing countries and can be superior to the immunoblot method during early seroconversion.

Biological phenotypes of HIV-1 subtypes A and B strains of diverse origins

The identification of specific biologic phenotypic traits that can be correlated with different HIV-1 genetic subtypes was sought. The genetic subtypes were determined by either sequencing (Cameroonian strains, n = 18) or by the heteroduplex mobility assay (HMA) (Belgian strains, n = 21 and Ivorian strains, n = 25). Seventeen (81%) of the 21 Belgian isolates belonged to subtype B and 4 (17%) were subtype A strains. Subtype A variants were predominant in the two African countries studied; 11 (61%) of 18 strains from Cameroon and 23 (92%) of 25 strains from the Ivory Coast. Of the 64 isolates, 38 (58%) and 19 (29%) belonged to subtypes A and B, respectively. No significant difference was observed for biological phenotypes (slow/low and rapid/high) of both genetic subtypes. In symptomatic individuals, however, a significantly higher number of subtype B isolates were of rapid/high phenotype, compared with subtype A (5 of 10; 50%) vs. 2 of 22; 9%), respectively; X2 = 6.7, P = 0.02). The findings suggest that overall HIV-1 isolates belonging to genetic subtype B are not distinguishable from subtype A variants on the basis of their biological phenotypes. Syncytium-inducing variants were less prevalent regardless of the geographic origin of the isolates.

Isolation of simian immunodeficiency viruses from two sooty mangabeys in Côte d'Ivoire: virological and genetic characterization and relationship to other HIV type 2 and SIVsm/mac strains

OBJECTIVE

To search for the presence of SIV in sooty mangabeys and other monkey species in Côte d'Ivoire, West Africa, and to compare viral isolates with HIV-2 strains from the same region.

METHODS

Forty-three captive housed monkeys (28 African green monkeys, 6 sooty mangabeys, 6 baboons, and 6 patas monkeys) were tested for the presence of HIV and SIV antibodies. Virus was isolated from the peripheral blood lymphocytes of seropositive animals and from HIV-2 antibody-positive patients originating from Côte d'Ivoire, Ghana, Senegal, and Belgium. Viruses were characterized by Western blot and radioimmunoprecipitation assay. Proviral DNA was amplified by PCR, cloned, and sequenced to construct a phylogenetic tree.

RESULTS

One African green monkey and three sooty mangabeys had antibodies that cross-reacted with HIV-2. From two mangabeys lentiviruses were isolated and designated as SIVsmCI2 and SIVsmCI8. Serological, virological, and sequence data showed that these isolates are members of the HIV-2/SIVsm/SIVmac group of primate lentiviruses. Furthermore, in the phylogenetic tree, these two new viruses form a distinct subgroup that is equidistant to the HIV-2 strains and the previously described SIVsm/SIVmac viruses.

CONCLUSION

This study provides additional evidence that sooty mangabey monkeys can be infected with a lentivirus in their natural habitat. Within the SIVsm and SIVmac viruses extensive genetic variation is observed.

Effect of methodology on detection of HIV-1/HIV-2 dual infections in Côte d'Ivoire

Dual seroreactivity to the human immunodeficiency virus (HIV) types 1 and 2 is common in Côte d'Ivoire. To assess whether dual infection is the reason for dual seroreactivity, different methods for detection of HIV-1 and HIV-2 viruses were compared. PCR on primary uncultured lymphocytes of 56 dually seropositive samples revealed the presence of both HIV-1 and HIV-2 proviral DNA in 23 (41%) cases. In 7 other dual seropositive persons, PCR was carried out on the primary lymphocytes as well as on lymphocytes after 3 and 6 weeks of cocultivation. More cultures, 5/7 (71%), were positive for both viruses at 3 weeks compared to 0/7 at 6 weeks post cultivation. Moreover, 2 out of 3 samples, where only HIV-1 was detected in uncultured cells, were positive for both viruses after 3 weeks of cultivation. These data indicate that the sensitivity of HIV-2 detection can be increased by stimulation of patients' lymphocytes. A higher number of dual seropositive individuals (10/23 (48%)) had antibodies able to neutralize simultaneously both HIV-1 and HIV-2 prototype viruses than did HIV-1 antibody-positive sera (5/21 (24%)) or HIV-2 antibody positive sera (3/18 (17%)). The prevalence of dual seropositives being infected with both viruses is highly dependent on the method used to detect infection. There is a need to standardize virological markers in order to gain a better insight into the relative proportions of HIV-1, HIV-2 and HIV-1/HIV-2 dually infected persons.

Molecular phylogeny of part of the env gene of HIV-1 strains isolated in Côte d'Ivoire

OBJECTIVES

To examine the genetic variation of HIV-1 isolates in Abidjan, Côte d'Ivoire, and to determine the extent to which phylogenetic trees based on sequence information of part of the env gene containing the principal neutralizing domain are representative for documenting genetic variability.

DESIGN

Phylogenetic comparison of 13 HIV-1 strains isolated from patients in Abidjan with previously documented HIV-1 strains of different geographic origin.

METHODS

To sequence a 900 base-pair fragment of the env gene containing V3, V4, V5 and the beginning of gp41 of three to four clones per isolate. Phylogenetic tree analysis was performed with the software package TREECON.

RESULTS

Eleven HIV-1 isolates of Abidjan were classified as genotype A, while two were classed as genotypes B and D. Intra-genotype A distances at the nucleotide level were a maximum of 14.1%. Inter-genotype distances between genotype A and genotypes B, C, and D varied from 16.0 to 22.6%. Phylogenetic trees, based on sequence data of a 300 base-pair fragment containing the V3 loop, showed significant differences in tree topology and statistical confidence with phylogenetic trees based on sequence data of the 900 base-pair env fragment.

CONCLUSIONS

Genotype A Côte d'Ivoire HIV-1 strains, which comprise 11 out of 13 isolates, predominate in Abidjan, which may indicate a local burst of particular variants. Phylogenetic trees should be interpreted with caution when based on a more limited number of nucleotides, such as the V3 region.

Phylogenetic analysis of gag genes from 70 international HIV-1 isolates provides evidence for multiple genotypes

OBJECTIVE

To determine the extent of genetic variation among internationally collected HIV-1 isolates, to analyse phylogenetic relationships and the geographic distribution of different variants.

DESIGN

Phylogenetic comparison of 70 HIV-1 isolates collected in 15 countries on four continents.

METHODS

To sequence the complete gag genome of HIV-1 isolates, build multiple sequence alignments and construct phylogenetic trees using distance matrix methods and maximum parsimony algorithms.

RESULTS

Phylogenetic tree analysis identified seven distinct genotypes. The seven genotypes were evident by both distance matrix methods and maximum parsimony analysis, and were strongly supported by bootstrap resampling of the data. The intra-genotypic gag distances averaged 7%, whereas the inter-genotypic distances averaged 14%. The geographic distribution of variants was complex. Some genotypes have apparently migrated to several continents and many areas harbor a mixture of genotypes. Related variants may cluster in certain areas, particularly isolates from a single city collected over a short time.

CONCLUSIONS

The genetic variation among HIV-1 isolates is more extensive than previously appreciated. At least seven distinct HIV-1 genotypes can be identified. Diversification, migration and establishment of local, temporal 'blooms' of particular variants may all occur concomitantly.

[The pathogenicity of the human immunodeficiency virus HIV-2 as seen by epidemiologists]

The purpose of this study is an evaluation of HIV-2 pathogenicity through an epidemiological analysis, specially in Africa. It is acknowledged that the incubation, or more specially the lapse of time between the infection and the AIDS disease, is longer with HIV-2 than with HIV-1. More over, a certain number of surveys done in Africa show that the average age is higher with HIV-2 than with HIV-1; this is a regular sign of lower pathogenicity. It appears that the sexual transmission of the virus is the same for the HIV-2 and the HIV-1, but it is less effective from mother to baby. Furthermore this type of virus is less prevalent with AIDS patients or AIDS suspects than the HIV-1; and the follow-up of HIV-2 seropositives show that fewer people fall ill than with the HIV-1. A few signs of AIDS standard diagnosis are less frequent among HIV-2 infected patients than among HIV-1 infected patients. Opportunist or associated infections, like tuberculosis or malnutrition, are less often found in HIV-2 patients.

Salivary and urinary diagnosis of human immunodeficiency viruses 1 and 2 infection in Côte d'Ivoire, using two assays

This investigation, done at the Institut Pasteur de Cote d'Ivoire 'blind' of the previous serological findings, suggests that GACELISA, a commercial immunoglobulin G capture enzyme immunoassay for anti-human immunodeficiency virus antibody, can be successfully applied to unprocessed saliva and urine specimens. Its accuracy may be as high as that of conventional enzyme assays on serum tested under similar conditions. However, the role of GACPAT, a similar assay, as a cheap alternative screening test for urine remains in doubt unless its non-specificity can be controlled.

Virological and polymerase chain reaction studies of HIV-1/HIV-2 dual infection in Côte d'Ivoire

Dual serological reactivity to the human immunodeficiency virus (HIV) types 1 and 2 is common in Côte d'Ivoire. To assess whether dual infection is the reason for dual seropositivity we sought HIV-1 and HIV-2 proviral DNA in primary uncultured peripheral blood mononuclear cells from selected seropositive patients in Côte d'Ivoire with the polymerase chain reaction (PCR). PCR on primary lymphocytes in 36 dually seropositive samples revealed the presence of both HIV-1 and HIV-2 proviral DNA in 12 cases and the presence of HIV-1 only in 24 cases. In 18 of these 36 samples a virus was isolated and identified by PCR. HIV-1 was isolated from the 9 specimens with only HIV-1 proviral DNA in the primary lymphocytes. Among dually PCR-positive samples, 2 viral isolates reacted with both HIV-1 and HIV-2 primers; and only HIV-2 (n = 1) or HIV-1 (n = 6) strains were isolated from the other samples. The findings show that surveys based on serology may overestimate the prevalence of mixed infections in areas where both HIV-1 and HIV-2 occur.

Isolation and characterization of a new chimpanzee lentivirus (simian immunodeficiency virus isolate cpz-ant) from a wild-captured chimpanzee

OBJECTIVE

To assess the prevalence of infection with simian immunodeficiency virus (SIV) isolate cpz, a lentivirus closely related to HIV-1, in chimpanzees, and to obtain new SIVcpz isolates.

METHODS

Forty-four wild-captured chimpanzees in Belgium and Côte d'Ivoire were tested for HIV and SIV antibodies. Virus was isolated from the peripheral blood lymphocytes of positive animals and characterized by electron microscopy, Western blot and radioimmunoprecipitation assay.

RESULTS

One animal had antibodies that cross-reacted with HIV-1. A lentivirus was isolated and referred to as SIVcpz-ant. With regard to molecular weight patterns, SIVcpz-ant differs from SIVcpz-gab' an HIV-1-related virus isolated from a wild-captured chimpanzee in Gabon. The major core protein, the transmembrane and outer membrane glycoproteins of the SIVcpz-ant strain consistently had higher molecular weights. Significantly more HIV-1-positive sera reacted with the envelope proteins of the Gabonese SIVcpz-gab strain than with the SIVcpz-ant strain.

CONCLUSIONS

This study shows that natural infection of wild-captured chimpanzees with an HIV-related virus may not be uncommon. The diversity of the two chimpanzee isolates, the different geographical origin and the absence of disease suggest that chimpanzees have not recently become SIVcpz-infected.

The present and future course of the AIDS epidemic in Côte d'Ivoire

An assessment of the current and future mortality and morbidity from acquired immunodeficiency syndrome (AIDS) in Côte d'Ivoire was made using the results of the 1989 national survey of the prevalence of human immunodeficiency (HIV) infection in the country and the AIDS projection model developed by WHO. For 1989 it was estimated that about 25,000 AIDS cases in adults and children had occurred, although the total number of cases reported for 1989 (up to 1 July 1991) was about 13% (1:6.9) of this estimated total. It is projected that by 1994 in Côte d'Ivoire the cumulative number of cases of AIDS in adults will be 89,000, and that for infants and children the corresponding number will be 41,000. It was also projected that about 371,000 uninfected children will have been born to HIV-infected mothers in Côte d'Ivoire by 1994 and that many of these children will have been orphaned by the deaths of their mothers from AIDS.

Cross-reactivity on western blots in HIV-1 and HIV-2 infections

To examine cross-reactivity of antibodies to heterologous antigens, on HIV-1 and HIV-2 Western blots, we tested sera from 1362 consecutive tuberculosis (TB) patients and 2127 consecutive blood donors. Specimens positive on enzyme-linked immunosorbent assay (ELISA) for HIV-1 or HIV-2 were further characterized by synthetic peptide-based tests, and tested by HIV-1- and HIV-2-specific Western blots. Dual serologic reactivity on synthetic peptide tests was proportionately more frequent in HIV-positive TB patients than in blood donors, and HIV-2 reactivity less frequent. Positive HIV-1 Western blots were seen in 73-83% of specimens specifically characterized as positive for HIV-2 on synthetic peptide tests. Cross-reactivity to HIV-2 Western blots by HIV-1-positive specimens was significantly more frequent in TB patients (35%) than in asymptomatic donors (9%; P less than 0.001). Using recently recommended criteria for HIV-2 Western blot interpretation (presence of two env bands) reduced the overall proportion of HIV-1-positive specimens having a positive HIV-2 Western blot from 27.5 to 16.4%, with [corrected] minimal effect on sensitivity in the diagnosis of HIV-2 reactivity on specimens positive on synthetic peptide tests.

Risk of tuberculosis in patients with HIV-I and HIV-II infections in Abidjan, Ivory Coast

OBJECTIVE

To examine the association between HIV-II infection and tuberculosis.

DESIGN

Cross sectional study comparing the prevalence of HIV-I and HIV-II infections in patients with tuberculosis and in blood donors.

SETTING

Abidjan, Ivory Coast, west Africa.

PATIENTS

2043 consecutive ambulant patients with tuberculosis (confirmed pulmonary, presumed pulmonary, or extrapulmonary) and 2127 volunteer blood donors.

MAIN OUTCOME MEASURE

Prevalence of HIV-I and HIV-II infections as assessed by presence of serum antibodies.

RESULTS

Overall rates of HIV infection were 40.2% in patients with tuberculosis (26.4% positive for HIV-I, 4.7% for HIV-II, and 9.0% for both); and 10.4% in blood donors (7.2% positive for HIV-I, 1.9% for HIV-II, and 1.3% for both). HIV-II infection was significantly more common in patients with all types of tuberculosis than in blood donors (97/2043, 4.7% v 40/2127, 1.9%; odds ratio 3.8%, 95% confidence interval 2.6 to 5.6).

CONCLUSION

Both HIV-I and HIV-II infections are associated with tuberculosis in Abidjan. 35% of adult tuberculosis in Abidjan is attributable to HIV infection and 4% specifically to HIV-II.

[A comparative study of the carriage of enteric viruses in urban and rural populations in the western region of the Ivory Coast]

Stool samples were collected from 300 persons of three classes of age (less than 6, 6-15, greater than 15) coming from urban and rural areas of Ivory Coast and tested for enteric viruses. This study has shown the high frequency of enteric viruses carriage, unrelated to sex or age. Carriage rates were significantly higher in rural areas than in urban areas. Both in urban and rural areas there was no difference of carriage among males and females. Polioviruses are predominant.

[Serologic survey on Chlamydia trachomatis in different populations of the Ivory Coast]

Chlamydial serum antibodies were screened in more than 1,000 persons by immunofluorescence test. C. trachomatis antibodies (greater than or equal to 1/16 for males, greater than or equal to 1/64 for females) were found more frequently in risk group (prostitutes: 64.7%, prisoners: 64.0%) than in control groups (pregnant women: 18.8%, children: 6.6%). The presence of antibodies to C. trachomatis was correlated with presence of T. pallidum and HIV antibodies.

[Ultrastructural changes caused by yellow fever virus at the level of the kidneys in newborn mice]

The author is studying the ultrastructural modifications provoked by the yellow fever virus in the kidneys of baby mice. As a result of the study it has been found that minor changes start appearing as early as the first day and these lead finally to necrosis. The process consists of 5 phases which are the development of endoplasmatic reticulum, the envelopment of the mitochondria by the folds of endoplasmatic reticulum, mitochondrial autophagocytosis, the development of microvilli at the cell surface and the total necrosis of the renal cell.