Evolution of human immunodeficiency virus type 1 in perinatally infected infants with rapid and slow progression to disease.

We addressed the relationship between the origin and evolution of human immunodeficiency virus type 1 (HIV-1) variants and disease outcome in perinatally infected infants by studying the V3 regions of viral variants in samples obtained from five transmitting mothers at delivery and obtained sequentially over the first year of life from their infected infants, two of whom (rapid progressors) rapidly progressed to having AIDS. Phylogenetic analyses disclosed that the V3 sequences from each mother-infant pair clustered together and were clearly distinct from those of the other pairs. Within each pair, the child's sequences formed a monophyletic group, indicating that a single variant initiated the infection in both rapid and slow progressors. Plasma HIV-1 RNA levels increased in all five infants during their first months of life and then declined within the first semester of life only in the three slow progressors. V3 variability increased over time in all infants, but no differences in the pattern of V3 evolution in terms of potential viral phenotype were observed. The numbers of synonymous and nonsynonymous substitutions varied during the first semester of life regardless of viral load, CD4+-cell count, and disease progression. Conversely, during the second semester of life the rate of nonsynonymous substitutions was higher than that of synonymous substitutions in the slow progressors but not in the rapid progressors, thus suggesting a stronger host selective pressure in the former. In view of the proposal that V3 genetic evolution is driven mainly by host immune constraints, these findings suggest that while the immune response to V3 might contribute to regulating viral levels after the first semester of life, it is unlikely to play a determinant role in the initial viral decline soon after birth.     

Primary care physicians' refusal to care for patients infected with the human immunodeficiency virus.

We conducted a telephone survey of a random sample of office-based primary care physicians in Los Angeles County to determine their practice experiences with patients infected with the human immunodeficiency virus (HIV). Telephone interviews included questions related to the physicians'' experiences evaluating patients for HIV infection during the past 6 months and the presence of HIV-infected patients in their practices. Those without HIV-infected patients were asked if this was because they had not encountered such patients, because those patients had died, or because the physicians had chosen to refer these patients elsewhere or the patients had gone elsewhere for care. Of physicians who participated in the survey, 78% had evaluated a patient for HIV infection in the past 6 months; 34% were currently providing primary care for infected patients; and 36% had elected to refer HIV-infected patients elsewhere, or their patients had elected to find other physicians. In all, 48% of physicians in the sample had elected not to care for, or said they would not provide care for, patients with HIV infection. Among Los Angeles County primary care physicians, 36% have refused to provide continuing care for HIV-infected patients and another 12% indicated their unwillingness to do so should such patients present themselves for care. As of 1991, the reservoir of primary care physicians in Los Angeles not yet involved with but willing to care for HIV-infected patients is relatively small (15%).     

Comprehensive screening reveals strong and broadly directed human immunodeficiency virus type 1-specific CD8 responses in perinatally infected children

Advances in antiviral therapy have dramatically shifted the demographics of pediatric human immunodeficiency virus type 1 (HIV-1) infection in the developed world, and a growing proportion of perinatally HIV-1-infected children are now entering their second or even third decade of life. Although cellular immune responses to HIV are known to be weak in early infancy, the magnitude, breadth, and specificity of responses later in childhood have not been characterized in detail. We performed a comprehensive characterization of HIV-1-specific CD8 responses in 18 perinatally infected children (age range, 6 to 17 years), most of whom were on antiviral therapy, using both previously defined HIV-1 epitopes and overlapping peptides spanning all HIV-1 proteins. Multispecific responses were detected in all subjects and accounted for a median of 0.25 to 0.3% of all peripheral blood mononuclear cells that was similar to the magnitude seen in HIV-infected adults. CD8 responses were broadly directed at an average of 11 epitopes (range, 2 to 27 epitopes) and targeted nearly all HIV-1 proteins, with the highest proportion in Gag. Responses were readily detected even in those children with suppressed viremia on highly active antiretroviral therapy, although the breadth (P = 0.037) and the magnitude (P = 0.021) were significantly lower in these subjects. Each child recognized only a small minority of the HIV-1 optimal epitopes defined for his or her class I HLA alleles. Together, these data indicate that perinatally infected children who survive infancy mount a robust HIV-1-specific CD8 response that is much stronger than previously thought and is comparable in magnitude and breadth to that of adults. Moreover, this response has the potential to be broadened to target more epitopes, making these children attractive candidates for immunotherapeutic interventions.     

Patterns of primary care of patients infected with human immunodeficiency virus.

To determine the patterns of care of patients infected with the human immunodeficiency virus (HIV), data from 2 sources were analyzed. Initial data obtained from the Washington State HIV/Acquired Immunodeficiency Syndrome (AIDS) Epidemiology Unit indicate that 46% of patients with class IV AIDS were seen by physicians who reported fewer than 5 patients with AIDS, and 68% of all Washington physicians who reported treating patients with AIDS have reported only 1 patient. Subsequent data obtained from a questionnaire distributed in 4 Northwest states suggest that 74% of primary care internists and 73% of family practitioners have some experience in caring for patients with HIV infection, but most of these physicians report fewer than 6 patients in the past 2 years. Although most providers seeing large numbers of HIV-infected patients in their practices were based in the region''s major metropolitan area, 59% of the internists and 55% of the family practitioners surveyed outside of the metropolitan area had seen at least 1 HIV-infected patient in their practices. These results suggest that primary care physicians with relatively little experience treating HIV infection are providing care for a large number of HIV-infected persons. Further study is needed to determine the extent and quality of care provided.     

Longitudinal studies of viral sequence, viral phenotype, and immunologic parameters of human immunodeficiency virus type 1 infection in perinatally infected twins with discordant disease courses.

Perinatal human immunodeficiency virus type 1 (HIV-1) infections cause a broad spectrum of clinical disease and are variable in both the age of the patient at onset of serious disease and the progression of the clinical course. Heterozygotic perinatally infected twins with a marked difference in their clinical courses were monitored during the first 2 years of life. Twin B, the second-born twin, developed AIDS by 6 months of age and died at 22 months of age, while twin A remained minimally symptomatic through the first 2 years. Sequential blood specimens were obtained from the twins in order to characterize the immunologic properties of the children and the phenotypes and genotypes of the HIV-1 isolates at various times. Twin A developed neutralizing antibodies and a high-level antibody-mediated cellular cytotoxicity (ADCC) response, while twin B had no neutralizing antibody and a much lower ADCC response. The virus isolates obtained from the two children at various time points proliferated equally well in peripheral blood mononuclear cells, were nonsyncytium inducing, and could not infect established T-cell lines. They differed in their ability to infect primary macrophages. In parallel to the biological studies, the HIV-1 tat and part of the env gene sequences of the longitudinal isolates at four time points were determined. Sequences of virus from both twins at different time points were highly conserved; the viruses evolved at a similar rate until the last analyzed time point, at which there was a dramatic increase in sequence diversity for the sicker child, especially in the tat gene. Our results show that the viruses isolated at different times do not have significant changes in growth properties. The absence or low levels of neutralizing antibodies may correlate with disease progression in the twins.     

Relationship between the V3 loop and the phenotypes of human immunodeficiency virus type 1 (HIV-1) isolates from children perinatally infected with HIV-1.

The third variable region (V3) of the envelope protein of human immunodeficiency virus type 1 (HIV-1) contains group- and type-specific epitopes for neutralizing antibodies and contains determinants involved in viral tropism and syncytium-inducing (SI) activity. We studied the in vivo relationship between V3 sequences and viral phenotypes in 24 perinatally HIV-1-infected children. To avoid in vitro selection of intrapatient minor variants, genetic studies were performed directly on uncultured peripheral blood mononuclear cells (PBMC), and the tropisms of HIV-1 isolates were evaluated by culturing patients' PBMC directly with monocyte-derived macrophages, lymphocytes, and MT-2 cells. According to their phenotypes, we could define five types of primary isolates: (i) non-syncytium-inducing (NSI) macrophagetropic, (ii) NSI macrophage-lymphotropic, (iii) NSI lymphotropic, (iv) SI lympho-T-cell line-tropic, and (v) SI pleiotropic. The SI viral phenotype was correlated with a more advanced status of disease. Genetic analysis of intrapatient molecular variants revealed that no relationship between the degree of intrapatient V3 variability and the pattern of viral tropism existed; moreover, within a single patient, the values for V3 variability between CD4+ lymphocytes and CD14+ monocytes were similar, thus suggesting that in vivo variability of the monocytotropic variants is more extensive than previously appreciated. A comparison between the intrapatient major variants and the phenotype of primary isolates disclosed that a negatively charged amino acid at residue site 25 was associated with an NSI macrophage- and macrophage-lymphotropic viral phenotype. Finally, by comparing the V3 sequences derived from our study population with those of several prototypes, we observed that the majority of isolates circulating in Italy are related to the North American subtype B macrophagetropic isolates.     

Persistence of transmitted drug resistance among subjects with primary human immunodeficiency virus infection

Following interruption of antiretroviral therapy among individuals with acquired drug resistance, preexisting drug-sensitive virus emerges relatively rapidly. In contrast, wild-type virus is not archived in individuals infected with drug-resistant human immunodeficiency virus (HIV) and thus cannot emerge rapidly in the absence of selective drug pressure. Fourteen recently HIV-infected patients with transmitted drug-resistant virus were followed for a median of 2.1 years after the estimated date of infection (EDI) without receiving antiretroviral therapy. HIV drug resistance and pol replication capacity (RC) in longitudinal plasma samples were assayed. Resistance mutations were characterized as pure populations or mixtures. The mean time to first detection of a mixture of wild-type and drug-resistant viruses was 96 weeks (1.8 years) (95% confidence interval, 48 to 192 weeks) after the EDI. The median time to loss of detectable drug resistance using population-based assays ranged from 4.1 years (conservative estimate) to longer than the lifetime of the individual (less conservative estimate). The transmission of drug-resistant virus was not associated with virus with reduced RC. Sexual transmission of HIV selects for highly fit drug-resistant variants that persist for years. The prolonged persistence of transmitted drug resistance strongly supports the routine use of HIV resistance genotyping for all newly diagnosed individuals.     

Pathogenesis of human immunodeficiency virus infection.

The lentivirus human immunodeficiency virus (HIV) causes AIDS by interacting with a large number of different cells in the body and escaping the host immune response against it. HIV is transmitted primarily through blood and genital fluids and to newborn infants from infected mothers. The steps occurring in infection involve an interaction of HIV not only with the CD4 molecule on cells but also with other cellular receptors recently identified. Virus-cell fusion and HIV entry subsequently take place. Following virus infection, a variety of intracellular mechanisms determine the relative expression of viral regulatory and accessory genes leading to productive or latent infection. With CD4+ lymphocytes, HIV replication can cause syncytium formation and cell death; with other cells, such as macrophages, persistent infection can occur, creating reservoirs for the virus in many cells and tissues. HIV strains are highly heterogeneous, and certain biologic and serologic properties determined by specific genetic sequences can be linked to pathogenic pathways and resistance to the immune response. The host reaction against HIV, through neutralizing antibodies and particularly through strong cellular immune responses, can keep the virus suppressed for many years. Long-term survival appears to involve infection with a relatively low-virulence strain that remains sensitive to the immune response, particularly to control by CD8+ cell antiviral activity. Several therapeutic approaches have been attempted, and others are under investigation. Vaccine development has provided some encouraging results, but the observations indicate the major challenge of preventing infection by HIV. Ongoing research is necessary to find a solution to this devastating worldwide epidemic.     

Acquired immunodeficiency syndrome and human immunodeficiency virus infection in Nevada.

We summarize information from three sets of epidemiologic data: the Nevada AIDS [acquired immunodeficiency syndrome] Surveillance System, which contains information about every case identified within the state boundaries through September 1989; the human immunodeficiency virus (HIV) seroprevalence reporting systems, which currently include data on all HIV-positive reports submitted statewide to public health authorities; and surveys on the knowledge, attitudes, and behaviors of Nevadans concerning HIV-related disease. The Nevada State AIDS Task Force outlined major policy recommendations, nearly half of which concerned testing; only 2 dealt with preventing HIV transmission. Greater efforts should go into education, particularly directed toward groups at greatest risk of exposure to HIV, and to improve community-based care of infected persons.     

Genotypic selection of simian immunodeficiency virus in macaque infants infected transplacentally.

To understand viral and host factors that contribute to transplacental transmission of human immunodeficiency virus, we developed an animal model using pregnant female macaques infected with simian immunodeficiency virus (SIV). Pregnant females were inoculated intravenously during midgestation with either a well-characterized primary isolate of SIV (SIV/DeltaB670) or a combination of SIV/DeltaB670 and the macrophage-tropic molecular clone SIV/17E-Fr. The viral genetic diversity in five infected female macaques and their in utero-infected infants was analyzed. All of the mothers harbored a genetically diverse virus population at parturition, whereas a single genotype from the maternal quasispecies was identified in the infants at birth. Only one of two variants was found in the infants: SIV/17E-Fr (two cases) or a genotype contained within the SIV/DeltaB670 quasispecies (three cases). The macrophage-tropic properties of both transmitted genotypes were suggested by productive replication in primary rhesus macrophage cultures in vitro and the clonal presence in central nervous system tissue of infected monkeys with encephalitis. These observations provide compelling evidence for both genotypic and phenotypic selection in transplacental transmission of SIV and suggest a critical role for macrophages in fetal infection in utero.     

Referral of mothers and infants for intensive care.

During 1975-7, 96 mothers were referred to University College Hospital for delivery from 39 other hospitals because their pregnancies were considered to be at very high risk. One hundred of the 111 infants born to the 96 mothers weighed 2500 g or less and 60 weighed 1500 g or less. A high proportion of the infants developed serious illnesses necessitating intensive care. The birth-weight-specific neonatal mortality rates of the infants were much lower than those of infants born in England and Wales as a whole and were also lower than those of the 370 infants transported to this hospital for intensive care after delivery elsewhere. Whenever possible mothers with very high-risk pregnancies should be referred for delivery to centres with full facilities for the intensive care of the mother, fetus, and newborn infant.     

The human immunodeficiency virus type 1 envelope confers higher rates of replicative fitness to perinatally transmitted viruses than to nontransmitted viruses

Selection of a minor viral genotype during perinatal transmission of human Immunodeficiency virus type 1 (HIV-1) has been observed, but there is a lack of information on the correlation of the restrictive transmission with biological properties of the virus, such as replicative fitness. Recombinant viruses expressing the enhanced green fluorescent protein or the Discosoma sp. red fluorescent (DsRed2) protein carrying the V1 to V5 regions of env from seven mother-infant pairs (MIPs) infected by subtype C HIV-1 were constructed, and competition assays were carried out to compare the fitness between the transmitted and nontransmitted viruses. Flow cytometry was used to quantify the frequency of infected cells, and the replicative fitness was determined based on a calculation that takes into account replication of competing viruses in a single infection versus dual infections. Transmitted viruses from five MIPs with the mothers chronically infected showed a restrictive env genotype, and all the recombinant viruses carrying the infants' Env had higher replicative fitness than those carrying the Env from the mothers. This growth fitness is lineage specific and can be observed only within the same MIP. In contrast, in two MIPs where the mothers had undergone recent acute infection, the viral Env sequences were similar between the mothers and infants and showed no further restriction in quasispecies during perinatal transmission. The recombinant viruses carrying the Env from the infants' viruses also showed replication fitness similar to those carrying the mothers' Env proteins. Our results suggest that newly transmitted viruses from chronically infected mothers have been selected to have higher replicative fitness to favor transmission, and this advantage is conferred by the V1 to V5 region of Env of the transmitted viruses. This finding has important implications for vaccine design or development of strategies to prevent HIV-1 transmission.     

Genital human papillomavirus infection and associated penile intraepithelial neoplasia in males infected with the human immunodeficiency virus

OBJECTIVE: To investigate the association between human papillomavirus (HPV) infections and penile intraepithelial neoplasia (PIN) in genital lesions from human immunodeficiency virus (HIV)+ men. For comparison, we also investigated the same association using specimens from HIV- men. STUDY DESIGN: Imprint smears from penile lesions were obtained from 70 men (mean age, 30 years) who visited a dermatologist. Thirty of them were known to be HIV seropositive. Two study groups were formed: one of 40 HIV- and another of 30 HIV+ males. The smears were examined cytologically for HPV identification or PIN, immunocytochemically for HPV detection and by in situ hybridization for HPV typing. RESULTS: The rates of detecting HPV infection cytologically were higher among men with HIV infection (50%) than among their HIV-seronegative counterparts (30%). There was immunocytochemical evidence of HPV in HIV-infected men in a greater proportion (50%) than in HIV noninfected men (37.5%). By in situ hybridization it was found that there was a higher prevalence of potentially oncogenic HPV (16/18, 31/33/35): 75% in moderate or severe dysplasia (PIN 2 and 3) and 66.6% in HIV+ men as compared with HIV- men (10-16.6%). CONCLUSION: HIV-seropositive males showed an unbalanced distribution of HPV, with a predominance of "high-risk" HPV types. This suggests that immunodepression encourages infection by this oncogenic virus, thereby contributing to the frequency of precancerous lesions in HIV+ men.