Isolation of AIDS-associated retrovirus from genital secretions of women with antibodies to the virus

Epidemiology and Control: Principles, Practice and Programs

Infectious disease epidemiology is concerned with the occurrence of both infection and disease in populations and the factors that determine their frequency, spread, expression and distribution. Viruses show characteristic infectivity, virulence and pathogenicity. The most well established host factors are age, sex and race, but other host biological and behavioral factors affect acquisition of viral infection and/or its course and manifestations. The physical, chemical and biological environment operates on the virus itself and may also alter the host biological or behavioral response. Viral infections have incubation periods lasting days or weeks, while their pathologic sequelae may not manifest for years or decades. Likewise the degree or intensity of host response and clinical expression may range from largely inapparent to highly lethal. The degree of cell, tissue and organ specificity is high. Common syndromes involve the respiratory, gastrointestinal, and central nervous systems, the liver, and mucocutaneous surfaces. Vertical transmission may produce a variety of congenital and perinatal conditions. Viruses spread by multiple modes, using nearly every bodily surface or fluid as a route of exit or entry, either by direct contact or indirectly through an animal vector or other inanimate vehicle. Different viral Infections occur nearly ubiquitously or sporadically; they may be present continuously throughout a population (endemic) or occur in seasonal rhythm or in unexpectedly explosive form (epidemic). Many viruses are refractory to all known therapeutic agents, while for a few, the increasing number of highly effective agents holds great promise. Vaccines have produced many historical successes including the ultimate goal of eradication, but many viral infections continue to elude effective vaccine development. Major government and private sector programs for treatment and prevention have raised expectations of successful control for certain widespread and serious viral diseases; however, in every case a unique set of scientific, socioeconomic, political and behavioral barriers remains to be overcome.

Women and AIDS prevention

Many women are unaware of their potential risk of becoming infected with the human immunodeficiency virus (HIV), the virus presumed to cause AIDS. Other women are confused about what prophylactic measures to adopt to lower their susceptibility to infection. Moreover, the needs of women who do not inject drugs have been largely ignored in media and public information campaigns. Rising rates of AIDS infection among women underscore the need for targeted prevention efforts. In this paper, the risks of the spectrum of HIV-related disease,i.e., HIV seropositive, lymphadenopathy syndrome, AIDS-related complex or full-blown AIDS, for women are described. Methods of disease transmission, prevention means, and issues and barriers to adopting practices for reducing risk of exposure to and transmission of the human immunodeficiency virus are reviewed. Finally, practice, research and policy initiatives for AIDS prevention are offered.

Sexual behavior and AIDS in sociocultural perspective

AIDS, its cause, effect, and possible cure, has become a complex sociopsychological issue with ramifications extending far beyond the purely medical sphere. Spreading rapidly, with a higher incidence rate recorded among young people, the disease transcended the biomedical sphere, presenting sociocultural and psychological ramifications that go beyond its physical impact. With a higher incidence rate among male homosexuals, the epidemic raises morally sensitive questions which further confuse an already clouded picture. Current knowledge on the sexual transmission of AIDS and the role of male homosexuality demonstrates the need for more serious research into the various social and cultural aspects of homosexuality itself. To this end, medical anthropology may provide important information to those dealing with educational and preventive programs for the general population, as well as those in high risk groups for acquiring the disease.

Heterosexual transmission of human immunodeficiency virus infection - Strategies for prevention

In Canada, over 90% of the acquired immune deficiency syndrome cases diagnosed so far have been acquired sexually, with an increasing proportion made up of heterosexual contacts of high risk individuals. In multiple studies, the transmission rate among steady heterosexual partners of infected individuals has been variable. It is likely that complex biological and epidemiological interactions exist between human immunodeficiency virus (HIV) and sexually transmitted diseases with respect to transmission and disease. Other important determinants in transmission of infection may relate to the virus itself. The importance of sexual practices other than vaginal intercourse (such as anal intercourse) in the heterosexual transmission of HIV has not been well studied. The major approach to the control of HIV-associated disease remains the control of primary infection. Sexual practices which are the major epidemiological determinants of HIV transmission can be successfully modified by appropriate educational interventions. The promotion of condom use must form a special part of these interventions. Results of ongoing trials should be available prior to the formulation of recommendations for the use of spermicides. Targeted education programs may allow us to make better use of our resources in a more efficient way. In Canada, groups that could be reached by such programs include: prostitutes and their clients; men and women attending sexually transmitted disease clinics; sexually active women attending family planning clinics; and children and adolescents who are becoming sexually active.

Non-polymeric nano-carriers in HIV/AIDS drug delivery and targeting

Development of an effective drug delivery approach for the treatment of HIV/AIDS is a global challenge. The conventional drug delivery approaches including Highly Active Anti Retroviral Therapy (HAART) have increased the life span of the HIV/AIDS patient. However, the eradication of HIV is still not possible with these approaches due to some limitations. Emergence of polymeric and non-polymeric nanotechnological approaches can be opportunistic in this direction. Polymeric carriers like, dendrimers and nanoparticles have been reported for the targeting of anti HIV drugs. The synthetic pathways as well polymeric framework create some hurdles in their successful formulation development as well as in the possible drug delivery approaches. In the present article, we have discussed the general physiological aspects of the infection along with the relevance of non-polymeric nanocarriers like liposomes, solid lipid nanoparticles (SLN), ethosomes, etc. in the treatment of this disastrous disease.

Neutralizing inter-clade cross-reactivity of HIV-1 V1/V2-specific secretory immunoglobulin A in Colombian and French cohorts

Neutralizing activity of secretory immunoglobulin A (S-IgA) directed against the V1/V2 domain of HIV-1 was studied in parotid saliva of HIV-1- infected patients in Colombian and French cohorts. Purified V1/V2-specific S-IgA antibodies were found to neutralize clades A, B and C primary isolates in five out 76 and 82 patients from each cohort, respectively. These results suggest that neutralizing S-IgA antibodies targeting the V1/V2 domain may provide protection against HIV-1 infection in vivo and may be beneficial in mucosal vaccines.

Heterosexual spread of HIV infection

Sexual transmission is the most common route of spread of human immunodeficiency virus (HIV), with heterosexual transmission of HIV infection accounting for 90% of those infected in 1992 and over 75% of the 10–12 million of those infected to date worldwide. Yet, heterosexual transmission is poorly understood. Since HIV can be transmitted from HIV-infected people who are asymptomatic as well as from those who have the acquired immunodeficiency syndrome (AIDS), we must better define the potential for transmission of HIV from HIV-infected individuals as well as the factors which influence the susceptibility of HIV-uninfected individuals.

Detection of infectious human immunodeficiency virus type 1 in female genital secretions by a short-term culture method

Infectious human immunodeficiency virus type 1 (HIV-1) is difficult to detect in female genital secretions by standard virus culture techniques. To improve detection of cell-free HIV-1 in female genital secretions, we adapted a short-term assay that uses the multinuclear-activation galactosidase indicator (MAGI) assay. When vaginal lavages from HIV-1-infected women were tested with the adapted MAGI assay, 25 (64%) of 39 lavages with detectable, cell-free HIV-1 RNA were shown to have infectious virus. No infectious virus was found in 10 vaginal lavages from HIV-1-infected women with undetectable vaginal viral loads. Significantly (P < 0.01) more lavages from HIV-1-infected women tested positive for infectious virus by the MAGI assay than by standard peripheral blood mononuclear cell (PBMC) coculture, which detected infectious virus in only 6 (17%) of 35 vaginal lavages. Lavages with viral loads of >10,000 copies per lavage yielded significantly (P < 0.01) more positive cultures than those with <10,000 copies by using the MAGI assay. Detection of infectious HIV-1 in vaginal lavages was not associated with the presence of genital tract infections or CD4(+)-T-cell counts. However, although the results were not significant (P = 0.08), the MAGI assay detected infectious virus from more vaginal lavages at a vaginal pH of >/=4.5 than at a pH of <4.5. These results indicate that the MAGI assay is more sensitive than PBMC culture methods for detecting infectious virus in female genital secretions. Accurate measurements of infectious virus in genital secretions will improve studies that evaluate sexual transmission of HIV-1.

Development of topical microbicides for prevention of human immunodeficiency virus and herpes simplex virus

Topical microbicides, designed for vaginal or rectal administration, are needed to prevent human immunodeficiency virus (HIV) and other sexually transmitted infections (STI). Presently marketed topical microbicides are cytotoxic and damage the vaginal epithelium with frequent use. Rational development of new candidate compounds should build on knowledge of the pathways of microbial invasion. The establishment of assays and models that predict efficacy and safety is critical. Comprehensive pre-clinical evaluation of promising microbicides should include rigorous assessment of the effects of repeated application of topical agents on mucosal inflammatory cells, cytokines, and the genital tract virus population. These studies will lay the groundwork for future clinical trials.

Clinical care issues for women living with HIV and AIDS in the United States

As the number of women infected with HIV in the United States continues to increase, the medical community is faced with the challenge of providing adequate and appropriate care to them. This paper reviews key questions concerning the state of knowledge on the epidemiology, biology, and clinical care of women living with HIV and AIDS in the United States. Because heterosexual transmission accounts for a growing number of cases among women, biological factors and cofactors that may enhance women's susceptibility to HIV infection are also reviewed. HIV-related gynecological issues are presented separately to evaluate whether gynecological complications are distinct in HIV-uninfected and HIV-infected women. Questions of whether there are sex-specific differences in the efficacy and adverse effects of new antiviral agents are discussed. In addition, significant gaps are highlighted that still exist in our understanding of both the effects of HIV and HIV-related drugs upon pregnancy. Finally, the psychiatric stresses and complications that affect women living with HIV and AIDS are also discussed. In each section of this review, gaps in our knowledge of these issues are identified. To properly address these disparities in knowledge, not only do efforts to gather sex-specific biomedical data need to be more exacting, but there is a distinct need to conduct more sex-specific research concerning HIV.

Detection and quantitation of human immunodeficiency virus type 1 in the female genital tract. The Division of AIDS Treatment Research Initiative 009 Study Group

Human immunodeficiency virus type 1 (HIV-1) was detected in the genital tracts of 59% of 225 women by RNA PCR and in 7% of the women by culture. In a comparison of two sampling methods, endocervical swabs were more sensitive than cervicovaginal lavage for HIV-1 RNA detection by PCR but not by culture and their sensitivity was independent of the concentration of HIV-1 RNA.

Effect of menstrual cycle on HIV-1 levels in the peripheral blood and genital tract. WHS 001 Study Team

OBJECTIVE

To assess the variation in HIV-1 over the menstrual cycle, including RNA levels in the female genital tract, plasma HIV-1-RNA levels, CD4 cell counts, and culturable virus.

DESIGN

A prospective analysis of 55 HIV-1-infected women.

METHODS

Blood and genital tract specimens were collected weekly over 8 weeks, spanning two complete menstrual cycles. Applying repeated-measures models that used menses as the reference level, the variation in viral RNA levels was compared in endocervical canal fluid and cells (collected by Sno-strips and cytobrush, respectively) and ectocervicovaginal lavage (CVL) fluid. Repeated-measures models were also used to assess the variation in plasma CD4 cell counts and viral load.

RESULTS

Shedding patterns differed among the three sampling methods, independent of genital tract co-infections. Genital tract HIV-1-RNA levels from CVL fluid and endocervical canal cytobrush specimens were highest during menses and lowest immediately thereafter (P = 0.001 and P = 0.04). The HIV-1-RNA level in endocervical canal fluid was highest in the week preceding menses (P = 0.003). The menstrual cycle had no effect on blood levels of RNA (P = 0.62), culturable virus (P = 0.34), or CD4 cell counts (P = 0.55). HIV-1-RNA levels were higher in endocervical canal fluid than in peripheral blood plasma during the late luteal phase (P = 0.03).

CONCLUSION

HIV-1-RNA levels vary with the menstrual cycle in the female genital tract but not the blood compartment. HIV-1-RNA levels are higher in endocervical canal fluid than in blood plasma. These findings may have important implications for sex-specific pathogenesis, heterosexual transmission, and contraceptive hormone interventions in HIV-1-infected women.

Effect of coinfection with STDs and of STD treatment on HIV shedding in genital-tract secretions: systematic review and data synthesis

OBJECTIVE

To determine whether coinfection with sexually transmitted diseases (STD) increases HIV shedding in genital-tract secretions, and whether STD treatment reduces this shedding.

DESIGN

Systematic review and data synthesis of cross-sectional and cohort studies meeting predefined quality criteria.

MAIN OUTCOME MEASURES

Proportion of patients with and without a STD who had detectable HIV in genital secretions, HIV load in genital secretions, or change following STD treatment.

RESULTS

Of 48 identified studies, three cross-sectional and three cohort studies were included. HIV was detected significantly more frequently in participants infected with Neisseria gonorrhoeae (125 of 309 participants, 41%) than in those without N gonorrhoeae infection (311 of 988 participants, 32%; P = 0.004). HIV was not significantly more frequently detected in persons infected with Chlamydia trachomatis (28 of 67 participants, 42%) than in those without C trachomatis infection (375 of 1149 participants, 33%; P = 0.13). Median HIV load reported in only one study was greater in men with urethritis (12.4 x 104 versus 1.51 x 104 copies/ml; P = 0.04). In the only cohort study in which this could be fully assessed, treatment of women with any STD reduced the proportion of those with detectable HIV from 39% to 29% (P = 0.05), whereas this proportion remained stable among controls (15-17%). A second cohort study reported fully on HIV load; among men with urethritis, viral load fell from 12.4 to 4.12 x 104 copies/ml 2 weeks posttreatment, whereas viral load remained stable in those without urethritis.

CONCLUSION

Few high-quality studies were found. HIV is detected moderately more frequently in genital secretions of men and women with a STD, and HIV load is substantially increased among men with urethritis. Successful STD treatment reduces both of these parameters, but not to control levels. More high-quality studies are needed to explore this important relationship further.

Quantitative assessment of cell-associated and cell-free virus in cervicovaginal samples of HIV-1-infected women

OBJECTIVE

To examine the amount of cell-free and cell-associated virus in cervicovaginal secretions (CVS) of HIV-infected women.

METHODS

Paired cervicovaginal and blood samples from 61 seropositive women were quantitatively evaluated by competitive polymerase chain reaction (cPCR) and reverse transcription-PCR (cRT-PCR) for: (1) genomic RNA from plasma and cell-free CVS, and (2) unspliced (u/s) RNA transcripts and proviral DNA in cells from secretions.

RESULTS

HIV DNA was detected in 42.6%, u/s transcripts in 32.7% and cell-free HIV RNA in 31.1% of 61 cervicovaginal samples. The median copy numbers of HIV DNA, u/s transcripts, and cell-free RNA were 125 copies/10(5) cells, 40 copies/10(5) cells, and 300 copies/mL of secretion, respectively. Nineteen of 26 (73.1%) and 17 of 26 (65.3%) women positive for DNA were also positive for RNA transcripts and cell-free RNA, respectively (P<0.001). A significant correlation between the amounts of cell-free and u/s transcripts was also found (Spearman Rho 0.618, P=0.014). The prevalences of u/s transcripts and cell-free RNA were 42.6% and 53.8% respectively among patients with detectable blood RNA, and 22.9% (P=0.09) and 14.3% (P=0.0017) among patients with undetectable blood RNA. In stepwise logistic regression, cell-free RNA was independently associated with the presence of detectable blood viremia. The amount of HIV DNA was lower among subiects currently under treatment (50 copies/10(5) cells) than in untreated subjects (250 copies/10(5) cells) (P=0.037).

CONCLUSIONS

Both cell-free and cell-associated HIV could be detected and quantitated in CVS, providing a means to examine the level of viral activity in the female genital tract.

Detection of simian immunodeficiency virus Gag-specific CD8(+) T lymphocytes in semen of chronically infected rhesus monkeys by cell staining with a tetrameric major histocompatibility complex class I-peptide complex

Evaluation of human immunodeficiency virus type 1-specific mucosal cytotoxic T lymphocytes can be hampered by limited cell yields from mucosal sites. We sought to characterize virus-specific CD8(+) T lymphocytes with cytotoxic activity in the male genital tracts of SIVmac-infected rhesus monkeys by using a peptide epitope-specific functional T-cell assay and a tetrameric major histocompatibility complex class I-peptide complex. This tetrameric complex was constructed with the rhesus monkey HLA-A homolog molecule Mamu-A*01 and a dominant-epitope 9-amino-acid fragment of SIVmac Gag (p11C, C-M). The proportion of tetramer-positive CD8(+) T cells in semen of SIVmac-infected monkeys ranged from 5.9 to 22.0%. By the use of a standard 51Cr release assay, these cells were found to have peptide epitope-specific cytolytic activity after in vitro expansion. Four-color flow-cytometric analysis of these seminal tetramer-positive CD8(+) T cells demonstrated that they express memory-associated (CD62L- CD45RA-) and activation-associated (CD11a+ Fas+ HLA-DR+) molecules. The present experiments illustrate the power of tetramer technology for evaluating antigen-specific CD8(+) T lymphocytes in a mucosal tissue compartment.

Timing of human immunodeficiency virus type 1 (HIV-1) transmission from mother to child: bayesian estimation using a mixture

The timing of mother-to-child HIV transmission is not directly observable but influences the infected child's viral and immune status in the neonatal period. A hierarchical model was developed in a Bayesian framework to 'back-calculate' the timing of HIV-1 transmission from mother to child from the virological and immunological kinetics in the infected infant. Joint evolution of viral markers and immune response was modelled as a continuous time Markov process. The modelling of the period from infection to birth was based on a mixture of three distributions taking into account the various mother-to-child transmission pathways: In utero (early or late in gestation) and intrapartum (during the delivery process), integrating the fact that transmission is a continuum during the pregnancy. Gibbs sampling was used to estimate the marginal posterior distributions of the transition intensities between stages of HIV infection and those of the individual times from infection to birth. We applied our model to data on 135 perinatally HIV-1-infected children included in the French Prospective Study on Pediatric HIV infection. The model suggested that transmission occurred late in utero during the last month of pregnancy and that the day of delivery was a particularly critical time in HIV-1 transmission from mother to child. The paper ends with a discussion of model assumptions and a comparison with results obtained using a non-parametric method.

Sexual and mother-to-child transmission of the human immunodeficiency virus type 1: a review

PROBLEM

Sexual and mother-to-child transmission of the human immunodeficiency virus (HIV) type 1 occurs only with a low percentage of infection. Many instances of sexual intercourse result in no transmission, and only 20% of children are infected from seropositive mothers (3% in mothers treated with azidothymidine).

METHOD OF STUDY

We analyzed the presence of HIV in various ejaculates of the same HIV-infected patients, as well as in the cervico-vaginal fluid. We have studied the mechanism of transmission from mother to child, by analyzing the cell-to-cell transmission in the trophoblast.

RESULTS

Some ejaculates collected at different times from the same HIV-infected males are free of virus, explaining the low rate of sexual transmission. We never found HIV in mobile spermatozoa. The trophoblast can be infected by HIV with a strain dependence and also transiently. By analyzing the tissue of the fetus, it was found that only some organs are infected, confirming the cell-to-cell transmission between the mother and child and not a true vertical transmission through the germinal lines.

CONCLUSIONS

HIV is not always present in the genital secretion, explaining the low rate of sexual transmission. Mother-to-child transmission occurs during pregnancy but often after the second trimester and at delivery after cell-to-cell or blood transmission, respectively.

Mucosal transmission of pathogenic CXCR4-utilizing SHIVSF33A variants in rhesus macaques

Infection of macaques with chimeric simian/human immunodeficiency virus (SHIV) expressing the envelope protein of HIV-1 provides a model system for studying HIV-1 infection in humans. To this end, four rhesus macaques (Macaca mulatta) were given a single intravaginal (IVAG) inoculation of cell-free SHIVSF33A and longitudinal samples of peripheral blood and lymph nodes were analyzed for viremia, antigenemia, and various T-cell populations. Rhesus macaques infected IVAG with SHIVSF33A demonstrated a dramatic decrease in the CD4(+) PBMC subset in the initial weeks after viral exposure, a time that corresponded to peak in plasma viremia and antigenemia. Within 4 months of SHIVSF33A inoculation, partial to complete rebound of the CD4(+) PBMC was seen in these animals. Notably, the regeneration of the CD4(+) subset was associated with regeneration of the naive T-cell population and was concordant with clearance of plasma viremia. DNA heteroduplex tracking assays revealed transmission of minor variants within the SHIVSF33A inoculum to the IVAG-inoculated animals. The cell-free SHIVSF33A inoculum as well as virus isolated from animals early after transmission used the chemokine molecule CXCR4 as the primary cellular coreceptor, demonstrating that viruses expressing envelope glycoproteins of the syncytia inducing (SI) phenotype can be transported across the vaginal mucosa. Although none of the animals has yet to develop clinical symptoms of simian AIDS (SAIDS), infectious virus and viral nucleic acids could be persistently isolated from each animal. Furthermore, animals transfused with blood from IVAG-infected macaques drawn 2 weeks after inoculation suffered a more profound and sustained CD4(+) T-cell loss, persistent plasma viremia, and the development of SAIDS in one animal, indicating that IVAG-passaged SHIVSF33A was pathogenic. Taken together, these results establish that a pathogenic CXCR4-utilizing SHIVSF33A species crossed the cervicovaginal mucosa. Different courses of infection in the IVAG versus transfusion animals suggest that host-mediated responses elicited upon transmission across mucosal barriers may serve to limit viral replication and delay disease progression in the IVAG-infected animals.

Efficient isolation of human immunodeficiency virus type 1 RNA from cervical swabs

An efficient method for the isolation of human immunodeficiency virus type 1 (HIV-1) nucleic acids from dry cervical swabs was developed. HIV-1 gag and env were detected in 96% (25 of 26) and 81% (21 of 26), respectively, of the samples tested by PCR from HIV-1-seropositive women in a Kenyan cohort study. Eighty-eight percent of the swabs (22 of 25) were positive for gag RNA, and 85% (17 of 20) were positive for env RNA. Fewer than 1,000 copies of HIV-1 gag RNA were detected in four swabs in which a competitive quantitative PCR assay was used. The method described here may be useful for both qualitative and quantitative analyses of HIV RNA in mucosal secretions as well as amplification and cloning of full-length viral genes for functional studies.

HIV quantitation in spiked vaginocervical secretions: lack of non-specific inhibitory factors. DATRI 005 Study Team. Division of AIDS Treatment Research Initiative

The objective of this study was to assess the effect of menstrual phase on the ability to quantitate HIV-1 in vaginocervical secretions (VCS) through reconstruction experiments with HIV seronegative VCS collected throughout the menstrual cycle. Measurement of HIV-1 inoculated into both fresh and frozen VCS was undertaken by quantitative micro co-culture, p24 antigen assay and polymerase chain reaction (PCR) for both HIV-1 RNA and pro-viral DNA. Two laboratories carried out these assays over a range of viral concentrations. The study involved a randomized factorial design and the factors were: (1) diluents (phases of the menstrual cycle and controls); (2) laboratories; (3) stock concentrations; and (4) frozen versus fresh VCS samples. Each assay was assessed independently using a random effects analysis of variance (ANOVA) model. No statistical differences due to menstrual cycle were seen in the assay results of p24 antigen (P = 0.08), PBMC culture (P = 0.74), plasma culture (P = 0.13), cell-free RNA (P = 0.44), cell-associated RNA (P = 0.58) and cell-associated DNA (P = 0.43). Inter-laboratory differences were statistically significant for cell-free RNA (P < 0.001), cell-associated DNA (P < 0.001) and p24 (P < 0.001). It is concluded that VCS obtained throughout the menstrual cycle from HIV-uninfected women lacks intrinsic inhibitory factors which could limit detection and quantification by antigen, culture or nucleic acid-based technologies for HIV-1 in VCS throughout the menstrual cycle. Using a standardized collection procedure, we suggest that variation in HIV quantity over time, when reported in VCS of infected women, should be attributed to HIV-associated biologic factors, rather than non-specific or other technical factors.

Changes to the cytokine microenvironment in the genital tract mucosa of HIV+ women

As previous studies have indicated that genital tract mucosal T cell function may be impaired in HIV infection, we investigated the T cell cytokine mRNA in the genital tract mucosa of HIV-infected women to determine if there are alterations in the cytokine profile which may explain the T cell impairment. The in situ hybridization technique was used to investigate the T helper-1 (Th1: IL-2, interferon-gamma (IFN-gamma)) and Th2 cytokine (IL-4, IL-5, IL-10) mRNA profile in cervical biopsies from 10 HIV+ and 10 HIV- subjects. Cervical intraepithelial neoplasia (CIN) and genital infection had previously been excluded and the distribution of immunocompetent cells within the cervical mucosa was known for each subject. Non-parametric tests were used to compare the optical density (OD) of cytokine mRNA in the HIV+ and HIV- groups. Comparisons were also made between peripheral CD4 lymphocyte counts, cervical CD4/CD8 T lymphocyte ratios and cytokine mRNA OD in HIV+ subjects. The HIV+ women had significantly higher mRNA OD for the Th2 cytokines IL-4, IL-5 and IL-10 than HIV women. There was also significantly lower IL-2 mRNA OD in the former group. HIV+ women had lower IFN-gamma mRNA than HIV- women, but the difference was not statistically significant. There was no correlation between cytokine mRNA OD and peripheral CD4 count or cervical CD4/CD8 ratio. The predominance of Th2 cytokines, which are immuno-inhibitory, in the cervical mucosa of HIV+ women may underlie the impaired cytotoxic potential observed in the CD8+ T lymphocytes and may contribute to the susceptibility of HIV-infected women to recurrent genital tract infections and cervical neoplasia.

Differential tropism and chemokine receptor expression of human immunodeficiency virus type 1 in neonatal monocytes, monocyte-derived macrophages, and placental macrophages

Laboratory-adapted (LA) macrophage-tropic (M-tropic) human immunodeficiency virus type 1 (HIV-1) isolates (e.g., HIV-1(Ba-L)) and low-passage primary (PR) isolates differed markedly in tropism for syngeneic neonatal monocytes, monocyte-derived macrophages (MDMs), and placental macrophages (PMs). Newly adherent neonatal monocytes and cultured PMs were highly refractory to infection with PR HIV-1 isolates yet were permissive for LA M-tropic isolates. Day 4 MDMs were also permissive for LA M-tropic isolates and additionally, were permissive for over half the PR isolates tested. Qualitative differences in PR HIV-1 infection of monocytes/MDMs could not be correlated with CD4 levels alone, and in all three cell types the block to PR HIV-1 strain replication preceded reverse transcription. Neonatal monocyte susceptibility to PR HIV-1 strains correlated with increasing CCR-5 expression during maturation. CCR-5 could not be detected on newly adherent (day 1) neonatal monocytes, in contrast to adult monocytes (H. Naif et al., J. Virol. 72:830-836, 1998), but was readily detectable after 4 to 7 days of culture. However, moderate CCR-5 mRNA levels were present in day 1 neonatal monocytes and remained constant during monocyte maturation. CCR-5 was not detectable on the surface of PMs, yet the receptor was present within permeabilized cells. Notably, two brain-derived PR HIV-1 isolates from a single patient, differing in their V3 loops, were discordant in their abilities to infect neonatal monocytes/MDMs and PMs, yet both isolates could infect newly adherent adult monocytes. Together these data strongly suggest that LA HIV-1 isolates are able to infect neonatal monocytes at earlier stages of maturation and lower-level expression of CCR-5 than PR isolates. The differences between neonatal and adult monocytes in susceptibility to PR isolates may also be related to the level of CCR-5 expression.

Oral sex and the transmission of viral STIs

OBJECTIVE

To review the literature on the role of oral sex in the transmission of viral sexually transmitted infections (STIs).

METHOD

A Medline search was performed using the keywords oro-genital sex, and those specific to each infection. Further references from each article identified by Medline were also included, as were relevant references from "Current contents".

CONCLUSIONS

Oral sex is a common sexual practice among both heterosexual and homosexual couples. The evidence suggests that HIV transmission can take place through oro-genital sex from penis to mouth and vagina to mouth. Case reports describe apparent transmission from mouth to penis although this appears less likely. The risk of oro-genital transmission of HIV is substantially less than from vaginal and anal intercourse. Receptive oro-genital sex carries a small risk of human papillomavirus infection and possibly hepatitis C, while insertive oro-genital contact is an important risk factor for acquisition of HSV 1. Oro-anal transmission can occur with hepatitis A and B. The transmission of other viruses may occur but is unproved. The relative importance of oral sex as a route for the transmission of viruses is likely to increase as other, higher risk sexual practices are avoided for fear of acquiring HIV infection.

Variation in virological parameters and antibody responses in macaques after atraumatic vaginal exposure to a pathogenic primary isolate of SIVmac251

We developed an animal model for the male-to-female transmission of human immunodeficiency virus, consisting of an atraumatic vaginal application of simian immunodeficiency virus onto the intact vaginal mucosa of cynomolgus macaques. Different doses of a pathogenic isolate of SIVmac251, with or without seminal plasma, were infused into the vaginas of female macaques. Infection of macaques could be achieved after a single exposure to the virus. Two patterns of infection were underscored with no relation to the virus dose inoculated: in 50% of the monkeys, SIV was persistently recovered and a strong antibody response to SIV was evidenced in blood and vaginal secretions. In the other infected animals, SIV infection was only transiently evidenced and a weak systemic antibody response was detected. It appeared that the presence of seminal plasma may be implicated in this variability only when low doses of virus are inoculated. Sequence analysis of the env gene of SIV revealed that most of the persistently viraemic animals were infected with a viral variant different from that of transiently viraemic macaques.

Hormonal contraception, vitamin A deficiency, and other risk factors for shedding of HIV-1 infected cells from the cervix and vagina

BACKGROUND

Factors that influence shedding of HIV-1 infected cells in cervical and vaginal secretions may be important determinants of sexual and vertical transmission of the virus. We investigated whether hormonal contraceptive use, vitamin A deficiency, and other variables were risk factors for cervical and vaginal shedding of HIV-infected cells.

METHODS

Between December, 1994, and April, 1996, women who attended a municipal sexually transmitted diseases (STDs) clinic in Mombasa, Kenya, and had previously tested positive for HIV-1, were invited to take part in our cross-sectional study. Cervical and vaginal secretions from 318 women were evaluated for the presence of HIV-1 infected cells by PCR amplification of gag DNA sequences.

FINDINGS

HIV-1 infected cells were detected in 51% of endocervical and 14% of vaginal-swab specimens. Both cervical and vaginal shedding of HIV-1 infected cells were highly associated with CD4 lymphocyte depletion (p = 0.00001 and p = 0.003, respectively). After adjustment for CD4 count, cervical proviral shedding was significantly associated with use of depot medroxyprogesterone acetate (odds ratio 2.9, 95% CI 1.5-5.7), and with use of low-dose and high-dose oral contraceptive pills (3.8, 1.4-9.9 and 12.3, 1.5-101, respectively). Vitamin A deficiency was highly predictive of vaginal HIV-1 DNA shedding. After adjustment for CD4 count, severe vitamin A deficiency, moderate deficiency, and low normal vitamin A status were associated with 12.9, 8.0, and 4.9-fold increased odds of vaginal shedding, respectively. Gonococcal cervicitis (3.1, 1.1-9.8) and vaginal candidiasis (2.6, 1.2-5.4) were also correlated with significant increases in HIV-1 DNA detection, but Chlamydia trachomatis and Trichomonas vaginalis were not.

INTERPRETATION

Our study documents several novel correlates of HIV-1 shedding in cervical and vaginal secretions, most notably hormonal contraceptive use and vitamin A deficiency. These factors may be important determinants of sexual or vertical transmission of HIV-1 and are of public health importance because they are easily modified by simple interventions.

Detection of human immunodeficiency virus type 1 and type 2 in the female genital tract: implications for the understanding of virus transmission

Risk of perinatal or female to male sexual transmission of HIV is likely to be associated with whether, and at what concentration, the virus is present in the cervical and vaginal secretions of the HIV-infected woman. Examining correlates of cervical and vaginal HIV shedding is, therefore, essential for the development of strategies to interrupt HIV transmission. This article presents the rationale for using detection of HIV in the female genital tract as a marker of infectivity, and briefly describes methods for detecting HIV-1 and HIV-2 in cervical or vaginal fluids. Findings from studies incorporating the measurement of HIV in the female genital tract are reviewed, placing particular emphasis on issues relevant to epidemiological studies of HIV transmission.

Inflammatory cytokine expression is correlated with the level of human immunodeficiency virus (HIV) transcripts in HIV-infected placental trophoblastic cells

The inflammatory cytokines interleukin-1beta (IL-1beta), IL-6, and tumor necrosis factor alpha (TNF-alpha) have been associated with increased human immunodeficiency virus (HIV) expression and enhanced lymphocyte adhesion to trophoblastic cells in experimental systems. To determine if there is a correlation between the expression of these cytokines and the levels of HIV transcripts in trophoblasts of term placentas from HIV-infected women, we studied the placentae of 30 HIV-positive and 13 control gravidae. Twenty-three of the HIV-positive women received zidovudine (ZDV) as prophylaxis against HIV vertical transmission; only one of the seven women who did not receive ZDV was a transmitter, for an overall vertical transmission rate of 3.8%. Cytokine production was measured by enzyme-linked immunosorbent assay in the supernatants of trophoblastic cell cultures. Additionally, cytokine transcripts and HIV gag sequences were determined by a quantitative reverse transcription-PCR assay. In general, trophoblastic cells of HIV-positive placentas expressed significantly higher levels of IL-1beta, IL-6, and TNF-alpha than those of control placentas. All placentas from HIV-positive women expressed HIV gag transcripts at either a low (<156 copies per microg of total RNA) or a high (>156 copies per microg of total RNA) level. There was a statistically significant positive association between the basal level of TNF-alpha production and the level of HIV gag transcripts of HIV-positive placental trophoblastic cells. Nevertheless, these data, coupled with a low transmission rate, would indicate that some other factors, perhaps working in concert with cytokines, are necessary for vertical transmission of HIV from mother to infant.

HIV risk assessment and prevention in lesbians and women who have sex with women: practical information for clinicians

Clinicians care for lesbians and women sexually active with women (WSWs) routinely in the course of practice. The Centers for Disease Control and Prevention now believe that there are small but significant numbers of lesbians with HIV infection and that woman-to-woman transmission of HIV is possible. Although the risk of HIV transmission between women, although underreported, is probably low, clinicians need a literature-based practical understanding of how to assess WSWs for their HIV risk and counsel them appropriately about prevention of HIV transmission. Understanding sexual behaviors of WSWs the safer sex techniques that are appropriate for them, and the various ways in which lesbians may contract HIV are important to all primary care clinicians. This article also reviews the principles of communicating with lesbians and WSWs.

Lymphocyte shedding from genital tract of human immunodeficiency virus-infected women: immunophenotypic and clinical correlates

OBJECTIVE

Our purpose was to describe the lymphocyte subpopulations in genital tract samples from human immunodeficiency virus-infected women and the clinical correlates associated with lymphocyte shedding.

STUDY DESIGN

Genital tract samples of women infected with human immunodeficiency virus-1 were processed for immunophenotyping analysis with a FACScan flow cytometer. Immunologic and virologic characteristics of women with and without lymphocyte shedding were compared with t test, Wilcoxon rank test, or Fisher's exact test.

RESULTS

The rate of genital lymphocyte shedding among human immunodeficiency virus-1-infected women was 39%. Genital shedding was not related to age, race, use of antiretroviral therapy, or positive human immunodeficiency virus-1 culture. A negative rank correlation (r = -0.71, p = 0.047) between CD3+ CD4+ counts in peripheral blood and genital tract was observed. The majority of the lymphocyte cells were CD3+ CD8+, and > 80% of the CD3+ CD4+ cells were memory cells.

CONCLUSION

The immune profile of the genital tract lymphocytes is suggestive of a local mucosal immune response.

Genital shedding of human immunodeficiency virus type 1 DNA during pregnancy: association with immunosuppression, abnormal cervical or vaginal discharge, and severe vitamin A deficiency

The presence of human immunodeficiency virus type 1 (HIV-1) in genital secretions may be a determinant of vertical HIV-1 transmission. Cervical and vaginal secretions from HIV-1-seropositive pregnant women were evaluated to determine prevalence and correlates of HIV-1-infected cells in the genital tract. HIV-1 DNA was detected by polymerase chain reaction in 32% of 212 cervical and 10% of 215 vaginal specimens. Presence of HIV-1 DNA in the cervix was associated with cervical mucopus and a significantly lower absolute CD4 cell count (354 vs. 469, P < .001). An absolute CD4 cell count <200 was associated with a 9.6-fold increased odds of cervical HIV-1 DNA detection compared with a count > or = 500 (95% confidence interval, 2.8-34.2). Detection of vaginal HIV- 1 DNA was associated with abnormal vaginal discharge, lower absolute CD4 cell count, and severe vitamin A deficiency. Presence of HIV-1-infected cells in genital secretions was associated with immunosuppression and abnormal cervical or vaginal discharge.

Antibodies to human herpesvirus type 8 in the general population and in Kaposi's sarcoma patients

BACKGROUND

Much of the evidence that human herpesvirus type 8 (HHV-8) is associated with Kaposi's sarcoma (KS) has come from molecular studies of HHV-8 DNA. Seroepidemiological studies have been hampered by the lack of a reliable assay.

METHODS

The serological data reported here were obtained by means of a mouse monoclonal antibody-enhanced immunofluorescence assay for antibodies to lytic and latent HHV-8 antigens. 1435 single samples of serum (or plasma) from many different disease groups and parts of the world were assayed.

FINDINGS

All patients with African endemic KS and 96% of American patients with AIDS-associated KS were seropositive for lytic antigen, as were 90% of American HIV-infected homosexual men; by contrast only 23% of HIV-seropositive drug users and 21% of HIV-seropositive women were positive for HHV-8 antibody. Factor VIII treatment before 1983 did not increase the risk of HHV-8 infection in patients with haemophilia. In the American general population, about 25% of adults (including volunteer blood donors) and 2-8% of children had antibodies to HHV-8.

INTERPRETATION

Our data are consistent with HHV-8 being primarily associated with sexual transmission, but the HHV-8 seropositivity rate in American children suggests that there is a non-sexual route of HHV-8 infection also. On the evidence available so far, the risk of parenteral transmission is low.

Presence of cell-free human immunodeficiency virus in cervicovaginal secretions is independent of viral load in the blood of human immunodeficiency virus-infected women

OBJECTIVE

The purpose of this study was to establish virologic or molecular criteria for evaluating the rate of transmission of human immunodeficiency virus type 1 and for defining the role of virus burden in the development of gynecologic diseases in human immunodeficiency virus-infected women.

STUDY DESIGN

Paired samples of blood and cervicovaginal secretions from 63 human immunodeficiency virus-seropositive women were evaluated for cell-free and cell-associated virus load by several methods, including quantitative cultures and reverse transcription polymerase chain reaction.

RESULTS

All women showed evidence of virus infection in both blood and cervicovaginal secretions by a combination of in vitro culture and molecular detection methods. The CD4+ cell counts in these women ranged from < 200/microliter to > 500/microliter. Blood plasma of 26% women (12/46) did not show detectable levels of human immunodeficiency virus ribonucleic acid by reverse transcription polymerase chain reaction (< 10(2)/100 microliters). These same women had significant amounts of human immunodeficiency virus in the cell-free cervicovaginal secretions (10(2) to 10(5) copies per 100 microliters). In contrast, 17% (8/46) women with significant quantity of human immunodeficiency virus ribonucleic acid in the blood plasma had negative results for human immunodeficiency virus in the cervicovaginal secretions. Further, treatment of women with the antiviral drug zidovudine did not change the human immunodeficiency virus-1 detection rate in plasma ribonucleic acid but showed significant reduction in the ability to detect human immunodeficiency virus ribonucleic acid in cell-free cervicovaginal secretions (p = 0.036).

CONCLUSIONS

We conclude that the replication kinetics of human immunodeficiency virus in the blood and cervicovaginal cells are unrelated, independent events. Further, there is no correlation between the virus load or the CD4+ cell counts in the blood and the presence or absence of quantifiable human immunodeficiency virus in cervicovaginal secretions.

Distinct but related human immunodeficiency virus type 1 variant populations in genital secretions and blood

For a HIV vaccine to be effective, it will be essential that it protect against the virus variants to which individuals are most frequently exposed. HIV-1 is predominantly a sexually acquired virus, thus, variants in genital secretions are a potentially important reservoir of viruses that are transmitted. Because there are no data available on variants in the genital mucosa, we analyzed this provirus population and compared it to the proviruses in the blood of individuals chronically infected with HIV-1. A major genetic difference between variants within a patient were insertions, which were apparently created by duplication of adjacent sequences, that resulted in acquisition of new potential glycosylation sites in V1 and V2. Comparisons of mucosal and PBMC variants suggest that these tissues harbor distinct, but related populations of HIV-1 variants. In two of three patients, the mucosal variants were most closely related to a minor variant genotype in blood. In a third individual, viruses in both tissues were surprisingly homogeneous, but the majority of variants in the cervix encoded a V1 sequence with a predicted glycosylation pattern similar to a minor variant in blood. The V3 sequence patterns of the mucosal isolates indicate they may be predominantly macrophage-tropic viruses.

Women, contraception and STDs including HIV

It is estimated that eight million women are infected with the human immunodeficiency virus (HIV) worldwide. Heterosexual transmission is the predominant mode of HIV transmission on a global basis and is becoming increasingly important in the Western world. Women have long used contraceptives as a means of protection against an unwanted pregnancy, some of which may also protect against sexually transmitted disease (STD) including HIV. We review the relationship between contraceptive methods and STD acquisition and transmission; HIV acquisition and transmission; and the implications of contraceptive use, particularly regarding disease progression, in those women who are already infected with the virus. It is important for all women that protection against both unwanted pregnancy and HIV acquisition and transmission are considered together and not in isolation as nowhere is the argument for a broad based multi-disciplinary approach more cogent.

Crack, crack house sex, and HIV risk

Limited attention has been focused on HIV risk behaviors of crack smokers and their sex partners, yet there is evidence that the crack house and the crack-using life-style may be playing significant roles in the transmission of HIV and other sexually transmitted diseases. The purposes of this research were to study the attributes and patterns of "sex for crack" exchanges, particularly those that occurred in crack houses, and to assess their potential impact on the spread of HIV. Structured interviews were conducted with 17 men and 35 women in Miami, Florida, who were regular users of crack and who had exchanged sex for crack (or for money to buy crack) during the past 30 days. In addition, participant observation was conducted in 8 Miami crack houses. Interview and observational data suggest that individuals who exchange sex for crack do so with considerable frequency, and through a variety of sexual activities. Systematic data indicated that almost a third of the men and 89% of the women had had 100 or more sex partners during the 30-day period prior to study recruitment. Not only were sexual activities anonymous, extremely frequent, varied, uninhibited (often undertaken in public areas of crack houses), and with multiple partners but, in addition, condoms were not used during the majority of contacts. Of the 37 subjects who were tested for HIV and received their test results 31% of the men and 21% of the women were HIV seropositive.

AIDS-like disease following mucosal infection of pig-tailed macaques with SIVsmmPBj14

Following exposure of the rectal or vaginal mucosa to cell-free SIVsmmPBj14, four male and two female pig-tailed macaques developed a characteristic acute disease, including mucoid diarrhea, lymphopenia, and anorexia. Two macaques infected by the rectal route died within 14 days, and one female died of an AIDS-like disease at five months after inoculation. The three other animals have survived more than nine months, but all are exhibiting lymphadenopathy, thrombocytopenia, and progressive declines in percentages and numbers of CD4+ lymphocytes.

Birth order, delivery route, and concordance in the transmission of human immunodeficiency virus type 1 from mothers to twins. International Registry of HIV-Exposed Twins

BACKGROUND

We evaluated data from prospectively identified twins to understand better the mechanisms and covariates of mother-to-infant transmission of human immunodeficiency virus (HIV).

METHODS

Using data obtained from an international collaboration and multivariate quasilikelihood modeling, we assessed concordance, birth order, route of delivery, and other factors for HIV infection in 115 prospectively studied twin pairs born to HIV-infected women. Actuarial methods were used to evaluate overall survival and survival free of acquired immunodeficiency syndrome for HIV-infected twins.

RESULTS

Infection with HIV occurred in 35% of vaginally delivered firstborn (A) twins, 16% of cesarean-delivered A twins, 15% of vaginally delivered second-born (B) twins, and 8% of cesarean-delivered B twins. In a multivariate model, the adjusted odds ratios for HIV infection were 11.8 (confidence interval: 3.1 to 45.3) for concordance of infection with the co-twin, 2.8 (confidence interval: 1.6 to 5.0) for A versus B twins, and 2.7 (confidence interval: 1.1 to 6.6) for vaginally delivered versus cesarean-delivered twins. Among A twins, 52% (lower confidence limit: 6%) of the transmission risk was related to vaginal delivery. Comparing vaginally delivered A twins (infants most exposed to vaginal mucus and blood) to cesarean-delivered B twins (infants least exposed), 76% (lower confidence limit: 48%) of the transmission risk was related to vaginal exposure. Infected B twins had slightly reduced Quetelet indexes and more rapid development of illnesses related to acquired immunodeficiency syndrome.

CONCLUSIONS

These results indicate that HIV infection of B twins occurs predominantly in utero, whereas infection of A twins (and, by implication, singletons) occurs predominantly intrapartum. We propose that intrapartum transmission is responsible for the majority of pediatric HIV infections and that reducing exposure to HIV in the birth canal may reduce transmission of the virus from mother to infant.

Aids em crianças: considerações sobre a transmissão vertical

Trata-se de uma revisão sobre os aspectos epidemiológicos da síndrome de imunodeficiência adquirida em crianças e sobre a transmissão vertical do vírus da imunodeficiência humana (HIV). Discutem-se as diversas vias pelas quais o HIV pode transmitir-se de mãe para filho, abordando questões inerentes à fisiopatologia da infecção intra-útero, periparto e/ou pós-parto.