Is the clinical course of HIV-1 changing? Cohort study.

OBJECTIVE: To assess whether the clinical course of HIV infection has changed from 1985 to 1995. DESIGN: Cohort Study. SETTING: Infectious disease clinic. SUBJECTS: 285 patients recruited from September 1985 to January 1995 with < or = 12 months between the dates of their last seronegative and first seropositive test result and with first follow up visit in the six months after seroconversion and at least 12 months'' follow up. Patients were grouped according to the date of seroconversion. MAIN OUTCOME MEASURES: Time to CD4 cell count of < 500, 400, and 200 x 10(6) cells/l, and clinical outcome defining AIDS; variation in cell count per day between consecutive visits, and ratio between this variation and time from estimated date of seroconversion at each visit. RESULTS: The groups were similar in age, number with acute primary HIV infection, CD4 cell count at intake, and cell count at the beginning of antiretroviral treatment; they differed in sex ratio, risk factors for HIV, probability of CD4 cell decline to < 500, 400, and 200 x 10(6) cells/l. and risk of developing AIDS. Acute infection, seroconversion after December 1989, and serum beta 2 microglobulin > 296 nmol/l were independent predictors of poor clinical course. The speed of CD4 cell decline, expressed as cell variation divided by the number of days between consecutive visits, increased with more recent seroconversion (P = 0.02). Ratio between the speed of CD4 cell decline and time from estimated date of seroconversion at each visit was also higher in the patients who seroconverted after December 1989. CONCLUSIONS: The faster disease progression and the higher speed of CD4 cell decline at early stages in the patients with recently acquired HIV infection suggest changes in the clinical course of HIV infection.     

Altered EBV viral load setpoint after HIV seroconversion is in accordance with lack of predictive value of EBV load for the occurrence of AIDS-related non-Hodgkin lymphoma

In contrast to the situation in the post-transplant setting, in HIV-infected individuals an elevated EBV load is not predictive of EBV-related malignancies. To study whether a high EBV load is already a normal situation early in HIV infection and is not related to a decrease in immune function over time, we investigated EBV load and EBV-specific CD8(+) T cells approximately 1 year before and 1 year after HIV seroconversion. EBV load significantly increased after HIV seroconversion from 205 to 1002 copies/10(6) PBMC (p < 0.001), whereas no further increase in EBV load was observed between 1 and 5 years after HIV seroconversion (median, 1827-2478 copies/10(6) PBMC; p = 0.530). Interestingly, the absolute number of EBV lytic epitope, RAKFKQLL-specific CD8(+) T cells increased over HIV seroconversion (4.78 to 9.54/ micro l; p = 0.011). Furthermore, the fraction of CD27-negative effector, RAK-specific CD8(+) T cells tended to increase (from 12.2 to 17.31% CD27(-); p = 0.051), in accordance with Ag-driven differentiation. In conclusion, both virological and immunological data support the idea that a new EBV viral setpoint is reached early in HIV infection, probably by EBV reactivation, as suggested by the preferential increase in EBV lytic epitope-specific CD8(+) T cells. These data may thus help to explain the lack of predictive value of EBV load for the occurrence of AIDS-related lymphoma.     

Clinical course of primary HIV infection: consequences for subsequent course of infection.

OBJECTIVE--To investigate the impact of the clinical course of the primary HIV infection on the subsequent course of the infection. DESIGN--Prospective documenting of seroconversion, follow up at six month intervals, and analysis of disease progression by life tables. PATIENTS--86 Men in whom seroconversion occurred within 12 months. PRIMARY OUTCOME MEASURE--Progression of HIV infection, defined as CD4 lymphocyte count less than 0.5 X 10(9)/l, recurrence of HIV antigenaemia, or progression to Centers for Disease Control group IV. MAIN RESULTS--Median follow up was 670 (range 45-1506) days. An acute illness like glandular fever occurred in 46 (53%) subjects. Three year progression rates to Centers for Disease Control group IV was 78% at three years for those who had longlasting illnesses (duration greater than or equal to 14 days) during seroconversion as compared with 10% for those who were free of symptoms or had mild illness. All six patients who developed AIDS had had longlasting primary illnesses. Three year progression rates to a CD4 lymphocyte count less than 0.5 X 10(9)/l and to recurrence of HIV antigenaemia were significantly higher for those who had longlasting primary illnesses than those who had no symptoms or mild illness (75% v 42% and 55% v 14%, respectively). CONCLUSION--The course of primary infection may determine the subsequent course of the infection.     

Abundance of early functional HIV-specific CD8+ T cells does not predict AIDS-free survival time

Background

T-cell immunity is thought to play an important role in controlling HIV infection, and is a main target for HIV vaccine development. HIV-specific central memory CD8⁺ and CD4⁺ T cells producing IFNγ and IL-2 have been associated with control of viremia and are therefore hypothesized to be truly protective and determine subsequent clinical outcome. However, the cause-effect relationship between HIV-specific cellular immunity and disease progression is unknown. We investigated in a large prospective cohort study involving 96 individuals of the Amsterdam Cohort Studies with a known date of seroconversion whether the presence of cytokine-producing HIV-specific CD8⁺ T cells early in infection was associated with AIDS-free survival time.

Methods and Findings

The number and percentage of IFNγ and IL-2 producing CD8⁺ T cells was measured after in vitro stimulation with an overlapping Gag-peptide pool in T cells sampled approximately one year after seroconversion. Kaplan-Meier survival analysis and Cox proportional hazard models showed that frequencies of cytokine-producing Gag-specific CD8⁺ T cells (IFNγ, IL-2 or both) shortly after seroconversion were neither associated with time to AIDS nor with the rate of CD4⁺ T-cell decline.

Conclusions

These data show that high numbers of functional HIV-specific CD8⁺ T cells can be found early in HIV infection, irrespective of subsequent clinical outcome. The fact that both progressors and long-term non-progressors have abundant T cell immunity of the specificity associated with low viral load shortly after seroconversion suggests that the more rapid loss of T cell immunity observed in progressors may be a consequence rather than a cause of disease progression.     

An observational study on patients treated or not for acute HIV infection

BACKGROUND: A vast majority of HIV-infected subjects who experience HIV acute seroconversion actually receive treatment. Open questions are how can we identify patients who will be slow progressors or long-term non progressors, and, as a consequence, do not require treatment. METHODS: An observational retrospective study on patients who experienced acute HIV seroconversion from August 1995 to June 2001, who are still alive and followed as outpatients at the Clinic of Infectious Diseases of Modena, Italy. RESULTS: Twelve patients were studied. Five patients (45.4%) were treated during acute seroconversion, while 7 were not treated. Two of these seven subjects received antiretroviral treatment 12 and 26 weeks after acute seroconversion. All the untreated patients were in good viro-immunological condition 6 months after seroconversion, and 2 of them also after 3 and 7 years. Patients who were treated showed a significant daily increase in CD4/CD8 T cell ratio with longer time spent on therapy (0.04% increase per day longer on antiretroviral therapy, p=0.02). CONCLUSIONS: This study suggests that treatment during primary HIV infection should not be considered in all patients. Randomized clinical trials enrolling patients with an asymptomatic primary HIV infection, with a high CD4 count and low HIV plasma viremia are needed to evaluate the indications for treatment in this subgroup of patients. On the other hand, this study confirms the good viro-immunological response obtained after treating patients during primary HIV infection.     

D-Dimer Levels before HIV Seroconversion Remain Elevated Even after Viral Suppression and Are Associated with an Increased Risk of Non-AIDS Events

The mechanism underlying the excess risk of non-AIDS diseases among HIV infected people is unclear. HIV associated inflammation/hypercoagulability likely plays a role. While antiretroviral therapy (ART) may return this process to pre-HIV levels, this has not been directly demonstrated. We analyzed data/specimens on 249 HIV+ participants from the US Military HIV Natural History Study, a prospective, multicenter observational cohort of >5600 active duty military personnel and beneficiaries living with HIV. We used stored blood specimens to measure D-dimer and Interleukin-6 (IL-6) at three time points: pre-HIV seroconversion, ≥6 months post-HIV seroconversion but prior to ART initiation, and ≥6 months post-ART with documented HIV viral suppression on two successive evaluations. We evaluated the changes in biomarker levels between time points, and the association between these biomarker changes and future non-AIDS events. During a median follow-up of 3.7 years, there were 28 incident non-AIDS diseases. At ART initiation, the median CD4 count was 361cells/mm³; median duration of documented HIV infection 392 days; median time on ART was 354 days. Adjusted mean percent increase in D-dimer levels from pre-seroconversion to post-ART was 75.1% (95% confidence interval 24.6–148.0, p = 0.002). This increase in D-dimer was associated with a significant 22% increase risk of future non-AIDS events (p = 0.03). Changes in IL-6 levels across time points were small and not associated with future non-AIDS events. In conclusion, ART initiation and HIV viral suppression does not eliminate HIV associated elevation in D-dimer levels. This residual pathology is associated with an increased risk of future non-AIDS diseases.     

Progression of HIV disease in a haemophilic cohort followed for 11 years and the effect of treatment.

OBJECTIVE--To describe the progression of HIV disease in a haemophilic cohort and to show the influence of treatment. DESIGN--11 year longitudinal clinical and laboratory study. SETTING--A haemophilia centre. PATIENTS--111 patients infected with HIV during October 1979 to July 1985. MAIN OUTCOME MEASURES--Symptoms of HIV infection, AIDs, and death. INTERVENTIONS--26 asymptomatic patients started taking zidovudine or placebo (1000 mg/day) during November 1988 to February 1990; 10 patients with CD4+ counts of 0.2 x 10(9)/l started zidovudine 500 mg/day during January to November 1990. 35 patients used pentamidine for primary or secondary prophylaxis. RESULTS--At 11 years from seroconversion the estimated rate of progression to AIDS was 42% (95% confidence interval 27% to 57%); to symptoms 85% (75% to 95%); and to death 41% (25% to 57%). Progression to AIDS was significantly faster in patients aged 25 and over than in those aged less than 25 (relative risk 5.0 (2.4 to 10.4); p less than 0.00001) and in those with previous cytomegalovirus infection than in those not infected (relative risk 3.0 (1.4 to 6.8); p = 0.006). 16 of 27 (59%) patients with p24 antigenaemia developed AIDS compared with 17 of 84 (20%) patients without p24 antigen (p less than 0.001). The risk of progression to AIDS before 30 November 1988 in patients with CD4+ counts less than or equal to 0.2 x 10(9)/l was higher than after November 1988 (relative risk 1.9 (0.85 to 4.43); p = 0.1). For 1989 and 1990 the observed cumulative numbers of AIDS cases (among 81 patients with sufficient CD4+ counts) were 22 and 25 compared with 29 and 37 predicted from the rate of fall of CD4+ counts up to the end of 1988 (p = 0.03). CONCLUSION--Treatment seems to be reducing the progression of HIV disease in this haemophilic cohort.     

HIV disease progression in 854 women and men infected through injecting drug use and heterosexual sex and followed for up to nine years from seroconversion. Italian Seroconversion Study.

OBJECTIVE--To compare the progression of HIV-1 infection in men and women followed up for up to nine years after an accurately estimated date of seroconversion. DESIGN--Prospective observational study. SETTING--16 HIV outpatient clinics across Italy. SUBJECTS--321 women and 533 men infected with HIV through injecting drug use or heterosexual sex and with accurately estimated dates of seroconversion. MAIN OUTCOME MEASURES--Progression to severe CD4 lymphocytopenia (CD4 lymphocyte count < 200 x 10(6)/l), development of AIDS defining diseases, and death from AIDS. RESULTS--Thirty two women and 67 men developed AIDS at Kaplan-Meier progression rates of 25% (95% confidence interval 13.8% to 35.5%) and 23% (15.6% to 30.4%), respectively, 7 years after seroconversion. In a Cox proportional hazards model the relative hazard was 0.93 (that is, a slightly lower hazard in women) before and 1.10 (0.70 to 1.72) after adjusting for age, HIV exposure group, and year of seroconversion. When CD4 lymphocytopenia and death from AIDS were used as end points the results were similar, with adjusted relative hazards of 0.95 (0.63 to 1.42) and 0.72 (0.48 to 1.79) respectively. In both women and men the risk of developing AIDS before the CD4 lymphocyte count had declined below 200 x 10(6)/l was small (3% in women, 6% in men). The estimated median count at which AIDS developed in women (34 x 10(6)/l; 10 x 10(6) to 44 x 10(6)) was similar to that for men (44 x 10(6)/l; 22 x 10(6) to 60 x 10(6)). CONCLUSION--There seems to be little evidence for appreciable differences in the natural course of HIV infection between men and women followed up from the time of seroconversion.     

Temporal relation of antigenaemia and loss of antibodies to core antigens to development of clinical disease in HIV infection.

A total of 276 sequential serum samples from 34 men with antibodies to the human immunodeficiency virus (HIV) followed up for two to seven years were analysed for HIV antigen and antibodies to the viral core and envelope proteins. Results were correlated with clinical outcome and CD4 T lymphocyte count. Both antigenaemia and the disappearance of antibodies to the core protein were associated with development of the acquired immune deficiency syndrome (AIDS) or AIDS related complex and depletion of CD4 cells. Thus AIDS or AIDS related complex developed in eight out of 16 patients with antigenaemia compared with one out of 18 patients without antigenaemia. Low counts of CD4 cells (less than 0.5 X 10(9)/l) were found in 14 of the 16 patients with antigenaemia and five of the 18 without antigenaemia. Nine patients seroconverted to HIV during the study; two of these developed antigenaemia 14 and 16 months after the estimated time of seroconversion. These results show that the late stages of HIV infection are characterised by increased production of antigen and a decrease in antibodies directed against the core protein. Antigenaemia indicates a poor prognosis; and as the antigen test is simple to do and interpret, it may therefore be useful for selecting patients for antiviral treatment.     

Testing Initiatives Increase Rates of HIV Diagnosis in Primary Care and Community Settings: An Observational Single-Centre Cohort Study

Objectives

The primary objective was to examine trends in new HIV diagnoses in a UK area of high HIV prevalence between 2000 and 2012 with respect to site of diagnosis and stage of HIV infection.

Design

Single-centre observational cohort study.

Setting

An outpatient HIV department in a secondary care UK hospital.

Participants

1359 HIV-infected adults.

Main Outcome Measures

Demographic information (age, gender, ethnicity, and sexual orientation), site of initial HIV diagnosis (Routine settings such as HIV/GUM clinics versus Non-Routine settings such as primary care and community venues), stage of HIV infection, CD4 count and seroconversion symptoms were collated for each participant.

Results

There was a significant increase in the proportion of new HIV diagnoses made in Non-Routine settings (from 27.0% in 2000 to 58.8% in 2012; p<0.001). Overall there was a decrease in the rate of late diagnosis from 50.7% to 32.9% (p=0.001). Diagnosis of recent infection increased from 23.0% to 47.1% (p=0.001). Of those with recent infection, significantly more patients were likely to report symptoms consistent with a seroconversion illness over the 13 years (17.6% to 65.0%; p<0.001).

Conclusions

This is the first study, we believe, to demonstrate significant improvements in HIV diagnosis and a shift in diagnosis of HIV from HIV/GUM settings to primary practice and community settings due to multiple initiatives.     

Double blind dose-response study of zidovudine in AIDS and advanced HIV infection. Nordic Medical Research Councils' HIV Therapy Group.

OBJECTIVE--To compare the efficacy and side effects of 400 mg, 800 mg, and 1200 mg zidovudine daily in patients with AIDS or advanced HIV infection. DESIGN--Randomised, double blind, parallel group multicentre study. SETTING--Hospital departments of infectious diseases and dermatology in Denmark, Sweden, Norway, Finland, and Iceland. SUBJECTS--474 patients: 126 (27%) with AIDS; 248 (52%) with HIV related symptoms; 100 (21%) with low CD4+ cell counts. INTERVENTIONS--Zidovudine 400 mg (160 patients), 800 mg (158), or 1200 mg (156) daily. All patients received one capsule from each of three bottles four times daily. MAIN OUTCOME MEASURES--Survival; incidence of new HIV related events; CD4+ cell count; quality of life; incidence of haematological side effects. RESULTS--460 (97%) of the 474 patients had not received zidovudine previously. The median follow up period was 19 months, during which the death rates in the three treatment groups were 23% (36/160 patients), 23% (36/158), and 19% (30/156) respectively (p = 0.49; log rank test). One year after the trial was terminated the death rates were 38% (61/160), 41% (64/158), and 44% (68/156) respectively (p = 0.54). There was no significant difference between the groups in time to a new AIDS defining event or death, average number of events per patient, decline in CD4+ cell counts, wellbeing (visual analogue scale), or Karnofsky score. Zidovudine was withdrawn in 132 (28%) patients, mainly because of side effects (71 cases; 15%). The incidences of anaemia and leucopenia, time to first dose reduction, and numbers of patients withdrawn were all dose related. CONCLUSION--Zidovudine should be limited to 400-600 mg daily in patients with AIDS or advanced HIV infection.     

Clinical symptoms associated with seroconversion for HIV-1 among misusers of intravenous drugs: comparison with homosexual seroconverters and infected and non-infected intravenous drug misusers.

OBJECTIVE--To study the clinical symptoms associated with seroconversion for HIV-1 among misusers of intravenous drugs. DESIGN--Case-control study in cohorts of drug misusers and homosexual men. SETTING--Outpatient clinic, Municipal Health Service, Amsterdam. SUBJECTS--Misusers of intravenous drugs from our prospective cohort who seroconverted for HIV. Controls were drug users positive for HIV, drug users negative for HIV, and homosexual men who had seroconverted. RESULTS--Five out of 18 (28%) drug users were admitted to hospital with bacterial pneumonia in the four to six months between their last visit at which they were HIV negative and their first visit when they were HIV positive. For comparison none of the 27 homosexual men who seroconverted for HIV, three out of 177 (2%) drug users negative for HIV, and 10 out of 112 (9%) drug users positive for HIV reported bacterial pneumonia. One out of the 18 drug users who seroconverted suffered from oesophageal candidiasis at the time of seroconversion. Other clinical symptoms did not differ between drug users who seroconverted and those who remained negative for HIV, probably due to the high background morbidity among the drug users. CONCLUSIONS--Seroconversion to HIV-1 among intravenous drug misusers is associated with bacterial pneumonia. Those drug users with previously negative test results for HIV who are admitted to hospital for bacterial pneumonia should be tested to detect primary infection with HIV-1.     

Symptomatic Illness and Low CD4 Cell Count at HIV Seroconversion as Markers of Severe Primary HIV Infection

Background

The risk/benefit of initiating ART in primary HIV infection (PHI) is unclear. The benefits are more likely to outweigh the risks in patients with severe PHI. An accepted definition of severe PHI is, however, lacking.

Methods

CASCADE patients with HIV test interval <6 months were classified as severe and non-severe PHI based on whether the following traits were recorded in the first 6 months following seroconversion: severe specific pre-defined symptoms, central nervous system-implicated illness, and ≥1, ≥2 CD4<350 (and <500) cells/mm³. For each definition, we used Kaplan-Meier curves and Cox survival models to compare time to AIDS/death, censoring at the earlier of last clinic visit or 1/1/1997, when combination antiretroviral therapy (cART) became available.

Results

Among 1108 included patients mostly males (85%) infected through sex between men (71%), 366 were diagnosed with AIDS/died. The risk of AIDS/death was significantly higher for individuals with severe symptoms, those with ≥1 CD4<350 cells/mm³ or ≥2 CD4 <500 cells/mm³ in the first 6 months [aHR (95% confidence interval) 2.1 (1.4,3.2), 2.0 (1.5,2.7), and 2.3, (1.5–3.5) respectively]. Median [interquantile range] survival for patients with ≥2, ≥1 and no CD4<350 cells/mm³ within 6 months of seroconversion was 3.9 [2.7,6.5], 5.4 [4.5,8.4] and 8.1 [4.3,10.3] years, respectively. The diagnosis of CNS-implicated symptoms was rare and did not appear to be prognostic.

Conclusion

One CD4 count <350 or two <500 cells/mm³ within 6 months of seroconversion and/or severe illness in PHI may be useful early indicators of individuals at high risk of disease progression.     

Does symptomatic primary HIV-1 infection accelerate progression to CDC stage IV disease,CD4 count below 200 x 10(6)/l,AIDS, and death from AIDS?

OBJECTIVE--To investigate the prognostic significance of symptomatic primary HIV-1 infection. DESIGN--Prospective study of homosexual men seroconverting to HIV in 1985 and 1986. Patients were followed up at least three times yearly with clinical examinations and T cell subset determinations for an average of 7.2 years. SETTING--Research project centred on attenders for treatment and screening for HIV at the Karolinska Institute, Stockholm. SUBJECTS--19 patients presenting with a glandular-fever-like illness associated with seroconversion to HIV and 29 asymptomatic seroconverters. MAIN OUTCOME MEASURES--Progression to Centers for Disease Control and Prevention stage IV disease, CD4 cell count below 200 x 10(6)/l, AIDS, and death from AIDS. RESULTS--Symptomatic seroconverters were significantly more likely to develop Centers for Disease Control and Prevention stage IV disease (95% v 66%), CD4 cell counts below 200 x 10(6)/l (84% v 55%), and AIDS (58% v 28%) and die of AIDS (53% v 7%). CONCLUSION--A glandular-fever-like illness associated with seroconversion to HIV-1 predicts accelerated progression to AIDS and other HIV related diseases.     

Use of CD4 lymphocyte count to predict long-term survival free of AIDS after HIV infection.

OBJECTIVE--To estimate the probability of remaining free of AIDS for up to 25 years after infection with HIV by extrapolation of changes in CD4 lymphocyte count. DESIGN--Cohort study of subjects followed from time of HIV seroconversion until 1 January 1993. Creation of model by using extrapolated linear regression slopes of CD4 count to predict development of AIDS after 1993. SETTING--Regional haemophilia centre in teaching hospital. SUBJECTS--111 men with haemophilia infected with HIV during 1979-85. Median length of follow up 10.1 years, median number of CD4 counts 17. The model was not fitted for three men because only one CD4 measurement was available. MAIN OUTCOME MEASURES--Development of AIDS. INTERVENTIONS--From 1989 prophylaxis against candida and Pneumocystis carinii pneumonia and antiretroviral drugs when CD4 count fell below 200 x 10(6)/l. RESULTS--44 men developed AIDS up to 1 January 1993. When AIDS was defined as a CD4 count of 50 x 10(6)/l the model predicted that 25% (95% confidence interval 16% to 34%) would survive for 20 years after seroconversion and 18% (11% to 25%) for 25 years. Changing the CD4 count at which AIDS was assumed to occur did not alter the results. Younger patients had a higher chance of 20 year survival than older patients (32% (12% to 52%) for those aged < 15, 26% (14% to 38%) for those aged 15-29, and 15% (0% to 31%) for those aged > or = 30). CONCLUSIONS--These results suggest that even with currently available treatment up to a quarter of patients with HIV infection will survive for 20 years after seroconversion without developing AIDS.     

CC chemokine receptor 5 cell-surface expression in relation to CC chemokine receptor 5 genotype and the clinical course of HIV-1 infection.

CCR5 cell-surface expression was studied in relation to CCR5 genotype and clinical course of HIV-1 infection. HIV-1 infected CCR5+/+ individuals had higher percentages of CCR5-expressing CD4+ T cells as compared with HIV-1-infected CCR532/+ individuals. For both genotypic groups, the percentages of CCR5-expressing cells were higher than for the uninfected counterparts (CCR5+/+, HIV+ 28% and HIV- 15% (p < 0.0001); CCR532/+, HIV+ 21% and HIV- 10% (p = 0.001), respectively). In HIV-1-infected individuals, high percentages of CCR5-expressing cells were associated with low CD4+ T cell numbers (p = 0.001), high viral RNA load in serum (p = 0.046), and low T cell function (p = 0.054). As compared with nonprogressors with similar CD4+ T cell numbers, individuals who did progress to AIDS had a higher percentage of CCR5-expressing CD4+ T cells (32% vs 21% (p = 0.002). Longitudinal analysis of CCR5+/+ individuals revealed slight, although not statistically significant, increases in CCR5-expressing CD4+ T cells and CD4+ T cell subsets characterized by the expression of CD45 isoforms, during the course of HIV-1 infection. Preseroconversion, the percentage of CCR5-expressing CD4+ T cells was higher in individuals who subsequently developed AIDS (28%) than in those who did not show disease progression within a similar time frame (20%; p = 0.059). Our data indicate that CCR5 expression increases with progression of disease, possibly as a consequence of continuous immune activation associated with HIV-1 infection. In turn, CCR5 expression may influence the clinical course of infection.     

Selection for specific sequences in the external envelope protein of human immunodeficiency virus type 1 upon primary infection.

Viral RNA was extracted from plasma samples collected from five individuals during the period of viremia before seroconversion in primary infection with human immunodeficiency virus type 1 (HIV-1) and amplified by polymerase chain reaction. Nucleotide sequence analysis of amplified DNA from the V3 and V4 hypervariable regions indicated that the initial virus population of each acutely infected individual was completely homogeneous in sequence. No intrasample variability was found among the 44,090 nucleotides sequenced in this region of env, contrasting with the high degree of variability normally found in seropositive individuals. Paradoxically, substantial sequence variability was found in the normally high conserved gag gene (encoding p17) in most of the preseroconversion samples. The diversity of p17 sequences in samples that were homogeneous in V3 and V4 can most readily be explained by the existence of strong selection for specific env sequences either upon transmission or in the interval between exposure and seroconversion in the exposed individual. Evidence that localizes the selected region upon transmission to V3 is provided by the similarity or identity of V3 loop sequences in five individuals with epidemiologically unrelated HIV-1 infections, while regions flanking the V3 loop and the V4 hypervariable region were highly divergent. The actual V3 sequences were similar to those associated with macrophage tropism in primary isolates of HIV, irrespective of whether infection was acquired by sexual contact or parenterally through transfusion of contaminated factor VIII. Proviral DNA sequences in peripheral blood mononuclear cells remained homogeneous in the V3 and V4 regions (and variable in p17gag) for several months after seroconversion. The persistence of HIV sequences in peripheral blood mononuclear cells identical to those found at primary infection in the absence of continued virus expression provides an explanation for the previously observed differences in the composition of circulating DNA and RNA populations in sequential samples from seropositive individuals.     

CD34+ bone marrow cells are infected with HIV in a subset of seropositive individuals.

Individuals infected with HIV frequently develop cytopenias and suppressed hematopoiesis. The role of direct HIV infection of hematopoietic progenitor cells in this process has not been defined. In this study, purified CD34+ bone marrow progenitor cells from 74 Zairian and American patients were studied by both coculture viral isolation and polymerase chain reaction for evidence of HIV infection. A total of 36.5% of Zairian and 14% of American patients had HIV infection of the CD34+ cell subset, with as many as 1 in 500 CD34+ cells infected. Most of the Zairian patients in this study had advanced HIV infection and markedly decreased CD4/CD8 T lymphocyte ratios (mean 0.160 +/- 0.08), and no laboratory value predicted the presence of infection in the CD34+ subset of a given Zairian individual. In contrast, American patients with CD34+ cell infection had total CD4 cells less than 20/mm3 and a greater decrease of the CD4/CD8 T lymphocyte ratio compared to seropositive Americans without CD34+ cell infection (p = 0.003). Hematopoiesis, studied by methylcellulose colony assays, was depressed in all seropositive patients studied with no significant further suppression when CD34+ cells were infected. Thus, CD34+ bone marrow progenitor cells are infected in vivo in a subset of seropositive individuals and may serve as an additional reservoir of virus in HIV-infected individuals.     

Characterization of a human cervical CD4+ T cell subset coexpressing multiple markers of HIV susceptibility

The HIV pandemic disproportionately affects women, with most infections acquired through receptive vaginal sex. Although the target cells by which HIV establishes infection in the female genital tract remain poorly defined, it is known that immune activation results in CD4(+) T cells with enhanced susceptibility, as does expression of the mucosal integrin α4β7 and the HIV coreceptor CCR5. Blood and cervical cytobrush specimens were collected from female sex workers (FSWs) in Nairobi, Kenya. Genital infection diagnostics were performed, T cell populations were defined by multiparameter flow cytometry based on their expression of surface receptors relevant to mucosal homing and/or HIV acquisition, and cytokine production was assayed by intracellular cytokine staining. The integrin α4β7 was expressed on 26.0% of cervical CD4(+) T cells, and these cells were more likely to express both the HIV coreceptor CCR5 (p < 0.0001) and the early activation marker CD69 (p < 0.0001) but not CXCR4 (p = 0.34). Cervical Th17 frequencies were enhanced compared with blood (7.02 versus 1.24%; p < 0.0001), and cervical IL-17A(+) CD4(+) T cells preferentially coexpressed α4β7 and CCR5. Expression of IFN-γ and IL-22 was greater in cervical Th17 cells than in blood Th17 cells. In keeping with the hypothesis that these cells are preferential HIV targets, gp120 preferentially bound CCR5(+) cervical T cells, and cervical Th17 cells were almost completely depleted in HIV(+) FSWs compared with HIV(-) FSWs. In summary, a subset of Th17 CD4(+) T cells in the cervical mucosa coexpresses multiple HIV susceptibility markers; their dramatic depletion after HIV infection suggests that these may serve as key target cells during HIV transmission.