Evolution of HIV-1 transmitted drug resistance in Italy in the 2007-2014 period: A weighted analysis

BACKGROUND

Recent studies suggest that transmitted drug resistance (TDR) may be decreasing in latest years, likely because of the reduced frequency of acquired resistance. However, specific risk factors, geographical areas and special HIV-infected populations may be disproportionally affected by TDR.

OBJECTIVES

Correlates of TDR and time trends were evaluated from 2007 to 2014.

STUDY DESIGN

We evaluated the genotypic results of 2155 naïve patients enrolled in the I.Co.N.A cohort at 23 clinical Centers in Italy between 2007 and 2014. A weighted analysis was performed to account for the patients enrolled in the cohort in each clinical Centre at each biennium (total number of patients: 3737).

RESULTS

Overall prevalence of TDR was 10.7%. Independent predictors of TDR were sexual risk factor (OR 2.315, p = 0.020) and non-Italian geographical origin (OR 1.57, p = 0.038). The weighted prevalence of TDR was 10.5% with a stable proportion over calendar years. Generally, TDR prevalence was numerically higher, although not significantly, in clinical Centers of metropolitan areas with more than 3 millions of residents as compared to others (11.3% vs. 9.2%). The difference in TDR prevalence between these Centers decreased in more recent years.

CONCLUSIONS

A stable frequency of TDR was observed during the most recent years in Italy, with opposite and converging trends in large metropolitan areas as compared to the rest of the country, suggesting a more homogeneous spread of TDR across the country in latest years. Concerns remain for sexual route of infection and non-Italian origin, reinforcing the need for specific prevention strategies prioritizing specific populations.

Transmission of HIV Drug Resistance and the Predicted Effect on Current First-line Regimens in Europe

Transmitted human immunodeficiency virus drug resistance in Europe is stable at around 8%. The impact of baseline mutation patterns on susceptibility to antiretroviral drugs should be addressed using clinical guidelines. The impact on baseline susceptibility is largest for nonnucleoside reverse transcriptase inhibitors.

Background. Numerous studies have shown that baseline drug resistance patterns may influence the outcome of antiretroviral therapy. Therefore, guidelines recommend drug resistance testing to guide the choice of initial regimen. In addition to optimizing individual patient management, these baseline resistance data enable transmitted drug resistance (TDR) to be surveyed for public health purposes. The SPREAD program systematically collects data to gain insight into TDR occurring in Europe since 2001.

Methods. Demographic, clinical, and virological data from 4140 antiretroviral-naive human immunodeficiency virus (HIV)–infected individuals from 26 countries who were newly diagnosed between 2008 and 2010 were analyzed. Evidence of TDR was defined using the WHO list for surveillance of drug resistance mutations. Prevalence of TDR was assessed over time by comparing the results to SPREAD data from 2002 to 2007. Baseline susceptibility to antiretroviral drugs was predicted using the Stanford HIVdb program version 7.0.

Results. The overall prevalence of TDR did not change significantly over time and was 8.3% (95% confidence interval, 7.2%–9.5%) in 2008–2010. The most frequent indicators of TDR were nucleoside reverse transcriptase inhibitor (NRTI) mutations (4.5%), followed by nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations (2.9%) and protease inhibitor mutations (2.0%). Baseline mutations were most predictive of reduced susceptibility to initial NNRTI-based regimens: 4.5% and 6.5% of patient isolates were predicted to have resistance to regimens containing efavirenz or rilpivirine, respectively, independent of current NRTI backbones.

Conclusions. Although TDR was highest for NRTIs, the impact of baseline drug resistance patterns on susceptibility was largest for NNRTIs. The prevalence of TDR assessed by epidemiological surveys does not clearly indicate to what degree susceptibility to different drug classes is affected.

Human immunodeficiency virus-1 B and non-B subtypes with the same drug resistance pattern respond similarly to antiretroviral therapy

We analysed the 12-week virological response to protease inhibitor (PI) or non-nucleoside reverse transcriptase inhibitor (NNRTI) therapy in 1108 patients carrying B or non-B human immunodeficiency virus (HIV)-1 subtypes with matched resistance mutation patterns. Response rates were not significantly different for non-B and B subtypes stratified for treatment status (51.5% vs. 41.5% in naïve patients; 46.7% vs. 38.7% in experienced patients) or regimens (46.9% vs. 39.7% with PI; 56.7% vs. 40% with NNRTI). No difference in response was detected in patients harbouring B and non-B subtypes with any resistance profile. Further studies are advisable to fully test this approach on larger datasets.

Changing patterns in HIV-1 non-B clade prevalence and diversity in Italy over three decades

BACKGROUND

HIV-1 non-B subtypes have recently entered Western Europe following immigration from other regions. The distribution of non-B clades and their association with demographic factors, over the entire course of the HIV-1 epidemic, have not been fully investigated in Italy.

METHODS

We carried out a phylogenetic analysis of HIV-1 pol sequences derived from 3670 patients followed at 50 Italian clinical centres over nearly three decades.

RESULTS

Overall, 417 patients (11.4%) carried non-B subtypes. The prevalence of non-B strains increased from 2.6% in 1980-1992 to 18.9% in 1993-2008 (P<0.0001) in a subset of 2479 subjects with a known year of diagnosis. A multivariate analysis on a subset of 1364 patients for whom relevant demographic data were available indicated that African ethnicity, heterosexual route of infection and year of diagnosis were independently associated with non-B HIV-1 infection (P ≤ 0.0001). All pure subtypes, except for clade K, and seven circulating recombinant forms were detected, accounting for 56.6 and 34.1% of the non-B infections, respectively. The F1 subtype was the most prevalent non-B clade among Europeans and was acquired heterosexually in half of this patient population. Unique recombinant forms accounted for 9.4% of the non-B sequences and showed a B/F1 recombination pattern in one-third of cases.

CONCLUSIONS

The circulation of non-B clades has significantly increased in Italy in association with demographic changes. Spread of the F1 subtype and B/F recombinants appears to predominate, which may result in a redistribution of the relative proportions of the different strains, and this could lead to overlapping epidemics. Thus, the HIV-1 landscape in Italy may in future be distinct from that of the rest of Europe.

Variability in the Interpretation of Transmitted Genotypic HIV-1 Drug Resistance and Prediction of Virological Outcomes of the Initial Haart by Distinct Systems

High level HIV-1 drug resistance in recently infected treatment-naive individuals correlates with sub-optimal virological responses to highly active antiretroviral therapy (HAART). To determine whether genotypic HIV-1 drug resistance in chronic naive patients, as interpreted by various systems, could predict the virological outcomes of HAART, isolates from patients enrolled in a prospective observational cohort (ICoNA) prior to treatment start were genotyped. Genotypic susceptibility scores (GSS) assigned to the initial HAART regimens using the interpretations of pre-therapy resistance mutations by 13 systems were related to virological outcomes. Of 415 patients, 42 (10%) had at least one major resistance mutation. According to the different interpretations, 1.9–20.5% of patients had some level of resistance to at least one drug in the initial regimen. In multivariable analysis, GSS from two systems significantly predicted the time to virological success: Rega 5.5, for each unit increase in GSS adjusted relative hazard (RH) 1.86 [95% confidence intervals (95% CI): 1.15–3.02] and hivresistanceWeb v3, RH 1.87 (95% CI: 1.00–3.48). With three other systems, GSS showed a trend towards a significant prediction of success: Retrogram 1.6, RH 2.33 (95% CI: 0.98–5.53), Menéndez 2002, RH 2.36 (95% CI: 0.97–5.72) and Stanford hivdb, RH 2.06 (95% CI: 0.94–4.49). Genotypic resistance testing coupled with adequate interpretation in chronic naive patients can usefully identify those at risk of sub-optimal virological response to HAART.

Comparison between HIV- and CMV-specific T cell responses in long-term HIV infected donors

The mechanisms underlying non-progression in HIV-1 infection are not well understood; however, this state has been associated previously with strong HIV-1-specific CD8+ T cell responses and the preservation of proliferative CD4+ T cell responses to HIV-1 antigens. Using a combination of interferon-gamma (IFN-gamma) ELISpot assays and tetramer staining, the HIV-1-specific CD8+ T cell populations were quantified and characterized in untreated long-term HIV-1-infected non-progressors and individuals with slowly progressive disease, both in relation to CD4+ T cell responses, and in comparison with responses to cytomegalovirus (CMV) antigens. High levels of CD8+ T cell responses specific for HIV-1 or CMV were observed, but neither their frequency nor their phenotype seemed to differ between the two patient groups. Moreover, while CMV-specific CD4+ T cell responses were preserved in these donors, IFN-gamma release by HIV-1-specific CD4+ T cells was generally low. These data raise questions with regard to the role played by CD8+ T cells in the establishment and maintenance of long-term non-progression.

Decreased function of Fas in patients displaying delayed progression of HIV-induced immune deficiency

INTRODUCTION

In acquired immune deficiency syndrome patients, apoptosis of uninfected lymphocytes may contribute to development of immune deficiency. This process may involve recruitment of Fas by human immunodeficiency virus products. In line with this possibility, the viral envelope glycoprotein gp120 does not induce death of T cells from subjects with the autoimmune/lymphoproliferative syndrome displaying defective Fas function. This study evaluates the possibility that Fas function defects delay progression of HIV-induced immune deficiency.

MATERIALS AND METHODS

The susceptibility to Fas-induced cell death was assessed on T cells from 18 'long-term non-progressor', four 'non-progressor', four 'progressor' asymptomatic HIV-1-infected, and nine AIDS patients using anti-Fas monoclonal antibodies.

RESULTS

Fas-induced cell death was significantly lower in long-term non-progressors and non-progressors than in normal controls, progressors, and AIDS. The single-patient data showed that 9/18 long-term non-progressors and 3/4 non-progressors, but no progressors or AIDS were resistant to Fas. Analysis of the uninfected parents of two long-term non-progressors displaying decreased Fas-function showed that the mother of one of them and the father of the other displayed the same Fas function defect as their children. Fusion of T cells from Fas-resistant individuals with a Fas-sensitive cell line gave rise to Fas-resistant hybrid lines not carrying HIV, which suggests that the resistant phenotype is due to molecules exerting a dominant negative effect on a normal Fas system.

CONCLUSION

These data suggest that Fas-resistance in long-term non-progressors may be due to inherited alterations of the Fas signaling pathway and may be a novel factor in delayed progression.

Secondary mutations in the protease region of human immunodeficiency virus and virologic failure in drug-naive patients treated with protease inhibitor-based therapy

The role of mutations in protease (PR) and reverse-transcriptase (RT) of human immunodeficiency virus (HIV) in predicting virologic failure was assessed in 248 antiretroviral-naive HIV-positive patients who began a PR inhibitor-containing antiretroviral regimen. Genotypic testing was performed on plasma samples stored before the start of therapy. Twenty-seven patients (10.9%) had mutations in the RT, 5 (2%) carried primary mutations in the PR, and 131 (52.8%) showed only secondary PR mutations. Virologic failure at week 24 occurred in 62 (25.0%) of 248 patients. There was a statistically significant correlation between virologic failure and the number of PR mutations (P= .04, chi(2) test). Mutations at codons 10 and 36 of PR (present in 39.3% and 40.0% of patients in whom treatment failed, respectively) were identified by stepwise logistic regression as the strongest predictors of virologic failure (odds ratio, 2.20; 95% confidence interval, 1.30-3.75; P= .004). If confirmed in independent studies, this result may justify the increased use of HIV genotyping in drug-naive patients requiring antiretroviral therapy.

Increasing prevalence of non-clade B HIV-1 strains in heterosexual men and women, as monitored by analysis of reverse transcriptase and protease sequences

OBJECTIVE

We evaluated the prevalence of HIV-1 non-clade B over time in a formerly clade B-restricted area. Protease and reverse transcriptase regions of the pol gene were used for phylogenetic and recombination analysis and for clade assignment to HIV-1 A-D, F-H, J, and K strains of the M group.

METHODS

The pol gene of 349 HIV-1 patients belonging to the Italian Cohort Naive for Antiretrovirals (ICONA) were genotypically analyzed to study the prevalence of antiretroviral-associated resistance mutations. All HIV-1 pol sequences and 32 HIV reference strains were analyzed, including the reference strains for the major HIV-1 subtypes. The non-clade B sequences according to the HIV-1 Subtyping Tool program were further studied by a bootscan analysis (SimPlot) to investigate the likelihood of recombination between subtypes.

RESULTS

Phylogenetic analysis detected 19 of 349 (5.4%) non-clade B subtypes. The proportions of patients carrying non-clade B virus before and after 1997 were 1.9% and 8.4%, respectively (p =.008). Among whites, heterosexual infection and female gender were significantly associated with the presence of non-clade B subtypes (p =.001 and.005, respectively). Non-clade B HIV-1 was harbored by 14.5% of the heterosexuals who were found to be HIV-1 positive after 1997, 60% of whom were women. Bootscan analysis identified four strains as F, two as A, one as C, one as G, and 11 (57.9 %) as non-clade B recombinant subtypes.

CONCLUSION

Detection of HIV-1 subtypes and intersubtype recombinants in a previously clade B-homogeneous area indicates that the HIV-1 epidemic is evolving in Italy and that heterosexuals and women are at increased risk of infection with non-clade B HIV-1 subtypes. Sequences inferred from the pol gene yield to establish the subtype of circulating HIV-1 strains. As a consequence, genotyping of pol gene for testing resistance to antiretrovirals warrants concomitant surveillance of non-clade B subtypes.

Role of CCR5, CCR2 and SDF-1 gene polymorphisms in a population of HIV-1 infected individuals

The finding that in addition to CD4 molecule HIV-1 uses, CCR5 or CXCR4 receptors to enter target cells prompted the research to identify polymorphisms in coreceptor genes affecting disease progression. In this study we analyzed the prevalence of CCR5-delta32, CCR2-641 and SDF1-3'A alleles in a highly selected group of 42 Long-Term Nonprogressors (LTNPs) compared to 112 subjects with a typical course of HIV-1 infection (TPs) and 117 healthy controls (HCs). In addition, we correlated CCR5, CCR2 and SDF-1 genotypes with molecular indexes of HIV-1 replication, cell-free RNA and both unspliced (US) and multiply spliced (MS) intracellular transcripts, to investigate the role of the mutant alleles in determining a long-term nonprogressive course of HIV-1 disease. Our results indicate a significantly higher prevalence of CCR5-delta32 allele in LTNPs compared to TPs (p=0.0434), while the proportions of CCR2-64I and SDF1-3'A alleles were comparable between the two groups. However, SDF-1 wild type LTNP subjects showed significantly lower levels of HIV-1 genomic RNA, US and MS transcripts than SDF1-3'A heterozygous ones (p=0.0021, 0.016, 0.0031, respectively), whereas both CCR5 and CCR2 wild type individuals had similar rates of viral replication compared to CCR5-delta32 and CCR2-64I heterozygous ones. CCR5, CCR2 and SDF-1 combined genotypes were also studied and this analysis did not identify a specific protective cluster of alleles in LTNPs. Taken together, our results indicate that genetic background involving CCR5, CCR2 and SDF-1 alleles may play a limited role in the natural history of HIV-1 infection.

Interaction of methadone with didanosine and stavudine

For opiate-dependent injection drug users infected with HIV, methadone therapy may facilitate adherence to complex highly active antiretroviral therapy (HAART) regimens. Current HAART regimens include one or more nucleoside analogues. We investigated the effects of methadone on the pharmacokinetics of the tablet formulation of didanosine (ddI) and of stavudine (d4T) in 17 study subjects on stable methadone therapy and in 10 untreated controls. Methadone treatment reduced the measured areas under the time-concentration curve (AUC0-6) by 63% for ddI (p =.04) and by 25% for d4T (p =.005) and the extrapolated AUCs for the full dosing interval (AUC0-12) by 57% for ddI (p =.11) and by 23% for d4T (p =. 02). Peak drug concentrations (Cmax) were reduced by 66% (p =.007) and 44% (p =.001) for ddI and d4T, respectively. The effects on AUC and Cmax appeared to result primarily from decreases in bioavailability. Methadone also delayed drug absorption. Trough levels for methadone did not differ significantly from those in historical controls, suggesting that ddI and d4T did not substantially alter methadone disposition. The results suggest that larger doses of the tablet formulation or an alternate formulation may be needed when didanosine is given to study subjects treated with methadone.

Quantitative evaluation of the recombinant HIV-1 phenotype to protease inhibitors by a single-step strategy

OBJECTIVE

To develop and optimize a fast and quantitative recombinant strategy for evaluating the HIV-1 phenotype to protease inhibitors (PI).

DESIGN AND METHODS

A non-replicative HIV-1 molecular vector (designated pdelta prodelta env) capable of expressing exogenous HIV-1 protease-encoding sequences was developed in this study. The HIV-1 protease sequences were amplified from either viral isolates or plasma samples (both from 21 HIV-1-infected individuals, 19 of whom were failing different anti-HIV-1 combination treatments) and cloned in the pdelta prodelta env backbone. The HIV-1 recombinant phenotype to PI was determined directly after transfection of viral chimeric clones by measuring protease activity and calculating a percentage sensitivity index (SI%; the ratio between the results from each clone and those from a PI-sensitive reference strain).

RESULTS

The SI% values obtained from the recombinant clones paralleled the IC50 results of the viral isolates and documented different degrees of resistance and cross-resistance to PI, compatible, with few exceptions, with the respective genotype. Interestingly, an inverse correlation between SI% values and the presence of primary mutations for resistance to PI (P = 0.0038 and P = 0.0414, for indinavir and ritonavir, respectively) and a difference in SI% between samples harbouring an increasing number of mutations (indinavir, P = 0.022; ritonavir, P = 0.0466) were observed.

CONCLUSION

The data substantiate the reliability of the novel strategy for a fast (5 day) quantitative evaluation of HIV-1 phenotype to PI, and indicate that this method may contribute to the understanding of mechanisms of virus resistance to PI.

Neurological symptoms during primary human immunodeficiency virus (HIV) infection correlate with high levels of HIV RNA in cerebrospinal fluid

This analysis involves 22 patients with diagnosed symptomatic human immunodeficiency virus (HIV) infection. Neurologic symptoms were present in 11 patients, ranging from severe and persistent headache to clinical signs suggestive of meningitis. A strong correlation between neurological symptoms and cerebrospinal fluid (CSF) viral load was found. The mean CSF HIV ribonucleic acid (RNA) level was 4. 12 log for patients with neurological symptoms and 2.58 log for patients without neurological symptoms (P<.00001). Plasma viral load alone does not correlate or predict central nervous system (CNS) involvement. In our sample of patients, HIV RNA levels could be detected in most patients regardless of the presence of neurological symptoms. Moreover, early treatment including drugs with high levels of penetration in the CNS must be considered for patients with primary HIV infection.

Susceptibility to PNU-140690 (Tipranavir) of human immunodeficiency virus type 1 isolates derived from patients with multidrug resistance to other protease inhibitors

In our study we examined the anti-human immunodeficiency virus type 1 (anti-HIV-1) activity of a novel HIV-1 protease inhibitor, PNU-140690 (tipranavir), against patient-derived isolates resistant to multiple other protease inhibitors (PIs). The aim of our experiments was to investigate the genotypes and the in vitro phenotypes of drug resistance of PNU-140690. We carried out drug susceptibility tests with peripheral blood mononuclear cells and a fixed amount of infectious virus (1,000 50% tissue culture infective doses) to determine the 50% inhibitory concentration (IC(50)) and IC(90), PCR assays for the detection of drug resistance mutations in RNA in plasma, and direct sequencing of PCR products. Phenotypic resistance to PIs was invariably related to genotypic mutations. The substitutions among the amino acid residues of the protease included L10I, K20R, L24I, M36I, N37D, G48V, I54V, L63P, I64V, A71V, V77I, V82A, I84V, and L90M. Isolates from all of the patients had developed a maximal degree of resistance to indinavir, ritonavir, and nelfinavir (IC(50)s, >0.1 microM). We also compared these mutations with the amino acid changes previously described in association with in vivo tipranavir administration. The mutations included the following: I15V, E35D, N37D, R41K, D60E, and A71T. Infections with IIIB, 14aPre, and N70 were inhibited by an average drug IC(90) of 0.18 +/- 0.02 microM in multiple experiments. The average mean +/- standard error of mean IC(90) for the entire group of multidrug-resistant isolates derived from the mean values for two culture wells with p24 antigen supernatant appeared to be 0.619 +/- 0.055 microM (range, 0.31 to 0.86 microM). Tipranavir retained a sustained antiviral activity against PI-MDR clinical isolates and might be useful in combination regimens with other antiretroviral agents for patients who have already failed other PI-containing therapies.

Prevalence of transmitted nucleoside analogue-resistant HIV-1 strains and pre-existing mutations in pol reverse transcriptase and protease region: outcome after treatment in recently infected individuals

We retrospectively studied 38 Italian recently HIV-1-infected subjects who seroconverted from 1994 to 1997 to investigate: (i) the prevalence of nucleoside reverse transcriptase inhibitors (NRTI)-related mutations at primary infection; (ii) the proportion of naturally occurring mutations in reverse transcriptase (RT) and protease regions of patients naive for non-nucleoside RT inhibitors (NNRTIs) and protease inhibitors (PIs); (iii) the drug-susceptibility to NRTIs and PIs in subjects with NRTI- and/or PI-related mutations; and (iv) the outcome of seroconverters treated with various NRTIs or NRTI/PI regimens. Baseline HIV-1 plasma viraemia and absolute CD4 count at baseline could not be used to distinguish patients with NRTI- and/or PI-related pre-existing mutations from those with wild-type virus (P = 0.693 and P = 0.542, respectively). The frequency of zidovudine-related mutations was 21% in the study period. The response to treatment was not significantly different in subjects with or without genotypic zidovudine-related mutations at primary infection (P = 0.744 for HIV-1 RNA and P = 0.102 for CD4 cells). Some natural variation (2.6%) was present within regions 98-108 and 179-190 of RT involved in NNRTI resistance. The high natural polymorphism in the protease region present in our patients was similar to that reported by others. In our study some PI-associated substitutions, thought to be compensatory in protease enzymatic function, could confer intermediate to high PI-resistance. As discrepancies between genotypic and phenotypic results may exist in recent seroconverters, our data suggest that the role of transmitted NRTI- and PI-resistant variants remain to be fully elucidated in vivo.

Persisting HIV-1 replication triggered by acute hepatitis A virus infection

We report the case of two patients in whom acute hepatitis A was associated with a marked and prolonged increase in human immunodeficiency virus type 1 (HIV-1) viral load. Although in one patient the rise in HIV-1 RNA might also have been related to the interruption of antiretroviral therapy, we also observed a similar pattern in the other patient who had a stable undetectable plasma viraemia prior to acute hepatitis and never received treatment with anti-retrovirals. Our observation supports the hypothesis that immune activation that is induced by acute hepatitis A virus (HAV) infection may trigger HIV-1 replication. This highlights the importance of maintaining antiretroviral therapy throughout the acute phase of hepatitis A and of preventing HAV infection through active immunization.

Prevalence of HIV-1 resistant strains in recent seroconverters

Twenty-nine HIV-1 recently infected subjects were retrospectively studied to investigate both the prevalence of nucleoside reverse transcriptase inhibitors (NRTI)-related mutations at primary infection and the proportion of naturally occurring mutations in protease inhibitor (PI)-naive patients. Neither HIV-1 plasma viremia nor CD4 absolute count at baseline could distinguish patients with NRTI pre-existing mutations from those with wild-type virus. An increasing proportion of ZDV-related mutations was observed over time with an overall frequency of 20.7% in the study period. Only 1 out of 6 patients (16.7%) with ZDV-related mutations showed a phenotypically ZDV resistant isolate. A striking proportion of polymorphic changes was present in the protease region of pol gene in newly infected individuals. As many as 80% of seroconverters presented at least one naturally occurring substitution. Some PI-associated substitutions, thought to be compensatory in protease enzymatic function, could confer intermediate to high PI-resistance. Their role following PI administration remains to be elucidated. Our data suggest that the choice of drugs should be oriented by both genotypic and phenotypic evaluations to tailor individual regimens in seroconverters.

Identification of two distinct subsets of long-term nonprogressors with divergent viral activity by stromal-derived factor 1 chemokine gene polymorphism analysis

Stromal-derived factor (SDF)-1, the natural ligand for CXCR4, is present in a common polymorphic variant defined by a G-->A transition in the 3' untranslated region of the gene. In persons infected with human immunodeficiency virus type 1 (HIV-1), the homozygous genotype (SDF1-3'A/3'A) has been postulated to interfere with the appearance of T-tropic syncytium-inducing strains. The polymorphism of SDF1 was correlated with HIV-1 phenotype, plasma viremia, and unspliced and multiply spliced specific transcripts in 158 virologically characterized HIV-1-infected patients (39 recent seroconverters, 75 typical progressors, and 44 AIDS patients) and in 42 HIV-1-infected long-term nonprogressors (LTNPs). Analysis of SDF1 allele distribution revealed that SDF1-3'A/3'A status is associated with low CD4 cell count (P=.0449) but not with a specific HIV-1 phenotype. In LTNPs, SDF1-+/+ condition defined a subset of persons with lower HIV-1 replication than in heterozygous subjects. The low viral activity in SDF1-+/+ LTNPs suggests that other factors play a major role in vivo in determining the course of HIV-1 infection.

Clinical outcome and predictive factors of failure of highly active antiretroviral therapy in antiretroviral-experienced patients in advanced stages of HIV-1 infection

OBJECTIVE

To verify the effectiveness of highly active antiretroviral therapy (HAART) and to identify any factors predictive of clinical outcome in a clinical setting.

DESIGN

Observational study.

METHODS

Treatment failure (i.e., the occurrence of new or recurrent AIDS-defining events, death or any definitive discontinuation) and the course of CD4+ cell counts and HIV RNA copies were evaluated in 250 heavily pretreated HIV-infected patients starting HAART [153 with indinavir (IDV), 55 with ritonavir (RTV), 43 with saquinavir (SQV)]. Univariate and multivariate analyses were performed to identify predictors of worse outcome.

RESULTS

During a median follow-up of 8 months, 75 patients (30%) had treatment failure because of the occurrence of an AIDS-defining event or death (n = 24), inefficacy (n = 24), or severe intolerance (n = 27). Twenty new and six recurrent AIDS-defining events, and nine deaths occurred (six out of 20 AIDS-defining events and two out of nine deaths within 1 month of treatment). CD4+ counts were above 200 x 10(6)/l at AIDS diagnosis in only two patients. None of the SQV patients, 12 (7.8%) of the IDV patients, and 15 (27.3%) of the RTV-treated patients were considered non-compliant. The SQV-containing regimens independently correlated with treatment failure (relative risk, 2.46; 95% confidence interval, 1.20-5.03; versus IDV). Low compliance partially determined outcome in RTV-treated patients; both severe immunodepression and AIDS at baseline were predictive of treatment failure. There was a 10-fold increase in CD4+ cell counts in the patients treated with IDV and RTV; the best virological outcome occurred in IDV-treated patients, with 68.4% of patients showing undetectable HIV RNA copies after 6 months.

CONCLUSIONS

HAART was effective in 70% of patients; low compliance and previous AIDS diagnosis represented predictive factors of therapy failure.

Low CD4 counts rather than superantigenic-like effects account for differences in expressed T-cell receptor (TCR) repertoires between HIV-1 seropositive long-term non-progressors and individuals with progressive disease

Analysis of HIV-infected individuals who have stable CD4 counts many years after seroconversion may provide an insight as to how the host's immune system can successfully control HIV infection. In this study we analysed the T-cell receptor (TCR) Vbeta repertoire in 13 HIV+ individuals, seven of whom were classed as long-term non-progressors (LTNP), using a technique which couples anchor PCR (AnPCR) amplification of beta-chain cDNA to differential probe hybridization with non-radioactively labelled Vbeta family specific oligonucleotide probes. There were no significant differences in the expressed TCR repertoires between the LTNP group and the other HIV-infected individuals. However, there was a statistically significant inverse correlation between CD4 count and the number of Vbeta family-specific perturbations in the recent seroconverters (SC) and those with progressive infection (PI), consistent with other shared features of clinical disease progression (Th1/Th2 switch and high frequency of viral isolation). We conclude that long-term clinical non-progression in HIV-1 infection is not associated with the loss or expansion of a particular Vbeta family; instead, low CD4 count in the PI and SC individuals was correlated with increased number of Vbeta family-specific perturbations relative to the LTNP group and that it is hence unlikely that HIV encodes a superantigen.

Long-term resistance to HIV infection in vertical HIV infection: cytokine production, HIV isolation, and HIV phenotype define long-term resistant hosts

We analyzed immunologic (CD4 and CD8 slopes; interferon-gamma, interleukin-2, interleukin-10, and chemokines production; concentration of IgE; beta 2-microglobulin) and virologic (p24; HIV isolability and phenotype; plasma viremia) parameters in HIV vertically infected children > or = 8 years of age without disease progression or mild symptoms and an absolute CD4+ count > or = 500/microliter with CD4+ percentage > or = 25%. The results were compared to those of two control groups: (1) slow progressors, children > or = 8 years of age with moderate symptomatology and/or moderate CD4 depletion, and (2) progressors, children > or = 8 years of age with severe clinical disease and/or severe CD4 depletion. Pediatric long-term resistant hosts were characterized by higher production of interleukin-2 and interferon-gamma and lower production of interleukin-10, normal concentration of IgE, HIV isolates with a non-syncytium-inducing phenotype, and lower plasma viremia. This condition was not associated with the concentration of beta 2-microglobulin, p24, and chemokines, or with HIV isolability. The IL-10/IL-2 ratio best correlated with both CD4 counts and disease progression. Thus, vertically infected children showing resistance to disease progression are immunologically and virologically distinct from those in whom progressive HIV infection is observed.

Patterns of in vitro anti-human immunodeficiency virus type 1 antibody production in long-term nonprogressors

With the aim of evaluating the specific pattern of in vitro antibody production (IVAP) in human immunodeficiency virus type 1 (HIV-1)-infected long-term non-progressors (LTNPs), we tested 20 subjects who had remained asymptomatic for more than 8 years with a CD4+ cell count higher than 500/microliter and 59 patients at different stages of HIV-1 infection as controls. In cell cultures, IVAP was detected in 14 out of 20 LTNPs (70%), in 5 out of 6 recent seroconverters (83%), and in all the other control patients. Anti-p24 antibody production was significantly lower in LTNPs than in asymptomatic patients with a more recent infection. Recent seroconverters and patients with AIDS did not produce anti-p24 antibodies (P = 0.02). Anti-gp160 antibodies were produced by peripheral blood mononuclear cells from LTNPs in 12/20 cases. CD4+ cell count was significantly higher in IVAP-negative than in IVAP-positive LTNPs (P = 0.013), while the viral load was not significantly different. Specific anti-HIV-1 antibody production did not seem to be a correlate of long-term nonprogression.

Homozygous delta 32 deletion of the CCR-5 chemokine receptor gene in an HIV-1-infected patient

BACKGROUND

Recent research has found that entry of non-syncytium-inducing (NSI), monocyte-macrophage-tropic HIV-1 isolates requires binding to both CD4 and CCR5 receptors, and that delta 32/delta 32 homozygous individuals are protected against infection.

OBJECTIVE

To analyse the polymorphism of CCR-5 gene in HIV-1-infected and uninfected subjects.

DESIGN AND METHODS

CCR-5 sequences were amplified by polymerase chain reaction (PCR) from DNA of peripheral blood mononuclear cells. Samples from 152 HIV-1-infected subjects and 122 uninfected controls were tested for the detection of the 32 base-pair deletion. HIV-1 phenotype was determined by viral isolation and MT-2 evaluation.

RESULTS

The wild-type/delta 32 heterozygous and delta 32/delta 32 homozygous conditions were represented in 10.7 and 0.8% of healthy controls and in 9.8 and 0.7% of HIV-1-infected subjects, respectively. Of note, the delta 32/delta 32 deletion of the CCR-5 gene was detected by PCR and sequencing confirmed in a patient with progressive infection harbouring a clade B virus with SI phenotype.

CONCLUSIONS

delta 32/delta 32 homozygosity for the CCR-5 gene does not confer absolute protection against HIV-1 infection, suggesting that either macrophage-tropic viral strains could use coreceptors other than CCR-5 or infect independently of the presence of a functional CCR-5 coreceptor. Alternatively, primary infection sustained by T-cell-tropic isolates, although exceptional, may occur.

Pentoxifylline improves cell-mediated immunity and reduces human immunodeficiency virus (HIV) plasma viremia in asymptomatic HIV-seropositive persons

The effects of pentoxifylline on immunologic and virologic parameters were evaluated in 10 human immunodeficiency virus-infected patients not receiving antiretroviral treatment. Patients were asymptomatic, had 300-500 CD4 cells/microL, and received pentoxifylline (1200 mg/day orally) for 4 months. Peripheral blood mononuclear cells were tested before and at five time points during therapy. A transient increase in CD4 cells was observed in 8 of 9 patients, and CD8 cells increased in 7 of 9 patients. These increases were negatively correlated with susceptibility to in vitro mitogen-stimulated apoptotic cell death. Pentoxifylline had a temporary effect on mitogen-stimulated cytokine production; thus, interferon-gamma, interleukin (IL)-2, tumor necrosis factor-alpha, and lymphotoxin increased more than IL-10. Pentoxifylline also potentiated antigen-stimulated IL-2 production and proliferation in 8 of 9 patients and induced significant but transient decreases in plasma viremia in 7 of 9 patients. These preliminary findings suggest that pentoxifylline in vivo has an interesting but temporary influence on both immunologic and virologic parameters.

Comparable biological and molecular determinants in HIV type 1-infected long-term nonprogressors and recently infected individuals

Human immunodeficiency virus type 1 (HIV-1) isolability, rate of replication, phenotype, plasma viremia, and specific intracellular transcripts were cross-sectionally analyzed in 61 HIV-1-seropositive individuals to evaluate the correlations between the virological and molecular correlates of protection and progression in different clinical subsets: recently infected subjects (RIs), long-term nonprogressors (LTNPs), late progressors (LPs), and typical progressors (TPs). Comparison of the major virological and molecular features of HIV-1 infection has defined distinct profiles for different subsets of patients. LTNPs or RIs, as well as LPs or TPs, exhibited similar titers of coculture p24 antigen; the differences between the former and the latter were statistically significant at all the time points tested (p = 0.0001; 0.0003 and 0.0001). Whereas LTNPs and RIs revealed comparable low levels of indexes of viral replication, LPs and TPs showed higher genome and mRNA copy numbers (p = 0.0004 and p = 0.0008, respectively). We demonstrated close biological and molecular similarities between RIs and LTNPs on the one hand, and LPs and TPs on the other. In LTNPs both viral biological properties and viral load are important determinants of the course of the disease.

Plasma viremia and virus phenotype are correlates of disease progression in vertically human immunodeficiency virus type 1-infected children

OBJECTIVE

To analyze the relationships among HIV-1 plasma viremia, phenotype and CD4 T cell counts in vertically infected children.

METHODS

Plasma viremia was quantified in 37 vertically infected children at different stages of the disease by a standardized molecular assay. Virus isolation and non-syncytia-inducing or syncytia-inducing (SI) HIV-1 phenotype evaluation were performed in parallel.

RESULTS

HIV-1 RNA genomes were found to be significantly different in CDC clinical classes N, A, B and C (P = 0.0135) and in immunologic classes 1, 2 and 3 (P = 0.0110). None of the children in Class N or A harbored HIV-1 isolates with SI phenotype, whereas SI primary isolates were detected in 2 of 7 (29%) and 7 of 10 (70%) Class B and C children, respectively. Similarly SI variants were present in only 9 of 13 children in immunologic Class 3 (70%). When stratified according to the increasing severity of virologic status, the children showed a significant difference (P = 0.0458) in viral burden.

CONCLUSIONS

Clinical symptoms, the most dramatic being reduction in the number of CD4 lymphocytes, and the highest plasma viremia levels were observed in the children in whom fast replicating, highly cytopathic SI variants were isolated. These data extend the virologic characterization of vertically HIV-1 infected children and suggest that both the plasma viremia levels and phenotype of primary isolates are viral correlates of disease progression in vertically infected children.

Viral load, viral phenotype modification, zidovudine susceptibility and reverse transcriptase mutations during the first 6 months of zidovudine monotherapy in HIV-1-infected people

We studied 14 zidovudine-naive, HIV-1-infected patients attending an infectious diseases clinic in Milan during zidovudine therapy for 6 months. We monitored CD4 cell counts, immune complex-dissociated p24 antigen, viral phenotype and viral load in plasma. The virus infecting a subset of patients was examined for zidovudine susceptibility and zidovudine resistance-associated mutations. A significant correlation was established between the increase in the CD4 cell count and the decrease in viral load (Spearman's coefficients < -0.5). Patients who were p24 antigen positive had a higher viral load (P < 0.005 at baseline and after 6 months of therapy). Patients with non-syncytium-inducing (NSI) virus had higher CD4 cell counts over time than those with syncytium-inducing (SI) virus. We also examined the viral load in relation to viral phenotype. The median viral load in patients with NSI virus was higher than in SI controls at baseline, but not after 3 and 6 months of therapy. Sequential isolates of HIV-1 were obtained from nine patients and tested for resistance to zidovudine by monitoring the drug susceptibility and the reverse transcriptase-encoding sequence. Amino acid changes at codons 70 and 215 were present in some but not all isolates with zidovudine-resistant phenotype in vitro. It was possible to perform a correlation between zidovudine susceptibility and zidovudine-associated pol gene mutations only at the 6-month time point (Spearman's coefficient = 0.076). SI phenotype was associated with the development of a decreased zidovudine susceptibility. A correlation between zidovudine-associated pol gene mutations and SI phenotype was detected at the 6-month time point.

Dynamics and modulation of human immunodeficiency virus type 1 transcripts in vitro and in vivo

The dynamics of human immunodeficiency virus type 1 (HIV-1) transcription was analyzed in vitro and in vivo by using a specific molecular approach which allows accurate quantitation of the different classes of viral mRNAs. Unspliced (US) and multiply spliced (MS) HIV-1 transcripts were assayed by competitive reverse transcription (cRT)-PCR, using a single competitor RNA bearing in tandem internally deleted sequences of both template species. Acute HIV-1 infection of primary peripheral blood mononuclear cells (PBMCs), monocytes/macrophages cells, and the A3.01 T-lymphocyte-derived cell line was studied; both classes of HIV-1 mRNAs increased exponentially (r2 > 0.98) at days 1 to 3 and 1 to 4 postinfection in HIV(IIIB)-infected A3.01 cells and PBMCs, respectively, whereas monocytes/macrophages infected with monocytotropic HIV(BaL) exhibited a linear (r2 = 0.81 to 0.94) accumulation of US and MS transcripts. Following induction of chronically infected ACH-2 cells, MS transcripts increased 2 h postinduction and peaked at 5 h (doubling time, 58 min), while at 24 h, US mRNAs increased 3,053-fold compared with basal time (doubling time, 137 min). To address the biopathological significance of HIV-1 expression pattern during infection progression, pilot cross-sectional and longitudinal analyses were carried out with samples from untreated and treated HIV-1-infected patients. In almost all untreated (recently infected, long-term nonprogressor, and progressor) patients, MS transcript levels followed the general trend of systemic HIV-1 activity. In patients under treatment with powerful antiretroviral compounds, viral MS transcripts rapidly fell to undetectable levels, indicating that in vivo, levels of MS mRNAs in PBMCs are closely associated with the number of newly infected cells and suggesting a new role for the quantitative analysis of HIV-1 transcription in infected patients.

HIV type 1 phenotype correlates with the stage of infection in vertically infected children

A cohort of 39 vertically infected children (class N, A, B, and C of the CDC HIV classification for pediatric infection) was studied by virus isolation and non-syncytium inducing (NSI)/syncytium inducing (SI) HIV-1 phenotype evaluation. The HIV-1 isolates were recovered from PBMCs and the MT-2 cell line was used to perform the syncytium assay. HIV-1 could be isolated in 34 of 39 (87%) infected children, regardless of the clinical and immunological stage of the disease. Class N and A subjects harbored exclusively NSI strains, whereas the SI phenotype was detected in two of eight class B and five of nine class C patients. All of the SI variants were observed in severely CD4-depleted children (class 3 patients). The capability of pediatric HIV-1 isolates to induce a cytopathic effect is associated with the clinical status and the degree of CD4 depletion. These data suggest that the biological properties of HIV-1 isolates in children do not differ from those observed in adults, and that viral phenotype strictly correlates with disease progression in vertically infected children.

Virologic and immunologic markers of disease progression in pediatric HIV infection

Correlates of progression of human immunodeficiency virus (HIV) infection to AIDS include the reduction in CD4+ T cells and the emergence of syncytium-inducing (SI) HIV variants. It has been suggested that progressive defects in interleukin 2 (IL-2), IL-12, and IFN- gamma production (type 1 cytokines), and increased production of IL-4 (and of IL-4-driven hyper-IgE), IL-6, and IL-10 (type 2 cytokines), could provide another correlate of disease progression. To determine the possible association among these markers, viral phenotype, cytokine production, IgE serum concentration, and rate of CD4 depletion were analyzed in a cohort of vertically HIV-infected children. We report that significantly higher production of type 2 cytokines and augmented IgE concentration are observed in children in whom HIV SI is isolated. In addition, we observed that the isolation of HIV SI and the production of high quantities of type 2 cytokines are correlated with increased loss of CD4 T cells in the 12 months preceding the determinations. These data suggest that the virologic and immunologic parameters characteristic of advanced HIV infection may be associated in pediatric HIV infection, and indicate a virologic-immunologic pathogenesis leading to the appearance of AIDS.

Type 1 cytokine production and low prevalence of viral isolation correlate with long-term nonprogression in HIV infection

Cytokine production, prevalence of viral isolation, and surface marker expression of peripheral blood mononuclear cells (PBMCs) were analyzed in HIV+ individuals with different patterns of disease progression to establish correlations between these parameters. Thus, mitogen-stimulated in vitro production of interferon gamma (IFN-gamma) and interleukin 2 (IL-2) (type 1 cytokines), and of IL-4 and IL-10 (type 2 cytokines) as well as prevalence of viral isolation were evaluated in 26 HIV+ long-term nonprogressors (LTNPs), in 28 HIV+ patients with progressive HIV infection (PI), and in 24 HIV-seronegative controls (HCs). Surface expression of activation and nonactivation markers was also analyzed in a group of these donors. We report that (1) IL-2 and IFN-gamma production is reduced and IL-4 and IL-10 production is increased in PI patients compared to HCs and LTNPs; (2) prevalence of HIV isolation is lower in LTNPs compared to PI, and the primary viral isolates in LTNPs show a slow/low (S/L) phenotype; and (3) the elevated production of type 2 cytokines is paralleled by an increase in CD57+CD4+CD7- lymphocytes. Thus, whereas a high IL-2, high IFN-gamma/low IL-4, low IL-10 cytokine production pattern is present in HC and in LTNP HIV+, progression of HIV infection is associated with a low IL-2 low IFN-gamma/high IL-4, high IL-10 cytokine profile; increased prevalence of HIV isolation; and an augmented percentage of CD57+CD4+CD7- lymphocytes. These findings further confirm that a dominant type 1 cytokine profile together with reduced prevalence of virus isolation is associated with lack of progression in HIV infection.

Human immunodeficiency virus (HIV) phenotype and interleukin-2/ interleukin-10 ratio are associated markers of protection and progression in HIV infection

Human immunodeficiency virus (HIV) isolability, rate of viral replication, HIV phenotype, type 1 and type 2 cytokine production, and CD4 counts were cross sectionally analyzed in 63 HIV seropositive (HIV+) individuals to establish possible correlations between virologic and immunologic markers of protection and progression. We observed that these markers are tightly correlated. Thus, lack or low prevalence of HIV isolability and the presence of nonsyncitium inducing strains are associated with the strongest type 1 cytokine production, the weakest type 2 cytokine production, and highest CD4 counts. Conversely, the isolation of highly replicating, syncitium-inducing HIV strains is associated with the weakest type 1 cytokine production, the strongest type 2 cytokine production, and lowest CD4 counts. Additionally, it was determined that the interleukin (IL)-10/IL-2 ratio best discriminates among different virologic scenarios. These data suggest that the virologic and immunologic correlates of disease protection and progression might be associated variables that define two different subsets of HIV+ individuals and lend support to a viro-immunologic hypothesis of HIV infection.

Evidence for type 2 cytokine production and lymphocyte activation in the early phases of HIV-1 infection

OBJECTIVE

To analyse changes in cytokine production in vitro and T-lymphocyte immunophenotype in the early phases of HIV-1 infection.

DESIGN AND METHODS

Mitogen-stimulated in vitro production of interferon (IFN)-gamma, interleukin (IL)-2 (type 1 cytokines), IL-4, and IL-10 (type 2 cytokines) and surface expression of activation and non-activation markers were evaluated in 11 individuals HIV-infected for > 3 but < 12 months (seroconverters). The data were compared to those obtained in 33 asymptomatic HIV-positive individuals infected > 3 years previously and who were stratified according to CD4+ lymphocyte count (group 1: > 500 x 10(6)/l, group 2: < 500 x 10(6)/l CD4 cells) and in 12 HIV-seronegative healthy controls.

RESULTS

We observed that the early phase of HIV infection is characterized by (1) reduced mitogen-stimulated IL-2 and IFN-gamma production, (2) increased mitogen-stimulated IL-4 and IL-10 production, (3) a relative decrease in CD4+ and CD4+CD7- as well as an increase in CD4+CD7-CD57+ lymphocytes, and (4) a relative increase in CD8+, CD8+CD38+ and CD8+CD57+ T lymphocytes. In addition, during a 6-month follow-up of six seroconverters we observed a dynamic pattern of changes of these parameters in most individuals, with a resulting profile similar to that observed in group 1 HIV-positive patients.

CONCLUSION

The early phase of HIV infection is immunologically characterized by type 2 cytokine secretion and alterations in the expression of phenotypic markers, and closely resembles the more advanced phases of HIV infection. These immunologic alterations are temporally limited by the successive return to a more normal profile. Thus, HIV infection is an immunological complex dynamic process even in its earliest phases.

Growth of macrophage-tropic and primary human immunodeficiency virus type 1 (HIV-1) isolates in a unique CD4+ T-cell clone (PM1): failure to downregulate CD4 and to interfere with cell-line-tropic HIV-1

Human immunodeficiency virus type 1 (HIV-1) isolates derived directly from clinical samples are usually unable to grow in cytokine-independent continuous cell lines, thus hindering the study of their biological features and their sensitivity to humoral and cellular protective immunity. To overcome these limitations, we have derived from the Hut78 T-cell line a CD4+ clone (PM1) characterized by a unique susceptibility to a wide range of HIV-1 isolates, including primary and biologically pure macrophage (M phi)-tropic isolates (e.g., HIV-1BaL), which are unable to infect other human T- or promonocytic cell lines. Both primary and M phi-tropic HIV-1 establish persistent infection in PM1, with sustained levels of virus replication for prolonged periods. Experiments with chimeric viruses containing envelope fragments of HIV-1BAL inserted into the genetic framework of HXB2, a molecular clone derived from the cell-line-tropic isolate HIV-1IIIB, showed the third hypervariable domain (V3) of gp120 to be a critical determinant of the cell line tropism of HIV-1. Nevertheless, the V3 loop of HIV-1BaL was not sufficient to confer on the chimeras a bona fide M phi tropism. The biological characteristics of HIV-1BaL and of a primary isolate (HIV-1(573)) were investigated by using the PM1 clone. Infection of PM1 by HIV-1BaL was critically dependent on the CD4 receptor, as shown by competition experiments with an anti-CD4 monoclonal antibody (OKT4a) or with soluble CD4. However, the amount of soluble CD4 required for inhibition of HIV-1BaL was approximately 100-fold higher than for HIV-1IIIB, suggesting that the affinity of HIV-1BaL for CD4 is significantly lower. Infection of PM1 with either HIV-1BaL or HIV-1(573) failed to induce downregulation of surface CD4 expression and syncytium formation. Analogous results were obtained with a chimeric virus (HXB2[BaL PvuII-BamHI]) encompassing a large portion of gp120 and gp41 of HIV-1BaL, indicating that the env genes contain critical determinants for CD4 downregulation and syncytium formation. Consistent with the lack of CD4 downregulation, persistent infection of PM1 by HIV-1BaL or HIV-1(573) failed to interfere with HIV-1IIIB superinfection, as revealed by the expression of a type-specific V3 loop epitope (M77) and by the induction of extensive syncytium formation. This lack of interference suggests that a direct viral interaction may occur in vivo between biologically diverse HIV-1 strains.(ABSTRACT TRUNCATED AT 400 WORDS)

Antisense phosphorothioate oligodeoxynucleotides targeted to the vpr gene inhibit human immunodeficiency virus type 1 replication in primary human macrophages

The replication of human immunodeficiency viruses (HIV) in human macrophages is influenced by genetic determinants which have been mapped predominantly to the viral envelope. However, in HIV-2, the vpr gene has also been suggested as an important modulator of viral expression in human macrophages. We synthesized five antisense phosphorothioate oligodeoxynucleotides complementary to the vpr mRNA of HIV-1Ba-L, a highly macrophage-tropic viral strain, and measured their effect on HIV-1Ba-L replication in primary human macrophages. All of the oligodeoxynucleotides displayed some level of non-sequence-specific inhibition of viral replication; however, only the antisense one had an additional effect on viral production in primary macrophages. Of the five antisense oligodeoxynucleotides tested, only one did not show any additional effect on viral production, whereas all the others inhibited viral replication to a similar degree (70 to 100%). Variation in the degree of inhibition was observed by using five different donors of human primary macrophages. The phosphorothioate oligonucleotides, targeted to the initiating methionine of the Vpr protein, had an inhibitory effect at both 20 and 10 microM only when the size was increased from 24 to 27 bases. Thus, HIV-1 replication in human macrophages is modulated by the expression of the vpr gene, and it is conceivable that vpr antisense oligodeoxynucleotides could be used in combination with antisense oligodeoxynucleotides against other HIV-1 regulatory genes to better control viral expression in human macrophages.

Soluble interleukin-2 receptor decrease in the sera of HIV-infected patients treated with zidovudine

Laboratory parameters which are modified following administration of zidovudine are becoming increasingly useful in monitoring the efficacy of treatment of early stages of HIV-1 infection. The serum levels of soluble interleukin (sILR)-2 receptor, which have been reported to increase early in HIV-1 infection, were found to be significantly lower in 24 patients being treated with zidovudine than in 69 patients who were not treated, 28 of whom had CD4+ counts greater than 400 x 10(6)/l, and 41 less than 400 x 10(6)/l, respectively (P less than 0.0001). A prospective study group of 33 subjects treated with zidovudine demonstrated a decrease in sIL-2R during therapy (base values 2113 +/- 1131 versus 1444 +/- 728 after 90 days of therapy; P less than 0.0007). The reduction of sIL-2R was greater in those subjects were p24 antigen became negative during treatment. sIL-2R therefore seems to be a useful tool in the monitoring of therapy with zidovudine.

Productive infection of CD4+ and CD8+ mature human T cell populations and clones by human herpesvirus 6. Transcriptional down-regulation of CD3

The susceptibility to infection by human herpes-virus 6 (HHV-6) of mature human T lymphocytes belonging to the two major subpopulations (i.e., CD3+ CD4+ CD8- and CD3+ CD4- CD8+) was investigated by using CD4+ or CD8+ T cell populations and clones derived from normal adult peripheral blood. Productive HHV-6 infection was observed in both CD4+ and CD8+ T cells. By days 2 to 6 after infection, increasing numbers of cells exhibited characteristic morphologic alterations, becoming enlarged, uniformly rounded and refractile as a consequence of the virus-induced cytopathic effect. During the course of HHV-6 infection, analysis of the surface membrane phenotype of the T cell populations and clones revealed a progressive decline in the expression of the CD3/TCR complex, whereas other T cell-associated markers (e.g., CD2) were unaffected. Northern blot analysis of mRNA extracted from HHV-6-infected T cells demonstrated a dramatic loss of the specific messages for the gamma-, delta-, and epsilon-chains of CD3. Infection by HHV-6, but not by HSV-1 or human CMV, elicited CD3/TCR down-regulation also in the neoplastic T cell line Jurkat. The down-regulation of CD3/TCR was dependent upon live virus infection, because previous inactivation of HHV-6 by heat (56 degrees C for 1 h) or UV light (16 J/m2) totally abrogated the effect. Expression of the immediate early or early genes of HHV-6 was not sufficient to induce CD3/TCR modulation, as indicated by studies with the viral DNA polymerase inhibitor phosphonoformic acid. The observation that both major subsets of mature TCR-alpha beta+ T lymphocytes are susceptible to HHV-6 infection indicates that this virus may have a broad spectrum of activity on the immune system. The transcriptional down-regulation of the CD3/TCR complex, by affecting a critical T cell recognition function, could be relevant to HHV-6 pathogenesis.

Productive infection of CD4+ and CD8+ mature human T cell populations and clones by human herpesvirus 6. Transcriptional down-regulation of CD3

The susceptibility to infection by human herpes-virus 6 (HHV-6) of mature human T lymphocytes belonging to the two major subpopulations (i.e., CD3+ CD4+ CD8- and CD3+ CD4- CD8+) was investigated by using CD4+ or CD8+ T cell populations and clones derived from normal adult peripheral blood. Productive HHV-6 infection was observed in both CD4+ and CD8+ T cells. By days 2 to 6 after infection, increasing numbers of cells exhibited characteristic morphologic alterations, becoming enlarged, uniformly rounded and refractile as a consequence of the virus-induced cytopathic effect. During the course of HHV-6 infection, analysis of the surface membrane phenotype of the T cell populations and clones revealed a progressive decline in the expression of the CD3/TCR complex, whereas other T cell-associated markers (e.g., CD2) were unaffected. Northern blot analysis of mRNA extracted from HHV-6-infected T cells demonstrated a dramatic loss of the specific messages for the gamma-, delta-, and epsilon-chains of CD3. Infection by HHV-6, but not by HSV-1 or human CMV, elicited CD3/TCR down-regulation also in the neoplastic T cell line Jurkat. The down-regulation of CD3/TCR was dependent upon live virus infection, because previous inactivation of HHV-6 by heat (56 degrees C for 1 h) or UV light (16 J/m2) totally abrogated the effect. Expression of the immediate early or early genes of HHV-6 was not sufficient to induce CD3/TCR modulation, as indicated by studies with the viral DNA polymerase inhibitor phosphonoformic acid. The observation that both major subsets of mature TCR-alpha beta+ T lymphocytes are susceptible to HHV-6 infection indicates that this virus may have a broad spectrum of activity on the immune system. The transcriptional down-regulation of the CD3/TCR complex, by affecting a critical T cell recognition function, could be relevant to HHV-6 pathogenesis.

Augmentation of monocyte chemotaxis by 1 alpha,25-dihydroxyvitamin D3. Stimulation of defective migration of AIDS patients

Preincubation for 20 h with 1 alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3) markedly augmented the chemotactic responsiveness of human blood monocytes to the classical chemoattractant, FMLP. A modest enhancement of monocyte spontaneous locomotion in the absence of chemoattractants was also observed. Maximal increase of monocyte migration was observed after pretreatment with 10(-9) M 1,25(OH)2D3 and was detectable at FMLP concentrations ranging from 10(-10) to 10(-7) M. Pretreatment with 1,25(OH)2D3 augmented the number of monocyte high affinity FMLP receptors (1500 +/- 220 and 3800 +/- 300 sites per cell for untreated and 1,25(OH)2D3-pretreated cells, respectively) with no significant changes in Kd values (2 +/- 0.5 nM and 4 +/- 1 nM, for untreated and 1,25(OH)2D3-pretreated monocytes). Enhanced chemotaxis was not restricted to FMLP, because 1,25(OH)2D3-treated monocytes showed enhanced migration also in response to activated C components and chemotactic cytokines. In agreement with previous observations, monocytes from AIDS patients showed defective migration capacity. In vitro exposure to 1,25(OH)2D3 stimulated monocyte migration in all 10 patients examined with considerable quantitative differences among individuals. Regulating the responsiveness of mature monocytes to chemo-attractants, 1,25(OH)2D3, produced systemically or in situ by immunocompetent cells, could play a role in the regulation of the recruitment of monocytes at sites of inflammation, cell-mediated immunity, or bone resorption. The potential of 1,25(OH)2D3 as a restorative agent under conditions of defective phagocyte recruitment deserves further exploration.