Cytomegalovirus viremia in HIV-exposed and HIV-unexposed infants in Malawi

In sub-Saharan Africa the great majority of infants acquire Cytomegalovirus (CMV) infection within the first year of life. Maternal long-term antiretroviral therapy (ART) has been suggested to reduce the rate of CMV acquisition in HIV-exposed infants. In the present study serum samples collected at 6 months of age from HIV-exposed and HIV-unexposed infants were analyzed for the presence of CMV DNA (with CMV positivity defined by levels of CMV DNA > 1000 UI/ml). Twenty out of 58 (34.5%) infants had CMV DNA > 1000 UI/ml. There was no difference in the prevalence of CMV viremia between HIV-exposed and -unexposed infants [33.3% (15/45) vs 38.5% (5/13), respectively, P = 0.488]. In the HIV-exposed group, mothers of CMV-negative infants had received a longer antiretroviral treatment before delivery in comparison to mothers of CMV-positive infants (28 vs 3 months, P = 0.187). No differences in weights and lengths at birth, and at 1, 6 and 12 months were observed between CMV-positive and CMV-negative infants. In this study, the prevalence of CMV viremia at six months of age was high in infants born to HIV-positive mothers receiving long-term ART, similar to that of HIV-unexposed infants. Considering the possible relevant impact of CMV on infant health, strategies for containment of the infection should be explored.

Rates of Seroprotection against Vaccine-Preventable Infectious Diseases in HIV-Exposed and -Unexposed Malawian Infants

BACKGROUND

The evaluation of seroprotection rates against vaccine-preventable infectious diseases allows for the identification of risk populations. HIV-exposed infants, even if not infected with HIV, have higher morbidity and mortality in comparison to unexposed counterparts. The aim of this study was to compare the specific IgG levels against Haemophilus influenzae type-B (HiB), Hepatitis-B (HBV), and Streptococcus pneumoniae (Spn) in two groups of infants (HIV-exposed and HIV-unexposed) living in Malawi.

METHODS

Blood samples from 62 infants, 49 HIV-exposed, uninfected (HEU), and born to women living with HIV and 13 HIV-unexposed and uninfected (HUU), were collected at 6 months, and specific IgG levels were determined using ELISA tests.

RESULTS

The antibody levels against HiB, HBV, and Spn were similar in the two groups. At six months, all HUU infants and 81.6% of HEU infants showed seroprotective levels against HiB, while a percentage of protection varying from 80.6 to 84.6% was observed for HBV and Spn regardless of HIV exposure. Only 59.2% of HEU and 69.2% of HUU infants showed antibody protection against all three pathogens.

CONCLUSIONS

These results indicate similar rates of seroprotection among HEU and HUU infants but also suggest that a consistent fraction of infants received incomplete vaccinations. Strategies to enforce participation in immunization programs in Malawi should be a health priority.

Different configurations of SARS-CoV-2 spike protein delivered by integrase-defective lentiviral vectors induce persistent functional immune responses, characterized by distinct immunogenicity profiles

Several COVID-19 vaccine strategies utilizing new formulations for the induction of neutralizing antibodies (nAbs) and T cell immunity are still under evaluation in preclinical and clinical studies. Here we used Simian Immunodeficiency Virus (SIV)-based integrase defective lentiviral vector (IDLV) delivering different conformations of membrane-tethered Spike protein in the mouse immunogenicity model, with the aim of inducing persistent nAbs against multiple SARS-CoV-2 variants of concern (VoC). Spike modifications included prefusion-stabilizing double proline (2P) substitutions, mutations at the furin cleavage site (FCS), D614G mutation and truncation of the cytoplasmic tail (delta21) of ancestral and Beta (B.1.351) Spike, the latter mutation to markedly improve IDLV membrane-tethering. BALB/c mice were injected once with IDLV delivering the different forms of Spike or the recombinant trimeric Spike protein with 2P substitutions and FCS mutations in association with a squalene-based adjuvant. Anti-receptor binding domain (RBD) binding Abs, nAbs and T cell responses were detected up to six months from a single immunization with escalating doses of vaccines in all mice, but with different levels and kinetics. Results indicated that IDLV delivering the Spike protein with all the combined modifications, outperformed the other candidates in terms of T cell immunity and level of both binding Abs and nAbs soon after the single immunization and persistence over time, showing the best capacity to neutralize all formerly circulating VoC Alpha, Beta, Gamma and Delta. Although present, the lowest response was detected against Omicron variants (BA.1, BA.2 and BA.4/5), suggesting that the magnitude of immune evasion may be related to the higher genetic distance of Omicron as indicated by increased number of amino acid substitutions in Spike acquired during virus evolution.

Persistent immunogenicity of integrase defective lentiviral vectors delivering membrane-tethered native-like HIV-1 envelope trimers

Integrase Defective Lentiviral Vectors (IDLVs) represent an attractive vaccine platform for delivering HIV-1 antigens, given their ability to induce specific and persistent immune responses in both mice and non-human primates (NHPs). Recent advances in HIV-1 immunogen design demonstrated that native-like HIV-1 Envelope (Env) trimers that mimic the structure of virion-associated Env induce neutralization breadth in rabbits and macaques. Here, we describe the development of an IDLV-based HIV-1 vaccine expressing either soluble ConSOSL.UFO.664 or membrane-tethered ConSOSL.UFO.750 native-like Env immunogens with enhanced bNAb epitopes exposure. We show that IDLV can be pseudotyped with properly folded membrane-tethered native-like UFO.750 trimers. After a single IDLV injection in BALB/c mice, IDLV-UFO.750 induced a faster humoral kinetic as well as higher levels of anti-Env IgG compared to IDLV-UFO.664. IDLV-UFO.750 vaccinated cynomolgus macaques developed unusually long-lasting anti-Env IgG antibodies, as underlined by their remarkable half-life both after priming and boost with IDLV. After boosting with recombinant ConM SOSIP.v7 protein, two animals developed neutralization activity against the autologous tier 1B ConS virus mediated by V1/V2 and V3 glycan sites responses. By combining the possibility to display stabilized trimeric Env on the vector particles with the ability to induce sustained humoral responses, IDLVs represent an appropriate strategy for delivering rationally designed antigens to progress towards an effective HIV-1 vaccine.

Safety and efficiency modifications of SIV-based integrase-defective lentiviral vectors for immunization

Integrase-defective lentiviral vectors (IDLVs) represent an attractive platform for vaccine development as a result of the ability to induce persistent humoral- and cellular-mediated immune responses against the encoded transgene. Compared with the parental integrating vector, the main advantages for using IDLV are the reduced hazard of insertional mutagenesis and the decreased risk for vector mobilization by wild-type viruses. Here we report on the development and use in the mouse immunogenicity model of simian immunodeficiency virus (SIV)-based IDLV containing a long deletion in the U3 region and with the 3′ polypurine tract (PPT) removed from the transfer vector for improving safety and/or efficacy. Results show that a safer extended deletion of U3 sequences did not modify integrase-mediated or -independent integration efficiency. Interestingly, 3′ PPT deletion impaired integrase-mediated integration but did not reduce illegitimate, integrase-independent integration efficiency, contrary to what was previously reported in the HIV system. Importantly, although the extended deletion in the U3 did not affect expression or immunogenicity from IDLV, deletion of 3′ PPT considerably reduced both expression and immunogenicity of IDLV.

Isolation and Characterization of Mouse Monoclonal Antibodies That Neutralize SARS-CoV-2 and Its Variants of Concern Alpha, Beta, Gamma and Delta by Binding Conformational Epitopes of Glycosylated RBD With High Potency

Antibodies targeting Receptor Binding Domain (RBD) of SARS-CoV-2 have been suggested to account for the majority of neutralizing activity in COVID-19 convalescent sera and several neutralizing antibodies (nAbs) have been isolated, characterized and proposed as emergency therapeutics in the form of monoclonal antibodies (mAbs). However, SARS-CoV-2 variants are rapidly spreading worldwide from the sites of initial identification. The variants of concern (VOC) B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma) and B.1.167.2 (Delta) showed mutations in the SARS-CoV-2 spike protein potentially able to cause escape from nAb responses with a consequent reduction of efficacy of vaccines and mAbs-based therapy. We produced the recombinant RBD (rRBD) of SARS-CoV-2 spike glycoprotein from the Wuhan-Hu 1 reference sequence in a mammalian system, for mice immunization to isolate new mAbs with neutralizing activity. Here we describe four mAbs that were able to bind the rRBD in Enzyme-Linked Immunosorbent Assay and the transmembrane full-length spike protein expressed in HEK293T cells by flow cytometry assay. Moreover, the mAbs recognized the RBD in supernatants of SARS-CoV-2 infected VERO E6 cells by Western Blot under non-reducing condition or in supernatants of cells infected with lentivirus pseudotyped for spike protein, by immunoprecipitation assay. Three out of four mAbs lost their binding efficiency to completely N-deglycosylated rRBD and none was able to bind the same recombinant protein expressed in Escherichia coli, suggesting that the epitopes recognized by three mAbs are generated by the conformational structure of the glycosylated native protein. Of particular relevance, three mAbs were able to inhibit Wuhan SARS-CoV-2 infection of VERO E6 cells in a plaque-reduction neutralization test and the Wuhan SARS-CoV-2 as well as the Alpha, Beta, Gamma and Delta VOC in a pseudoviruses-based neutralization test. These mAbs represent important additional tools for diagnosis and therapy of COVID-19 and may contribute to the understanding of the functional structure of SARS-CoV-2 RBD.

Neutralizing antibody responses to SARS-CoV-2 in symptomatic COVID-19 is persistent and critical for survival

Understanding how antibody responses to SARS-CoV-2 evolve during infection may provide important insight into therapeutic approaches and vaccination for COVID-19. Here we profile the antibody responses of 162 COVID-19 symptomatic patients in the COVID-BioB cohort followed longitudinally for up to eight months from symptom onset to find SARS-CoV-2 neutralization, as well as antibodies either recognizing SARS-CoV-2 spike antigens and nucleoprotein, or specific for S2 antigen of seasonal beta-coronaviruses and hemagglutinin of the H1N1 flu virus. The presence of neutralizing antibodies within the first weeks from symptoms onset correlates with time to a negative swab result (p = 0.002), while the lack of neutralizing capacity correlates with an increased risk of a fatal outcome (p = 0.008). Neutralizing antibody titers progressively drop after 5-8 weeks but are still detectable up to 8 months in the majority of recovered patients regardless of age or co-morbidities, with IgG to spike antigens providing the best correlate of neutralization. Antibody responses to seasonal coronaviruses are temporarily boosted, and parallel those to SARS-CoV-2 without dampening the specific response or worsening disease progression. Our results thus suggest compromised immune responses to the SARS-CoV-2 spike to be a major trait of COVID-19 patients with critical conditions, and thereby inform on the planning of COVID-19 patient care and therapy prioritization.

Robust Neutralizing Antibodies to SARS-CoV-2 Develop and Persist in Subjects with Diabetes and COVID-19 Pneumonia

CONTEXT

Demonstrating the ability to mount a neutralizing antibody response to SARS-CoV-2 in the presence of diabetes is crucial to understand COVID-19 pathogenesis, reinfection potential, and vaccine development.

OBJECTIVE

The aim of this study was to characterize the kinetics and durability of neutralizing antibody (Nab) response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the presence of hyperglycemia.

METHODS

Using a lentiviral vector-based SARS-CoV-2 neutralization assay to measure Nabs, we characterized 150 patients randomly selected from a cohort of 509 patients with confirmed COVID-19 pneumonia. We analyzed Nab response according to the presence of diabetes or hyperglycemia, at the time of hospitalization and during the postdischarge follow-up: 1-, 3-, and 6-month outpatient visits.

RESULTS

Among 150 randomly selected patients 40 (26.6%) had diabetes. Diabetes (hazard ratio [HR] 8.9, P < .001), glucose levels (HR 1.25 × 1.1 mmol/L, P < .001), and glucose variability (HR 1.17 × 0.6 mmol/L, P < .001) were independently associated with an increased risk of mortality. The neutralizing activity of SARS-CoV-2 antibodies in patients with diabetes was superimposable, as for kinetics and extent, to that of patients without diabetes. It was similar across glucose levels and correlated with the humoral response against the SARS-CoV-2 spike protein. Positivity for Nabs at the time of hospital admission conferred protection on mortality, both in the presence (HR 0.28, P = .046) or absence of diabetes (HR 0.26, P = .030). The longevity of the Nab response was not affected by diabetes.

CONCLUSION

Diabetes and hyperglycemia do not affect the kinetics and durability of the neutralizing antibody response to SARS-CoV-2. These findings provide the rational to include patients with diabetes in the early phase of the vaccination campaign against SARS-CoV-2.

Integrase-Defective Lentiviral Vector Is an Efficient Vaccine Platform for Cancer Immunotherapy

Integrase-defective lentiviral vectors (IDLVs) have been used as a safe and efficient delivery system in several immunization protocols in murine and non-human primate preclinical models as well as in recent clinical trials. In this work, we validated in preclinical murine models our vaccine platform based on IDLVs as delivery system for cancer immunotherapy. To evaluate the anti-tumor activity of our vaccine strategy we generated IDLV delivering ovalbumin (OVA) as a non-self-model antigen and TRP2 as a self-tumor associated antigen (TAA) of melanoma. Results demonstrated the ability of IDLVs to eradicate and/or controlling tumor growth after a single immunization in preventive and therapeutic approaches, using lymphoma and melanoma expressing OVA. Importantly, LV-TRP2 but not IDLV-TRP2 was able to break tolerance efficiently and prevent tumor growth of B16F10 melanoma cells. In order to improve the IDLV efficacy, the human homologue of murine TRP2 was used, showing the ability to break tolerance and control the tumor growth. These results validate the use of IDLV for cancer therapy.

Development and Preclinical Evaluation of an Integrase Defective Lentiviral Vector Vaccine Expressing the HIVACAT T Cell Immunogen in Mice

Cellular immune responses play a fundamental role in controlling viral replication and AIDS progression in human immunodeficiency virus (HIV)-infected subjects and in simian immunodeficiency virus (SIV)-infected macaques. Integrase defective lentiviral vector (IDLV) represents a promising vaccine candidate, inducing functional and durable immune responses in mice and non-human primates. Here, we designed HIV- and SIV-based IDLVs to express the HIVACAT T cell immunogen (HTI), a mosaic antigen designed to cover vulnerable sites in HIV-1 Gag, Pol, Vif, and Nef. We observed that HTI expression during lentiviral vector production interfered profoundly with IDLV particles release because of sequestration of both HIV- and SIV-Gag proteins in the cytoplasm of the vector-producing cells. However, modifications in IDLV design and vector production procedures greatly improved recovery of both HIV- and SIV-based IDLV-HTI. Immunization experiments in BALB/c mice showed that both IDLVs elicited HTI-specific T cell responses. However, immunization with HIV-based IDLV elicited also a T cell response toward exogenous HIV proteins in IDLV particles, suggesting that SIV-based IDLV may be a preferable platform to assess the induction of transgene-specific immune responses against rationally designed HIV structural antigens. These data support the further evaluation of IDLV as an effective platform of T cell immunogens for the development of an effective HIV vaccine.

Markers of microbial translocation during pregnancy: differences among HIV+ women of African and European provenance

INTRODUCTION

Microbial translocation (MT) markers are indicators of HIV-related immune activation, but reference values are mostly derived from European or North American populations and could be substantially different in populations living in developing countries. Here we evaluate possible differences in MT markers levels in HIV+ pregnant women of different geographical provenance.

METHODOLOGY

This study is nested within an observational study of pregnant women with HIV in Italy. Women were dichotomized on the basis of provenance in two groups of European (n = 14) and African (n = 26) origin. Soluble CD14, lipopolysaccharide-binding protein (LBP) and intestinal-fatty acid binding protein (I-FABP) were measured in plasma samples collected between the first and second trimester of pregnancy.

RESULTS

Demographic and viroimmunological characteristics were similar between groups, although European women were more commonly smokers and HCV-coinfected. Irrespective of origin, LBP plasma levels were positively correlated with I-FABP (r = 0.467, p = 0.004) and sCD14 levels (r = 0.312 p = 0.060). Significantly higher levels of sCD14 (1885 vs. 1208 ng/mL, p = 0.005) LBP (28.5 vs. 25.3 µg/mL, p = 0.050) and I-FABP (573.4 vs. 358.2 pg/mL, p = 0.002) were observed in European compared with African women. A multivariable linear regression analysis, adjusted for smoking and HCV coinfection confirmed the association between sCD14 levels and women provenance (p = 0.03).

CONCLUSIONS

Our observations indicate significant differences in soluble markers among women of different provenance. In the design and analysis of studies evaluating MT markers, population-specific reference values should be considered.

High CMV IgG antibody levels are associated to a lower CD4+ RESPONSE to antiretroviral therapy in HIV-infected women

BACKGROUND

Virtually all HIV-infected women in sub-Saharan Africa have evidence of Cytomegalovirus (CMV) infection and levels of specific anti-CMV IgG have been suggested to represent more intense reactivation of subclinical infection. Studies have also shown direct influence of CMV on lymphocytes.

OBJECTIVE

The aim of this study was to determine if levels of anti-CMV specific antibodies could impact on the immunological response to antiretroviral treatment (ART) in HIV-infected pregnant women.

STUDY DESIGN

CMV-specific IgG were measured in HIV-infected pregnant women at 26 weeks of gestation (before ART initiation). Women received ART until 6 months postpartum or indefinitely according to local guidelines at the time of the study. Immunological and virological responses were assessed 6 months and 24 months after delivery.

RESULTS

A total of 81 women were studied. At baseline high levels (above the median) of specific IgG were associated to a low CD4+ cell count (P<0.001), a high viral load (P=0.003), and to an older age (P=0.051). In a multivariate model adjusting for baseline CD4+ count, baseline viral load and age, the presence of low levels of CMV IgG was the only independent predictor of a a CD4+ count above 500/mm³ 24 months after delivery among women on continuous therapy.

CONCLUSIONS

In this cohort, levels of CVM IgG had a significant influence on the immunological response to ART, adding information to the known impact of CMV infection in the HIV-positive population, and underlining the need of new strategies to contain the infection.

Virological failure at one year in triple-class experienced patients switching to raltegravir-based regimens is not predicted by baseline factors

We evaluated rates and determinants of virological failure in triple-class experienced patients receiving raltegravir-based regimens from a national observational study over 48 weeks, defined by any one of the following: (1) no HIV-RNA suppression to undetectable levels (<50 copies/mL) during follow-up; (2) detectable viral load after obtaining undetectable levels; and (3) leaving the study before 48 weeks. Among 101 eligible patients, 26 (25.7%; 95% CI 17.2–34.2) had virological failure. No significant differences between patients with and without virological failure were observed for gender, age, route of transmission, baseline CD4/HIV-RNA, CDC group, hepatitis B or C co-infections, resistance (based on the last genotype available), type and number of concomitant drug classes, concomitant use of darunavir, atazanavir, etravirine, enfuvirtide or maraviroc, and health-related quality-of-life measures. A high rate of treatment response was observed. The analyses did not identify any baseline factor associated with failure, including resistance status. Even if we cannot exclude the presence of pre-existing minority resistant variants not captured by genotypic tests, the lack of baseline predictors of failure suggests the need to monitor patients closely during follow up for other factors, such as potential drug interactions and reduced levels of adherence, which may favour virological failure.

CMV infection in a cohort of HIV-exposed infants born to mothers receiving antiretroviral therapy during pregnancy and breastfeeding

Antiretroviral therapy has been shown to reduce rates of congenital CMV infection. Little information is available on the possible impact of antiretroviral therapy on postnatal breastfeeding-associated CMV infection acquisition. A cohort of 89 HIV-infected mothers and their children was studied. Women received antiretroviral therapy from week 25 of gestation until 6 months postpartum or indefinitely if meeting the criteria for treatment. All women were evaluated for CMV IgG presence and CMV DNA in breast milk. Children were tested for CMV infection by either the presence of IgM or the presence of CMV DNA in plasma at 1, 6 and 12 months and by the presence of IgG at 24 months. All mothers had high titers of CMV DNA in breast milk (5.7 log at Month 1 and 5.1 log at Month 6). Cumulative CMV infection rates were 60.3 % at Month 6, 69 % at Month 12 and 96.4 % at Month 24. There was a significant negative correlation between the duration of antiretroviral treatment during pregnancy and levels of CMV DNA in breast milk at Month 1 (P = 0.033). There was a trend for a correlation between high titers of CMV DNA in breast milk at 6 months and CMV infection at 6 months (P = 0.069). In this cohort, more than 95 % of the children had acquired CMV infection by 2 years of age. Besides breastfeeding, which played a major role, also horizontal transmission between 1 and 2 years was certainly relevant in determining CMV infection acquisition.

Virological Response and Drug Resistance 1 and 2 Years Post-Partum in HIV-Infected Women Initiated on Life-Long Antiretroviral Therapy in Malawi

The objective of this study was to determine the virological response and the possible emergence of drug resistance at 1 and 2 years postpartum in HIV-positive pregnant women enrolled under the Option B approach and meeting the criteria for treatment. In the study, women with baseline CD4(+) <350/mm(3) received a combination of stavudine, lamivudine, and nevirapine during pregnancy (from week 25 of gestation) and continued it indefinitely after delivery. HIV-RNA was measured at 12 and 24 months postpartum. Drug resistance mutations were assessed in those with HIV-RNA >50 copies/ml. Baseline resistance mutations were assessed in the entire cohort. A total of 107 women were studied. At baseline, resistance mutations were seen in 6.6% of the women. At 12 months, 26.7% of the women had >50 copies/ml and among them 12.9% had virological failure (HIV-RNA >1,000 copies/ml). At 24 months, detectable HIV-RNA was seen in 28.3% of the women and virological failure in 10.1% of the women. Resistance mutations (mainly non-nucleoside reverse transcriptase inhibitors mutations) were seen in 40% of the women with detectable HIV-RNA. Baseline mutations did not correlate with virological failure or the emergence of resistance at later time points. Virological failure 2 years postpartum and emergence of resistance were rare in this cohort of HIV-infected women. These findings are reassuring in the light of the new strategies for the prevention of mother-to-child HIV transmission, recommending life-long antiretroviral therapy administration.

HIV-1 DNA dynamics and variations in HIV-1 DNA protease and reverse transcriptase sequences in multidrug-resistant patients during successful raltegravir-based therapy

There is limited information on the variations of HIV-1 DNA mutation profile in reverse transcriptase (RT) and protease (PR) genes during suppressive antiretroviral treatment (plasma HIV-1 RNA continuously <50 copies/ml) with raltegravir (RAL)-based regimens in patients with baseline RT/PR resistant HIV. Twelve multidrug resistant (RT: 12/12, PR: 8/12) HIV-infected patients were followed during effectively suppressive RAL-based therapy. Total and integrated HIV-1 DNA were assessed by real time PCR at baseline and every 6 months. Ultrasensitive (threshold: 2.5 copies/ml) plasma HIV-1 RNA and genotypic analysis of RT and PR in proviral DNA were performed at baseline and at 24 months. Half of the patients had full viral suppression (plasma HIV-RNA < 2.5 copies/ml) at month 12. Total HIV-1 DNA declined significantly after 12 months of therapy (from 249.2 to 145.7 copies/10⁶ cells, P = 0.023), and remained stable until 24 months, when total HIV-1 DNA levels raised, concomitantly with a less stringent suppression of HIV-1 RNA (81.8% of patients with >2.5 copies/ml). Integrated HIV-1 DNA did not show fluctuations during the study period. Sequencing of the PR and RT regions from HIV-1 DNA revealed changes in the resistance mutation profile in five patients. Total HIV-1 DNA declined after the introduction of RAL-based therapy, with a rebound after 2 years. No changes were observed in levels of integrated DNA, suggesting limited effect on archived HIV. The RT and PR sequence changes in archived HIV-1 DNA suggest that variation of the mutation profile can occur even in the absence of detectable HIV-1 RNA. J. Med. Virol. 88:2115-2124, 2016. © 2016 Wiley Periodicals, Inc.

Hepatitis B virus mother-to-child transmission among HIV-infected women receiving lamivudine-containing antiretroviral regimens during pregnancy and breastfeeding

The study included 309 HIV-infected pregnant women receiving a lamivudine-containing antiretroviral regimen from week 25 of gestational age until 6 months postpartum, during breastfeeding. Twenty-seven of them (8.7%) were hepatitis B virus surface antigen (HBsAg) positive; at baseline, hepatitis B virus (HBV) DNA levels >3 log(10) IU/mL (with a median level of 6.2 log(10) IU/mL) were found in 10 women, who at one, three and six months postpartum had median levels of 5.2 log(10) IU/mL, 4.5 log(10) IU/mL and 2.8 log(10) IU/mL, respectively. Twenty-four of the 30 breast milk samples evaluated had undetectable HBV DNA and the other six had values between 15 and 155 IU/mL. Median lamivudine concentrations were 1070 ng/mL in serum and 684 ng/mL in breast milk. Among the 24 HBV-exposed children with available samples, 16 always tested negative, four had a transient infection, one had an undetermined status and three (12.5%) first tested positive at Month 12 or Month 24. Among the children born to the HBV-uninfected mothers of the same cohort, the rate of HBsAg positivity at 12-24 months was 2% (4/196). Our finding of the absence of significative levels of HBV DNA in the breast milk of co-infected mothers supports the present recommendations for breastfeeding in HBV-infected women. Horizontal transmission can be hypothesized for the infections detected in children at 12-24 months. Children born to HBV-positive mothers remained at higher risk of postnatal HBV acquisition compared to those born to HBV-negative women.

Rate and determinants of residual viremia in multidrug-experienced patients successfully treated with raltegravir-based regimens

Residual HIV viremia, defined by low levels of plasma HIV RNA with enhanced-sensitivity assays, may persist even in the presence of successful antiretroviral therapy, but little is known about its determinants. Our objective was to evaluate the rate and determinants of residual viremia in patients who show stable undetectable plasma HIV-1 RNA with conventional assays. Forty-four multidrug-experienced patients with undetectable levels of HIV RNA for at least 2 years under raltegravir-based regimens were evaluated. An ultrasensitive (2.5 copies/ml) real-time PCR method was used to quantify plasma HIV RNA. After 12 months of salvage treatment, 48.3% of the patients had residual viremia between 2.5 and 37 copies/ml. The proportion of patients with plasma HIV RNA below 2.5 copies/ml decreased from 51.7% at 12 months to 30.8% at 24 months. The presence of residual viremia was not associated with levels of viremia before starting raltegravir. Considering CD4 counts, hepatitis B or C virus (HBV or HCV) coinfection, or other demographic characteristics, for the time interval between HIV diagnosis and initiation of antiretroviral therapy, patients with a longer interval (>1 year) were significant less likely to have RNA levels below 2.5 copies/ml at 12 months compared to patients who started therapy within 1 year of HIV diagnosis (28.6% vs. 73.3%, p=0.027). Half of the patients showing undetectable HIV viremia with conventional assays had low-level viremia with ultrasensitive assays, with no predictive role of viroimmunological status at the start of the regimen. The potential influence of the interval between HIV diagnosis and initiation of treatment should be confirmed in subjects with a known date of seroconversion.

The impact of HBV or HCV infection in a cohort of HIV-infected pregnant women receiving a nevirapine-based antiretroviral regimen in Malawi

Background

Coinfection with the hepatitis viruses is common in the HIV population in sub-Saharan Africa. The aim of this study was to assess, in a cohort of HIV-infected pregnant women receiving antiretroviral drugs (ARVs), the prevalence of HBV and HCV infections and to determine the impact of these infections on the occurrence of liver toxicity and on the viro-immunological response.

Methods

Women were screened for HBsAg and HCV-RNA before starting, at week 25 of gestational age, an antiretroviral regimen consisting of lamivudine and nevirapine plus either stavudine or zidovudine. Women with CD4+ < 350/mm³ continued ARVs indefinitely, while the other women interrupted treatment 6 months postpartum (end of breastfeeding period). Both groups were followed for 2 years after delivery. Liver function was monitored by alanine aminotransferase (ALT) measurement. The Cox proportional hazards model was used to identify factors associated with the emergence of liver toxicity.

Results

A total of 28 women out of the 309 enrolled in the study (9.1%) were coinfected with HBV (n. 27), or HCV (n. 1). During follow-up 125 women (40.4%) developed a grade ≥ 1 ALT elevation, 28 (9.1%) a grade ≥ 2 and 6 (1.9%) an elevation defining grade 3 toxicity. In a multivariate model including age, baseline CD4+ count and hemoglobin level, the presence of either HBV or HCV infection was significantly associated with the development of an ALT increase of any grade (P = 0.035). Moderate or severe liver laboratory toxicity (grade ≥ 2) was more frequent among women with baseline CD4+ > 250/mm³ (P = 0.030). In HBV-infected women a baseline HBV-DNA level above 10,000 IU/ml was significantly associated to the development of liver toxicity of grade ≥ 1 (P = 0.040). Coinfections had no impact on the immunological and virological response to antiretroviral drugs up to 2 years after delivery.

Conclusions

In this cohort of nevirapine-treated women the presence of HBV or HCV was associated only to the development of mild liver toxicity, while the occurrence of moderate or severe hepatoxicity was correlated to a baseline CD4+ count > 250/mm³. No statistically significant effect of the coinfections was observed on the efficacy of antiretroviral therapy.

HIV-1 coreceptor switch during 2 years of structured treatment interruptions

The purpose of this investigation was to determine the impact on human immunodeficiency virus (HIV) tropism of uncontrolled virus exposure during 2 years of intermittent highly active antiretroviral therapy (HAART). The Istituto Superiore di Sanità-Pulsed Antiretroviral Therapy (ISS-PART) randomized study compared the outcome of 2 years of structured treatment interruptions (STIs) versus standard continuous treatment in first-line HAART responder subjects. The STI schedule consisted of five STIs of 1, 1, 2, 2, and 3 months, respectively, separated by four periods of 3-month therapy. In the present study, coreceptor tropism was assessed in 12 patients of the STI arm at different time points over a period of 2 years. Tropism was determined on DNA and RNA by V3 loop region sequencing. The Geno2pheno algorithm (false-positive rate, FPR: 20%) was used for data interpretation. At baseline, 9/12 subjects (75.0%) had CCR5-tropic viruses in their HIV. Three had a CXCR4-tropic virus. Ten patients maintained the same coreceptor in DNA after 2 years, whereas in two patients, a shift occurred (one R5-X4, one X4-R5). In a patient with an R5 virus at baseline, a transient change to X4 tropism was seen in the rebounding virus during STI. Changes in tropism were not associated with the amplitude and duration of virus exposure during STIs, residual viremia at baseline, or the development of resistance mutations in the RT region. Our preliminary results suggest that viral replication, observed after short periods of treatment interruption, is not enough to drive the evolution of HIV tropism.

Evolution of proviral DNA HIV-1 tropism under selective pressure of maraviroc-based therapy

OBJECTIVES

To evaluate the evolution of HIV-1 coreceptor tropism in proviral DNA of patients during maraviroc-based therapy.

METHODS

Fourteen heavily high active antiretroviral therapy (HAART)-treated patients with a CCR5 Trofile profile were monitored over a 24 month period from the start of maraviroc therapy. Whole-blood samples were obtained at different timepoints, and coreceptor tropism was determined for proviral DNA from the V3-loop region sequence using the Geno2Pheno algorithm [false positive rate (FPR): 20%].

RESULTS

At the start of maraviroc treatment, 13/14 patients were viraemic (median: 4.33 log copies/mL). Concordance in R5 tropism (R5/R5) was observed between circulating HIV-RNA (Trofile) and HIV-DNA provirus in 10/14 patients (median FPR = 54.0%), while 4 patients showed a CXCR4-tropic R5/X4 variant in their provirus (FPR: 5.8%, 5.7%, 16.6% and 1.1%, respectively). All R5/R5 patients showed a stable HIV-1 DNA coreceptor usage. Two out of four R5/X4 patients showed a tropism shift in their archived provirus and, after 6 months a prevalence of R5-tropic virus was detected in DNA. The other two R5/X4 patients harboured the 11/25 genotype, and maintained X4 tropism in provirus during the study. Virological response did not reveal differences in RNA decay and CD4+ cell recovery in patients with discordant tropism.

CONCLUSIONS

A relatively good correlation between RNA and DNA tropism was observed at baseline. Proviral DNA tropism remained stable over 24 months of maraviroc-based therapy, indicating that determination of proviral DNA V3 sequence could be used in tropism prediction in clinical practice. The data also confirm the importance of the 11/25 rule in predicting viral tropism.

Quantification of HIV-RNA from dried blood spots using the Siemens VERSANT® HIV-1 RNA (kPCR) assay

OBJECTIVES

Simplified methods for virological monitoring in resource-limited settings are increasingly needed. We evaluated the performance of the VERSANT(®) HIV-1 RNA (kPCR) assay for the determination of HIV-1 viral load from dried blood spots (DBS). Assay sensitivity and correlation with plasma quantification values were assessed.

METHODS

A total of 98 DBS were prepared from fresh blood samples of HIV-infected patients. DBS were kept at room temperature for 6 weeks or 7 months before processing while the corresponding plasma samples were stored at -80°C. DBS were first pre-treated in a special DBS buffer. The DBS extracts and the plasma samples were then purified and amplified using the VERSANT assay reagents.

RESULTS

In the first series of tests, performed after 6 weeks of storage, there was good correlation between quantification of viral load in plasma and in DBS (r = 0.95, P < 0.001). The detection rate in DBS was 100% when plasma levels were >1000 copies/mL. The sensitivity and specificity of the DBS assay were 88.2% [95% confidence interval (CI) 79.4-93.6] and 69.2% (95% CI 42.0-87.4), respectively. Using the 5000 copies/mL threshold (defining virological failure in resource-limited settings), both positive and negative predictive values were high (95.2% and 87.5%, respectively). After 7 months of storage there was a modest decrease in the detection rate and less significant correlations for samples with HIV-RNA <5000 copies/mL.

CONCLUSIONS

Quantification of HIV-RNA from DBS by the VERSANT automated sample preparation and detection method can be used to diagnose virological failure in HIV-positive patients.

Microbial translocation is associated with residual viral replication in HAART-treated HIV+ subjects with <50copies/ml HIV-1 RNA

BACKGROUND

Recent data have shown that plasma levels of lipopolysaccharide (LPS) are a quantitative indicator of microbial translocation in HIV infected individuals.

OBJECTIVES

To assess the impact of residual viral replication on plasma LPS in HAART-treated HIV+ subjects with <50copies/ml HIV-1 RNA and to evaluate LPS changes during repeated HAART interruptions not exceeding 2-month duration.

STUDY DESIGN

LPS was measured in 44 HIV+ subjects at T0 (during HAART) and at day 15 of the first and fourth HAART interruption. Ten uninfected, healthy donors were studied as well. Residual plasma HIV-1 RNA was measured at T0 by an ultra-ultrasensitive method with limit of detection of 2.5copies HIV-1 RNA/ml. Subjects with less than 2.5copies/ml (fully suppressed - FS) were compared to those with 2.5-50copies/ml (partially suppressed - PS).

RESULTS

At T0, plasma LPS levels were comparable in FS and uninfected subjects, whereas in PS they were higher than in uninfected subjects (p=0.049). After 4 HAART interruptions, they did not change significantly. However, LPS values were lower in FS than in PS (p=0.020). An inverse correlation was found between CD4 and LPS levels (p=0.044) in PS group only.

CONCLUSIONS

A reduced degree of microbial translocation was seen in subjects with a more complete suppression of viral replication. Repeated HAART interruptions had no significant impact on plasma LPS levels.

Comparison of HIV type 1 sequences from plasma, cell-free breast milk, and cell-associated breast milk viral populations in treated and untreated women in Mozambique

We analyzed the sequences of the HIV viral populations obtained from plasma, cell-free breast milk, and breast milk cells of HAART-treated (23) and untreated (30) HIV-infected women to obtain information about the origin of the breast milk virus. Sequence analyses of viruses were performed using the TruGene HIV-1 assay. Direct sequences of the reverse transcriptase (RT) and protease (PR) genes were analyzed using the Phylip 3.68 suite of sequence analysis program and pairwise evolutionary distances were calculated with the Kimura two parameter model for estimation of distances. We found that the genetic distances between the plasma and the cell-free breast milk viruses and between the cell-free and cell-associated breast milk viruses for RT were higher in HAART-receiving women than in untreated women, suggesting viral evolution under selective drug pressure in breast milk. Our data support the hypothesis of the presence of an actively replicating viral population in the breast milk compartment, distinct from that present in plasma.

Pharmacokinetics of nelfinavir in HIV-1-infected pregnant and nonpregnant women

AIMS

To compare steady-state nelfinavir (NFV) pharmacokinetics in pregnant and nonpregnant HIV-infected women.

METHODS

Twenty-five pregnant HIV-infected women were selected from an ongoing observational study evaluating the pharmacokinetics of antiretroviral agents during pregnancy. Twenty of them were in the third and five in the second trimester. Data for the control group of 21 HIV-infected nonpregnant women were taken from a previous multicentre pharmacokinetic trial. All the participating women achieved steady-state plasma concentrations while on a highly active antiretroviral therapy (HAART) regimen including NFV (1250 mg bid) and two nucleoside reverse transcriptase inhibitors (NRTIs). Blood samples for NFV measurement were collected predose (C(trough)) and at 0.5, 1, 2, 3, 4, 5, 6, 8 and 12 h post dose.

RESULTS

During the third trimester of pregnancy NFV AUC(0-12 h) median (range) values were 25.76 (12.61-42.74) microg h(-1) ml(-1), and were 32.49 (19.16-63.81) microg h(-1) ml(-1) in the control group [mean difference - 9.30 microg h(-1) ml(-1); 95% confidence interval (CI) -15.76, -2.83; P < 0.05). Median oral clearance (CL/F) was significantly higher in pregnant women than in the control group (48.5 l h(-1), range 29.3-99.1 l h(-1) vs. 38.5 l h(-1), range 19.6-65.2 l h(-1); mean difference 12.6 l h(-1); 95% CI 3.3, 21.9) but the difference disappeared when CL/F was adjusted for body weight. C(trough) was significantly (P < 0.01) lower in pregnant compared with nonpregnant women (median 0.8 microg ml(-1), range 0-2.6 microg ml(-1) vs. 1.5 microg ml(-1), range 0.5-4.9 microg ml(-1); mean difference -1.0 microg ml(-1); 95% CI -1.7, -0.31). The median elimination half-life of NFV observed during pregnancy was 3.7 h (range 1.4-6.6 h), compared with 5.2 (range 3.1-10.1 h) in the control group (mean difference -1.7; 95% CI -2.8, -0.51).

CONCLUSIONS

Our results indicate that women in the later stages of pregnancy may be exposed to subtherapeutic concentrations of NFV. Thus, adjustments in drug dosage or frequency of administration may be required.

Residual viraemia in subjects with chronic HIV infection and viral load < 50 copies/ml: the impact of highly active antiretroviral therapy

OBJECTIVE

To determine factors associated with < 2.5 copies/ml plasma HIV RNA in subjects treated with highly active antiretroviral therapy (HAART) and with viraemia < 50 copies/ml.

DESIGN

Cross-sectional analysis of 84 HIV-positive patients taking HAART with plasma HIV RNA < 50 copies/ml for at least 6 months and no history of virological failure.

METHODS

Current HAART therapy was based on a non-nucleoside reverse transcriptase inhibitor (NNRTI) in 66%, a protease inhibitor in 26% and nucleoside reverse transcriptase inhibitors in 7%. Viraemia levels were measured using a modified ultrasensitive Roche Amplicor HIV-1 Monitor test able to quantify plasma HIV RNA to a lower limit of 2.5 copies /ml; proviral DNA was measured with a real-time polymerase chain reaction assay. Analysis of variance and multiple logistic regression analysis were utilized to test for associations between residual replication and other variables.

RESULTS

Residual HIV viraemia > 2.5 copies/ml was found in 50% of subjects; 94% of subjects had detectable proviral DNA (>or= 20 copies/10(6) peripheral blood mononuclear cells) and 21% had archived mutations. Usage of a NNRTI-based HAART was the only independent predictor of viral suppression below the cut-off value of the modified ultrasensitive assay.

CONCLUSIONS

In our population, NNRTI-based HAART seems to have a stronger impact on residual replication than protease inhibitor-based HAART. This finding may be considered in therapeutic decisions such as the choice of initial HAART regimen and the interruption or simplification of treatment.

Risk factors and occurrence of rash in HIV-positive patients not receiving nonnucleoside reverse transcriptase inhibitor: data from a randomized study evaluating use of protease inhibitors in nucleoside-experienced patients with very low CD4 levels (<50 cells/mmuL)

BACKGROUND

Most of the studies evaluating rash in HIV-positive patients have focused on nonnucleoside reverse transcriptase inhibitors (NNRTI), particularly nevirapine, and little is known about the occurrence of rash and the risk factors for its development in patients receiving regimens not based on NNRTI.

METHODS

We evaluated all cases of rash observed during a 48-week randomized multicentre trial in 1251 nucleoside-experienced patients who started treatment with protease inhibitors (ritonavir or indinavir) at CD4 counts below 50 cells/microL. Incidence rates for rash were calculated according to gender, clinical status, age, use of highly active antiretroviral therapy (HAART), Pneumocystis carinii pneumonia (PCP) prophylaxis and use of individual antiretroviral drugs at enrollment. Differences between groups defined according to the above characteristics were tested for statistical significance using the log-rank test in a Kaplan-Meier survival analysis. All factors that gave results in the univariate analyses below the significance level of 0.05 were included in a multivariate analysis using a Cox regression model.

RESULTS

During a follow-up period of 9690 person-months, 66 patients (5.3%) developed rash (0.68 events/100 person-months). In the univariate analyses, risk of rash did not differ with trial treatment (indinavir or ritonavir), clinical status, PCP prophylaxis, or age. During follow-up, rash was observed in 7.5% of enrolled women and in 4.5% of enrolled men (P=0.03). Serious rash occurred in 4.5% of enrolled women and in 1.6% of enrolled men (P=0.003). Use of HAART (P<0.001) and inclusion of zidovudine and of zalcitabine in the prescribed regimen (P=0.02) appeared to be associated with a lower risk of rash. In the multivariate analysis, the variables that remained significantly predictive of rash were gender (risk for women compared to men: 1.65, 95% confidence interval (CI): 1.00-2.72, P=0.048) and use of a non-HAART regimen (risk for non-HAART patients compared to HAART: 2.73, 95% CI: 1.49-5.02, P=0.001).

CONCLUSIONS

In our study, about 5% of HIV-positive patients who started treatment with protease inhibitors at very low CD4 counts developed rash, generally in the first few weeks after treatment. Risk was significantly higher in women and in patients who did not receive a HAART regimen. Our data indicate that women have a higher risk of rash than men, also with regimens that do not include NNRTI.

HIV-related morbidity and mortality in patients starting protease inhibitors in very advanced HIV disease (CD4 count of < 50 cells/microL): an analysis of 338 clinical events from a randomized clinical trial

BACKGROUND

AIDS defining events occur infrequently in the presence of CD4 counts above 200 cells/microL. It is, however, uncertain for most of the AIDS defining conditions whether this threshold can be considered equally safe in patients with a previously very low CD4 nadir.

METHODS

We evaluated in detail all the AIDS defining events observed during a 48-week clinical trial in 1251 nucleoside reverse transcriptase inhibitor-experienced patients who started protease inhibitors (PIs) at CD4 counts below 50 cells/microL. The type of event, immunological status at the moment of event and time between start of PI treatment and event occurrence were analysed cumulatively and by event type; event rates were calculated.

RESULTS

Concomitant data on CD4 counts were available for 338 AIDS defining events (81% of total events). Median time between start of treatment with PI and event was 94.5 days and median absolute CD4 value at the occurrence of event was 20 per microL. Only 14 events (in 12 patients) were observed above the threshold of 200 CD4 cells/microL. An analysis of the 67 deaths with concomitantly available CD4 counts (57%) showed a median CD4 count of 10 cells/microL, with only four deaths occurring in the presence of a CD4 count above 100 cells/microL.

CONCLUSIONS

Very few clinical AIDS defining conditions were observed in patients who start PIs at very low CD4 counts and with treatment restore absolute values in CD4 counts above 200 cells/microL. This threshold can therefore be considered a clinically effective goal of treatment with respect to occurrence of all AIDS defining conditions in patients starting PIs in very advanced HIV disease.

A randomized trial comparing the introduction of ritonavir or indinavir in 1251 nucleoside-experienced patients with advanced HIV infection

ISS-IP1, a multicenter, randomized, 48-week open trial, was designed to compare the introduction of ritonavir or indinavir in patients with previous nucleoside experience and CD4+ cell counts below 50/mm3. Concomitant antiretroviral treatment with nucleoside analogs was allowed. Primary efficacy measures were survival and time to a new AIDS-defining event or death, analyzed through the whole period of observation by the intention-to-treat approach. Primary toxicity measures were time to treatment discontinuation and adverse events, grade at least 3/serious, analyzed by an on-treatment approach. Evaluation-of efficacy also included CD4+ cell and RNA response. The trial enrolled 1251 patients in 5 months. At baseline, mean CD4+ cell count was about 20 cells/mm3 and mean HIV RNA copy number was 4.9 log10/ml in both groups. Overall, 402 patients in the ritonavir group and 250 patients in the indinavir group permanently discontinued the assigned treatment (relative risk, 1.96; 95% CI, 1.68-2.30; p = 0.0001), with most of this difference dependent on a higher number of discontinuation for adverse events in the ritonavir group. After a mean follow-up of 307 days (ritonavir, 304; indinavir, 309), 124 deaths (ritonavir, 61; indinavir, 63; relative risk, 0.96; 95% CI, 0.67-1.36; p = 0.80) and 330 new AIDS-defining events (ritonavir, 170; indinavir, 160; relative risk, 1.05; 95% CI, 0.85-1.31; p = 0.60) were observed. CD4+ cell counts increased in both groups in patients still receiving treatment, with about 100 cells gained by week 24 and 150 cells gained by week 48. Body weight also increased over time in both groups. Analysis of RNA response showed a decrease of 1.5 log10 or higher in both treatment groups. Overall, 400 patients in the ritonavir group and 338 patients in the indinavir group developed at least one grade 3/serious new adverse event during follow-up (relative risk, 1.48; 95% CI, 1.28-1.72; p = 0.0001). Favorable CD4+ cell and RNA responses at 24 and 48 weeks were observed in both groups of patients remaining on treatment. Indinavir showed slightly better effects in sustaining RNA, CD4+ cell, and body weight responses. Ritonavir and indinavir results were comparable in terms of clinical outcome (survival and AIDS-defining events).

Quality of life outcomes of combination zidovudine- didanosine-nevirapine and zidovudine-didanosine for antiretroviral-naive advanced HIV-infected patients

OBJECTIVES

To evaluate the quality of life outcomes in antiretroviral-naive patients randomized to zidovudine plus didanosine versus zidovudine plus didanosine plus nevirapine for treatment of advanced HIV disease (the Istituto Superiore di Sanità 047 trial).

DESIGN

A 48-week randomized, double-blind trial.

METHODS

Sixty patients were enrolled and evaluated over 24 weeks. Quality of life was assessed using a modified version of the Medical Outcomes Study-HIV Health Survey. For analysis, we calculated two summary scores reflecting the physical (PHS) and the mental (MHS) components of health.

RESULTS

Although the three-drug combination was superior at inducing immunologic and virologic responses, the two-drug regimen was superior for both PHS and MHS, especially at week 8 where differences were both statistically and clinically significant (5.8 and 9.2 points, respectively, P< 0.02 for both). Quality of life changes paralleled trends in body weight and Karnofsky performance status score.

CONCLUSION

Although a three-drug antiretroviral therapy regimen was superior in terms of short term virologic/immunologic response, the two-drug regimen was better in terms of quality of life. In general, triple therapy remains the most effective treatment option. However, quality of life assessments can yield results that may be discordant with and complementary to those obtained using conventional endpoints. Comparative trials should collect a comprehensive range of outcome measures, including patient-reported quality of life, in order to provide clinicians and patients with additional information that may influence treatment decisions.

Plasma HIV-1 copy number and in vitro infectivity of plasma prior to and during combination antiretroviral treatment

Some studies on untreated patients have shown a general correlation between plasma HIV copy number and plasma infectivity in in vitro models. Recent observations also indicate that HIV-RNA level is an important predictor of perinatal transmission and may also have a role in heterosexual transmission. To further analyse the correlation between HIV viral load and plasma infectivity, we studied the relationship between HIV-1 plasma copy number and plasma infectivity prior to and during treatment with antiretroviral combination regimens in HIV-1 infected adults. Plasma infectivity was assessed in vitro by coculture of plasma from HIV-positive patients with PHA-stimulated fresh PBMC from uninfected donors. A positive plasma isolation, in almost all cases (43/45) and irrespective of treatment status, was associated with an HIV viral load higher than 100000 copies per ml, with higher plasma HIV-1 RNA values in isolation-positive samples compared with isolation-negative samples (median values, 710000 vs. 37500 copies per ml, respectively). SI and NSI strains had similarly high viral load values (470000 vs. 790000 copies per ml), but CD4 counts were lower in the SI phenotype group. Our data indicate that low levels of viral load are only exceptionally associated with isolation from plasma in the in vitro model we used. This observation confirms indirectly the presence of an association between viral load and infectivity. The requisite of a high plasma viral load in order to obtain infectivity (i.e. positivity of HIV isolation from plasma) also seems maintained under antiretroviral treatment, adding confidence in the conclusion that reductions in viral load translate into reduction of plasma infectivity. Due to the extreme complexity of factors determining transmission, a very prudent interpretation of the results is essential when information from experimental studies has to be transferred to clinical situations requiring assessment of risks or clinical decisions.

Hospitalizations and costs of treatment for protease inhibitor-based regimens in patients with very advanced HIV-infection (CD4 < 50/mm(3))

PURPOSE

To describe the cost of hospitalization and treatment in patients with very advanced disease who tart different regimens based on a protease inhibitor (PI).

METHOD

An observational retrospective analysis was performed on data from a 48-week randomized, multicenter study. Analysis was based on a subgroup of centers that were geographically defined. Costs of ordinary hospital admissions and of antiretroviral treatment were considered. Incidence of hospitalization and number of days free from hospitalization during the period of observation were calculated. Cost and hospitalization measures were compared among patients receiving three different therapeutic regimens: only PI, PI plus one nucleoside, or PI plus two nucleosides. A multivariate analysis was used to assess cost differences, controlling for variables potentially able to influence outcome.

RESULTS

Overall, among 166 patients starting PI (PI plus two nucleosides, 71;PI plus one nucleoside, 65; only PI, 30), 162 ordinary hospital admissions were observed during about 1 year of follow-up. Monthly rates of admission per person and incidence of first hospitalization on 100 person-months showed a clear inverse relationship with the number of drugs comprising the baseline treatment regimen, with the lower rates for the triple therapy group (0.06 and 3.9, respectively), intermediate values for the dual therapy group (0.10 and 8.1, respectively), and higher rates for the PI monotherapy group (0.15 and 13.7, respectively). The average number of days free from hospitalization per month was 29.5 in the triple therapy group, 28.6 in the dual therapy group, and 27.9 in the monotherapy group. The results of cost analysis showed, despite higher cost of antiretroviral treatment, that global costs were progressively lower using regimens of increasing potency: Compared to PI monotherapy, global cost (costs of antiretroviral treatment and of hospitalizations combined) per month per patient was 31.9% lower for the triple therapy group and 19.3% lower for the dual therapy. Global cost for the triple therapy was 15.7% lower compared to global cost for dual therapy. After adjustment for CD4 count, AIDS status, and Karnofsky score, both hospitalization costs and global costs were significantly lower for triple therapy compared to monotherapy (p =.002 and.039, respectively).

CONCLUSION

In advanced and nucleoside-experienced patients, PI-containing regimens have a differential impact according to the overall strength of the regimen, with the best effects on both hospitalizations and treatment costs obtained using PI within potent combination regimens.

Prevalence and characteristics of multinucleoside-resistant human immunodeficiency virus type 1 among European patients receiving combinations of nucleoside analogues

The prevalence and the genotypic and phenotypic characteristics of multinucleoside-resistant (MNR) human immunodeficiency virus type 1 (HIV-1) variants in Europe were investigated in a multicenter study that involved centers in nine European countries. Study samples (n = 363) collected between 1991 and 1997 from patients exposed to two or more nucleoside analogue reverse transcriptase inhibitors (NRTIs) and 274 control samples from patients exposed to no or one NRTI were screened for two marker mutations of multinucleoside resistance (the Q151M mutation and a mutation with a 2-amino-acid insertion at codon 69, T69S-XX). Q151M was identified in six of the study samples (1. 6%), and T69S-XX was identified in two of the study samples (0.5%; both of them T69S-SS), but both patterns were absent among control samples. Non-NRTI (NNRTI)-related changes were observed in viral strains from two patients, which displayed the Q151M resistance pattern, although the patients were NNRTI naive. The patients whose isolates displayed multinucleoside resistance had received treatment with zidovudine and either didanosine, zalcitabine, or stavudine. Both resistance patterns conferred broad cross-resistance to NRTIs in vitro and a poor response to treatment in vivo. MNR HIV-1 is found only among multinucleoside-experienced patients. Its prevalence is low in Europe, but it should be closely monitored since it seriously limits treatment options.

A randomized, double-blind trial on the use of a triple combination including nevirapine, a nonnucleoside reverse transcriptase HIV inhibitor, in antiretroviral-naive patients with advanced disease

The immunologic and virologic activity of nevirapine in combination with two nucleosides (zidovudine [ZDV] and didanosine [ddI]) was evaluated in antiretroviral-naive patients with a CD4 count <200/mm3 or clinical AIDS. In all, 68 patients were enrolled in a 48-week double-blind, placebo-controlled trial. A group of 32 patients received ZDV + ddI + nevirapine, and 36 patients received ZDV + ddI. Primary efficacy parameters were the activity on HIV-1 RNA and on peripheral blood CD4+ cells, with differences between groups analyzed by the Wilcoxon's nonparametric two-sample test. Baseline RNA was high in both treatment groups (median values, 5.8 and 5.7 log10). RNA and CD4 responses were significantly higher with the triple combination (median RNA reductions, 2.69 versus 1.05 log10 at 24 weeks and 1.97 versus 1.20 log10 at 48 weeks; median CD4 increases, 81 versus 64 cells/mm3 at 24 weeks and 101 versus 27 cells/mm3 at 48 weeks). This study demonstrates that a triple combination of ZDV + ddI + nevirapine used as first-line regimen in antiretroviral-naive patients can induce sustained virologic and immunologic response in patients with low CD4 count or a previous diagnosis of AIDS.

Long-term evaluation of cellular immunity during antiretroviral therapy and immunization with human immunodeficiency virus type 1 (HIV-1) Env glycoprotein in HIV-1-infected persons

Cellular immune responses to human immunodeficiency virus type 1 (HIV-1) antigens, microbial recall antigens, and CD3 monoclonal antibody were studied in HIV-1-infected asymptomatic patients in a phase II, double-blind trial of immunization with recombinant HIV-1 gp160 in or not in association with zidovudine. A vigorous and persistent lymphoproliferative response (LPR) to HIV-1 Env antigens was observed in vaccinated patients. Neither Env-specific lymphocyte cytotoxicity nor LPR to recall antigens was significantly influenced by gp160 administration. The induction of LPRs to HIV-1 envelope proteins did not show positive effects on the course of HIV-1 infection. Patients treated with zidovudine alone or in combination with the immunogen showed improvement of T lymphocyte responses and transient reduction of viremia. These results suggest that antiretroviral therapy is more beneficial than immunization with gp160 and should always be considered in association with future vaccination and immunotherapeutic interventions in HIV-1-infected subjects.

Correlation between changes in plasma HIV RNA levels and in plasma infectivity in response to antiretroviral therapy

We evaluated the degree of correlation between the variation of different HIV-1 viral load measures in response to antiretroviral therapy. A quantitative reverse transcriptase polymerase chain reaction (RT-PCR) for plasma HIV-RNA, and HIV plasma infectivity titration, were performed on prospective samples obtained from 86 antiretroviral-naive patients with symptomatic infection and CD4+ < 300/mm3, enrolled in a randomized double-blind trial of the HIV protease inhibitor saquinavir (SQV) in combination with zidovudine (ZDV). Subjects were stratified according to plasma virus infectivity and examined for correlations between distinct response categories with respect to CD4 count and HIV RNA copy number changes. Infectious virus could be titrated in 72% of patients at baseline. A significant reduction (< 1 log10) in HIV plasma infectivity titer was observed during the study in 69% of these patients. The reduction in plasma infectivity was a good predictor of sustained CD4+ cell increases and of sustained decrease in HIV RNA plasma copies. A decrease of at least 0.5 log10 in HIV RNA copy number was observed in 82% of the treated patients. A good correlation was found between HIV plasma infectivity titer and plasma HIV RNA copy number variations (p < 0.001). However, 10 of 17 patients with unchanged plasma infectivity titer showed a significant reduction in HIV RNA copies. While a good correlation was found between plasma infectivity and RNA plasma copies variations, only a minor correlation was found between CD4+ cell count variation and plasma infectivity titer variation. However, reduction in plasma infectivity was a very good predictor of high CD4 changes.

Effect of antibiotics on polycation-treated Escherichia coli HB101 (pRI203)

In the present paper, we demonstrated that low concentrations of various polycationic agents sensitize E. coli HB 101 harboring the plasmid pRI203, containing the Y. pseudotuberculosis invasion region, to antibiotics rifampicin, amikacin, ceftazidime and cefotaxime. These antibiotics, known to be excluded, to various degrees, by the bacterial outer membrane, resulted several-fold more active towards polycation-treated bacteria by comparison with controls. This increased permeability to antibiotics of E. coli HB 101 (pRI203) probably depends upon the binding of polycations to the acidic moieties of lipopolysaccharide, as already suggested for other gram-negative bacteria.