Marina Giuliano

Antibody responses and persistence in the two years after immunization with two acellular vaccines and one whole-cell vaccine against pertussis

OBJECTIVE To evaluate the persistence of specific antibodies induced by primary immunization with three doses of two three-component acellular vaccines against pertussis with an observed efficacy of 84%, and one whole-cell vaccine with an observed efficacy of 36%. STUDY DESIGN Serum samples were collected from a subsample of 1572 children from the Italian double-blind, placebo-controlled, randomized trial of vaccines used in 15,601 children at three time points: before administration of the first dose of vaccine, and 1 month and approximately 15 months after administration of the third dose. Further evaluation included pooled cross-sectional analysis of serum specimens associated with episodes of cough (which were not laboratory confirmed as pertussis infection) occurring among the entire population enrolled in the trial. RESULTS With both acellular vaccines there was a fast and steep decrease in geometric mean antibody titers to pertussis toxin, filamentous hemagglutinin, and pertactin after vaccination. Mean titers were close to the limit of detection 15 months after primary immunization. The immunogenicity of the whole-cell study vaccine was poor 1 month after the third dose, and no antibody was detected in nearly all children 15 months after whole-cell vaccination. CONCLUSIONS Although the study acellular pertussis vaccines induced a strong primary specific antibody response in almost all recipients, the duration of the response was limited. Sustained high-level production of antibody to the antigens tested does not account for the observed efficacy of acellular pertussis vaccines.

A Randomized Trial of 2 Different 4-Drug Antiretroviral Regimens versus a 3-Drug Regimen, in Advanced Human Immunodeficiency Virus Disease

To compare long-term virologic benefits of antiretroviral regimens in persons with advanced human immunodeficiency virus (HIV) disease, a randomized, open-label study was conducted of 517 subjects with no or limited previous experience with antiretroviral therapy. Subjects received lamivudine plus zidovudine and indinavir (indinavir group), efavirenz plus indinavir (efavirenz + indinavir group), or nelfinavir plus indinavir (nelfinavir + indinavir group) and were monitored for 2.1 years. Virologic failure was lower in the efavirenz + indinavir group (P=.04) and higher in the nelfinavir + indinavir group (P=.006), compared with that in the indinavir group. No difference in grade 3 or 4 adverse event rates in the efavirenz + indinavir group (P=.97) and a trend toward an increased rate in the nelfinavir + indinavir group (P=.07), compared with the indinavir group, were noted. A 4-drug regimen containing efavirenz plus indinavir resulted in a superior virologic response, whereas one containing nelfinavir plus indinavir resulted in an inferior response and a greater likelihood of toxicity.

Persistence of protection through 33 months of age provided by immunization in infancy with two three-component acellular pertussis vaccines

A large, randomized, placebo-controlled clinical trial in Italy on two three-component pertussis vaccines, given as DTaP in infancy, one manufactured by SmithKline and Beecham (SB) and one by Chiron Biocine (CB), found each vaccine to be 84% efficacious through the average age of 24 months. The cohort of children enrolled in the trial was followed with unmodified case ascertainment procedures for nine additional calendar months, during which partial unblinding occurred, for the unvaccinated randomized group. For the DTaP groups, the specific vaccine assignment remained double-blinded throughout the entire additional observation period. Pertussis was defined as paroxysmal cough lasting at least 21 days and confirmed by culture or serology. In the additional 9 months the observed absolute efficacy was 78% (95% CI, 62-87%) for SB DTaP vaccine and 89% (95% CI, 79-94%) for CB DTaP. The relative risk of developing pertussis in SB DTaP recipients compared to CB DTaP vaccinees was 1.99 (95% CI, 1.13-3.51). By combining observations from the initial and additional follow-up periods, the overall observed vaccine efficacy through an average age of 33 months of SB DTaP was 80% and of CB DTaP, 85%.

Triple antiretroviral prophylaxis administered during pregnancy and after delivery significantly reduces breast milk viral load: A study within the Drug Resource Enhancement Against AIDS and Malnutrition Program.

Background:The administration of antiretroviral therapy to lactating women could represent a possible strategy to reduce postnatal HIV transmission. In this study, we assessed the effect of antiretroviral treatment on breast milk viral load and determined plasma and breast milk drug concentrations in pregnant women receiving highly active antiretroviral therapy (HAART). Methods:We studied 40 women receiving zidovudine, lamivudine, and nevirapine from 28 weeks of gestation to 1 month postpartum (group A) and 40 untreated pregnant women (group B). Blood and breast milk samples were collected at delivery and 7 days postpartum. Results:Women in group A had received a median of 85 days of therapy before delivery. Median breast milk concentrations of nevirapine, lamivudine, and zidovudine were 0.6, 1.8, and 1.1 times, respectively, those in maternal plasma. HIV RNA levels in breast milk were significantly lower in group A than in group B (median of 2.3 vs. 3.4 log at delivery and 1.9 vs. 3.6 log at day 7; P < 0.001 for both comparisons). Conclusions:Antiretroviral drugs administered during the last trimester of pregnancy and after delivery reach levels similar to or higher than plasma concentrations in breast milk and can significantly reduce HIV RNA levels. Our data support the potential role of maternal HAART prophylaxis in reducing the risk of breast-feeding-associated transmission.

Mode of infant feeding and HIV infection in children in a program for prevention of mother-to-child transmission in Uganda

Objective:To evaluate the impact of different modalities of infant feeding on HIV transmission in children in a prevention of mother-to-child transmission (PMTCT) program in an urban hospital in Uganda. Methods:HIV-infected pregnant women in the PMTCT program at St Francis Hospital Nsambya, Kampala were offered the chance to participate in the study. Short-course antiretroviral regimens were provided and formula feeding offered free of charge for women choosing not to breastfeed. Mother–infant pairs were followed until 6 months postpartum. HIV status in children was assessed at week 6 and month 6. For the analyses, mother–infant pairs were classified into three groups according to the mode of infant feeding: exclusive formula feeding (EFF), exclusive breastfeeding (EBF) and mixed feeding (MF). Results:A total of 306 children were enrolled. Transmission rates were 8.9% at week 6 (3.4% in the EFF group, 11.2% in the EBF group, 17.1% in the MF group) and 12.0% at month 6 (3.7% in the EFF group, 16.0% in the EBF group, and 20.4% in the MF group). The EBF and MF groups were associated with a significantly higher risk of HIV transmission than the EFF group. No significant risk difference was observed between the EBF and the MF groups. Conclusions:HIV transmission rates were significantly lower in formula-fed infants in comparison with both exclusively breastfed and mixed-fed infants. Transmission through breastfeeding seems to occur mainly in the first weeks after delivery.

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

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 (≥ 20 copies/106 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.

Effect of sex, age, and transmission category on the progression to AIDS and survival of zidovudine-treated symptomatic patients

ObjectiveTo evaluate the effect of transmission category and demographic, clinical and immunological characteristics on the progression to AIDS and survival of zidovudine-treated patients. DesignProspective multicentre cohort study of symptomatic non-AIDS patients. SettingEighty-three clinical centres reporting data to the National Zidovudine Registry. PatientsA total of 1468 patients enrolled between July 1987 and January 1991 were analysed. Main outcome measuresThree-year AIDS-free survival probability estimates since therapy start. Cox proportional hazards regression analysis was used to identify independent predictors of progression to AIDS and survival. ResultsFaster progression was associated with increasing age (8% risk increase for a 5-year increase), low baseline CD4+ count (39% risk increase for 100 × 106/l cells decrease), and zidovudine > 1000 mg/day (20% risk increase compared with ≤ 1000 mg/day). Homosexual men had a 33% risk increase compared with other risk groups. The presence of fever and oral candidiasis at enrolment were also independently associated with a higher risk of progression. Differences in the risk of progression were not significant between men and women. Older age, baseline CD4+ count, homosexual behaviour, fever and oral candidiasis were independently associated with a shorter survival. ConclusionsOur results confirm that age and baseline CD4+ count are independent predictors of progression, but do not provide evidence for differences in clinical outcome between the sexes. The higher risk of progression to AIDS and shorter survival for homosexual men appears to be correlated with the higher risk of developing Kaposis sarcoma.

Correlation between HIV-1 viral load quantification in plasma, dried blood spots, and dried plasma spots using the Roche COBAS Taqman assay

BACKGROUND The use of simplified methods for viral load determination could greatly increase access to treatment monitoring of HIV patients in resource-limited countries. OBJECTIVE The aim of the present study was to optimize and evaluate the performance of the Roche COBAS Taqman assay in HIV-RNA quantification from dried blood spots (DBS) and dried plasma spots (DPS). STUDY DESIGN EDTA blood samples from 108 HIV-infected women were used to prepare 129 DBS and 76 DPS on Whatman 903 card. DBS and DPS were stored at -20 degrees C. HIV-1 RNA was extracted from DBS/DPS using the MiniMAG system (bioMerieux). Amplification and detection were performed using the Roche COBAS TaqMan assay. Plasma viral load results were used as standard. RESULTS There was a high correlation between measures of viral load in plasma and in DBS/DPS (r=0.96 and 0.85 respectively, P<0.001). Overall, viral load values in DBS and DPS tended to be lower than in plasma with mean (SD) differences of 0.32 log(0.22) for DBS and of 0.35 (0.33) for DPS. Detection rates were 96.4% for DBS and 96.1% for DPS in samples with corresponding plasma values >3.0 log copies/ml. Samples with HIV-RNA below 50 copies/ml were correctly identified in 18/19 DBS and in 7/7 DPS. CONCLUSIONS Both DBS and DPS provided results highly correlated to the plasma values. High detection rate was obtained with both DBS and DPS when HIV-RNA was >3.0 log copies/ml. Our results support the use of DBS/DPS to detect virologic failure in resource-limited settings.

Effects of Clostridium Difficile toxins A and B on cytoskeleton organization in HEp-2 cells: A comparative morphological study

A comparative study on the effects of toxin A and toxin B from Clostridium difficile on HEp-2 cells was carried out. Both toxins caused cell retraction and rounding and seemed to exert their effect on cell morphology via a rearrangement of actin and alpha-actinin microfilaments. Such a rearrangement occurred at an early stage, when no change in microtubular and cytokeratin systems was detectable. Nevertheless, several structural modifications accompanying the cytopathological process induced by toxins A and B appeared to be quite different. In particular, toxin B-treated cells showed an arborized phenotype as a result of cell retraction and rounding, whereas toxin A caused cell rounding without arborization. Moreover, nuclear polarization following disorganization of the microfilament system was only observed in toxin A-treated cells. The structural features distinguishing intoxication processes induced by the two toxins probably reflect a different mechanism of action and suggest the presence of a distinct subcellular component as a primary target for each toxin.