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Dive into the research topics where Marcelo Losso is active.

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Featured researches published by Marcelo Losso.


The Journal of Infectious Diseases | 2008

Major clinical outcomes in antiretroviral therapy (ART)-naive participants and in those not receiving ART at baseline in the SMART study.

Sean Emery; Jacqueline Neuhaus; Andrew N. Phillips; Abdel Babiker; Calvin Cohen; José M. Gatell; Pierre Marie Girard; Birgit Grund; Matthew Law; Marcelo Losso; Adrian Palfreeman; Robin Wood

BACKGROUND The SMART study randomized 5,472 human immunodeficiency virus (HIV)-infected patients with CD4+ cell counts >350 cells/microL to intermittent antiretroviral therapy (ART; the drug conservation [DC] group) versus continuous ART (the viral suppression [VS] group). In the DC group, participants started ART when the CD4+ cell count was <250 cells/microL. Clinical outcomes in participants not receiving ART at entry inform the early use of ART. METHODS Patients who were either ART naive (n=249) or who had not been receiving ART for >or= 6 months (n=228) were analyzed. The following clinical outcomes were assessed: (i) opportunistic disease (OD) or death from any cause (OD/death); (ii) OD (fatal or nonfatal); (iii) serious non-AIDS events (cardiovascular, renal, and hepatic disease plus non-AIDS-defining cancers) and non-OD deaths; and (iv) the composite of outcomes (ii) and (iii). RESULTS A total of 477 participants (228 in the DC group and 249 in the VS group) were followed (mean, 18 months). For outcome (iv), 21 and 6 events occurred in the DC (7 in ART-naive participants and 14 in those who had not received ART for >or= 6 months) and VS (2 in ART-naive participants and 4 in those who had not received ART for 6 months) groups, respectively. Hazard ratios for DC vs. VS by outcome category were as follows: outcome (i), 3.47 (95% confidence interval [CI], 1.26-9.56; p=.02); outcome (ii), 3.26 (95% CI, 1.04-10.25; p=.04); outcome (iii), 7.02 (95% CI, 1.57-31.38; p=.01); and outcome (iv), 4.19 (95% CI, 1.69-10.39; p=.002 ). CONCLUSIONS Initiation of ART at CD4+ cell counts >350 cells/microL compared with <250 cells/microL may reduce both OD and serious non-AIDS events. These findings require validation in a large, randomized clinical trial.Background. The SMART study randomized 5472 human immunodeficiency virus (HIV)-infected patients with CD4 + cell counts >350 cells/μL to intermittent antiretroviral therapy (ART; the drug conservation [DC] group) versus continuous ART (the viral supression [VS] group). In the DC group, participants started ART when the CD4 + cell count was 350 cells/μL compared with <250 cells/μL may reduce both OD and serious non-AIDS events. These findings require validation in a large, randomized clinical trial.


Pediatrics | 2007

Infectious Disease Morbidity Among Young HIV-1–Exposed But Uninfected Infants in Latin American and Caribbean Countries: The National Institute of Child Health and Human Development International Site Development Initiative Perinatal Study

Marisa M. Mussi-Pinhata; Laura Freimanis; Aparecida Yulie Yamamoto; James Korelitz; Jorge Andrade Pinto; Maria Letícia Santos Cruz; Marcelo Losso; Jennifer S. Read

OBJECTIVE. The goal was to describe the frequency, characteristics, and correlates of infectious disease morbidity during the first 6 months of life among HIV-1–exposed but uninfected infants. METHODS. The study population consisted of infants enrolled in the National Institute of Child Health and Human Development International Site Development Initiative Perinatal Study who were HIV-1 uninfected and had follow-up data through the 6-month study visit. Definitive and presumed infections were recorded at study visits (birth, 6–12 weeks, and 6 months). RESULTS. Of 462 HIV-1–uninfected infants with 11644 child-weeks of observation, 283 experienced ≥1 infection. These 283 infants experienced 522 infections (1.8 infections per infant). The overall incidence rate of infections was 4.5 cases per 100 child-weeks of observation. Overall, the most common infections were skin or mucous membrane infections (1.9 cases per 100 child-weeks) and respiratory tract infections (1.7 cases per 100 child-weeks). Thirty-six percent of infants had >1 respiratory tract infection (1.8 cases per 100 child-weeks). Incidence rates of upper and lower respiratory tract infections were similar (0.89 cases per 100 child-weeks and 0.9 cases per 100 child-weeks, respectively). Cutaneous and/or oral candidiasis occurred in 48 neonates (10.3%) and 92 older infants (19.3%). Early neonatal sepsis was diagnosed in 12 infants (26.0 cases per 1000 infants). Overall, 81 of 462 (17.5%) infants were hospitalized with an infection. Infants with lower respiratory tract infections were hospitalized frequently (40.7%). The occurrence of ≥1 neonatal infection was associated with more-advanced maternal HIV-1 disease, tobacco use during pregnancy, infant anemia, and crowding. Lower maternal CD4+ cell counts, receipt of intrapartum antibiotic treatment, and country of residence were associated with postneonatal infections. CONCLUSIONS. Close monitoring of HIV-1–exposed infants, especially those who are anemic at birth or whose mothers have more-advanced HIV-1 disease or who smoked during pregnancy, remains important.


The Journal of Infectious Diseases | 2000

A Randomized, Controlled, Phase II Trial Comparing Escalating Doses of Subcutaneous Interleukin-2 plus Antiretrovirals versus Antiretrovirals Alone in Human Immunodeficiency Virus—Infected Patients with CD4+ Cell Counts ⩾350/mm3

Marcelo Losso; W. H. Belloso; Sean Emery; Jorge Benetucci; Pedro Cahn; M. C. Lasala; G. Lopardo; Horacio Salomón; M. Saracco; E. Nelson; Matthew Law; Richard T. Davey; M. C. Allende; Lane Hc

A total of 73 patients with baseline CD4+ cell counts >/=350 cells/mm3 who were receiving combination antiretroviral therapy (ART) were randomized to receive subcutaneous interleukin-2 (IL-2; n=36) in addition to ART or to continue ART alone (n=37). Subcutaneous IL-2 was delivered at 1 of 3 doses (1.5 million international units ¿MIU, 4.5 MIU, and 7.5 MIU per dose) by twice-daily injection for 5 consecutive days every 8 weeks. After 24 weeks, the time-weighted mean change from baseline CD4+ cell count was 210 cells/mm3 for recipients of subcutaneous IL-2, compared with 29 cells/mm3 for recipients of ART alone (P<.001). There were no significant differences between treatment groups for measures of plasma human immunodeficiency virus RNA (P=.851). Subcutaneous IL-2 delivered at doses of 4.5 MIU and 7.5 MIU resulted in significant increases in CD4+ cell count (P=.006 and P<.001, respectively), compared with that seen in control patients. These changes were not significant in the 1.5 MIU dose group compared with that in the control patients (P=.105). Side effects that occurred from subcutaneous IL-2 administration were generally low grade, of short duration, and readily managed in an outpatient environment.


Journal of Virology | 2013

Sequence Analysis of In Vivo Defective Interfering-Like RNA of Influenza A H1N1 Pandemic Virus

Kazima Saira; Xudong Lin; Jay V. DePasse; Rebecca A. Halpin; Alan Twaddle; Timothy B. Stockwell; Brian Angus; Alessandro Cozzi-Lepri; Marina Delfino; Vivien G. Dugan; Dominic E. Dwyer; Matthew S. Freiberg; Andrzej Horban; Marcelo Losso; Ruth Lynfield; Deborah Wentworth; Edward C. Holmes; Richard T. Davey; David E. Wentworth; Elodie Ghedin

ABSTRACT Influenza virus defective interfering (DI) particles are naturally occurring noninfectious virions typically generated during in vitro serial passages in cell culture of the virus at a high multiplicity of infection. DI particles are recognized for the role they play in inhibiting viral replication and for the impact they have on the production of infectious virions. To date, influenza virus DI particles have been reported primarily as a phenomenon of cell culture and in experimentally infected embryonated chicken eggs. They have also been isolated from a respiratory infection of chickens. Using a sequencing approach, we characterize several subgenomic viral RNAs from human nasopharyngeal specimens infected with the influenza A(H1N1)pdm09 virus. The distribution of these in vivo-derived DI-like RNAs was similar to that of in vitro DIs, with the majority of the defective RNAs generated from the PB2 (segment 1) of the polymerase complex, followed by PB1 and PA. The lengths of the in vivo-derived DI-like segments also are similar to those of known in vitro DIs, and the in vivo-derived DI-like segments share internal deletions of the same segments. The presence of identical DI-like RNAs in patients linked by direct contact is compatible with transmission between them. The functional role of DI-like RNAs in natural infections remains to be established.


AIDS | 2011

Fatal and nonfatal Aids and non-aids events in Hiv-1-positive individuals with high Cd4 cell counts according to viral load strata

Joanne Reekie; José M. Gatell; Israel Yust; Elzbieta Bakowska; Aza Rakhmanova; Marcelo Losso; Maksym Krasnov; Patrick Francioli; Justyna D. Kowalska; Amanda Mocroft

Background:This study compared the incidence of fatal and nonfatal AIDS and non-AIDS events in HIV-positive individuals with a CD4 cell count more than 350 cells/&mgr;l among viral load strata: low (<500 copies/ml), intermediate (500–9999.9 copies/ml) and high (≥10000 copies/ml). Methods:Individuals contributed person-years at risk if their most recent CD4 cell count was more than 350 cells/&mgr;l. Follow-up was censored if their CD4 cell count dropped below 350 cells/&mgr;l. Poisson regression analysis investigated the relationship between viraemia and the incidence of AIDS and non-AIDS events. Results:Three hundred and fifty-four AIDS events occurred during 51 732 person-years of follow-up (PYFU), crude incidence rate of AIDS across the three strata was 0.53, 0.90 and 2.12 per 100 PYFU, respectively. After adjustment, a higher rate of AIDS was observed in individuals with moderate [incidence rate ratio (IRR) 1.44, 1.02–2.05, P = 0.03] and high viraemia had a higher rate (IRR 3.91, 2.89–5.89, P < 0.0001) compared with low viraemia. Five hundred and seventy-two non-AIDS events occurred during 43 784 PYFU, the crude incidence rates were 1.28, 1.52, and 1.38 per 100 PYFU, respectively. After adjustment, particularly for age, region of Europe and starting combination antiretroviral therapy, there was a 61% (IRR 1.61, 1.21–2.14, P = 0.001) and 66% (IRR 1.66, 1.17–2.32, P = 0.004) higher rate of non-AIDS in individuals with intermediate and high viraemia compared with low viraemia. Conclusion:In individuals with a CD4 cell count more than 350 cells/&mgr;l, an increased incidence of AIDS and a slightly increased incidence of non-AIDS was found in those with uncontrolled viral replication. The association with AIDS was clear and consistent. However, the association with non-AIDS was only apparent after adjustment and no differences were observed between intermediate and high viraemia.


Clinical Infectious Diseases | 2013

Contribution of Genetic Background, Traditional Risk Factors, and HIV-Related Factors to Coronary Artery Disease Events in HIV-Positive Persons

Margalida Rotger; Tracy R. Glass; Thomas Junier; Jens D. Lundgren; James D. Neaton; Estella S. Poloni; Angélique B. van 't Wout; Rubin Lubomirov; Sara Colombo; Raquel Martinez; Andri Rauch; Huldrych F. Günthard; Jacqueline Neuhaus; Deborah Wentworth; Daniëlle van Manen; Luuk Gras; Hanneke Schuitemaker; Laura Albini; Carlo Torti; Lisa Jacobson; Xiuhong Li; Lawrence A. Kingsley; Federica Carli; Giovanni Guaraldi; Emily S. Ford; Irini Sereti; Colleen Hadigan; Esteban Martínez; Mireia Arnedo; Lander Egaña-Gorroño

BACKGROUND Persons infected with human immunodeficiency virus (HIV) have increased rates of coronary artery disease (CAD). The relative contribution of genetic background, HIV-related factors, antiretroviral medications, and traditional risk factors to CAD has not been fully evaluated in the setting of HIV infection. METHODS In the general population, 23 common single-nucleotide polymorphisms (SNPs) were shown to be associated with CAD through genome-wide association analysis. Using the Metabochip, we genotyped 1875 HIV-positive, white individuals enrolled in 24 HIV observational studies, including 571 participants with a first CAD event during the 9-year study period and 1304 controls matched on sex and cohort. RESULTS A genetic risk score built from 23 CAD-associated SNPs contributed significantly to CAD (P = 2.9 × 10(-4)). In the final multivariable model, participants with an unfavorable genetic background (top genetic score quartile) had a CAD odds ratio (OR) of 1.47 (95% confidence interval [CI], 1.05-2.04). This effect was similar to hypertension (OR = 1.36; 95% CI, 1.06-1.73), hypercholesterolemia (OR = 1.51; 95% CI, 1.16-1.96), diabetes (OR = 1.66; 95% CI, 1.10-2.49), ≥ 1 year lopinavir exposure (OR = 1.36; 95% CI, 1.06-1.73), and current abacavir treatment (OR = 1.56; 95% CI, 1.17-2.07). The effect of the genetic risk score was additive to the effect of nongenetic CAD risk factors, and did not change after adjustment for family history of CAD. CONCLUSIONS In the setting of HIV infection, the effect of an unfavorable genetic background was similar to traditional CAD risk factors and certain adverse antiretroviral exposures. Genetic testing may provide prognostic information complementary to family history of CAD.


Journal of Acquired Immune Deficiency Syndromes | 2009

Hepatitis C Virus Coinfection Does Not Influence the CD4 Cell Recovery in HIV-1-Infected Patients With Maximum Virologic Suppression

Lars Peters; Amanda Mocroft; Vincent Soriano; Jiirgen Rockstroh; Marcelo Losso; Laure Valerio; Pauls Aldins; Peter Reiss; Bruno Ledergerber; Jens D. Lundgren

Background:Conflicting data exist whether hepatitis C virus (HCV) affects the CD4 cell recovery in patients with HIV starting antiretroviral treatment. Objective:To investigate the influence of HCV coinfection on the CD4 recovery in patients with maximum virologic suppression within the EuroSIDA cohort. Methods:Patients tested for anti-HCV antibodies and with at least 2 consecutive HIV viral loads (VLs) <50 copies per milliliter after starting combination antiretroviral therapy were eligible for inclusion. For each pair of VL <50 copies per milliliter, the annual change in CD4 count was calculated and compared between (1) HCV-seronegative vs. HCV-seropositive patients, (2) HCV genotypes 1-4 in HCV-RNA+ patients, and (3) viremic vs. aviremic (HCV-RNA < 615 IU/mL) in HCV-seropositive patients. Results were adjusted for known confounders. Results:Four thousand two hundred eight patients were included, representing 39,474 pairs of HIV VL measurements with VL <50 copies per milliliter and 12,492 person-years of follow-up. The unadjusted annual change in CD4 count for HCV-seropositive and HCV-seronegative patients was 35.5 cells per milliliter (95% confidence interval 27.2 to 43.9) and 38.3 cells per milliliter (95% confidence interval 34.8 to 41.9), respectively. After adjustment, there was no difference in CD4 change when comparing, according to HCV serostatus (P = 0.17), between genotypes (P = 0.23) or when comparing HCV viremic vs. aviremic patients (P = 0.57). Adjusting additionally for HCV treatment and HCV-RNA VL did not change the findings. Conclusions:HCV serostatus did not influence the CD4 recovery in patients with HIV with maximum virologic suppression after starting combination antiretroviral therapy. Furthermore, no difference in CD4 gain was found when comparing distinct HCV genotypes in HCV-RNA+ patients or when comparing HCV viremic vs. aviremic HCV-seropositive patients.


Obstetrics & Gynecology | 2007

Management of human immunodeficiency virus-infected pregnant women at Latin American and Caribbean sites.

Jennifer S. Read; Pedro Cahn; Marcelo Losso; Jorge Andrade Pinto; Esau Joao; Geraldo Duarte; Edmundo Cardoso; Laura Freimanis-Hance; Sonia K. Stoszek

OBJECTIVE: To describe the management of a population of human immunodeficiency virus (HIV)–infected pregnant women in Latin America and the Caribbean, and to assess factors associated with maternal viral load of 1,000 copies/mL or more and with infant HIV-1 infection. METHODS: Eligibility criteria were enrollment in the prospective cohort study as of March 2006; delivery of a liveborn, singleton infant; and completion of the 6-month postpartum or postnatal visit. RESULTS: Of 955 women enrolled in Argentina, the Bahamas, Brazil, and Mexico, 770 mother-infant pairs were eligible. At enrollment, most women were relatively healthy (87% asymptomatic, 59% with viral load less than 1,000 copies/mL, 62% with CD4+% of 25% or more). Most (99%) received antiretrovirals during pregnancy (56% prophylaxis, 44% treatment), and 38% delivered by cesarean before labor and before ruptured membranes. Only 18% of women had a viral load of 1,000 copies/mL or more after delivery (associated in adjusted analyses with receipt of antiretrovirals at conception, CD4+% [lower], viral load [higher], and country at enrollment, enrollment late in pregnancy, and inversely related to antiretroviral regimen [two nucleoside or nucleotide analogue reverse transcriptase inhibitors plus one nonnucleoside reverse transcriptase inhibitor] during pregnancy). None of the infants breastfed, and all received antiretroviral prophylaxis. Seven infants became infected (0.91%; 95% confidence interval 0.37–1.86). Low birth weight infants and those whose mothers had a low CD4+% at hospital discharge after delivery and were not receiving antiretrovirals at enrollment were at higher risk of HIV infection. CONCLUSION: Only a minority of women had a viral load of 1,000 copies/mL or more around delivery, and mother-to-child transmission of HIV occurred rarely (1%). LEVEL OF EVIDENCE: II


Clinical Infectious Diseases | 2004

CD4 Cell Response to 3 Doses of Subcutaneous Interleukin 2: Meta-analysis of 3 Vanguard Studies

Roberto C. Arduino; Esteban C. Nannini; Maria C. Rodriguez Barradas; Shannon Schrader; Marcelo Losso; Kiat Ruxrungtham; Maria C. Allende; Sean Emery; Lisa Fosdick; James D. Neaton; Jorge A. Tavel; Richard T. Davey; H. Clifford Lane

BACKGROUND In advance of a large clinical end point trial evaluating the effectiveness of subcutaneous interleukin 2 (scIL-2) for treatment of patients with human immunodeficiency virus (HIV) infection, 3 identically designed Vanguard trials were conducted in Buenos Aires, Argentina; Bangkok, Thailand; and Houston, Texas. To more precisely quantitate the effect on CD4 cell response of 3 different doses of scIL-2 that were administered twice daily for 5 days every 8 weeks, the results of these 3 trials were pooled in a meta-analysis. METHODS Two hundred eighteen HIV-1-infected subjects who were receiving antiretroviral therapy and who had a baseline CD4 cell count of > or =350 cells/mm3 were consecutively randomized to receive scIL-2 at a dose of 1.5 mIU (n=36) or a control regimen (n=36); or scIL-2 at a dose of 4.5 mIU (n=36) or a control regimen (n=36); or scIL-2 at a dose of 7.5 mIU (n=37) or a control regimen (n=37). After completion of 3 cycles of therapy, the subjects were enrolled in an extension phase (months 6-12). Subjects were encouraged to receive additional cycles of scIL-2 to maintain a CD4 cell count of more than twice the baseline count or >1000 cells/mm3. RESULTS After completion of 3 cycles of scIL-2, the mean CD4 cell count changes from baseline (calculated as changes from baseline in a scIL-2 group minus changes from baseline in its contemporaneous control group) were 67 (P=.14), 339 (P<.0001), and 605 cells/mm3 (P<.0001) for the 1.5, 4.5, and 7.5 mIU dose groups, respectively (P<.0001 for differences among dose groups). Between months 6 and 12, a total of 78%, 39%, and 32% of subjects assigned to the 1.5, 4.5, and 7.5 mIU dose groups, respectively, needed at least 1 additional cycle to achieve the CD4 cell count goal. At 12 months, the differences in the mean change in CD4 cell count from baseline between each scIL-2 dose group and its contemporaneous control group were 184, 369, and 432 cells/mm3, respectively (P=.01 for differences among dose groups). CONCLUSIONS Although CD4 cell count increases were seen in all 3 dose groups, higher scIL-2 doses resulted in greater CD4 cell count changes after 6 months, compared with control groups.


Journal of Hepatology | 2013

Does hepatitis C viremia or genotype predict the risk of mortality in individuals co-infected with HIV?

Jürgen K. Rockstroh; Lars Peters; Daniel Grint; Vincent Soriano; Peter Reiss; Antonella d'Arminio Monforte; Marek Beniowski; Marcelo Losso; Ole Kirk; Bernd Kupfer; Amanda Mocroft

BACKGROUND & AIMS The influence of HCV-RNA levels and genotype on HCV disease progression is not well studied. The prognostic value of these markers was investigated in HIV/HCV co-infected individuals from the EuroSIDA cohort. METHODS EuroSIDA is a prospective cohort of 18,295 HIV-1 infected patients in 105 centres across Europe, Israel, and Argentina. All subjects with known HCV antibody (HCVAb) status (n=13,025) were enrolled in the present study. RESULTS 4044 (31.0%) patients had detectable HCVAb. After adjustment, HCVAb+ patients had an increased incidence of liver-related death (LRD) compared to HCVAb- individuals (IRR 8.90; 95% CI 5.60-14.14, p<0.0001). Information on HCV-RNA was available for 2709 (67.0%) HCVAb+ patients and 2010 (74.2%) were HCV-RNA+. Of 1907 patients with measured HCV genotype, 1008 (52.9%), 62 (3.3%), 567 (29.7%), and 270 (14.2%) were infected with genotype 1, 2, 3 and 4, respectively. Patients with detectable HCV-RNA had similar incidence of non-LRD, but higher incidence of LRD compared to HCVAb+ aviremic patients (adjusted IRR 1.18; 95% CI 0.93-1.50, p=0.17) and (adjusted IRR 2.11; 95% CI 1.30-3.42, p=0.0025), respectively. In patients with HCV viremia, HCV-RNA levels and HCV genotype did not influence the risk of non-LRD or LRD. CONCLUSIONS HCV seropositive HIV patients had a 9-fold increased risk of LRD compared to patients who were HCV seronegative. Risk of death from any cause or LRD was not influenced by level of HCV viremia or HCV genotype.

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Amanda Mocroft

University College London

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Ole Kirk

University of Copenhagen

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Frank Post

University of Cambridge

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Jennifer S. Read

United States Department of Health and Human Services

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Sean Emery

University of New South Wales

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Niels Obel

Copenhagen University Hospital

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