ESPER GEORGES KALLAS

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Departamento de Moléstias Infecciosas e Parasitárias, Faculdade de Medicina - Docente
LIM/60 - Laboratório de Imunologia Clínica e Alergia, Hospital das Clínicas, Faculdade de Medicina - Líder

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  • article 4 Citação(ões) na Scopus
    HIV-1 genetic diversity and divergence and its correlation with disease progression among antiretroviral naive recently infected individuals
    (2020) LEDA, Ana Rachel; HUNTER, James; OLIVEIRA, Ursula Castro de; AZEVEDO, Inacio Junqueira de; KALLAS, Esper G.; SUCUPIRA, Maria Cecilia Araripe; DIAZ, Ricardo Sobhie
    HIV-1 genetic diversity evolution was deeply characterized during the first year of infection among recently-infected patients using deep sequencing technology and correlated with disease progression surrogate markers. RNA and DNA samples from twenty-five individuals (13 female) encoding the protease and reverse transcriptase regions of the poi gene, and the V3 region of the env gene were evaluated at recent infection and during established infection. Infection by a unique HIV-1 strain was inferred in 70.1% of the individuals, with no differences between genders. Infections by multiple strains were associated with higher viral loads and faster CD4(+) T cell declines. Either low or high levels of viral loads accompanied low levels of genetic diversity and lower selective pressure. With massive sequence data from 3 distinct genomic HIV-1 regions from plasma and PBMCs over time, we propose a model for HIV-1 genetic diversity, which correlates to basal viral loads of patients.
  • article 13 Citação(ões) na Scopus
    Cellular immune correlates analysis of an HIV-1 preexposure prophylaxis trial
    (2015) KUEBLER, Peter J.; MEHROTRA, Megha L.; MCCONNELL, J. Jeff; HOLDITCH, Sara J.; SHAW, Brian I.; TAROSSO, Leandro F.; LEADABRAND, Kaitlyn S.; MILUSH, Jeffrey M.; YORK, Vanessa A.; RAPOSO, Rui Andre Saraiva; CHENG, Rex G.; ERIKSSON, Emily M.; MCMAHAN, Vanessa; GLIDDEN, David V.; SHIBOSKI, Stephen; GRANT, Robert M.; NIXON, Douglas F.; KALLAS, Esper G.
    HIV-1-specific T-cell responses in exposed seronegative subjects suggest that a viral breach of the exposure site is more common than current transmission rates would suggest and that host immunity can extinguish subsequent infection foci. The Preexposure Prophylaxis Initiative (iPrEx) chemoprophylaxis trial provided an opportunity to rigorously investigate these responses in a case-control immunology study; 84 preinfection peripheral blood mononuclear cell samples from individuals enrolled in the iPrEx trial who later seroconverted were matched with 480 samples from enrolled subjects who remained seronegative from both the placebo and active treatment arms. T-cell responses to HIV-1 Gag, Protease, Integrase, Reverse Transcriptase, Vif, and Nef antigens were quantified for all subjects in an IFN-gamma enzyme-linked immunospot (ELISpot) assay. IFN-gamma responses varied in magnitude and frequency across subjects. A positive response was more prevalent in those who remained persistently HIV-1-negative for Gag (P = 0.007), Integrase (P < 0.001), Vif (P < 0.001), and Nef (P < 0.001). When correlated with outcomes in the iPrEx trial, Vif- and Integrase-specific T-cell responses were associated with reduced HIV-1 infection risk [hazard ratio (HR) = 0.36, 95% confidence interval (95% CI) = 0.19-0.66 and HR = 0.52, 95% CI = 0.28-0.96, respectively]. Antigen-specific responses were independent of emtricitabine/tenofovir disoproxil fumarate use. IFN-gamma secretion in the ELISpot was confirmed using multiparametric flow cytometry and largely attributed to effector memory CD4+ or CD8+ T cells. Our results show that HIV-1-specific T-cell immunity can be detected in exposed but uninfected individuals and that these T-cell responses can differentiate individuals according to infection outcomes.
  • conferenceObject
    ELEVATED ROS LEVELS AND DNA FRAGMENTATION IN SPERM FROM CONVALESCENT MEN IN SARS-COV-2 INFECTION
    (2022) HALLAK, Jorge; BERNARDES, Felipe; TEIXEIRA, Thiago Afonso Carvalho Celestino; SALDIVA, Paulo Hilario Nascimento; KALLAS, Esper Georges; CALDINI, Elia Tamaso Espin Garcia; DUARTE NETO, Amaro Nunes; FAQUINETI, Heloisa; JESUS, Vinicius Luiz Menezes; GUTIERREZ, Raul Segundo Sanchez; DREVET, Joel R.
  • article 5 Citação(ões) na Scopus
    Lower numbers of natural killer T cells in HIV-1 and Mycobacterium leprae co-infected patients
    (2012) CARVALHO, Karina I.; BRUNO, Fernanda R.; SNYDER-CAPPIONE, Jennifer E.; MAEDA, Solange M.; TOMIMORI, Jane; XAVIER, Marilia B.; HASLETT, Patrick A.; NIXON, Douglas F.; KALLAS, Esper G.
    Natural killer T (NKT) cells are a heterogeneous population of lymphocytes that recognize antigens presented by CD1d and have attracted attention because of their potential role linking innate and adaptive immune responses. Peripheral NKT cells display a memory-activated phenotype and can rapidly secrete large amounts of pro-inflammatory cytokines upon antigenic activation. In this study, we evaluated NKT cells in the context of patients co-infected with HIV-1 and Mycobacterium leprae. The volunteers were enrolled into four groups: 22 healthy controls, 23 HIV-1-infected patients, 20 patients with leprosy and 17 patients with leprosy and HIV-1-infection. Flow cytometry and ELISPOT assays were performed on peripheral blood mononuclear cells. We demonstrated that patients co-infected with HIV-1 and M.leprae have significantly lower NKT cell frequencies [median 0.022%, interquartile range (IQR): 0.0070.051] in the peripheral blood when compared with healthy subjects (median 0.077%, IQR: 0.0320.405, P < 0.01) or HIV-1 mono-infected patients (median 0.072%, IQR: 0.0300.160, P < 0.05). Also, more NKT cells from co-infected patients secreted interferon-? after stimulation with DimerX, when compared with leprosy mono-infected patients (P = 0.05). These results suggest that NKT cells are decreased in frequency in HIV-1 and M.leprae co-infected patients compared with HIV-1 mono-infected patients alone, but are at a more activated state. Innate immunity in human subjects is strongly influenced by their spectrum of chronic infections, and in HIV-1-infected subjects, a concurrent mycobacterial infection probably hyper-activates and lowers circulating NKT cell numbers.
  • article 0 Citação(ões) na Scopus
    From trials to the public health: pre-exposure prophylaxis for HIV prevention
    (2013) KALLAS, Esper Georges; MIRAGLIA, Luiz Joao
  • article 3 Citação(ões) na Scopus
    Attitudes and Knowledge About Human Immunodeficiency Virus Pre-Exposure Prophylaxis Among Brazilian Infectious Disease Physicians
    (2020) CERQUEIRA, Natalia Barros; VASCONCELOS, Ricardo; HOJILLA, J. Carlo; KALLAS, Esper Georges; I, Vivian Avelino-Silva
    The objective was to describe levels and predictors of knowledge, attitudes, and willingness to prescribe pre-exposure prophylaxis (PrEP) among Brazilian Infectious Disease (ID) Physicians. The design was a cross-sectional study. We collected information on demographics and attitudes/knowledge about PrEP using an anonymous electronic survey. Willingness to prescribe PrEP, fear of adherence issues, and concerns about risk compensation were addressed in three case vignettes that varied by a single characteristic (i.e., by gender identity, drug use, and socioeconomic status) randomly assigned to physicians. Three hundred seventy ID physicians responded to the survey. Although most identified as informed/well informed about PrEP (75%) and believed PrEP availability to be necessary (38%), concerns with adherence (49%), side effects (38%), risk compensation (28%), and increase in sexually transmitted infection incidence (38%) were raised. We found no statistically significant differences in willingness to prescribe PrEP and concerns around risk compensation across the three case vignettes. ID physicians who declared having a religion reported more concerns about risk compensation compared to those self-identified as atheists (72% vs. 46%,p < .001). Most Brazilian ID physicians reported a positive attitude toward PrEP. Patients' gender identity, drug use, and socioeconomic status were not associated with willingness to prescribe PrEP. However, ID physicians who declared having a religion were more frequently concerned about risk compensation among PrEP users, suggesting that personal beliefs can influence PrEP implementation.
  • conferenceObject
    Increased Risk of for Cytomegalovirus Reactivation after Allogeneic HSCT in T-Cell Depleted Patients
    (2020) MOLLA, Vinicius Campos; AZEVEDO, Roberta; RAMOS, Jessica Fernandes; PONCIANO, Danilo Belchior; MORAES, Pedro Henrique Arruda de; FONSECA, Ana Rita Da; SEIWALD, Maria Cristina Nunez; SERPA, Mariana; FERREIRA, Aliana Meneses; SZOR, Roberta Shcolnik; LEONEL, Rayana Bomfim; XAVIER, Erick Menezes; ROCHA, Vanderson; TUCUNDUVA, Luciana; NOVIS, Yana; NUCCI, Marcio; KALLAS, Esper; ARRAIS, Celso
  • conferenceObject
    Immunogenicity and Safety of an Inactivated Virus Vaccine Against SARS-CoV-2 in Patients with Autoimmune Rheumatic Diseases
    (2021) MEDEIROS-RIBEIRO, Ana; AIKAWA, Nadia; SAAD, Carla Goncalves Schahin; YUKI, Emily Figueiredo Vieira Neves; PEDROSA, Tatiana do Nascimento; FUSCO, Solange; ROJO, Priscila; PEREIRA, Rosa; SHINJO, Samuel; ANDRADE, Danieli; SAMPAIO-BARROS, Percival; RIBEIRO, Carolina; DEVEZA, Giordano; MARTINS, Victor Adriano de Oliveira; SILVA, Clovis Artur; LOPES, Marta; DUARTE, Alberto; ANTONANGELO, Leila; SABINO, Ester; KALLAS, Esper; PASOTO, Sandra Gofinet; BONFA, Eloisa
  • article 2 Citação(ões) na Scopus
    Kidney function and daily emtricitabine/tenofovir disoproxil fumarate pre-exposure prophylaxis against HIV: results from the real-life multicentric demonstrative project PrEP Brazil
    (2022) PETRUCCELLI, Karla Cristina Silva; BAIA-DA-SILVA, Djane Clarys; VAL, Fernando; VALOES, Monica Santos; CUBAS-VEGA, Nadia; SILVA-NETO, Alexandre Vilhena; SAMPAIO, Vanderson; ALENCAR, Aline; PECOITS-FILHO, Roberto; MOREIRA, Rodrigo Carvalho; CARDOSO, Sandra Wagner; I, Ronaldo Moreira; LEITE, Iuri Costa; MADRUGA, Jose Valdez; KALLAS, Esper G.; ALENCASTRO, Paulo R.; HOAGLAND, Brenda; GRINSZTEJN, Beatriz; SANTOS, Valdilea Goncalves Veloso; LACERDA, Marcus Vinicius Guimaraes
    Background Pre-Exposure Prophylaxis (PrEP) has demonstrated efficacy in the reduction of sexually transmitted HIV infections. The prolonged use of tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) co-formulation (TDF/FTC), however, may result in augmented risk of renal toxicity. We aimed to evaluate changes in the estimated Glomerular Filtration Rate (eGFR) in a real-world population setting of participants enrolled in PrEP Brazil, a 48-week prospective, open-label, demonstration study to assess the feasibility of daily oral TDF/FTC used by men who have sex with men and transgender women at high-risk of HIV infection, all over 18 years old. Methods Kidney function was assessed by serial measurement of serum creatinine and eGFR with the Modification of Diet in Renal Disease Study (MDRD) formula on weeks 4, 12, 24, 36 and 48. Adherence to PrEP was assessed by dosing TDF concentration in dried blood spots at weeks 4 and 48, measured by liquid chromatography-mass spectrometry or mass spectrometry. Results Of 392 participants completing the 48-week follow-up protocol with TDF blood detectable levels and eGFR measures, 43.1% were young adults, of Caucasian ethnic background (57.9%), with BMI below 30 kg/m(2), without arterial hypertension. At screening, median eGFR was 93.0 mL/min/1.73 m(2). At week 4 follow-up, 90 (23% of the study population) participants presented reductions in eGFR greater than 10 mL/min/1.73 m(2) as compared to baseline eGFR, some as large as 59 mL/min/1.73 m(2), but with no clinical outcomes (adverse events and renal adverse events) severe enough to demand TDF/FTC discontinuation. A negative relationship was observed between TDF blood levels and eGFR at weeks 4 (r = - 0.005; p < 0.01) and 48 (r = - 0.006; p < 0.01). Conclusions These results suggest that the renal function profile in individuals on TDF/FTC may be assessed on week 4 and then only annually, allowing a more flexible medical follow-up in primary care centers.
  • article 63 Citação(ões) na Scopus
    Vaccine-Induced Gag-Specific T Cells Are Associated With Reduced Viremia After HIV-1 Infection
    (2013) JANES, Holly; FRIEDRICH, David P.; KRAMBRINK, Amy; SMITH, Rebecca J.; KALLAS, Esper G.; HORTON, Helen; CASIMIRO, Danilo R.; CARRINGTON, Mary; GERAGHTY, Daniel E.; GILBERT, Peter B.; MCELRATH, M. Juliana; FRAHM, Nicole
    The contribution of host T-cell immunity and HLA class I alleles to the control of human immunodeficiency virus (HIV-1) replication in natural infection is widely recognized. We assessed whether vaccine-induced T-cell immunity, or expression of certain HLA alleles, impacted HIV-1 control after infection in the Step MRKAd5/HIV-1 gag/pol/nef study. Vaccine-induced T cells were associated with reduced plasma viremia, with subjects targeting >= 3 gag peptides presenting with half-log lower mean viral loads than subjects without Gag responses. This effect was stronger in participants infected proximal to vaccination and was independent of our observed association of HLA-B(star)27, -B(star)57 and -B(star)58:01 alleles with lower HIV-1 viremia. These findings support the ability of vaccine-induced T-cell responses to influence postinfection outcome and provide a rationale for the generation of T-cell responses by vaccination to reduce viremia if protection from acquisition is not achieved. Clinical trials identifier: NCT00095576.