ORCID Profile
0000-0003-1363-3985
Current Organisations
Universidad Peruana Cayetano Heredia
,
Socios En Salud Sucursal Peru
,
Harvard School of Public Health
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Oxford University Press (OUP)
Date: 08-04-2020
Abstract: In human blood, mucosal-associated invariant T (MAIT) cells are abundant T cells that recognize antigens presented on non-polymorphic major histocompatibility complex-related 1 (MR1) molecules. The MAIT cells are activated by mycobacteria, and prior human studies indicate that blood frequencies of MAIT cells, defined by cell surface markers, decline during tuberculosis (TB) disease, consistent with redistribution to the lungs. We tested whether frequencies of blood MAIT cells were altered in patients with TB disease relative to healthy Mycobacterium tuberculosis-exposed controls from Peru and South Africa. We quantified their frequencies using MR1 tetramers loaded with 5-(2-oxopropylideneamino)-6-D-ribitylaminouracil. Unlike findings from prior studies, frequencies of blood MAIT cells were similar among patients with TB disease and latent and uninfected controls. In both cohorts, frequencies of MAIT cells defined by MR1-tetramer staining and coexpression of CD161 and the T-cell receptor alpha variable gene TRAV1-2 were strongly correlated. Disease severity captured by body mass index or TB disease transcriptional signatures did not correlate with MAIT cell frequencies in patients with TB. Major histocompatibility complex (MHC)-related 1-restrictied MAIT cells are detected at similar levels with tetramers or surface markers. Unlike MHC-restricted T cells, blood frequencies of MAIT cells are poor correlates of TB disease but may play a role in pathophysiology.
Publisher: The American Association of Immunologists
Date: 15-03-2022
Abstract: Mucosal-associated invariant T (MAIT) cells are innate-like T cells that are highly abundant in human blood and tissues. Most MAIT cells have an invariant TCRα-chain that uses T cell receptor α-variable 1-2 (TRAV1-2) joined to TRAJ33/20/12 and recognizes metabolites from bacterial riboflavin synthesis bound to the Ag-presenting molecule MHC class I related (MR1). Our attempts to identify alternative MR1-presented Ags led to the discovery of rare MR1-restricted T cells with non–TRAV1-2 TCRs. Because altered Ag specificity likely alters affinity for the most potent known Ag, 5-(2-oxopropylideneamino)-6-d-ribitylaminouracil (5-OP-RU), we performed bulk TCRα- and TCRβ-chain sequencing and single-cell–based paired TCR sequencing on T cells that bound the MR1-5-OP-RU tetramer with differing intensities. Bulk sequencing showed that use of V genes other than TRAV1-2 was enriched among MR1-5-OP-RU tetramerlow cells. Although we initially interpreted these as erse MR1-restricted TCRs, single-cell TCR sequencing revealed that cells expressing atypical TCRα-chains also coexpressed an invariant MAIT TCRα-chain. Transfection of each non–TRAV1-2 TCRα-chain with the TCRβ-chain from the same cell demonstrated that the non–TRAV1-2 TCR did not bind the MR1-5-OP-RU tetramer. Thus, dual TCRα-chain expression in human T cells and competition for the endogenous β-chain explains the existence of some MR1-5-OP-RU tetramerlow T cells. The discovery of simultaneous expression of canonical and noncanonical TCRs on the same T cell means that claims of roles for non–TRAV1-2 TCR in MR1 response must be validated by TCR transfer-based confirmation of Ag specificity.
Publisher: Springer Science and Business Media LLC
Date: 13-02-2019
Publisher: The American Association of Immunologists
Date: 15-12-2019
Abstract: High-throughput TCR sequencing allows interrogation of the human TCR repertoire, potentially connecting TCR sequences to antigenic targets. Unlike the highly polymorphic MHC proteins, monomorphic Ag-presenting molecules such as MR1, CD1d, and CD1b present Ags to T cells with species-wide TCR motifs. CD1b tetramer studies and a survey of the 27 published CD1b-restricted TCRs demonstrated a TCR motif in humans defined by the TCR β-chain variable gene 4-1 (TRBV4-1) region. Unexpectedly, TRBV4-1 was involved in recognition of CD1b regardless of the chemical class of the carried lipid. Crystal structures of two CD1b-specific TRBV4-1+ TCRs show that germline-encoded residues in CDR1 and CDR3 regions of TRBV4-1–encoded sequences interact with each other and consolidate the surface of the TCR. Mutational studies identified a key positively charged residue in TRBV4-1 and a key negatively charged residue in CD1b that is shared with CD1c, which is also recognized by TRBV4-1 TCRs. These data show that one TCR V region can mediate a mechanism of recognition of two related monomorphic Ag-presenting molecules that does not rely on a defined lipid Ag.
Publisher: Elsevier BV
Date: 05-2015
Publisher: European Respiratory Society (ERS)
Date: 07-2017
DOI: 10.1183/23120541.00026-2017
Abstract: Cross-sectional studies reveal an association between tuberculosis (TB) and chronic airflow obstruction, but cannot adequately address confounding. We hypothesised that treated pulmonary TB is an independent risk factor for chronic airflow obstruction. The Pulmones Post TB cohort study enrolled participants from Lima, Peru, aged 10–70 years with a history of drug-susceptible (DS)- or multidrug-resistant (MDR)-TB who had completed treatment and were clinically cured. Unexposed participants without TB were randomly selected from the same districts. We assessed respiratory symptoms, relevant environmental exposures, and spirometric lung function pre- and post-bronchodilator. In total, 144 participants with DS-TB, 33 with MDR-TB and 161 unexposed participants were fully evaluated. Compared with unexposed participants, MDR-TB patients had lower lung volumes (adjusted mean difference in forced vital capacity −370 mL, 95% CI −644– −97) and post-bronchodilator airflow obstruction (adjusted OR 4.89, 95% CI 1.27–18.78). Participants who had recovered from DS-TB did not have lower lung volumes than unexposed participants, but were more likely to have a reduced forced expiratory volume in 1 s/forced vital capacity ratio .70 (adjusted OR 2.47, 95% CI 1.01–6.03). In iduals successfully treated for TB may experience long-lasting sequelae. Interventions facilitating earlier TB treatment and management of chronic respiratory disease should be explored.
Publisher: International Union Against Tuberculosis and Lung Disease
Date: 2018
Abstract: The increasing prevalence of non-communicable diseases (NCDs) poses a major challenge to low- and middle-income countries. Patients' engagement with health services for anti-tuberculosis treatment provides an opportunity for screening for NCDs and for linkage to care. We explored the feasibility and yield of screening for NCDs in patients treated for tuberculosis (TB) in Lima, Peru, as part of a study focused on chronic respiratory sequelae. A representative s le of community controls was recruited from the same geographical area. Screening entailed taking a medical history and performing ambulatory blood pressure measurement and urinalysis. A total of 177 participants with previous TB (33 with multidrug-resistant TB) and 161 community controls were evaluated. There was an almost four-fold increased prevalence of self-reported diabetes mellitus (DM) in the TB group (adjusted prevalence ratio 3.66, 95%CI 1.68-8.01). Among those without self-reported DM, 3.3% had glycosuria, with a number needed to screen (NNS) of 31. The NNS to find one (new) case of hypertension or proteinuria in the TB group was respectively 24 and 5. Patient-centred care that includes pragmatic NCD screening is feasible in TB patients, and the treatment period provides a good opportunity to link patients to ongoing care.
Publisher: Elsevier BV
Date: 03-2015
DOI: 10.1016/J.IJID.2014.12.016
Abstract: Chronic respiratory disease causes substantial global morbidity and mortality. The contribution of pulmonary tuberculosis to the aetiology of chronic respiratory disease is rarely considered, but may be important in tuberculosis-endemic areas. We performed a systematic literature review to assess the association between a history of tuberculosis and the presence of chronic obstructive pulmonary disease (COPD) or chronic suppurative lung disease (bronchiectasis). Study quality was evaluated using the National Heart Lung and Blood Institute quality assessment tool. Meta-analysis was performed using the DerSimonian and Laird random effects model. We identified 9 eligible studies for COPD and 2 for bronchiectasis. Overall, there was a significant association between a history of tuberculosis and the presence of COPD in adults aged over 40 years (pooled odds ratio 3.05 (95% confidence interval 2.42, 3.85). Among in idual COPD studies the strongest associations were found in countries with a high incidence of tuberculosis, as well as among never smokers and younger people. In tuberculosis endemic areas, tuberculosis is strongly associated with the presence of chronic respiratory disease in adults. Efforts to improve long-term lung health should be part of tuberculosis care.
Publisher: Elsevier BV
Date: 05-2023
No related grants have been discovered for Leonid Lecca.