Innate biosignature of treatment failure in human cutaneous leishmaniasis.

The quality and magnitude of the immune and inflammatory responses determine the clinical outcome of infection, and contribute to the efficacy of antileishmanial treatments. However, the precise immune mechanisms involved in healing or in chronic immunopathology of human cutaneous leishmaniasis (CL) are not completely understood. Through sequential transcriptomic profiling of blood monocytes (Mo), neutrophils (Nφ), and eosinophils (Eφ) over the course of systemic treatment with meglumine antimoniate, we discovered that a heightened and sustained Type I interferon (IFN) response signature is a hallmark of treatment failure (TF) in CL patients.

Macrophage metallothioneins participate in the antileishmanial activity of antimonials.

Host cell functions that participate in the pharmacokinetics and pharmacodynamics (PK/PD) of drugs against intracellular pathogen infections are critical for drug efficacy. In this study, we investigated whether macrophage mechanisms of xenobiotic detoxification contribute to the elimination of intracellular upon exposure to pentavalent antimonials (Sb). Primary macrophages from patients with cutaneous leishmaniasis (CL) (n=6) were exposed to infection and Sb, and transcriptomes were generated.

Consolidation of a Molecular Signature of Healing in Cutaneous Leishmaniasis Is Achieved during the First 10 Days of Treatment.

The immune response is central to the pathogenesis of cutaneous leishmaniasis (CL). However, most of our current understanding of the immune response in human CL derives from the analysis of systemic responses, which only partially reflect what occurs in the skin. In this study, we characterized the transcriptional dynamics of skin lesions during the course of treatment of CL patients and identified gene signatures and pathways associated with healing and nonhealing responses.

Quality parameters for RNA preparations from biopsies of ulcerated human skin.

Obtaining high quality RNA from skin biopsies is complex due the physical composition and high content of nucleases of this tissue. This becomes particularly challenging when using compromised skin samples with necrotic, inflammed or damaged areas, such as those from patients suffering skin conditions, which affect more than 900 million people annually. We evaluated the impact of the biopsy size and tissue preservation method on the quality and quantity of RNA extracts.

Leishmania RNA Virus Is Not Detected in All Species of the Leishmania Viannia Subgenus: The Case of L. (V.) panamensis in Colombia.

The endosymbiotic Leishmania RNA virus 1 (LRV1) has been associated with severity and clinical manifestations of American tegumentary leishmaniasis caused by species of the Leishmania (Viannia) subgenus. Between and within Leishmania species, and among endemic countries, the prevalence of LRV is highly variable. The LRV virus has not been detected in L.

Sequencing of hsp70 for discernment of species from the Leishmania (Viannia) guyanensis complex from endemic areas in Colombia.

Background: Colombia is ranked very high among countries with the highest numbers of endemic Leishmania species (n = 9) causing human disease. Although much effort has been devoted to generating simple and specific tools for Leishmania species identification, challenges remain in the discrimination of species belonging to the Leishmania (Viannia) guyanensis complex: L. (V.

Early Leukocyte Responses in Models of Healing and Non-Healing Human Infections.

Early host-pathogen interactions drive the host response and shape the outcome of natural infections caused by intracellular microorganisms. These interactions involve a number of immune and non-immune cells and tissues, along with an assortment of host and pathogen-derived molecules. Our current knowledge has been predominantly derived from research on the relationships between the pathogens and the invaded host cell(s), limiting our understanding of how microbes elicit and modulate immunological responses at the organismal level.

Performance verification of the Abbott SARS-CoV-2 test for qualitative detection of IgG in Cali, Colombia.

Background: Adequate testing is critically important for control of the SARS-CoV-2 pandemic. Antibody testing is an option for case management and epidemiologic studies, with high specificity and variable sensitivity. However, characteristics of local populations may affect performance of these tests.

Inductively coupled plasma mass spectrometry method for plasma and intracellular antimony quantification applied to pharmacokinetics of meglumine antimoniate.

A high-throughput method using inductively coupled plasma mass spectrometry (ICP-MS) was developed and validated for the quantitative analysis of antimony in human plasma and peripheral blood mononuclear cells from patients with cutaneous leishmaniasis undergoing treatment with meglumine antimoniate. Antimony was digested in clinical samples with 1% tetramethylammonium hydroxide/1% EDTA and indium was used as internal standard. Accuracy, precision and stability were evaluated.

Immuno-pharmacokinetics of Meglumine Antimoniate in Patients With Cutaneous Leishmaniasis Caused by Leishmania (Viannia).

Background: Control of cutaneous leishmaniasis (CL) relies on chemotherapy, yet gaps in our understanding of the determinants of therapeutic outcome impede optimization of antileishmanial drug regimens. Pharmacodynamic (PD) parameters of antimicrobials are based on the relationship between drug concentrations/exposure and microbial kill. However, viable Leishmania persist in a high proportion of individuals despite clinical resolution, indicating that determinants other than parasite clearance are involved in drug efficacy.

Comparative Assessment of DNA Targets and Amplification Methods for Detection in Human Samples.

Multiple polymerase chain reaction (PCR)-based approaches have been developed for detection in clinical and laboratory samples, and this diversity limits inter-study comparisons, meta-analyses, and generalization of findings. Towards harmonization of a molecular tool for detection of for research purposes we evaluated the concordance of 18SrDNA quantitative polymerase chain reaction (qPCR) and minicircle kinetoplastid DNA (mkDNA) PCR followed by Southern blot (PCR-SB) in in vitro infection systems and in lesion and mucosal swab samples from Colombian patients with cutaneous leishmaniasis caused by . The lower limit of parasite detection of 18SrDNA qPCR and mkDNA PCR-SB was 10 promastigotes and one intracellular amastigote per reaction.

Immune Profile of the Nasal Mucosa in Patients with Cutaneous Leishmaniasis.

Localized skin lesions are characteristic of cutaneous leishmaniasis (CL); however, () species, which are responsible for most CL cases in the Americas, can spread systemically, sometimes resulting in mucosal disease. Detection of has been documented in healthy mucosal tissues (conjunctiva, tonsils, and nasal mucosa) and healthy skin of CL patients and in individuals with asymptomatic infection in areas of endemicity of () and () transmission. However, the conditions and mechanisms that favor parasite persistence in healthy mucosal tissues are unknown.

Profiles of Local and Systemic Inflammation in the Outcome of Treatment of Human Cutaneous Leishmaniasis Caused by ().

The immune mechanisms that contribute to the efficacy of treatment of cutaneous leishmaniasis (CL) are not fully understood. The aim of this study was to define immune correlates of the outcome of treatment of CL caused by () species during standard of care treatment with pentavalent antimonials. We conducted a comparative expression profiling of immune response genes in peripheral blood mononuclear cells (PBMCs) and lesion biopsy specimens obtained from CL patients before and at the end of treatment (EoT) with meglumine antimoniate.

Phenotypic and functional stability of leukocytes from human peripheral blood samples: considerations for the design of immunological studies.

Background: Human peripheral blood mononuclear cells (PBMCs) are extensively used for research of immune cell functions, identification of biomarkers and development of diagnostics and therapeutics for human diseases, among others. The assumption that "old blood samples" are not appropriate for isolation of PBMCs for functional assays has been a dogma in the scientific community. However, partial data on the impact of time after phlebotomy on the quality and stability of human PBMCs preparations impairs the design of studies in which time-controlled blood sampling is challenging such as field studies involving multiple sampling centers/sites.

Resistance of to Meglumine Antimoniate or Miltefosine Modulates Neutrophil Effector Functions.

is the main causative agent of cutaneous leishmaniasis in Colombia and is usually treated with either meglumine antimoniate (MA) or miltefosine (MIL). In recent years, there has been increasing evidence of the emergence of drug-resistance against these compounds. Neutrophils are known to play an important role in immunity against .

Development and Evaluation of a Novel Loop-Mediated Isothermal Amplification Assay for Diagnosis of Cutaneous and Visceral Leishmaniasis.

A novel pan- loop-mediated isothermal amplification (LAMP) assay for the diagnosis of cutaneous and visceral leishmaniasis (CL and VL) that can be used in near-patient settings was developed. Primers were designed based on the 18S ribosomal DNA (rDNA) and the conserved region of minicircle kinetoplast DNA (kDNA), selected on the basis of high copy number. LAMP assays were evaluated for CL diagnosis in a prospective cohort trial of 105 patients in southwest Colombia.

Profiling gene expression of antimony response genes in Leishmania (Viannia) panamensis and infected macrophages and its relationship with drug susceptibility.

The mechanisms of Leishmania resistance to antimonials have been primarily determined in experimentally derived Leishmania strains. However, their participation in the susceptibility phenotype in field isolates has not been conclusively established. Being an intracellular parasite, the activity of antileishmanials is dependent on internalization of drugs into host cells and effective delivery to the intracellular compartments inhabited by the parasite.

Screening of TNFα, IL-10 and TLR4 single nucleotide polymorphisms in individuals with asymptomatic and chronic cutaneous leishmaniasis in Colombia: a pilot study.

Background: Clinical manifestations of cutaneous leishmaniasis (CL) caused by Leishmania (Viannia) range from asymptomatic infection to self-limited, or chronic (non-healing) cutaneous lesions. Given the critical role of the immune response in the clinical outcome of CL, it is plausible that functional polymorphisms in immune-related genes contribute to define the clinical manifestations of human infection.

Methods: DNA samples from a retrospective cohort of individuals from an endemic area of L.