ABSTRACT
The recent increase in babies born with brain and eye malformations in Brazil is associated with Zika virus (ZIKV) infection in utero. ZIKV alters host DNA methylation in vitro. Using genome-wide DNA methylation profiling we compared 18 babies born with congenital ZIKV microcephaly with 20 controls. We found ZIKV-associated alteration of host methylation patterns, notably at RABGAP1L which is important in brain development, at viral host immunity genes MX1 and ISG15, and in an epigenetic module containing the causal microcephaly gene MCPH1. Our data support the hypothesis that clinical signs of congenital ZIKV are associated with changes in DNA methylation.
Subject(s)
DNA Methylation , Immunity/genetics , Microcephaly/virology , Neurogenesis/genetics , Zika Virus Infection , Brain/growth & development , Brain/virology , Brazil , Cell Cycle Proteins/genetics , Child, Preschool , Cytoskeletal Proteins/genetics , Female , Humans , Infant , Male , Pregnancy , Pregnancy Complications, Infectious/virology , Zika Virus/immunologyABSTRACT
BACKGROUND: Visceral leishmaniasis (VL), due to Leishmania infantum, is a persistent intracellular parasitic infection transmitted by the bite of infected sand flies. Symptomatic VL has been reported in U.S. soldiers with Iraq deployment. Untreated symptomatic VL can be fatal; asymptomatic VL (AVL) may establish a lifelong risk of reactivation. We report prevalence and AVL risk factors in Operation Iraqi Freedom (OIF) deployers during 2002-11. METHODS: Healthy soldiers exposed to VL endemic areas in Iraq and 50 controls who never traveled to endemic regions were recruited through military healthcare facilities (2015-17). Responses to a risk factor survey and blood samples were obtained. Leishmania research diagnostics utilized included enzyme-linked immunosorbent assay (ELISA), rk39 test strips, quantitative polymerase chain reaction (PCR), and interferon gamma release (IGRA) assays. Statistical analyses included Fisher exact test, Pearson χ2 test, Mann-Whitney U test, and logistic regression. RESULTS: 200 deployed subjects were enrolled, mostly males (84.0%), of white ethnicity (79.0%), and median age 41 (range 24-61) years. 64% were seropositive for Phlebotomus alexandri saliva antibodies. Prevalence of AVL (any positive test result) was 39/200 (19.5%, 95% confidence interval 14.4%-25.8%). Two (1.0%) PCR, 10 (5%) ELISA, and 28 (14%) IGRA samples were positive. Travel to Ninewa governorate increased risk for AVL (P = .01). CONCLUSION: AVL was identified in 19.5% of OIF deployers; travel to northwest Iraq correlated with infection. Further studies are needed to inform risk for reactivation VL in US veterans and to target additional blood safety and surveillance measures.
Subject(s)
Asymptomatic Infections , Leishmania infantum , Leishmaniasis, Visceral/epidemiology , Leishmaniasis, Visceral/parasitology , Military Personnel , Adult , Female , Geography , Humans , Iraq/epidemiology , Leishmaniasis, Visceral/diagnosis , Male , Middle Aged , Public Health Surveillance , United States/epidemiology , Young AdultABSTRACT
During visceral leishmaniasis (VL), Th1-based inflammation is induced to control intracellular parasites. Inflammation-based pathology was shown to be dampened by IL-10 and eventual programmed death 1-mediated T cell exhaustion. Cell type(s) responsible for the initiation of T cell-produced IL-10 during VL are unknown. CD19(+), CD5(-), CD1d(-), IgD(hi) regulatory B cells from healthy controls produced IL-10 in the absence of infection or stimulation, in contrast to IgD(lo/neg) B cells. IgD(hi) B cells may have a de novo versus induced regulatory program. The population of IgD(hi) B cells increased 3-fold as VL progressed. B cells from VL dogs were necessary and sufficient to suppress Th1 cell effector function. IgD(hi) B cells induced IL-10 production by T cells and IgD(lo) B cells. Blockage of B cell-specific PD-L1 restored Th1 responses. IgD(hi) regulatory B cells represent a novel regulatory B cell that may precipitate T cell exhaustion during VL.
Subject(s)
Antigens, Protozoan/immunology , B-Lymphocytes, Regulatory/immunology , B7-H1 Antigen/metabolism , Interleukin-10/metabolism , Leishmania infantum/immunology , Leishmaniasis, Visceral/immunology , Protozoan Proteins/immunology , Th1 Cells/immunology , Animals , Antibodies, Blocking/metabolism , Antibodies, Protozoan/metabolism , B-Lymphocytes, Regulatory/parasitology , B7-H1 Antigen/immunology , Cells, Cultured , Disease Progression , Dogs , Female , Humans , Immune Tolerance , Immunoglobulin D/metabolism , Male , Th1 Cells/parasitologyABSTRACT
OBJECTIVE: The Erasmus Guillain Barre Outcome Score (EGOS) is a prognostic model that predicts the chance of being able to walk independently at 6 months after Guillain Barré syndrome (GBS). This study was conducted aiming to determine the validity of EGOS in a Brazilian population. MATERIAL AND METHODS: Data collected from GBS patients in Rio Grande do Norte, Brazil, were used to determine the validity of EGOS. GBS disability score was assessed in the second week of disease and at 6 months. RESULTS: A total of 206 subjects were studied. The Brazilian patients were younger, with a more severe clinical presentation, with higher percentage of cranial nerve involvement and upper respiratory infection. There was no difference relative to sex or presence of anti-gangliosides antibodies. The demyelinating variant was more common (73.9%). However, only 24% of the Brazilians with EGOS 5.5-7 were not able to walk after 6 months, compared to 52% to European Group. Nine patients (3.8%) presented nodopathies, of these four had an EGOS >5, but only one of the latter group was unable to walk after 6 months of GBS. CONCLUSIONS: Erasmus Guillain Barre Outcome Score was not a good predictor for the ability to walk after 6 months of GBS in Rio Grande do Norte, Brazil. Differences could be that the Brazilian GBS were younger, or alternatively, it could be due to a different infection profile or in the incidence of nodopathies.
Subject(s)
Guillain-Barre Syndrome/complications , Recovery of Function , Severity of Illness Index , Adult , Brazil/epidemiology , Female , Guillain-Barre Syndrome/epidemiology , Humans , Incidence , Male , Middle Aged , Prognosis , WalkingABSTRACT
Genetic risk factors contribute to asymptomatic versus symptomatic visceral leishmaniasis (VL) outcomes following infection with Leishmania infantum. We therefore carried out a family-based (n = 918 post-quality control fully genotyped and phenotyped individuals) candidate gene study for symptomatic VL or asymptomatic delayed-type hypersensitivity (DTH) skin test phenotypes in highly endemic neighborhoods of northeast Brazil. A total of 248 SNPs were genotyped in 42 genes selected as candidates on the basis of prior genetic, immunological, and transcriptional profiling studies. The most significant association with the VL phenotype was with SNP rs6785358 (P = 5.7e-04; pcorrected = 0.026) 3.8 kb upstream of TGFBR2, the gene encoding the type 2 receptor for transforming growth factor beta (TGFß). A second inhibitory member of the TGBß superfamily signaling pathway, SMAD7, was associated with the DTH phenotype (SNP rs7238442: P = 0.001; pcorrected = 0.051). The most significant association for the DTH phenotype was with SNP rs10800309 (P = -8.4e-06; pcorrected = 3.9e-04) situated 3.1 kb upstream of FCGR2A, the gene encoding the low-affinity IIa receptor for the Fc fragment of IgG. Overall, our results imply a role for IgG-mediated inflammation in determining DTH associated with asymptomatic infection and contribute to growing evidence that the TGFß pathway is important in the immunopathogenesis of VL.
Subject(s)
Leishmania infantum , Leishmaniasis, Visceral/genetics , Protein Serine-Threonine Kinases/genetics , Receptors, IgG/genetics , Receptors, Transforming Growth Factor beta/genetics , Adolescent , Asymptomatic Infections , Brazil , Child , Female , Genetic Association Studies , Genetic Predisposition to Disease , Humans , Leishmaniasis, Visceral/parasitology , Linkage Disequilibrium , Male , Polymorphism, Single Nucleotide , Receptor, Transforming Growth Factor-beta Type IIABSTRACT
Approaches based on linear mixed models (LMMs) have recently gained popularity for modelling population substructure and relatedness in genome-wide association studies. In the last few years, a bewildering variety of different LMM methods/software packages have been developed, but it is not always clear how (or indeed whether) any newly-proposed method differs from previously-proposed implementations. Here we compare the performance of several LMM approaches (and software implementations, including EMMAX, GenABEL, FaST-LMM, Mendel, GEMMA and MMM) via their application to a genome-wide association study of visceral leishmaniasis in 348 Brazilian families comprising 3626 individuals (1972 genotyped). The implementations differ in precise details of methodology implemented and through various user-chosen options such as the method and number of SNPs used to estimate the kinship (relatedness) matrix. We investigate sensitivity to these choices and the success (or otherwise) of the approaches in controlling the overall genome-wide error-rate for both real and simulated phenotypes. We compare the LMM results to those obtained using traditional family-based association tests (based on transmission of alleles within pedigrees) and to alternative approaches implemented in the software packages MQLS, ROADTRIPS and MASTOR. We find strong concordance between the results from different LMM approaches, and all are successful in controlling the genome-wide error rate (except for some approaches when applied naively to longitudinal data with many repeated measures). We also find high correlation between LMMs and alternative approaches (apart from transmission-based approaches when applied to SNPs with small or non-existent effects). We conclude that LMM approaches perform well in comparison to competing approaches. Given their strong concordance, in most applications, the choice of precise LMM implementation cannot be based on power/type I error considerations but must instead be based on considerations such as speed and ease-of-use.
Subject(s)
Genome-Wide Association Study , Leishmaniasis, Visceral/genetics , Linear Models , Models, Theoretical , Brazil , Humans , Leishmaniasis, Visceral/pathology , Pedigree , Phenotype , Polymorphism, Single Nucleotide/genetics , SoftwareABSTRACT
Chronic kidney disease is a major contributor to human and companion animal morbidity and mortality. Renal complications are sequelae of canine and human visceral leishmaniasis (VL). Despite the high incidence of infection-mediated glomerulonephritis, little is known about pathogenesis of VL-associated renal disease. Leishmania infantum-infected dogs are a naturally occurring model of VL-associated glomerulonephritis. Membranoproliferative glomerulonephritis type I [24 of 25 (96%)], with interstitial lymphoplasmacytic nephritis [23 of 25 (92%)], and glomerular and interstitial fibrosis [12 of 25 (48%)] were predominant lesions. An ultrastructural evaluation of glomeruli from animals with VL identified mesangial cell proliferation and interposition. Immunohistochemistry demonstrated significant Leishmania antigen, IgG, and C3b deposition in VL dog glomeruli. Asymptomatic and symptomatic dogs had increased glomerular nucleotide-binding domain leucine-rich repeat-containing-like receptor family, pyrin domain containing 3 and autophagosome-associated microtubule-associated protein 1 light chain 3 associated with glomerular lesion severity. Transcriptional analyses from symptomatic dogs confirmed induction of autophagy and inflammasome genes within glomeruli and tubules. On the basis of temporal VL staging, glomerulonephritis was initiated by IgG and complement deposition. This deposition preceded presence of nucleotide-binding domain leucine-rich repeat-containing-like receptor family, pyrin domain containing 3-associated inflammasomes and increased light chain 3 puncta indicative of autophagosomes in glomeruli from dogs with clinical VL and renal failure. These findings indicate potential roles for inflammasome complexes in glomerular damage during VL and autophagy in ensuing cellular responses.
Subject(s)
Autophagy/physiology , Carrier Proteins/metabolism , Glomerulonephritis/veterinary , Inflammasomes/metabolism , Leishmania infantum , Leishmaniasis, Visceral/veterinary , Animals , Dogs , Glomerulonephritis/metabolism , Glomerulonephritis/parasitology , Kidney Glomerulus/metabolism , Kidney Glomerulus/parasitology , Kidney Glomerulus/pathology , Leishmaniasis, Visceral/complications , Leishmaniasis, Visceral/metabolismABSTRACT
BACKGROUND: Leprosy morbidity is increased by 2 pathologic immune reactions, reversal reaction (RR) and erythema nodosum leprosum (ENL). METHODS: To discover host factors related to immune reactions, global transcriptional profiles of peripheral blood mononuclear cells were compared between 11 RR, 11 ENL, and 19 matched control patients, with confirmation by quantitative polymerase chain reaction. Encoded proteins were investigated in skin biopsy specimens by means of immunohistochemistry. RESULTS: There were 275 genes differentially expressed in RR and 517 differentially expressed in ENL on the microarray. Pathway analysis showed immunity-related pathways represented in RR and ENL transcriptional profiles, with the "complement and coagulation" pathway common to both. Interferon γ was identified as a significant upstream regulator of the expression changes for RR and ENL. Immunohistochemical staining of skin lesions showed increased C1q in both RR and ENL. CONCLUSIONS: These data suggest a previously underrecognized role for complement in the pathogenesis of both RR and ENL, and we propose new hypotheses for reaction pathogenesis.
Subject(s)
Gene Expression Profiling , Leprosy/genetics , Leprosy/immunology , Adult , Aged , Case-Control Studies , Complement System Proteins/immunology , Female , Humans , Immunohistochemistry , Leprosy/pathology , Leukocytes, Mononuclear/immunology , Male , Microarray Analysis , Middle Aged , Real-Time Polymerase Chain Reaction , Skin/pathology , Young AdultABSTRACT
Leishmania infantum, the causative agent of visceral leishmaniasis (VL) in Brazil, is spread mostly by the bite of the sand fly Lutzomyia longipalpis (Lutz & Neiva). We trapped sand flies in endemic neighborhoods near Natal, Brazil, where cases of human and dog VL were documented. Amplification of species-specific cytochrome b (Cyt b) genes by polymerase chain reaction revealed that sand flies from rural and periurban areas harbored blood from different sources. The most common source ofbloodmeal was human, but blood from dog, chicken, and armadillo was also present. We tested the preference for a source of bloodmeal experimentally by feeding L. longipalpis F1 with blood from different animals. There were significant differences between the proportion of flies engorged and number of eggs laid among flies fed on different sources, varying from 8.4 to 19 (P < 0.0001). Blood from guinea pig or horse was best to support sand fly oviposition, but human blood also supported sand fly oviposition well. No sand flies fed on cats, and sand flies feeding on the opossum Monodelphis domestica Wagner produced no eggs. These data support the hypothesis that L. longipalpis is an eclectic feeder, and humans are an important source of blood for this sand fly species in periurban areas of Brazil.
Subject(s)
Food Preferences , Host Specificity , Insect Vectors/physiology , Psychodidae/physiology , Animals , Biodiversity , Brazil , Cytochromes b/genetics , Dogs , Female , Humans , Leishmania infantum , Leishmaniasis, Visceral/transmission , Oviposition , Polymerase Chain Reaction , TemperatureABSTRACT
The incidence of human Visceral Leishmaniasis (VL) has decreased in Brazil; however, the number of areas reporting human and canine cases has increased, with Leishmania infantum usually preceding human infection. This study aimed to analyze the profile of infectious diseases that are endemic for both human and canine VL, in dogs housed in a shelter located in the state of Rio Grande do Norte, Northeast Brazil. Data was obtained between November/2021 to April/2022. All dogs residing at the shelter (98 dogs) were examined and blood was collected for testing for L. infantum, Ehrlichia canis, and Babesia sp. Statistical analyses considered the clinical and laboratory findings. Of the 98 animals, approximately 43% were positive for L. infantum antibodies, 19% were positive for L. infantum kDNA, and 18% were L. infantum positive by culture. Greater levels of anti-leishmania antibodies were observed in dogs with symptoms suggestive of VL. The dogs tested positive for E. canis (19/98) and B. canis (18/98). Lutzomyia longipalpis was captured inside the shelter, representing 74.25% (n = 225) of whole sandflies in the dog shelter. Concomitant infection by L. infantum and E. canis increased the odds of death. Treatment of VL included the use of allopurinol (n = 48) and miltefosine (n = 8). Treated animals showed more signs of Leishmania infection. Tickborn parasites and Leishmania were prevalent in sheltered dogs in a VL-endemic area, which increases the odds of death and poses an additional challenge for caring for abandoned dogs and at the same time setting protocols to manage reservoirs of L. infantum.
Subject(s)
Babesia , Dog Diseases , Leishmania infantum , Leishmaniasis, Visceral , Leishmaniasis , Psychodidae , Humans , Animals , Dogs , Leishmaniasis, Visceral/parasitology , Leishmaniasis, Visceral/veterinary , Leishmaniasis/drug therapy , Leishmaniasis/veterinary , Leishmania infantum/genetics , Psychodidae/parasitology , Dog Diseases/epidemiologyABSTRACT
Visceral leishmaniasis (VL) is a neglected tropical disease that is globally distributed and has the potential to cause very serious illness. Prior literature highlights the emergence and spread of VL is influenced by multiple factors, such as socioeconomic status, sanitation levels or animal and human reservoirs. The study aimed to retrospectively investigate the presence and infectiousness of VL in Rio Grande do Norte (RN), Brazil between 2007 and 2020. We applied a hierarchical Bayesian approach to estimate municipality-specific relative risk of VL across space and time. The results show evidence that lower socioeconomic status is connected to higher municipality-specific VL risk. Overall, estimates reveal spatially heterogeneous VL risks in RN, with a high probability that VL risk for municipalities within the West Potiguar mesoregion are more than double the expected VL risk. Additionally, given the data available, results indicate there is a high probability of increasing VL risk in the municipalities of Natal, Patu and Pau dos Ferros. These findings demonstrate opportunities for municipality-specific public health policy interventions and warrant future research on identifying epidemiological drivers in at-risk regions.
Subject(s)
Leishmaniasis, Visceral , Animals , Humans , Leishmaniasis, Visceral/epidemiology , Retrospective Studies , Brazil/epidemiology , Bayes Theorem , Cities , Neglected DiseasesABSTRACT
An outbreak of births of microcephalic patients in Brazil motivated multiple studies on this incident. The data left no doubt that infection by Zika virus (ZIKV) was the cause, and that this virus promotes reduction in neuron numbers and neuronal death. Analysis of patients' characteristics revealed additional aspects of the pathology alongside the decrease in neuronal number. Here, we review the data from human, molecular, cell and animal model studies attempting to build the natural history of ZIKV in the embryonic central nervous system (CNS). We discuss how identifying the timing of infection and the pathways through which ZIKV may infect and spread through the CNS can help explain the diversity of phenotypes found in congenital ZIKV syndrome (CZVS). We suggest that intraneuronal viral transport is the primary mechanism of ZIKV spread in the embryonic brain and is responsible for most cases of CZVS. According to this hypothesis, the viral transport through the blood-brain barrier and cerebrospinal fluid is responsible for more severe pathologies in which ZIKV-induced malformations occur along the entire anteroposterior CNS axis.
Subject(s)
Microcephaly , Zika Virus Infection , Zika Virus , Animals , Humans , Zika Virus Infection/complications , Microcephaly/etiology , Microcephaly/pathology , Central Nervous System/pathology , Blood-Brain Barrier/pathology , Brain/pathologyABSTRACT
BACKGROUND: Visceral leishmaniasis (VL) is caused by Leishmania donovani and Leishmania infantum chagasi. Genome-wide linkage studies from Sudan and Brazil identified a putative susceptibility locus on chromosome 6q27. METHODS: Twenty-two single-nucleotide polymorphisms (SNPs) at genes PHF10, C6orf70, DLL1, FAM120B, PSMB1, and TBP were genotyped in 193 VL cases from 85 Sudanese families, and 8 SNPs at genes PHF10, C6orf70, DLL1, PSMB1, and TBP were genotyped in 194 VL cases from 80 Brazilian families. Family-based association, haplotype, and linkage disequilibrium analyses were performed. Multispecies comparative sequence analysis was used to identify conserved noncoding sequences carrying putative regulatory elements. Quantitative reverse-transcription polymerase chain reaction measured expression of candidate genes in splenic aspirates from Indian patients with VL compared with that in the control spleen sample. RESULTS: Positive associations were observed at PHF10, C6orf70, DLL1, PSMB1, and TBP in Sudan, but only at DLL1 in Brazil (combined P = 3 × 10(-4) at DLL1 across Sudan and Brazil). No functional coding region variants were observed in resequencing of 22 Sudanese VL cases. DLL1 expression was significantly (P = 2 × 10(-7)) reduced (mean fold change, 3.5 [SEM, 0.7]) in splenic aspirates from patients with VL, whereas other 6q27 genes showed higher levels (1.27 × 10(-6) < P < .01) than did the control spleen sample. A cluster of conserved noncoding sequences with putative regulatory variants was identified in the distal promoter of DLL1. CONCLUSIONS: DLL1, which encodes Delta-like 1, the ligand for Notch3, is strongly implicated as the chromosome 6q27 VL susceptibility gene.
Subject(s)
Chromosomes, Human, Pair 6 , Genetic Predisposition to Disease , Intercellular Signaling Peptides and Proteins/genetics , Leishmaniasis, Visceral/genetics , Membrane Proteins/genetics , Polymorphism, Single Nucleotide , Calcium-Binding Proteins , Genotype , Haplotypes , Humans , Intercellular Signaling Peptides and Proteins/physiology , Membrane Proteins/physiologyABSTRACT
Genome-wide association studies (GWASs) are a research approach used to identify genetic variants associated with common diseases, like COVID-19. The lead genetic variants (n = 41) reported by the eleven largest COVID-19 GWASs are mapped to 22 different chromosomal regions. The loci 3q21.31 (LZTFL1 and chemokine receptor genes) and 9q34.2 (ABO), associated with disease severity and susceptibility to infection, respectively, were the most replicated findings across studies. Genes involved with mucociliary clearance (CEP97, FOXP4), viral-entry (ACE2, SLC6A20) and mucosal immunity (MIR6891) are associated with the risk of SARS-CoV-2 infection while genes of antiviral immune response (IFNAR2, OAS1), leukocyte trafficking (CCR9, CXCR6) and lung injury (DPP9, NOTCH4) are associated with severe disease. The biological processes underlying the risk of infection occur prominently, but not exclusively, in the upper airways whereas the severe COVID-19-associated processes in alveolar-capillary interface. The COVID-19 GWASs has unraveled key genetic mechanisms of SARS-CoV-2 pathogenesis, although the genetic basis of other COVID-19 related phenotypes (long COVID and neurological impairment) remains to be elucidated.
Subject(s)
COVID-19 , Humans , COVID-19/genetics , SARS-CoV-2/genetics , Genome-Wide Association Study , Post-Acute COVID-19 Syndrome , Antiviral Agents , Membrane Transport ProteinsABSTRACT
BACKGROUND: The first case of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection in Rio Grande do Norte, northeastern Brazil, was diagnosed on March 12, 2020; thereafter, multiple surges of infection occurred, similar to what was seen elsewhere. These surges were mostly due to SARS-CoV-2 mutations leading to emergence of variants of concern (VoC). The introduction of new VoCs in a population previously exposed to SARS-CoV-2 or after vaccination has been a challenge to understanding the kinetics of the protective immune response against this virus. The aim of this study was to investigate the outbreak of SARS-CoV-2 reinfections observed in mid-January 2022 in Rio Grande do Norte state, Brazil. It describes the clinical and genomic characteristics of nine cases of reinfection that occurred coincident with the introduction of the omicron variant. METHODOLOGY/PRINCIPAL FINDINGS: Of a total of 172,965 individuals with upper respiratory symptoms tested for SARS-CoV-2, between March 2020 through mid-February 2022, 58,097 tested positive. Of those, 444 had documented a second SARS-CoV-2 infection and nine reinfection cases were selected for sequencing. Genomic analysis revealed that virus lineages diverged between primary infections and the reinfections, with the latter caused by the Omicron (BA.1) variant among individuals fully vaccinated against SARS-CoV-2. CONCLUSIONS/SIGNIFICANCE: Our findings suggest that the Omicron variant is able to evade both natural and vaccine-induced immunity, since all nine cases had prior natural infection and, in addition, were fully vaccinated, emphasizing the need to develop effective blocking vaccines.
Subject(s)
COVID-19 , Viral Vaccines , Brazil/epidemiology , COVID-19/epidemiology , COVID-19/prevention & control , Humans , Reinfection , SARS-CoV-2/geneticsABSTRACT
We examined the role of immunoglobulin (Ig)G antibodies in mediating host defense to the intracellular parasite, Leishmania. We show that IgG not only fails to provide protection against this intracellular pathogen, but it actually contributes to disease progression. The J(H) strain of BALB/c mice, which lack IgG because they have a targeted deletion in the Ig heavy chain (J) locus, were more resistant to infection with Leishmania major than were normal BALB/c mice. However, the passive administration of anti-Leishmania IgG caused J(H) mice to develop large lesions containing high numbers of parasites. Antibody administration correlated with an increase in interleukin (IL) 10 production in lesions, and blocking the murine IL-10 receptor prevented antibody-mediated disease exacerbation. In human patients with active visceral leishmaniasis, high IgG levels are predictive of disease. Patients with ongoing disease had high IgG antibody titers and no delayed-type hypersensitivity (DTH) responses to Leishmania antigens. This pattern was reversed upon disease resolution after treatment, resulting in a decrease in total IgG, which was accompanied by a progressive increase in DTH responsiveness. We conclude that IgG can cause a novel form of immune enhancement due to its ability to induce IL-10 production from macrophages.
Subject(s)
Antigen-Antibody Complex/immunology , Immunoglobulin G/immunology , Leishmania major/immunology , Leishmaniasis/immunology , Animals , Cells, Cultured , Humans , Hypersensitivity, Delayed/immunology , Interleukin-10/biosynthesis , Interleukin-10/immunology , Leishmaniasis/metabolism , Leishmaniasis/pathology , Mice , Mice, Inbred BALB C , Monocytes/metabolism , Monocytes/parasitologyABSTRACT
The Leishmania species cause a variety of human disease syndromes. Methods for diagnosis and species differentiation are insensitive and many require invasive sampling. Although quantitative PCR (qPCR) methods are reported for leishmania detection, no systematic method to quantify parasites and determine the species in clinical specimens is established. We developed a serial qPCR strategy to identify and rapidly differentiate Leishmania species and quantify parasites in clinical or environmental specimens. SYBR green qPCR is mainly employed, with corresponding TaqMan assays for validation. The screening primers recognize kinetoplast minicircle DNA of all Leishmania species. Species identification employs further qPCR set(s) individualized for geographic regions, combining species-discriminating probes with melt curve analysis. The assay was sufficient to detect Leishmania parasites, make species determinations, and quantify Leishmania spp. in sera, cutaneous biopsy specimens, or cultured isolates from subjects from Bangladesh or Brazil with different forms of leishmaniasis. The multicopy kinetoplast DNA (kDNA) probes were the most sensitive and useful for quantification based on promastigote standard curves. To test their validity for quantification, kDNA copy numbers were compared between Leishmania species, isolates, and life stages using qPCR. Maxicircle and minicircle copy numbers differed up to 6-fold between Leishmania species, but the differences were smaller between strains of the same species. Amastigote and promastigote leishmania life stages retained similar numbers of kDNA maxi- or minicircles. Thus, serial qPCR is useful for leishmania detection and species determination and for absolute quantification when compared to a standard curve from the same Leishmania species.
Subject(s)
Clinical Laboratory Techniques/methods , Leishmania/classification , Leishmania/isolation & purification , Leishmaniasis/diagnosis , Leishmaniasis/parasitology , Parasitology/methods , Real-Time Polymerase Chain Reaction/methods , Bangladesh , Benzothiazoles , Brazil , DNA Primers/genetics , Diamines , Environmental Microbiology , Humans , Leishmania/genetics , Organic Chemicals/metabolism , Quinolines , Staining and Labeling/methodsABSTRACT
Visceral leishmaniasis [VL] represents a major public health problem in many areas of the world. This review focuses on the impact of periurbanization on the epidemiology and treatment of VL, using Brazil as an example. VL continues to be mostly a disease of poverty with impact on families. However, the disease has expanded in Latin America, with foci reported as far south as Argentina. There is an increasing overlap of Leishmania infantum chagasi and HIV infections and other immunosuppressive conditions, resulting in VL emerging as an opportunistic infection. This new setting poses new challenges for VL disease control and patient management.
ABSTRACT
The role of Renin-Angiotensin-System (RAS) in the pathogenesis of preeclampsia and eclampsia is still unclear. Our aim was to investigate plasma angiotensin II concentration [Ang II] in women with normotensive pregnancies (NP, n = 22) and severe preeclampsia in use of magnesium sulfate (SPE, n = 29). Despite no difference between the groups (SPE: 47.8 pg/ml vs NP: 39.7 pg/ml, p = 0.195), lower maternal age (p = 0.007) and primigravida (p = 0.028) were associated with lower [Ang II]. Plasma [Ang II] increased over the 24 h of magnesium sulfate administration (r = 0.48, p = 0.009). Our findings suggest that RAS may be involved with the mechanism of magnesium protection against eclamptic seizure.
Subject(s)
Angiotensin II/drug effects , Magnesium Sulfate/pharmacology , Pre-Eclampsia/drug therapy , Age Factors , Angiotensin II/blood , Case-Control Studies , Female , Humans , Magnesium Sulfate/administration & dosage , Pre-Eclampsia/blood , Pregnancy , Seizures/prevention & controlABSTRACT
Accurate designing of polymerase chain reaction (PCR) primers targeting conserved segments in viral genomes is desirable for preventing false-negative results and decreasing the need for standardization across different PCR protocols. In this work, we designed and described a set of primers and probes targeting conserved regions identified from a multiple sequence alignment of 2341 Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) genomes from the Global Initiative on Sharing All Influenza Data (GISAID). We subsequently validated those primers and probes in 211,833 SARS-CoV-2 whole-genome sequences. We obtained nine systems (forward primer + reverse primer + probe) that potentially anneal to highly conserved regions of the virus genome from these analyses. In silico predictions also demonstrated that those primers do not bind to nonspecific targets for human, bacterial, fungal, apicomplexan, and other Betacoronaviruses and less pathogenic sub-strains of coronavirus. The availability of these primer and probe sequences will make it possible to validate more efficient protocols for identifying SARS-CoV-2.