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

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 Leishmania (Viannia) 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. The ex vivo response of PBMCs to L (V) panamensis partially reflected that of lesion microenvironments. Significant downregulation of gene expression profiles consistent with local innate immune responses (monocyte and neutrophil activation and chemoattractant molecules) was observed at EoT in biopsy specimens of patients who cured (n = 8), compared to those from patients with treatment failure (n = 8). Among differentially expressed genes, pretreatment expression of CCL2 was significantly predictive of the therapeutic response (receiver operating characteristic [ROC] curve, area under the curve [AUC] = 0.82, P = 0.02). Polymorphisms in regulatory regions of the CCL2 promoter were analyzed in a pilot cohort of DNA samples from CL patients (cures, n = 20, and treatment failure, n = 20), showing putative association of polymorphisms rs13900(C/T) and rs2857656(G/C) with treatment outcome. Our data indicate that dampening gene expression profiles of monocyte and neutrophil activation characterize clinical cure after treatment of CL, supporting participation of parasite-sustained inflammation or deregulated innate immune responses in treatment failure.

Cyclic GMP-AMP Synthase Is the Cytosolic Sensor of Plasmodium falciparum Genomic DNA and Activates Type I IFN in Malaria.

Innate immune receptors have a key role in the sensing of malaria and initiating immune responses. As a consequence of infection, systemic inflammation emerges and is directly related to signs and symptoms during acute disease. We have previously reported that plasmodial DNA is the primary driver of systemic inflammation in malaria, both within the phagolysosome and in the cytosol of effector cells. In this article, we demonstrate that Plasmodium falciparum genomic DNA delivered to the cytosol of human monocytes binds and activates cyclic GMP-AMP synthase (cGAS). Activated cGAS synthesizes 2'3'-cGAMP, which we subsequently can detect using liquid chromatography-tandem mass spectrometry. 2'3'-cGAMP acts as a second messenger for STING activation and triggers TBK1/IRF3 activation, resulting in type I IFN production in human cells. This induction of type I IFN was independent of IFI16. Access of DNA to the cytosolic compartment is mediated by hemozoin, because incubation of purified malaria pigment with DNase abrogated IFN-ß induction. Collectively, these observations implicate cGAS as an important cytosolic sensor of P. falciparum genomic DNA and reveal the role of the cGAS/STING pathway in the induction of type I IFN in response to malaria parasites.

Malaria in Pregnancy in Endemic Regions of Colombia: High Frequency of Asymptomatic and Peri-Urban Infections in Pregnant Women with Malaria.

Background: Malaria in pregnancy (MiP) has been associated with adverse pregnancy outcomes. There is limited information on MiP in low transmission regions as Colombia. This study aimed to describe the epidemiology of MiP through active surveillance of infections by microscopy and polymerase chain reaction (PCR). Methods: A cross-sectional study was conducted between May 2016 and January 2017 in five municipalities (Apartadó, Turbo, El Bagre, Quibdó, and Tumaco) in Colombia. Pregnant women self-presenting at health centers for antenatal care visits, seeking medical care for suspected malaria, or delivery, were enrolled. Diagnosis of Plasmodium spp was made in peripheral and placental blood samples by microscopy and PCR. Results: A total of 787 pregnant women were enrolled; plasmodial infection was diagnosed by microscopy in 4.2% (95% CI 2.8-5.6; 33/787) or by nPCR in 5.3% (95% CI 3.8-6.9; 42/787) in peripheral blood. Most of the infections were caused by P. falciparum (78.5%), and 46% were afebrile (asymptomatic). Women in the first and second trimester of pregnancy were more likely to be infected (aOR = 3.06, 95%CI = 1.6 - 5.8). To live in the urban/peri-urban area (aOR = 3.04, 95%CI = 1.4 - 6.56), to have a history of malaria during last year (aOR = 5.45, 95%IC = 2.16 - 13.75), and the infrequent bed net usage (aOR = 2.8, 95%CI = 1.31 - 5.97) were associated with the infection. Pregnant infected women had a higher risk of anaemia (aOR = 2.18, 95%CI = 1.15 - 4.12) and fever (aOR = 14.2, 95%CI = 6.89 - 29.8). Conclusion: The screening for malaria during antenatal care in endemic areas of Colombia is highly recommended due to the potential adverse effects of Plasmodium spp. infection in pregnancy and as an important activity for the surveillance of asymptomatic infections in the control of malaria.

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. V. panamensis transmission in Colombia were used to determine the frequency of SNPs in TNFα, IL-10 and TLR4 genes. DNA samples were obtained from 74 adult participants: 38 patients presenting chronic cutaneous leishmaniasis (CCL) and 36 individuals with asymptomatic infection. Genotyping of TNFα-308G/A, IL-10-819C/T, and TLR4 Asp299Gly and Thr399Ile SNPs, was conducted by PCR-restriction fragment length polymorphisms. Allele, genotype frequencies and associations between SNPs and clinical groups were evaluated. RESULTS: The A allele in TNFα-308G/A SNP was found more frequently in individuals with asymptomatic infection (16% vs 7%), whereas the CC genotype in IL-10-819 C/T SNP was more frequent in patients with CCL (34% vs. 27% in asymptomatic individuals). No differences in allele frequencies for TLR4 SNPs were found among groups. CONCLUSION: This study provides a reference base for statistical power calculation and design of association studies of genetic polymorphisms in immune response related-genes and the pathogenesis of infections caused by L. V. panamensis.

DNA-Containing Immunocomplexes Promote Inflammasome Assembly and Release of Pyrogenic Cytokines by CD14+ CD16+ CD64high CD32low Inflammatory Monocytes from Malaria Patients.

UNLABELLED: High levels of circulating immunocomplexes (ICs) are found in patients with either infectious or sterile inflammation. We report that patients with either Plasmodium falciparum or Plasmodium vivax malaria have increased levels of circulating anti-DNA antibodies and ICs containing parasite DNA. Upon stimulation with malaria-induced ICs, monocytes express an NF-κB transcriptional signature. The main source of IC-induced proinflammatory cytokines (i.e., tumor necrosis factor alpha [TNF-α] and interleukin-1ß [IL-1ß])in peripheral blood mononuclear cells from acute malaria patients was found to be a CD14(+) CD16 (FcγRIIIA)(+) CD64 (FcγRI)(high) CD32 (FcγRIIB)(low) monocyte subset. Monocytes from convalescent patients were predominantly of the classical phenotype (CD14(+) CD16(-)) that produces high levels of IL-10 and lower levels of TNF-α and IL-1ß in response to ICs. Finally, we report a novel role for the proinflammatory activity of ICs by demonstrating their ability to induce inflammasome assembly and caspase-1 activation in human monocytes. These findings illuminate our understanding of the pathogenic role of ICs and monocyte subsets and may be relevant for future development of immunity-based interventions with broad applications to systemic inflammatory diseases. IMPORTANCE: Every year, there are approximately 200 million cases of Plasmodium falciparum and P. vivax malaria, resulting in nearly 1 million deaths, most of which are children. Decades of research on malaria pathogenesis have established that the clinical manifestations are often a consequence of the systemic inflammation elicited by the parasite. Recent studies indicate that parasite DNA is a main proinflammatory component during infection with different Plasmodium species. This finding resembles the mechanism of disease in systemic lupus erythematosus, where host DNA plays a central role in stimulating an inflammatory process and self-damaging reactions. In this study, we disclose the mechanism by which ICs containing Plasmodium DNA activate innate immune cells and consequently stimulate systemic inflammation during acute episodes of malaria. Our results further suggest that Toll-like receptors and inflammasomes have a central role in malaria pathogenesis and provide new insights toward developing novel therapeutic interventions for this devastating disease.

Clinical validation of a western blot assay for congenital toxoplasmosis and newborn screening in a hospital in Armenia (Quindio) Colombia.

Congenital Toxoplasma infection can only be discovered or prevented by the appropriate serological screening and subsequent treatment of the mother and her offspring. In Colombia, there is no obligatory Toxoplasma screening for pregnant women and both the reporting and follow-up of congenital toxoplasmosis cases is limited, thereby is a public health problem that have no been addressed by health authorities. The aim of this study was to investigate the occurrence of congenital toxoplasmosis in a public hospital from Armenia, Colombia. A total of 200 serum samples of cord blood were collected. We applied a western blot assay (ID Blot DPC Diagnostics, US) for Toxoplasma IgG, IgM and IgA antibodies that was validated in a cohort of children with confirmed presence or absence of congenital infection. The sensitivity of western blot assay was 91 per cent and the specificity was 100 per cent. In the cord blood samples, we found one infected child that died at day 4 of life and his infection was confirmed by PCR of the B1 specific Toxoplasma gene on brain biopsy. This results show a high prevalence (0.5 per cent, IC95 per cent 0.2-0.8) of Toxoplasma infection in Colombian newborns. Thus, we recommend additional studies to determine the cost-effectiveness of a newborn screening program for congenital toxoplasmosis in other settings in Colombia.