Browsing by Author "Pradeep Das"

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A global comparative evaluation of commercial immunochromatographic rapid diagnostic tests for visceral leishmaniasis
(Oxford University Press, 2012) Jane Cunningham; Epco Hasker; Pradeep Das; Sayda El Safi; Hiro Goto; Dinesh Mondal; Margaret Mbuchi; Maowia Mukhtar; Ana Rabello; Suman Rijal; Shyam Sundar; Monique Wasunna; Emily Adams; Joris Menten; Rosanna Peeling; Marleen Boelaert; Murari Das; Edward Oliveira; Tália Machado de Assis; Khondaker Rifathassan Bhaskar; M. Mamun Huda; Mukidul Hassan; Asim Osman Abdoun; Aymen Awad; Mohamed Osman; Dinesh Kumar Prajapati; Kamlesh Gidwani; Puja Tiwary; Anamaria Mello Miranda Paniago; Maria Carmen Arroyo Sanchez; Beatriz Julieta Celeste; Diane Jacquet; Charles Magiri; A. Muia; J. Kesusu; Al Farazdag Ageed; Nuha Galal; Osman Salih Osman; A.K. Gupta; Afrad S. Bimal; V.N.R. Das
Background. Poor access to diagnosis stymies control of visceral leishmaniasis (VL). Antibody-detecting rapid diagnostic tests (RDTs) can be performed in peripheral health settings. However, there are many brands available and published reports of variable accuracy. Methods. Commercial VL RDTs containing bound rK39 or rKE16 antigen were evaluated using archived human sera from confirmed VL cases (n = 750) and endemic non-VL controls (n = 754) in the Indian subcontinent (ISC), Brazil, and East Africa to assess sensitivity and specificity with 95 confidence intervals. A subset of RDTs were also evaluated after 60 days' heat incubation (37°C, 45°C). Interlot and interobserver variability was assessed. Results. All test brands performed well against ISC panels (sensitivity range, 92.8-100; specificity range, 96-100); however, sensitivity was lower against Brazil and East African panels (61.5-91 and 36.8-87.2, respectively). Specificity was consistently > 95 in Brazil and ranged between 90.8 and 98 in East Africa. Performance of some products was adversely affected by high temperatures. Agreement between lots and readers was good to excellent ( > 0.73-0.99). Conclusions. Diagnostic accuracy of VL RDTs varies between the major endemic regions. Many tests performed well and showed good heat stability in the ISC; however, reduced sensitivity against Brazilian and East African panels suggests that in these regions, used alone, several RDTs are inadequate for excluding a VL diagnosis. More research is needed to assess ease of use and to compare performance using whole blood instead of serum and in patients coinfected with human immunodeficiency virus. © 2012 The Author.
A phase II, non-comparative randomised trial of two treatments involving liposomal amphotericin B and miltefosine for post-kala-azar dermal leishmaniasis in India and Bangladesh
(Public Library of Science, 2024) Shyam Sundar; Krishna Pandey; Dinesh Mondal; Major Madhukar; Roshan Kamal Topno; Ashish Kumar; Vinod Kumar; Deepak Kumar Verma; Jaya Chakravarty; Rahul Chaubey; Poonam Kumari; Md. Utba Rashid; Shomik Maruf; Prakash Ghosh; Sheeraz Raja; Joelle Rode; Margriet Den Boer; Pradeep Das; Jorge Alvar; Suman Rijal; Fabiana Alves
Background In Southeast Asia, treatment is recommended for all patients with post-kala-azar dermal leishmaniasis (PKDL). Adherence to the first-line regimen, twelve weeks of miltefosine (MF), is low and ocular toxicity has been observed with this exposure period. We assessed the safety and efficacy of two shorter-course treatments: liposomal amphotericin B (LAmB) alone and combined with MF. Methodology/Principal findings An open-label, phase II, randomized, parallel-arm, non-comparative trial was conducted in patients with parasitologically confirmed PKDL, 6 to ≤60 years. Patients were assigned to 20 mg/kg LAmB (total dose, in five injections over 15 days) alone or combined with allome-tric MF (3 weeks). The primary endpoint was definitive cure at 12 months, defined as complete resolution of papular and nodular lesions and >80% re-pigmentation of macular lesions. Definitive cure at 24 months was a secondary efficacy endpoint. 118/126 patients completed the trial. Definitive cure at 12 months was observed in 29% (18/63) patients receiving LAmB and 30% (19/63) receiving LAmB/MF (mITT), increasing to 58% and 66%, respectively, at 24 months. Most lesions had resolved/improved at 12 and 24 months for patients receiving LAmB (90%, 83%) and LAmB/MF (85%, 88%) by qualitative assessment. One death, unrelated to study drugs, was reported; no study drug-related serious adverse events were observed. The most frequent adverse drug reactions were MF-related vomiting and nausea, and LAmB-related hypokalaemia and infusion reactions. Most adverse events were mild; no ocular adverse events occurred. Conclusions/Significance Both regimens are suitably safe and efficacious alternatives to long-course MF for PKDL in South Asia. © 2024 Sundar et al.
Active case detection in national visceral leishmaniasis elimination programs in Bangladesh, India, and Nepal: Feasibility, performance and costs
(2012) M Mamun Huda; Siddhivinayak Hirve; Niyamat Ali Siddiqui; Paritosh Malaviya; Megha Raj Banjara; Pradeep Das; Sangeeta Kansal; Chitra Kumar Gurung; Eva Naznin; Suman Rijal; Byron Arana; Axel Kroeger; Dinesh Mondal
Background: Active case detection (ACD) significantly contributes to early detection and treatment of visceral leishmaniasis (VL) and post kala-azar dermal leishmaniasis (PKDL) cases and is cost effective. This paper evaluates the performance and feasibility of adapting ACD strategies into national programs for VL elimination in Bangladesh, India and Nepal. Methods. The camp search and index case search strategies were piloted in 2010-11 by national programs in high and moderate endemic districts / sub-districts respectively. Researchers independently assessed the performance and feasibility of these strategies through direct observation of activities and review of records. Program costs were estimated using an ingredients costing method. Results: Altogether 48 camps (Bangladesh-27, India-19, Nepal-2) and 81 index case searches (India-36, Nepal-45) were conducted by the health services across 50 health center areas (Bangladesh-4 Upazillas, India-9 PHCs, Nepal-37 VDCs). The mean number of new case detected per camp was 1.3 and it varied from 0.32 in India to 2.0 in Bangladesh. The cost (excluding training costs) of detecting one new VL case per camp varied from USD 22 in Bangladesh, USD 199 in Nepal to USD 320 in India. The camp search strategy detected a substantive number of new PKDL cases. The major challenges faced by the programs were inadequate preparation, time and resources spent on promoting camp awareness through IEC activities in the community. Incorrectly diagnosed splenic enlargement at camps probably due to poor clinical examination skills resulted in a high proportion of patients being subjected to rK39 testing. Conclusion: National programs can adapt ACD strategies for detection of new VL/PKDL cases. However adequate time and resources are required for training, planning and strengthening referral services to overcome challenges faced by the programs in conducting ACD. © 2012 Huda et al.; licensee BioMed Central Ltd.
Adjuvantation of whole-killed Leishmania vaccine with anti-CD200 and anti-CD300a antibodies potentiates its efficacy and provides protection against wild-type parasites
(Elsevier Ltd, 2023) Rajan Singh; Anshul Anand; Baishakhi Mahapatra; Shashi Saini; Abhishek Singh; Samer Singh; Vinod Kumar; Pradeep Das; Sangram Singh; Rakesh K. Singh
One of the major reasons behind the limited success of vaccine candidates against all forms of leishmaniasis is the inability of parasitic antigens to induce robust cell-mediated immunity and immunological memory. Here we find, for the first time, that the adjuvantation of whole-killed Leishmania vaccine (Leishvacc) with anti-CD200 and anti-CD300a antibodies enhances CD4+ T cells mediated immunity in vaccinated mice and provides protection against wild-type parasites. The antibody adjuvantation, either alone or with a TLR4 agonist monophosphoryl A (MPL-A), induced the production of pro-inflammatory cytokines viz., IFN-γ, TNF-α, and IL-2 by antigen experienced CD4+ T cells, and also enhanced their rate of conversion into their memory phenotypes against Leishvacc antigens. The antibody adjuvanted vaccine also promoted the generation of IgG2a-mediated protective humoral immunity in vaccinated mice. Further, the mice vaccinated with antibodies adjuvanted vaccine showed strong resilience against metacyclic forms of L. donovani parasites as we observed reduced clinical features such as splenomegaly, hepatomegaly, granulomatous tissues in the liver, and parasitic load in their spleen. The findings of this study demonstrate that the anti-CD200 and anti-CD300a antibodies have potential to increase the protective efficacy of the whole-killed Leishmania vaccine, and opens up a new gateway to diversify the roles of immune checkpoints in vaccine development against leishmaniasis. © 2023 Elsevier Ltd
CD300a Receptor Blocking Enhances Early Clearance of Leishmania donovani From Its Mammalian Host Through Modulation of Effector Functions of Phagocytic and Antigen Experienced T Cells
(Frontiers Media S.A., 2022) Rajan Singh; Anshul Anand; Arun K. Rawat; Shashi Saini; Baishakhi Mahapatra; Naveen K. Singh; Alok K. Mishra; Samer Singh; Nisha Singh; Dhiraj Kishore; Vinod Kumar; Pradeep Das; Rakesh K. Singh
The parasites of the genus Leishmania survive and proliferate in the host phagocytic cells by taking control over their microbicidal functions. The parasite also promotes differentiation of antigen-specific anti-inflammatory cytokines producing effector T cells, which eventually results in disease pathogenesis. The mechanisms that parasites employ to dominate host adaptive immunity are largely unknown. For the first time, we report that L. donovani, which causes visceral leishmaniasis in the Indian subcontinent, upregulates the expression of an immune inhibitory receptor i.e., CD300a on antigen presenting and phagocytic cells to dampen their effector functions. The blocking of CD300a signals in leishmania antigens activated macrophages and dendritic cells enhanced the production of nitric oxide, pro-inflammatory cytokines along with MHCI/II genes expression, and reduced parasitic uptake. Further, the abrogation of CD300a signals in Leishmania infected mice benefited antigen-experienced, i.e., CD4+CD44+ and CD8+CD44+ T cells to acquire more pro-inflammatory cytokines producing phenotypes and helped in the early clearance of parasites from their visceral organs. The CD300a receptor blocking also enhanced the conversion of CD4+ T effectors cells to their memory phenotypes i.e., CCR7high CD62Lhigh up to 1.6 and 1.9 fold after 14 and 21 days post-infection, respectively. These findings implicate that CD300a is an important determinant of host phagocytic cells functions and T cells differentiation against Leishmania antigens. Copyright © 2022 Singh, Anand, Rawat, Saini, Mahapatra, Singh, Mishra, Singh, Singh, Kishore, Kumar, Das and Singh.
Comparison of short-course multidrug treatment with standard therapy for visceral leishmaniasis in India: An open-label, non-inferiority, randomised controlled trial
(Elsevier B.V., 2011) Shyam Sundar; Prabhat Kumar Sinha; Madhukar Rai; Deepak Kumar Verma; Kumar Nawin; Shanawwaj Alam; Jaya Chakravarty; Michel Vaillant; Neena Verma; Krishna Pandey; Poonam Kumari; Chandra Shekhar Lal; Rakesh Arora; Bhawna Sharma; Sally Ellis; Nathalie Strub-Wourgaft; Manica Balasegaram; Piero Olliaro; Pradeep Das; Farrokh Modabber
Improved treatment approaches are needed for visceral leishmaniasis. We assessed the efficacy and safety of three potential short-course combination treatments compared with the standard monotherapy in India. Standard treatment (1 mg/kg amphotericin B infusion on alternate days for 30 days, total dose 15 mg/kg) was compared with three drug combinations (single injection of 5 mg/kg liposomal amphotericin B and 7-day 50 mg oral miltefosine or single 10-day 11 mg/kg intramuscular paromomycin; or 10 days each of miltefosine and paromomycin) in an open-label, parallel-group, non-inferiority, randomised controlled trial in two hospital sites in Bihar, India. Patients aged 5-60 years with parasitologically confirmed visceral leishmaniasis were randomly assigned one of the four treatments by the trial statistician by use of a computer-generated list. Clinical assessments were done at the end of treatment (15 days on combination treatment; 31 days for standard treatment) and after 45 days and 6 months. The primary endpoint was definitive cure (defined as no sign or symptom of visceral leishmaniasis and parasitologically cured to the last follow-up). Analyses were done both by intention to treat and per protocol. This trial is registered with ClinicalTrials.gov, number NCT00696969. Between June, 2008, and July, 2009, 634 patients were assigned amphotericin B (n=157), liposomal amphotericin B with miltefosine (n=160) or paromomycin (n=158), or miltefosine and paromomycin (n=159). 618 patients were in the per-protocol population. There were two relapses in each group. The numbers with definitive cure at 6 months for the intention-to-treat population were 146 (cure rate 93·0; CI 87·5-96·3) for amphotericin B, 156 (97·5; 93·3-99·2) for liposomal amphotericin B and miltefosine, 154 (97·5; 93·24-99·2) for liposomal amphotericin B and paromomycin, and 157 (98·7; 95·1-99·8) for miltefosine and paromomycin. All combinations were non-inferior to the standard treatment, in both the intention-to-treat and per-protocol populations. Patients in the combination groups had fewer adverse events than did those assigned standard treatment. Combination treatments for visceral leishmaniasis are efficacious and safe, and decrease the duration of therapy, thereby encouraging adherence and reducing emergence of drug-resistant parasites. Drugs for Neglected Diseases initiative and the Indian Council of Medical Research. © 2011 Elsevier Ltd.
Effect of village-wide use of long-lasting insecticidal nets on visceral Leishmaniasis vectors in India and Nepal: A cluster randomized trial
(2010) Albert Picado; Murari L. Das; Vijay Kumar; Shreekant Kesari; Diwakar S. Dinesh; Lalita Roy; Suman Rijal; Pradeep Das; Mark Rowland; Shyam Sundar; Marc Coosemans; Marleen Boelaert; Clive R. Davies
Background: Visceral leishmaniasis (VL) control in the Indian subcontinent is currently based on case detection and treatment, and on vector control using indoor residual spraying (IRS). The use of long-lasting insecticidal nets (LN) has been postulated as an alternative or complement to IRS. Here we tested the impact of comprehensive distribution of LN on the density of Phlebotomus argentipes in VL-endemic villages. Methods: A cluster-randomized controlled trial with household P. argentipes density as outcome was designed. Twelve clusters from an ongoing LN clinical trial - three intervention and three control clusters in both India and Nepal - were selected on the basis of accessibility and VL incidence. Ten houses per cluster selected on the basis of high pre-intervention P. argentipes density were monitored monthly for 12 months after distribution of LN using CDC light traps (LT) and mouth aspiration methods. Ten cattle sheds per cluster were also monitored by aspiration. Findings:A random effect linear regression model showed that the cluster-wide distribution of LNs significantly reduced the P. argentipes density/house by 24.9% (95% CI 1.80%-42.5%) as measured by means of LTs. Interpretation: The ongoing clinical trial, designed to measure the impact of LNs on VL incidence, will confirm whether LNs should be adopted as a control strategy in the regional VL elimination programs. The entomological evidence described here provides some evidence that LNs could be usefully deployed as part of the VL control program. Trial registration: ClinicalTrials.gov CT-2005-015374. © 2010 Picado et al.
Effectiveness and feasibility of active and passive case detection in the visceral leishmaniasis elimination initiative in India, Bangladesh, and Nepal
(2010) Siddhivinayak Hirve; Shri Prakash Singh; Narendra Kumar; Megha Raj Banjara; Pradeep Das; Shyam Sundar; Suman Rijal; Anand Joshi; Axel Kroeger; Beena Varghese; Chandreshwar Prasad Thakur; M. Mamun Huda; Dinesh Mondal
This study analyzed the effectiveness of active case detection (ACD) for new visceral leishmaniasis (VL) cases. ACD detection was carried out using house to house screening in Bangladesh and India and by neighborhood screening around index cases in Nepal. The percent increase of new VL cases through ACD compared to PCD was 6.7-17.1% in India; 38.8% in Nepal; and 60% in Bangladesh. The screening effort was high in India and Bangladesh (house to house screening) compared to Nepal (index case screening). The additional cost per new VL case detected varied: $50 to $106 in India; $172 in Bangladesh; $262 in Nepal depending on the type of screening staff, transport and training costs. The estimated annual VL incidence in the ACD arm ranged from 315-383 in India; 109 in Bangladesh, and 43 per 100,000 in Nepal. The additional effort and cost rises as disease incidence declines or PCD improves. Copyright © 2010 by The American Society of Tropical Medicine and Hygiene.
Efficacy and Safety of Amphotericin B Emulsion versus Liposomal Formulation in Indian Patients with Visceral Leishmaniasis: A Randomized, Open-Label Study
(Public Library of Science, 2014) Shyam Sundar; Krishna Pandey; Chandreshwar Prasad Thakur; Tara Kant Jha; Vidya Nand Ravi Das; Neena Verma; Chandra Shekhar Lal; Deepak Verma; Shahnawaz Alam; Pradeep Das
India is home to 60% of the total global visceral leishmaniasis (VL) population. Use of long-term oral (e.g. miltefosine) and parenteral drugs, considered the mainstay for treatment of VL, is now faced with increased resistance, decreased efficacy, low compliance and safety issues. The authors evaluated the efficacy and safety of an alternate treatment option, i.e. single infusion of preformed amphotericin B (AmB) lipid emulsion (ABLE) in comparison with that of liposomal formulation (LAmB).; In this multicentric, open-label study, 500 patients with VL were randomly assigned in a 3∶1 ratio to receive 15 mg/kg single infusion of either ABLE (N = 376) or LAmB (N = 124). Initial cure (Day 30/45), clinical improvement (Day 30) and long term definitive cure (Day 180) were assessed.; A total of 326 (86.7%) patients in the ABLE group and 122 (98.4%) patients in the LAmB group completed the study. Initial cure was achieved by 95.9% of patients in the ABLE group compared to 100% in the LAmB group (p = 0.028; 95% CI: −0.0663, −0.0150). Clinical improvement was comparable between treatments (ABLE: 98.9% vs. LAmB: 98.4%). Definitive cure was achieved in 85.9% with ABLE compared to 98.4% with LAmB. Infusion-related pyrexia (37.2% vs. 32.3%) and chills (18.4% vs. 18.5%) were comparable between ABLE and LAmB, respectively. Treatment-related serious adverse events were fewer in ABLE (0.3%) compared to LAmB (1.6%). Two deaths occurred in the ABLE group, of which one was probably related to the study drug. Nephrotoxicity and hepatotoxicity was not observed in either group.; ABLE 15 mg/kg single infusion had favorable efficacy and was well tolerated. Considering the demographic profile of the population in this region, a single dose treatment offers advantages in terms of compliance, cost and applicability.; Trial Registration: www.clinicaltrials.gov NCT00876824. © 2014 Sundar et al.
Eliminating visceral leishmaniasis in South Asia: The road ahead
(BMJ Publishing Group, 2019) Suman Rijal; Shyam Sundar; Dinesh Mondal; Pradeep Das; Jorge Alvar; Marleen Boelaert
Suman Rijal and colleagues highlight lessons from a regional collaboration to eliminate visceral leishmaniasis and identify priorities for the post-elimination plan. © Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to.
How do health care providers deal with kala-azar in the Indian subcontinent?
(2011) Narendra Kumar; Shri Prakash Singh; Dinesh Mondal; Anand Joshi; Pradeep Das; Shyam Sundar; Axel Kroeger; Siddhivinayak Hirve; N.A. Siddiqui; Marleen Boelaert
Background & objectives: Three countries, Bangladesh, India and Nepal, set out to eliminate kala-azar by 2015. This study was aimed to document the knowledge and practices in kala-azar case management of public and private health providers in these three countries. Methods: A health care provider survey was conducted in 2007 at 4 study sites, viz., Muzaffarpur and Vaishali districts in India, Mahottari district in Nepal, and Rajshahi district in Bangladesh. Interviews were conducted with formal and informal health care providers at their home or practice. Results: About half of the providers in India and Nepal knew the rapid diagnostic test rK39 recommended by the elimination initiative, but this was not in Bangladesh. Knowledge of the recommended first-line drug, miltefosine, was good in India and Nepal but less so in Bangladesh. Interpretation & conclusions: Innovative tools for VL care have not yet been fully taken up by private for profit care providers in the three countries that launched a VL elimination initiative. The elimination initiative needs to address these gaps in private providers' knowledge, given their substantial share in the care of VL patients.
Insecticide susceptibility of Phlebotomus argentipes in visceral leishmaniasis endemic districts in India and Nepal
(2010) Diwakar Singh Dinesh; Murari Lal Das; Albert Picado; Lalita Roy; Suman Rijal; Shri Prakash Singh; Pradeep Das; Marleen Boelaert; Marc Coosemans
Objectives: To investigate the DDT and deltamethrin susceptibility of Phlebotomus argentipes, the vector of Leishmania donovani, responsible for visceral leishmaniasis (VL), in two countries (India and Nepal) with different histories of insecticide exposure. Methods: Standard WHO testing procedures were applied using 4% DDT and 0.05% deltamethrin impregnated papers. The effect of the physiological status (fed and unfed) of females on the outcome of the bioassays was assessed and the optimal time of exposure for deltamethrin was evaluated on a colony population. Field populations from both countries were tested. Results: Fed and unfed females responded in a similar way. For exposure time on field samples 60 min was adopted for both DDT and deltamethrin. In Bihar, knockdown and mortality with DDT was respectively 20 and 43%. In Nepal almost all sand flies were killed, except at the border with Bihar (mortality 62%). With 0.05% deltamethrin, between 96 and 100% of the sand flies were killed in both regions. Conclusions: Based on literature and present data 4% DDT and 0.05% deltamethrin seem to be acceptable discriminating concentrations to separate resistant from susceptible populations. Resistance to DDT was confirmed in Bihar and in a border village of Nepal, but the sand flies were still susceptible in villages more inside Nepal where only synthetic pyrethroids are used for indoor spraying. The low effectiveness of indoor spraying with DDT in Bihar to control VL can be partially explained by this resistance hence other classes of insecticides should be tested. In both countries P. argentipes sand flies were susceptible to deltamethrin. © 2010 Dinesh et al.
Investments in Research and Surveillance Are Needed to Go Beyond Elimination and Stop Transmission of Leishmania in the Indian Subcontinent
(Public Library of Science, 2017) Piero L. Olliaro; Tushar A. K. M. Shamsuzzaman; Baburam Marasini; A.C. Dhariwal; Ahmed Be-Nazir; Dinesh Mondal; Megha Raj Banjara; Pradeep Das; Shyam Sundar; Suman Rijal; Byron Arana; Jorge Alvar; Daniel Argaw; Rosanna W. Peeling; Axel Kroeger; Greg Matlashewski
[No abstract available]
Leishmania antigens activated CD4+ T cells expressing CD200R receptors are the prime IL-10 producing phenotype and an important determinant of visceral leishmaniasis pathogenesis
(Academic Press, 2024) Abhishek Singh; Baishakhi Mahapatra; Arpita Banerjee; Samer Singh; Sangram Singh; Vikash K. Dubey; Pradeep Das; Rakesh K. Singh
The excessive production of IL-10, an anti-inflammatory cytokine, by Leishmania antigen-activated T cells is supposed to be a key player in the onset and progression of visceral leishmaniasis (VL). The IL-10-producing sources in VL remain unidentified and uncharacterized. In this study, we reveal that antigen-activated CD4+ T cells, i.e., CD44+CD4+ T cells expressing CD200R receptors, are the prime IL-10-producing phenotypes in Leishmania donovani infection-induced pathogenesis. These phenotypes are separate from CD25+Foxp3+CD4+ T regulatory cells, which are classical IL-10-producing phenotypes. In order to ascertain the role of CD200R and CD25 receptors in IL-10 overexpression-associated VL pathogenesis, we abrogated CD200R and CD25 receptor-mediated signaling in the infected mice. The splenic load of parasites and the size of the liver and spleen were significantly reduced in CD200-blocked mice as compared to CD25-blocked mice. Further, the CD200 blocking polarized CD4+ T cells to pro-inflammatory cytokines-producing phenotypes, as we observed a higher frequency of IFN-γ, TNF-α, and IL-12 positive cells as compared to controls including the CD25 blocking. Our findings suggest that in L. donovani infection-induced pathogenesis the expression of CD200R on antigen-activated T cells helps them to acquire IL-10-producing abilities as part of its one of the survival strategies. However, more studies would be warranted to better understand CD200R receptors role in VL pathogenesis and to develop the next generation of therapeutic and prophylactic control measures. © 2023 Elsevier Ltd
Leishmania donovani activates hypoxia inducible factor-1α and miR-210 for survival in macrophages by downregulation of NF-κB mediated pro-inflammatory immune respons
(Frontiers Media S.A., 2018) Vinod Kumar; Ajay Kumar; Sushmita Das; Ashish Kumar; Kumar Abhishek; Sudha Verma; Abhishek Mandal; Rakesh K. Singh; Pradeep Das
Micro RNAs (miRNAs) have emerged as a critical regulator of several biological processes in both animals and plants. They have also been associated with regulation of immune responses in many human diseases during recent years. Visceral leishmaniasis (VL) is the most severe form of leishmaniasis, which is characterized by impairment of both innate and adaptive immune responses. In the present study, we observed that Leishmania establishes hypoxic environment in host macrophages that induces the expression of hypoxia inducible factor-1α (HIF-1α) and miRNA-210. Further, the expression of miRNA-210 was found to be dependent on activation of HIF-1α expression. The HIF-1α silencing by siRNA resulted in significantly (p < 0.001) decreased expression of miR-210 in parasites infected macrophages. We also observed that in siHIF-1α or antagomir-210 treated L. donovani infected macrophages, the parasitic load and percentage infectivity were significantly (p < 0.001) decreased. Furthermore, we found that inhibition of miR-210 leads to activation of NF-κB subunit p50, and it forms heterodimer with p65 and translocates into the nucleus from the cytoplasm. This significantly (p < 0.05) induced the transcription of pro-inflammatory cytokines genes such as TNF-α and IL-12 in miRNA-210 inhibited macrophages compared to uninhibited macrophages whereas the level of IL-10, an anti-inflammatory cytokine, was found to be significantly decreased (p < 0.001). These findings suggested that L. donovani infection induces hypoxic environment inside the macrophages that activates HIF-1α. Further, HIF-1α upregulates miR-210, which eventually establishes a suitable environment for the survival of parasite inside the host macrophages by downregulating NF-κB mediated pro-inflammatory immune responses. © 2018 Kumar, Kumar, Das, Kumar, Abhishek, Verma, Mandal, Singh and Das.
Leishmania donovani infection induce differential miRNA expression in CD4+ T cells
(Nature Research, 2020) Vinod Kumar; Sushmita Das; Ajay Kumar; Neeraj Tiwari; Ashish Kumar; Kumar Abhishek; Abhishek Mandal; Manjay Kumar; Taj Shafi; Tanvir Bamra; Rakesh Kumar Singh; Saravanan Vijayakumar; Abhik Sen; Pradeep Das
Visceral leishmaniasis is characterized by mixed production of Th1/2 cytokines and the disease is established by an enhanced level of Th2 cytokine. CD4+ T cells are main cell type which produces Th1/2 cytokine in the host upon Leishmania infection. However, the regulatory mechanism for Th1/2 production is not well understood. In this study, we co-cultured mice CD4+ T cells with Leishmania donovani infected and uninfected macrophage for the identification of dysregulated miRNAs in CD4+ T cells by next-generation sequencing. Here, we identified 604 and 613 known miRNAs in CD4+ T cells in control and infected samples respectively and a total of only 503 miRNAs were common in both groups. The expression analysis revealed that 112 miRNAs were up and 96 were down-regulated in infected groups, compared to uninfected control. Nineteen up-regulated and 17 down-regulated miRNAs were statistically significant (p < 0.05), which were validated by qPCR. Further, using insilco approach, we identified the gene targets of significant miRNAs on the basis of CD4+ T cell biology. Eleven up-regulated miRNAs and 9 down-regulated miRNAs were associated with the cellular immune responses and Th1/2 dichotomy upon Leishmania donovani infection. The up-regulated miRNAs targeted transcription factors that promote differentiation of CD4+ T cells towards Th1 phenotype. While down-regulated miRNAs targeted the transcription factors that facilitate differentiation of CD4+ T cells towards Th2 populations. The GO and pathway enrichment analysis also showed that the identified miRNAs target the pathway and genes related to CD4+ T cell biology which plays important role in Leishmania donovani infection. © 2020, The Author(s).
Measurement of recent exposure to Phlebotomus argentipes, the vector of indian visceral leishmaniasis, by using human antibody responses to sand fly saliva
(2010) Meredith F. Clements; Kamlesh Gidwani; Rajiv Kumar; Jitka Hostomska; Diwakar S. Dinesh; Vijay Kumar; Pradeep Das; Ingrid Müller; Gordon Hamilton; Vera Volfova; Marleen Boelaert; Murari Das; Suman Rijal; Albert Picado; Petr Volf; Shyam Sundar; Clive R. Davies; Matthew E. Rogers
Antibody (IgG) responses to the saliva of Phlebotomus argentipes were investigated using serum samples from regions of India endemic and non-endemic for visceral leishmaniasis (VL). By pre-adsorbing the sera against the saliva of the competing human-biting but non-VL vector P. papatasi, we significantly improved the specificity of a P. argentipes saliva enzyme-linked immunosorbent assay. Using this method, we observed a statistically significant correlation between antibodies to P. argenitpes saliva and the average indoor density of female sand flies. Additionally, the method was able to detect recent changes in vector exposure when sera from VL patients were assayed before, during, and after hospitalization and protected from sand fly bites under untreated bed nets. Collectively, these results highlight the utility of antibodies to P. argentipes saliva as an important tool to evaluate VL vector control programs. Copyright © 2010 by The American Society of Tropical Medicine and Hygiene.
Options for active case detection of visceral leishmaniasis in endemic districts of India, Nepal and Bangladesh, comparing yield, feasibility and costs
(2011) Shri Prakash Singh; Siddhivinayak Hirve; M. Mamun Huda; Megha Raj Banjara; Narendra Kumar; Dinesh Mondal; Shyam Sundar; Pradeep Das; Chitra Kumar Gurung; Suman Rijal; C.P. Thakur; Beena Varghese; Axel Kroeger
Background:The VL elimination strategy requires cost-effective tools for case detection and management. This intervention study tests the yield, feasibility and cost of 4 different active case detection (ACD) strategies (camp, index case, incentive and blanket approach) in VL endemic districts of India, Nepal and Bangladesh.Methodology/Principal Findings:First, VL screening (fever more than 14 days, splenomegaly, rK39 test) was performed in camps. This was followed by house to house screening (blanket approach). An analysis of secondary VL cases in the neighborhood of index cases was simulated (index case approach). A second screening round was repeated 4-6 months later. In another sub-district in India and Nepal, health workers received incentives for detecting new VL cases over a 4 month period (incentive approach). This was followed by house screening for undetected cases. A total of 28 new VL cases were identified by blanket approach in the 1st screening round, and used as ACD gold standard. Of these, the camp approach identified 22 (sensitivity 78.6%), index case approach identified 12 (sensitivity - 42.9%), and incentive approach identified 23 new VL cases out of 29 cases detected by the house screening (sensitivity - 79.3%). The effort required to detect a new VL case varied (blanket approach - 1092 households, incentive approach - 978 households; index case approach - 788 households had to be screened). The cost per new case detected varied (camp approach $21 - $661; index case approach $149 - $200; incentive based approach $50 - $543; blanket screening $112 - $629). The 2nd screening round yielded 20 new VL cases. Sixty and nine new PKDL cases were detected in the first and second round respectively.Conclusions/Significance:ACD in the VL elimination campaign has a high yield of new cases at programme costs which vary according to the screening method chosen. Countries need the right mix of approaches according to the epidemiological profile, affordability and organizational feasibility. © 2011 Singh et al.
Phlebotomus argentipes seasonal patterns in India and Nepal
(2010) Albert Picado; Murari Lal Das; Vijay Kumar; Diwakar S. Dinesh; Suman Rijal; Shri P. Singh; Pradeep Das; Marc Coosemans; Marleen Boelaert; Clive Davies
The current control of Phebotomus argentipes (Annandale and Brunetti), the vector of Leishmania donovani (Laveran and Mesnil), on the Indian subcontinent is base on indoor residual spraying. The efficacy of this method depends, among other factors, on the timing and number of spraying rounds, which depend on the P. argentipes seasonality. To describe P. argentipes' seasonal patterns, six visceral leishmaniasis (VL) endemic villages, three in Muzaffarpur and three in Sunsari districts in India and Nepal, respectively, were selected based on accessibility and VL incidence. Ten houses per cluster with the highest P. argentipes density were monitored monthly for 1516 mo using Center for Disease Control and Prevention light traps. Minimum and maximum temperature and rainfall data for the months January 2006 through December 2007 were collected from the nearest available weather stations. Backwards stepwise regression was used to generate the minimal adequate model for explaining the monthly variation in P. argentipes populations. The seasonality of P. argentipes is similar in India and Nepal, with two annual density peaks around May and October. Monthly P. argentipes density is positively associated with temperature and negatively associated with rainfall in both study sites. The multivariate climate model explained 57% of the monthly vectorial abundance. Vector control programs against P. argentipes (i.e., indoor residual spraying) should take into account the seasonal described here when implementing and monitoring interventions. Monitoring simple meteorological variables (i.e., temperature, rainfall) may allow prediction of VL epidemics on the Indian subcontinent. © 2010 Entomological Society of America.
Skin pharmacokinetics of miltefosine in the treatment of post-kala-azar dermal leishmaniasis in South Asia
(Oxford University Press, 2024) Semra Palić; Wan-Yu Chu; Shyam Sundar; Dinesh Mondal; Pradeep Das; Krishna Pandey; Sheeraz Raja; Suman Rijal; Ignace C. Roseboom; Abdullah Hamadeh; Paul R.V. Malik; Jos H. Beijnen; Alwin D.R. Huitema; Erik Sjögren; Fabiana Alves; Thomas P.C. Dorlo
Introduction: Post-kala-azar dermal leishmaniasis (PKDL) arises as a dermal complication following a visceral leishmaniasis (VL) infection. Current treatment options for PKDL are unsatisfactory, and there is a knowledge gap regarding the distribution of antileishmanial compounds within human skin. The present study investigated the skin distribution of miltefosine in PKDL patients, with the aim to improve the understanding of the pharmacokinetics at the skin target site in PKDL. Methods: Fifty-two PKDL patients underwent treatment with liposomal amphotericin B (20 mg/kg) plus miltefosine (allometric dosing) for 21 days. Plasma concentrations of miltefosine were measured on study days 8, 15, 22 and 30, while a punch skin biopsy was taken on day 22. A physiologically based pharmacokinetic (PBPK) model was developed to evaluate the distribution of miltefosine into the skin. Results: Following the allometric weight-based dosing regimen, median miltefosine concentrations on day 22 were 43.73 μg/g (IQR: 21.94-60.65 μg/g) in skin and 33.29 μg/mL (IQR: 25.9-42.58 μg/mL) in plasma. The median individual concentration ratio of skin to plasma was 1.19 (IQR: 0.79-1.9). In 87% (45/52) of patients, skin exposure was above the suggested EC90 PK target of 10.6 mg/L associated with in vitro susceptibility. Simulations indicated that the residence time of miltefosine in the skin would be more than 2-fold longer than in plasma, estimated by a mean residence time of 604 versus 266 hours, respectively. Conclusion: This study provides the first accurate measurements of miltefosine penetration into the skin, demonstrating substantial exposure and prolonged retention of miltefosine within the skin. These findings support the use of miltefosine in cutaneous manifestations of leishmaniasis. In combination with parasitological and clinical data, these results are critical for the future optimization of combination therapies with miltefosine in the treatment of PKDL. © 2024 The Author(s).