Polymerase chain reaction detection of Leishmania kDNA from the urine of Peruvian patients with cutaneous and mucocutaneous leishmaniasis

Metagenomic sequencing for identifying pathogen-specific circulating DNAs and development of diagnostic methods for schistosomiasis

Timely diagnosis of Schistosoma infection, particularly in the early stage is crucial for identifying infected hosts and then taking effective control strategies. Here, metagenomic next-generation sequencing was used to identify pathogen-specific circulating DNAs (cDNAs) in the sera/plasma of New Zealand rabbits infected with S. japonicum, and the identified cDNAs were validated by PCR and qPCR. Loop-mediated isothermal amplification (LAMP)-based CRISPR-Cas12a and recombinase polymerase amplification-based lateral flow strip (RPA-LF) methods combined with the newly identified cDNA were developed to evaluate the potentials for diagnosing murine and human schistosomiasis. The results indicated that twenty-two cDNAs were identified. The developed LAMP-based CRISPR/Cas12a and RPA-LF methods showed a good potential for diagnosing murine or human schistosomiasis as early as 5 days of post-infection with 5 cercariae infection. In a word, S. japonicum specific cDNAs in circulation of infected hosts could be effective biomarkers for detecting Schistosoma infection particularly for early stages.

Dosing implications for liposomal amphotericin B in pregnancy

Liposomal amphotericin B (LAmB) is used in the treatment of opportunistic fungal and parasitic infections, including leishmaniasis. Given its lack of known teratogenicity in pregnancy, LAmB is a preferred agent for treatment for these patients. However, significant gaps remain in determining optimal dosing regimens for LAmB in pregnancy. We describe the use of LAmB for a pregnant patient with mucocutaneous leishmaniasis (MCL) using a dosing strategy of 5 mg/kg/day for days 1-7 using ideal body weight followed by 4 mg/kg weekly using adjusted body weight. We reviewed the literature for LAmB dosing strategies, particularly dosing weight, in pregnancy. Of the 143 cases identified in 17 studies, only one reported a dosing weight, in which ideal body weight was used. Five Infectious Diseases Society of America guidelines in total discussed the use of amphotericin B in pregnancy but no guidelines included recommendations for dosing weight. This review describes our experience in using ideal body weight for dosing LAmB in pregnancy for the treatment of MCL. Use of ideal body weight may minimize risk of adverse effects to the fetus compared to the use of total body weight while maintaining efficacy for treatment of MCL in pregnancy.

Liquid Biopsy for Promising Non-invasive Diagnostic Biomarkers in Parasitic Infections

BACKGROUND

Liquid biopsy refers to the sampling and molecular analysis of body fluids such as blood, saliva, and urine in contrast to conventional tissue biopsies. Liquid biopsy approach can offer powerful non-invasive biomarkers (circulating markers) for diagnosis and monitoring treatment response of a variety of diseases, including parasitic infections.

METHODS

In this review, we concentrate on cell-free DNA (cfDNA), microRNA (miRNA), and exosomes in the published literature.

RESULTS

Considering the high prevalence and severity of parasitic infections worldwide, circulating biomarkers can provide a new insight into the diagnosis and prognosis of parasites in the near future. Moreover, identifying and characterizing parasite- or host-derived circulating markers are important for a better understanding of the pathogenesis of parasite infection and host-parasite relationship at the molecular level. Profiling of biomarkers for parasitic diseases is a promising potential field, though further studies and optimization strategies are required, both in vitro and in vivo.

CONCLUSION

In this review, we discuss three approaches in the liquid biopsy including circulating cfDNA, miRNAs, and exosomes for diagnosis and evaluation of parasites and summarize circulating biomarkers in non-invasive samples during parasitic infections.

Selection of new diagnostic markers for Dirofilaria repens infections with the use of phage display technology

Dirofilaria repens is a parasitic nematode causing vector-borne disease (dirofilariasis), considered an emerging problem in veterinary and human medicine. Although main hosts are carnivores, particularly dogs, D. repens shows high zoonotic potential. The disease spreads uncontrollably, affecting new areas. Since there is no vaccine against dirofilariasis, the only way to limit disease transmission is an early diagnosis. Currently, diagnosis depends on the detection of microfilariae in the host bloodstream using modified Knott's test or multiplex PCR. However, the efficacy of tests relying on microfilariae detection is limited by microfilariae periodic occurrence. Therefore, a new reliable diagnostic test is required. Our study aimed to select new diagnostic markers for dirofilariasis with potential application in diagnostics. We focused on single epitopes to ensure high specificity of diagnosis and avoid cross-reactivity with the other parasite infections common in dogs. Using phage display technology and 12-mer peptides library, we selected epitopes highly reactive with IgG from sera of infected dogs. Additionally, our study presents the possibility of detecting D. repens specific cell-free DNA in dogs with no microfilaria but high IgG and IgM antibody levels against parasite somatic antigen.

Comparison of Three In-House Real PCR Assays Targeting Kinetoplast DNA, the Small Subunit Ribosomal RNA Gene and the Glucose-6-Phosphate Isomerase Gene for the Detection of Leishmania spp. in Human Serum

To perform PCR from serum for the diagnosis of visceral leishmaniasis is convenient and much less invasive than the examination of deeper compartments such as bone marrow. We compared three Leishmania-specific real-time PCRs with three different molecular targets (kinetoplast DNA, the small subunit-ribosomal RNA-(ssrRNA-)gene, the glucose-6-phosphate isomerase-(gpi-)gene) regarding their sensitivity and specificity in human serum. Residual sera from previous diagnostic assessments at the German National Reference Center for Tropical Pathogens Bernhard Nocht Institute for Tropical Medicine Hamburg and the Swiss Tropical and Public Health Institute were used. The sensitivities of kinetoplast DNA-PCR, ssrRNA-gene PCR, and gpi-PCR were 93.3%, 73.3%, and 33.3%, respectively, with 15 initial serum samples from visceral leishmaniasis patients, as well as 9.1%, 9.1%, and 0.0%, respectively, with 11 follow-up serum samples taken at various time points following anti-leishmanial therapy. Specificity was 100.0% in all assays as recorded with 1.137 serum samples from deployed soldiers and migrants without clinical suspicion of visceral leishmaniasis. Kinetoplast-DNA PCR from serum was confirmed as a sensitive and specific approach for the diagnosis of visceral leishmaniasis. The results also indicate the suitability of serum PCR for diagnostic follow-up after therapy, in particular regarding therapeutic failure in case of persisting positive PCR results.

Diagnosing point-of-care diagnostics for neglected tropical diseases

Inadequate and nonintegrated diagnostics are the Achilles' heel of global efforts to monitor, control, and eradicate neglected tropical diseases (NTDs). While treatment is often available, NTDs are endemic among marginalized populations, due to the unavailability or inadequacy of diagnostic tests that cause empirical misdiagnoses. The need of the hour is early diagnosis at the point-of-care (PoC) of NTD patients. Here, we review the status quo of PoC diagnostic tests and practices for all of the 24 NTDs identified in the World Health Organization's (WHO) 2021-2030 roadmap, based on their different diagnostic requirements. We discuss the capabilities and shortcomings of current diagnostic tests, identify diagnostic needs, and formulate prerequisites of relevant PoC tests. Next to technical requirements, we stress the importance of availability and awareness programs for establishing PoC tests that fit endemic resource-limited settings. Better understanding of NTD diagnostics will pave the path for setting realistic goals for healthcare in areas with minimal resources, thereby alleviating the global healthcare burden.

Urine-Based Molecular Diagnostic Tests for Leishmaniasis Infection in Human and Canine Populations: A Meta-Analysis

Leishmaniasis is a neglected tropical disease affecting humans and domesticated animals with high mortality in endemic countries. The pleiotropy of symptoms and the complicated gold-standard methods make the need for non-invasive, highly sensitive diagnostic tests imperative. Individual studies on molecular-based Leishmania diagnosis in urine show high discrepancy; thus, a data-evidenced comparison of various techniques is necessary. We performed a systematic review and meta-analysis using the bivariate method of diagnostic methods to pool sensitivities and specificities. We investigated the impact of DNA-extraction method, PCR type, amplified locus, host species, leishmaniasis form, and geographical region. The pooled sensitivity was 69.2%. Tests performed with the kit-based DNA extraction method and qPCR outweighed in sensitivity the phenol-chloroform-based and PCR methods, while their combination showed a sensitivity of 79.3%. Amplified locus, human or canine as host and cutaneous or visceral leishmaniasis revealed similar sensitivities. Tests in European and Middle Eastern countries performed better than tests in other regions (sensitivity 81.7% vs. 43.7%). A combination of kit-based DNA extraction and qPCR could be a safer choice for molecular diagnosis for Leishmania infection in urine samples in European–Middle Eastern countries. For the rest of the world, more studies are needed to better characterize the endemic parasite species.

Comprehensive characterization of plasma cell-free Echinococcus spp. DNA in echinococcosis patients using ultra-high-throughput sequencing

Background

Echinococcosis is a life-threatening parasitic disease caused by Echinococcus spp. tapeworms with over one million people affected globally at any time. The Echinococcus spp. tapeworms in the human body release DNA to the circulatory system, which can be a biomarker for echinococcosis. Cell-free DNA (cfDNA) is widely used in medical research and has been applied in various clinical settings. As for echinococcosis, several PCR-based tests had been trialed to detect cell-free Echinococcus spp. DNA in plasma or serum, but the sensitivity was about 20% to 25%. Low sensitivity of PCR-based methods might be related to our limited understanding of the features of cell-free Echinococcus spp. DNA in plasma, including its concentration, fragment pattern and release source. In this study, we applied ultra-high-throughput sequencing to comprehensively investigate the characteristics of cell-free Echinococcus spp. DNA in plasma of echinococcosis patients.

Methodology/Principal findings

We collected plasma samples from 23 echinococcosis patients. Total plasma cfDNA was extracted and sequenced with a high-throughput sequencing platform. An average of 282 million read pairs were obtained for each plasma sample. Sequencing data were analyzed with bioinformatics workflow combined with Echinococcus spp. sequence database. After identification of cell-free Echinococcus spp. reads, we found that the cell-free Echinococcus spp. reads accounted for 1.8e-5 to 4.0e-9 of the total clean reads. Comparing fragment length distribution of cfDNA between Echinococcus spp. and humans showed that cell-free Echinococcus spp. DNA of cystic echinococcosis (CE) had a broad length range, while that of alveolar echinococcosis (AE) had an obvious peak at about 135 bp. We found that most of the cell-free Echinococcus spp. DNA reads were from the nuclear genome with an even distribution, which might indicate a random release pattern of cell-free Echinococcus spp. DNA.

Conclusions/Significance

With ultra-high-throughput sequencing technology, we analyzed the concentration, fragment length, release source, and other characteristics of cell-free Echinococcus spp. DNA in the plasma of echinococcosis patients. A better understanding of the characteristics of cell-free Echinococcus spp. DNA in plasma may facilitate their future application as a biomarker for diagnosis.

Echinococcosis is one of the most neglected tropical diseases caused by the metacestodes of Echinococcus spp. tapeworms, which affect both humans and livestock. Plasma cell-free DNA (cfDNA) consists of nucleic acid fragments found extracellularly and may contain DNA released from the parasites. Research shows that a variety of parasites can be detected from plasma cfDNA. Cell-free Echinococcus spp. DNA in plasma or serum had been tested with PCR-based methods, but these PCR methods had low sensitivity ranged from 20% to 25%. Low sensitivity may be due to our limited understanding of cell-free Echinococcus spp. DNA in plasma. Here, we take advantage of high-throughput sequencing to get a comprehensive characterization of cell-free Echinococcus spp. DNA. Our results showed that with high-throughput sequencing we could detect cell-free Echinococcus spp. DNA in all samples, though at a very low level. Based on the sequencing data, we found that cell-free Echinococcus spp. DNA in plasma had a different fragment length distribution to cell-free human DNA, and fragment length distribution of cell-free Echinococcus spp. DNA is also different between cystic echinococcosis (CE) and alveolar echinococcosis (AE). The sequencing data can also help trace the release source of cell-free Echinococcus spp. DNA from the genome. According to the mapping results of cell-free Echinococcus spp. DNA reads, we found that most of them were from the nuclear genome rather than the mitochondrial genome, and their release position showed an even distribution on the genome. These characteristics of cell-free Echinococcus spp. DNA in echinococcosis patients’ plasma could facilitate their future application in research or clinical settings.

Liquid biopsy for infectious diseases: a focus on microbial cell-free DNA sequencing

Metagenomic next-generation sequencing (mNGS) of microbial cell-free DNA (mcfDNA sequencing) is becoming an attractive diagnostic modality for infectious diseases, allowing broad-range pathogen detection, noninvasive sampling, and rapid diagnosis. At this key juncture in the translation of metagenomics into clinical practice, an integrative perspective is needed to understand the significance of emerging mcfDNA sequencing technology. In this review, we summarized the actual performance of the mcfDNA sequencing tests recently used in health care settings for the diagnosis of a variety of infectious diseases and further focused on the practice considerations (challenges and solutions) for improving the accuracy and clinical relevance of the results produced by this evolving technique. Such knowledge will be helpful for physicians, microbiologists and researchers to understand what is going on in this quickly progressing field of non-invasive pathogen diagnosis by mcfDNA sequencing and promote the routine implementation of this technique in the diagnosis of infectious disease.

Noninvasive Biological Samples to Detect and Diagnose Infections due to Trypanosomatidae Parasites: A Systematic Review and Meta-Analysis

Unicellular eukaryotes of the Trypanosomatidae family include human and animal pathogens that belong to the Trypanosoma and Leishmania genera. Diagnosis of the diseases they cause requires the sampling of body fluids (e.g., blood, lymph, peritoneal fluid, cerebrospinal fluid) or organ biopsies (e.g., bone marrow, spleen), which are mostly obtained through invasive methods. Body fluids or appendages can be alternatives to these invasive biopsies but appropriateness remains poorly studied. To further address this question, we perform a systematic review on clues evidencing the presence of parasites, genetic material, antibodies, and antigens in body secretions, appendages, or the organs or proximal tissues that produce these materials. Paper selection was based on searches in PubMed, Web of Science, WorldWideScience, SciELO, Embase, and Google. The information of each selected article (n = 333) was classified into different sections and data were extracted from 77 papers. The presence of Trypanosomatidae parasites has been tracked in most of organs or proximal tissues that produce body secretions or appendages, in naturally or experimentally infected hosts. The meta-analysis highlights the paucity of studies on human African trypanosomiasis and an absence on animal trypanosomiasis. Among the collected data high heterogeneity in terms of the I2 statistic (100%) is recorded. A high positivity is recorded for antibody and genetic material detection in urine of patients and dogs suffering leishmaniasis, and of antigens for leishmaniasis and Chagas disease. Data on conjunctival swabs can be analyzed with molecular methods solely for dogs suffering canine visceral leishmaniasis. Saliva and hair/bristles showed a pretty good positivity that support their potential to be used for leishmaniasis diagnosis. In conclusion, our study pinpoints significant gaps that need to be filled in order to properly address the interest of body secretion and hair or bristles for the diagnosis of infections caused by Leishmania and by other Trypanosomatidae parasites.

Urine as a promising sample for Leishmania DNA extraction in the diagnosis of visceral leishmaniasis - a review

Visceral leishmaniasis is a serious and debilitating infection with high fatality rate in tropical and subtropical countries. As clinical symptoms of visceral leishmaniasis are not so specific, confirmatory diagnostic methods with high sensitivity and specificity are needed. Noninvasive methods have been developed using urine as a clinical sample for visceral leishmaniasis diagnosis. In fact, there is a clear correlation between kidney impairment and Leishmania DNA in urine. However, it has been proved that Leishmania nucleic acid may also be isolated from patients without any sign of renal involvement. Even though urine has become a promissing biological sample, it is still not widely used due to several issues, such as (i) incomprehension of the whole renal pathophysiology process in visceral leishmaniasis, (ii) presence of many amplification inhibitors in urine, and (iii) lack of an efficient urinary DNA extraction method. In this article, we performed a literature review to bring a new perspective for Leishmania DNA isolation in urine.

Case Report: Mucosal Leishmaniasis Presenting with Nasal Septum Perforation after Almost Thirty Years

Mucosal leishmaniasis (ML) is associated with progressive tissue destruction and granuloma formation, often after a considerable period of latency from an initial cutaneous infection. We report a case of recurrent epistaxis of 3 years duration and nasopharyngeal obstruction in a woman with treated cutaneous leishmaniasis nearly 30 years before and with no further exposure to Leishmania. Computed tomography revealed nasal septal perforation and histopathology demonstrated chronic inflammation. Microscopy was negative for amastigotes, but molecular testing of nasal mucosa biopsy detected Leishmania (Viannia) braziliensis. The patient underwent 28 days of treatment with IV sodium stibogluconate and her symptoms improved significantly. Sixteen months after treatment, she continues to have episodic epistaxis and detectable parasite load in her nasal lesion. Although ML is known to take years to decades to develop, there are few reported cases in the literature of such a long latency period. This report highlights the importance of considering ML in the differential diagnosis of chronic epistaxis in countries where leishmaniasis is endemic or in immigrants from these countries, even when presentation occurs decades after leaving an endemic region.

Potential of cell-free DNA as a screening marker for parasite infections in dog

Parasitic infections are common in stray dogs and accurate knowledge of parasite communities in dogs would provide insight into the epidemiology of parasitic diseases. In this study, we used Illumina sequencing technology to evaluate cell-free DNA (cfDNA) as a marker for screening of parasitic infections in dogs. Plasma samples from 14 stray dogs captured in Bangladesh were used in the experiments. An average of 2.3 million reads was obtained for each sample. BLASTn analysis identified 150 reads with high similarity with parasites from 19 different genera. In particular, we detected sequences of Babesia spp. in five dogs; consistent with this, a previous study using conventional PCR showed that four of these dogs were positive for B. gibsoni. Several reads with similarity to Leishmania and filarial nematodes were also identified. These findings indicate that cfDNA in blood can be a potential screening marker for identifying parasite diversity in dogs.

Immunodetection and molecular determination of visceral and cutaneous Leishmania infection using patients' urine

The diagnosis of leishmaniasis relies mainly on the use of invasive processes, to collect the biological material for detecting Leishmania parasites. Body fluids, which can be collected by non-invasive process, would greatly facilitate the leishmaniasis diagnosis. In the present study, we investigated the potency of urine immunoblotting to diagnose cutaneous and visceral leishmaniasis and we compared with routine molecular methods. A total of 80 samples, including 40 sera and their 40 corresponding urine samples were collected from 37 suspected patients with cutaneous and visceral leishmaniasis, and 3 healthy individuals (as control), in Ilam and Ardabil provinces of Iran. All sera and urine samples were analyzed, using immunoblotting. The confirmation of leishmaniasis infection was performed, using conventional and quantitative PCRs as well as by sequencing the amplicons. Among 37 suspected patients, 23 patients presented cutaneous lesions (CL) and 14 exhibited clinical symptoms reminiscent of visceral leishmaniasis (L. infantum). Among cutaneous patients, 15 were positive for zoonotic cutaneous leishmaniasis (L. major), and eight for anthroponotic cutaneous leishmaniasis (L. tropica). Molecular quantification of Leishmania parasites was performed on sera, urines and cutaneous biopsies of CL and VL patients, demonstrating that parasite load is lower in urines, compared to sera or biopsy. DNA can be detected in 20 out of 23 (86.9%) CL urine samples and in 13 out of 14 (92.8%) VL urine samples. Immunodetection analysis demonstrates that 22 out of 23 (95.6%) sera from CL patients and all patients suspected with VL are positive. For urine samples, 18 out of 23 (78.2%) urine of CL patients and 13 out of 14 (92.8%) urine of VL patients were positive, using Western blot. Therefore, immunodetection and molecular analysis using urine samples can be used as a diagnostic tool for surveying cutaneous and visceral leishmaniasis.

Cell-Free DNA as a Diagnostic Tool for Human Parasitic Infections

Parasites often cause devastating diseases and represent a significant public health and economic burden. More accurate and convenient diagnostic tools are needed in support of parasite control programmes in endemic regions, and for rapid point-of-care diagnosis in nonendemic areas. The detection of cell-free DNA (cfDNA) is a relatively new concept that is being applied in the current armamentarium of diagnostics. Here, we review the application of cfDNA detection with nucleic acid amplification tests for the diagnosis and evaluation of different human parasitic infections and highlight the significant benefits of the approach using non-invasive clinical samples.

Accuracy of mucocutaneous leishmaniasis diagnosis using polymerase chain reaction: systematic literature review and meta-analysis

The diagnosis of mucocutaneous leishmaniasis (MCL) is hampered by the absence of a gold standard. An accurate diagnosis is essential because of the high toxicity of the medications for the disease. This study aimed to assess the ability of polymerase chain reaction (PCR) to identify MCL and to compare these results with clinical research recently published by the authors. A systematic literature review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses: the PRISMA Statement was performed using comprehensive search criteria and communication with the authors. A meta-analysis considering the estimates of the univariate and bivariate models was performed. Specificity near 100% was common among the papers. The primary reason for accuracy differences was sensitivity. The meta-analysis, which was only possible for PCR samples of lesion fragments, revealed a sensitivity of 71% [95% confidence interval (CI) = 0.59; 0.81] and a specificity of 93% (95% CI = 0.83; 0.98) in the bivariate model. The search for measures that could increase the sensitivity of PCR should be encouraged. The quality of the collected material and the optimisation of the amplification of genetic material should be prioritised.

Detection of Plasmodium knowlesi DNA in the urine and faeces of a Japanese macaque (Macaca fuscata) over the course of an experimentally induced infection

Background

Diagnostic techniques based on PCR for the detection of Plasmodium DNA can be highly sensitive and specific. The vast majority of these techniques rely, however, on the invasive sampling of blood from infected hosts. There is, currently, considerable interest in the possibility of using body fluids other than blood as sources of parasite DNA for PCR diagnosis.

Methods

Urine and faeces were obtained from a Plasmodium knowlesi infected-Japanese macaque (Macaca fuscata) over the course of an experimentally induced infection. P. knowlesi DNA (PkDNA) extracted from urine and faeces were monitored by nested PCR targeting the P. knowlesi specific cytochrome b (cytb) gene.

Results

Urinary PkDNA was detected on day 2, but was not amplified using DNA templates extracted from the samples on day 4, day 5 and day 6. Subsequently, urinary PkDNA was detected from day 7 until day 11, and from day 20 until day 30. PkDNA in faeces was detected from day 7 until day 11, and from day 20 until day 37. Moreover, real-time quantitative PCR showed a remarkable increase in the amount of urinary PkDNA following anti-malarial treatment. This might have been due to the release of a large amount of PkDNA from the degraded parasites as a result of the anti-malarial treatment, leading to excretion of PkDNA in the urine.

Conclusions

The cytb-PCR system using urine and faecal samples is of potential use in molecular epidemiological surveys of malaria. In particular, monkey faecal samples could be useful for the detection of zoonotic primate malaria in its natural hosts.

Electronic supplementary material

The online version of this article (doi:10.1186/1475-2875-13-373) contains supplementary material, which is available to authorized users.

Treatment failure in leishmaniasis: drug-resistance or another (epi-) phenotype?

Two major leishmaniasis treatments have shown a significant decrease in effectiveness in the last few decades, mostly in the Indian subcontinent but also in other endemic areas. Drug resistance of Leishmania correlated only partially to treatment failure (TF) of pentavalent antimonials, and has so far proved not to be important for the increased miltefosine relapse rates observed in the Indian subcontinent. While other patient- or drug-related factors could also have played a role, recent studies identified several parasite features such as infectivity and host manipulation skills that might contribute to TF. This perspective aims to discuss how different parasitic features other than drug resistance can contribute to TF of leishmaniasis and how this may vary between different epidemiological contexts.

Applicability of kDNA-PCR for routine diagnosis of American tegumentary leishmaniasis in a tertiary reference hospital

SUMMARY

This study evaluated the applicability of kDNA-PCR as a prospective routine diagnosis method for American tegumentary leishmaniasis (ATL) in patients from the Instituto de Infectologia Emílio Ribas (IIER), a reference center for infectious diseases in São Paulo - SP, Brazil. The kDNA-PCR method detected Leishmania DNA in 87.5% (112/128) of the clinically suspected ATL patients, while the traditional methods demonstrated the following percentages of positivity: 62.8% (49/78) for the Montenegro skin test, 61.8% (47/76) for direct investigation, and 19.3% (22/114) for in vitro culture. The molecular method was able to confirm the disease in samples considered negative or inconclusive by traditional laboratory methods, contributing to the final clinical diagnosis and therapy of ATL in this hospital. Thus, we strongly recommend the inclusion of kDNA-PCR amplification as an alternative diagnostic method for ATL, suggesting a new algorithm routine to be followed to help the diagnosis and treatment of ATL in IIER.

Detection of soluble antigen and DNA of Trypanosoma cruzi in urine is independent of renal injury in the guinea pig model

The diagnosis of Chagas disease in humans is generally limited to the detection of specific antibodies. Detection of T. cruzi antigens in urine has been reported previously, but is not used in the diagnosis. In this study, soluble T. cruzi antigens and DNA were detected in urine samples and were associated with kidney injury and systemic detection of the parasite. We used 72 guinea pigs infected with T. cruzi Y strain and 18 non-infected guinea pigs. Blood, kidney, heart and urine samples were collected during the acute phase and chronic phase. Urine samples were concentrated by ultrafiltration. Antigens were detected by Western Blot using a polyclonal antibody against trypomastigote excretory-secretory antigen (TESA). T. cruzi DNA was detected by PCR using primers 121/122 and TcZ1/TcZ2. Levels of T. cruzi DNA in blood, heart and kidney were determined by quantitative PCR. T. cruzi antigens (75 kDa, 80 kDa, 120 kDa, 150 kDa) were detected in the acute phase (67.5%) and the chronic phase (45%). Parasite DNA in urine was detected only in the acute phase (45%). Kidney injury was characterized by high levels of proteinuria, kidney injury molecule-1 (KIM-1) and urea, and some histopathological changes such as inflammation, necrosis, fibrosis and scarce parasites. The detection of antigens and DNA in urine was associated with the presence of parasite DNA in blood and heart and with high levels of parasite DNA in blood, but not with the presence of parasite in kidney or kidney injury. These results suggest that the detection of T. cruzi in urine could be improved to be a valuable method for the diagnosis of Chagas disease, particularly in congenital Chagas disease and in immunocompromised patients.