The association of systemic inflammation and cognitive functions of pre-school aged children residing in a Schistosoma haematobium endemic area in Zimbabwe.

Background: Cognitive function is negatively impacted by schistosomiasis and might be caused by systemic inflammation which has been hypothesized to be one of the mechanisms driving cognitive decline, This study explored the association of systemic inflammatory biomarkers; interleukin (IL)-10, IL-6, IL-17, transforming growth factor (TGF-ß), tumor necrosis factor (TNF-α), C-reactive protein (CRP) and hematological parameters with cognitive performance of preschool-aged children (PSAC) from an Schistosoma haematobium endemic area. Methods: The Griffith III tool was used to measure the cognitive performance of 136 PSAC. Whole blood and sera were collected and used to quantify levels of IL-10, TNF-α, IL-6, TGF-ß, IL-17 A and CRP using the enzyme-linked immunosorbent assay and hematological parameters using the hematology analyzer. Spearman correlation analysis was used to determine the relationship between each inflammatory biomarker and cognitive performance. Multivariate logistic regression analysis was used to determine whether systemic inflammation due to S. haematobium infection affected cognitive performance in PSAC. Results: Higher levels of TNF-α and IL-6, were correlated with lower performance in the Foundations of Learning domain (r = -0.30; p < 0.001 and r = -0.26; p < 0.001), respectively. Low cognitive performance in the Eye-Hand-Coordination Domain was observed in PSAC with high levels of the following inflammatory biomarkers that showed negative correlations to performance; TNF-α (r = -0.26; p < 0.001), IL-6 (r = -0.29; p < 0.001), IL-10 (r = -0.18; p < 0.04), WBC (r = -0.29; p < 0.001), neutrophils (r = -0.21; p = 0.01) and lymphocytes (r = -0.25; p = 0.003) The General Development Domain correlated with TNF-α (r = -0.28; p < 0.001) and IL-6 (r = -0.30; p < 0.001). TGF-ß, L-17A and MXD had no significant correlations to performance in any of the cognitive domains. The overall general development of PSAC was negatively impacted by S. haematobium infections (OR = 7.6; p = 0.008) and (OR = 5.6; p = 0.03) where the PSAC had higher levels of TNF-α and IL-6 respectively. Conclusion: Systemic inflammation and S. haematobium infections are negatively associated with cognitive function. We recommend the inclusion of PSAC into mass drug treatment programs.

Diagnostic performances of Schistosoma haematobium and Schistosoma mansoni recombinant proteins, peptides and chimeric proteins antibody based tests. Systematic scoping review.

BACKGROUND: Traditional diagnostic tests for schistosome infections are suboptimal, particularly when the parasite burden is low. In the present review we sought to identify recombinant proteins, peptides, and chimeric proteins with potential to be used as sensitive and specific diagnostic tools for schistosomiasis. METHODS: The review was guided by PRISMA-ScR guidelines, Arksey and O'Malley's framework, and guidelines from the Joanna Briggs Institute. Five databases were searched: Cochrane library, PubMed, EMBASE, PsycInfo and CINAHL, alongside preprints. Identified literature were assessed by two reviewers for inclusion. A narrative summary was used to interpret the tabulated results. RESULTS: Diagnostic performances were reported as specificities, sensitivities, and AUC. The AUC for S. haematobium recombinant antigens ranged from 0.65 to 0.98, and 0.69 to 0.96 for urine IgG ELISA. S. mansoni recombinant antigens had sensitivities ranging from 65.3% to 100% and specificities ranging from 57.4% to 100%. Except for 4 peptides which had poor diagnostic performances, most peptides had sensitivities ranging from 67.71% to 96.15% and specificities ranging from 69.23% to 100%. S. mansoni chimeric protein was reported to have a sensitivity of 86.8% and a specificity of 94.2%. CONCLUSION: The tetraspanin CD63 antigen had the best diagnostic performance for S. haematobium. The tetraspanin CD63 antigen Serum IgG POC-ICTs had a sensitivity of 89% and a specificity of 100%. Peptide Smp_150390.1 (216-230) serum based IgG ELISA had the best diagnostic performance for S. mansoni with a sensitivity of 96.15% and a specificity of 100%. Peptides were reported to demonstrate good to excellent diagnostic performances. S. mansoni multi-peptide chimeric protein further improved the diagnostic accuracy of synthetic peptides. Together with the advantages associated with urine sampling technique, we recommend development of multi-peptide chimeric proteins urine based point of care tools.

Peptide microarray analysis of in-silico predicted B-cell epitopes in SARS-CoV-2 sero-positive healthcare workers in Bulawayo, Zimbabwe.

Immunogenic peptides that mimic linear B-cell epitopes coupled with immunoassay validation may improve serological tests for emerging diseases. This study reports a general approach for profiling linear B-cell epitopes derived from SARS-CoV-2 using an in-silico method and peptide microarray immunoassay, using healthcare workers' SARS-CoV-2 sero-positive sera. SARS-CoV-2 was tested using rapid chromatographic immunoassays and real-time reverse-transcriptase polymerase chain reaction. Immunogenic peptides mimicking linear B-cell epitopes were predicted in-silico using ABCpred. Peptides with the lowest sequence identity with human protein and proteins from other human pathogens were selected using the NCBI Protein BLAST. IgG and IgM antibodies against the SARS-CoV-2 spike protein, membrane glycoprotein and nucleocapsid derived peptides were measured in sera using peptide microarray immunoassay. Fifty-three healthcare workers included in the study were RT-PCR negative for SARS-CoV-2. Using rapid chromatographic immunoassays, 10 were SARS-CoV-2 IgM sero-positive and 7 were SARS-CoV-2 IgG sero-positive. From a total of 10 SARS-CoV-2 peptides contained on the microarray, 3 (QTH34388.1-1-14, QTN64908.1-135-148, and QLL35955.1-22-35) showed reactivity against IgG. Three peptides (QSM17284.1-76-89, QTN64908.1-135-148 and QPK73947.1-8-21) also showed reactivity against IgM. Based on the results we predicted one peptide (QSM17284.1-76-89) that had an acceptable diagnostic performance. Peptide QSM17284.1-76-89 was able to detect IgM antibodies against SARS-CoV-2 with area under the curve (AUC) 0.781 when compared to commercial antibody tests. In conclusion in silico peptide prediction and peptide microarray technology may provide a platform for the development of serological tests for emerging infectious diseases such as COVID-19. However, we recommend using at least three in-silico peptide prediction tools to improve the sensitivity and specificity of B-cell epitope prediction, to predict peptides with excellent diagnostic performances.

Multiplex peptide microarray profiling of antibody reactivity against neglected tropical diseases derived B-cell epitopes for serodiagnosis in Zimbabwe.

INTRODUCTION: Peptides (B-cell epitopes) have broad applications in disease diagnosis and surveillance of pathogen exposure. In this framework, we present a pilot study to design and produce a peptide microarray for the integrated surveillance of neglected tropical diseases. The peptide microarray was evaluated against peptides derived from Ascaris lumbricoides, Necator americanus, Schistosoma haematobium, Schistosoma mansoni, Trichuris trichiura, Bacillus anthracis, Mycobacterium leprae, Wuchereria bancrofti, Rabies lyssavirus, Chlamydia trachomatis and Trypanosoma brucei. METHODS: S. haematobium was diagnosed using the urine filtration technique. S. mansoni, A. lumbricoides, N. americanus and T. trichiura were diagnosed using the Kato Katz and formal ether concentration techniques. Immunogenic peptides were retrieved from the Tackling Infection to Benefit Africa infectious diseases epitope microarray. Further peptides were predicted using ABCpred. IgG and IgM reactivity against the derived peptides were evaluated using peptide microarray multiplex immunoassays. Positive response was defined as fluorescence intensity ≥ 500 fluorescence units. Immunodominant peptides were identified using color-coded heat maps and bar graphs reflecting the obtained fluorescence signal intensities. Receiver Operating Characteristic analysis and Mann-Whitney-U test were performed to determine the diagnostic validity of the peptides. RESULTS: Species-specific responses with at least one peptide derived from each NTD pathogen were observed. The reactive peptides included; for S. haematobium, XP_035588858.1-206-220 and XP_035588858.1-206-220 immunodominant for IgG and IgM respectively, for S. mansoni, P20287.1-58-72 immunodominant for both antibodies and for T. trichiura, CDW52482.1-326-340 immunodominant for IgG and CDW57769.1-2017-2031 and CDW57769.1-1518-1532 immunodominant for IgM. According to ROC analysis most of the peptides selected were inaccurate; with AUC < 0.5. Some peptides had AUC values ranging from 0.5 to 0.5875 for both IgM and IgG suggesting no discrimination. CONCLUSION: Multiplex peptide microarrays are a valuable tool for integrated NTDs surveillance and for screening parasites exposure in endemic areas. Species sero-reactivity observed in the study maybe indicative of exposure to the different NTDs parasites. However, although peptides with the least cross reactivity were selected there is need to validate the sero-reactivity with recombinant antigens and immune-blotting techniques such as western blotting.

Scoping review of the applications of peptide microarrays on the fight against human infections.

INTRODUCTION: This scoping review explores the use of peptide microarrays in the fight against infectious diseases. The research domains explored included the use of peptide microarrays in the mapping of linear B-cell and T cell epitopes, antimicrobial peptide discovery, immunosignature characterisation and disease immunodiagnostics. This review also provides a short overview of peptide microarray synthesis. METHODS: Electronic databases were systematically searched to identify relevant studies. The review was conducted using the Joanna Briggs Institute methodology for scoping reviews and data charting was performed using a predefined form. The results were reported by narrative synthesis in line with the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews guidelines. RESULTS: Ninety-five articles from 103 studies were included in the final data charting process. The majority (92. 0%) of the articles were published during 2010-2020 and were mostly from Europe (44.2%) and North America (34.7%). The findings were from the investigation of viral (45.6%), bacterial (32. 0%), parasitic (23.3%) and fungal (2. 0%) infections. Out of the serological studies, IgG was the most reported antibody type followed by IgM. The largest portion of the studies (77.7%) were related to mapping B-cell linear epitopes, 5.8% were on diagnostics, 5.8% reported on immunosignature characterisation and 8.7% reported on viral and bacterial cell binding assays. Two studies reported on T-cell epitope profiling. CONCLUSION: The most important application of peptide microarrays was found to be B-cell epitope mapping or antibody profiling to identify diagnostic and vaccine targets. Immunosignatures identified by random peptide microarrays were found to be applied in the diagnosis of infections and interrogation of vaccine responses. The analysis of the interactions of random peptide microarrays with bacterial and viral cells using binding assays enabled the identification of antimicrobial peptides. Peptide microarray arrays were also used for T-cell linear epitope mapping which may provide more information for the design of peptide-based vaccines and for the development of diagnostic reagents.

Clinical utility of peptide microarrays in the serodiagnosis of neglected tropical diseases in sub-Saharan Africa: protocol for a diagnostic test accuracy systematic review.

INTRODUCTION: Neglected tropical diseases tend to cluster in the same poor populations and, to make progress with their control, they will have to be dealt with in an integrated manner. Peptide microarrays may be a solution to these problems, where diagnosis for co-infection can be detected simultaneously using the one tool. A meta-analysis using hierarchical models will be performed to assess the diagnostic accuracy of peptide microarrays for detecting schistosomiasis (Schistosoma mansoni and S. haematobium), soil-transmitted helminths (Trichuris trichiura, Ascaris lumbricoides and Necator americanus), trachoma (Chlamydia trachomatis), lymphatic filariasis (Wuchereria bancrofti) and onchocerciasis (Onchocerca volvulus) in people residing in sub-Saharan Africa. METHODS AND ANALYSIS: A comprehensive search of the following databases will be performed: Cochrane Infectious Diseases Group Specialised Register, PubMed, EMBASE and The Web of Science. Studies comparing peptide microarrays with a reference standard from a random or consecutive series of patients will be included in the study. Two review authors will independently screen titles and abstracts for relevance, assess full-text articles for inclusion and carry out data extraction using a tailored data extraction form. The quality Assessment of Diagnostic Accuracy Studies-2 tool will be used to assess the quality of the selected studies. The bivariate model and the hierarchical summary receiver operating characteristic curve model will be performed to evaluate the diagnostic accuracy of the peptide microarrays. Meta-regression analyses will be performed to investigate heterogeneity across studies. ETHICS AND DISSEMINATION: There is no requirement for ethical approval because the work will be carried out using previously published data, without human beings involvement. Findings will be disseminated through peer-reviewed publication and in conference presentations. PROSPERO REGISTRATION NUMBER: CRD42020175145.

Effects of TNF-α and IL-10-819 T>C single nucleotide polymorphisms on urogenital schistosomiasis in preschool children in Zimbabwe.

BACKGROUND: Knowledge gaps exist between host genetic factors and susceptibility to schistosomiasis. OBJECTIVE: This study determined cytokine levels and single nucleotide polymorphisms of tumour necrosis factor (TNF)-α (rs1800629) and interleukin (IL)-10 (rs1800871) and their possible impact on susceptibility to schistosomiasis in preschool-age children in the Madziva area of Shamva district, Mashonaland Central province, Zimbabwe. METHODS: Urogenital schistosomiasis was diagnosed using the urine filtration method, while a sandwich enzyme-linked immunosorbent assay was used for cytokine level determination. The survey was done in August 2015 and reinfection levels post treatment were assessed at 3, 6 and 12 months. Amplification refractory mutation system polymerase chain reaction with visualisation on 2% agarose gel electrophoresis was used for genotyping. RESULTS: Schistosomiasis prevalence was found to be 10.5% (59/563). Reinfections were detected in only six children at 3 months and only one was reinfected at 12 months. There were no significant differences in TNF-α-308 G/A allele or genotype frequencies between the Schistosoma haematobium infected participants (p = 0.360) and uninfected participants (p = 0.279). However, no children with the IL-10-819 TT genotype had schistosomiasis. The TNF-α GG genotype corresponded with significantly lower TNF-α levels when compared with the GA or AA genotypes (p < 0.001), and TNF-α levels were significantly lower in infected children compared to uninfected children (p < 0.001). CONCLUSION: Higher TNF-α levels and lower IL-10 levels are potentially protective against schistosomiasis infection. The IL-10-819 TT genotype is potentially protective against infection through its association with lower IL-10 levels.

Association of TNF (rs1800629) promoter polymorphism and schistosomiasis with sub-microscopic asymptomatic Plasmodium falciparum infections in a schistosomiasis-endemic area in Zimbabwe.

OBJECTIVES: Infection with Plasmodium falciparum parasites may result in a wide spectrum of symptoms ranging from asymptomatic to mild or severe. A number of factors are associated with this heterogeneous response to P. falciparum infection. In the present study, associations of sub-microscopic asymptomatic P. falciparum with Schistosoma species and TNF (rs1800629) polymorphism were investigated. METHODS: 361 clinically healthy primary school children were microscopically screened for S. haematobium, S. mansoni and P. falciparum. Sub-microscopic asymptomatic P. falciparum infections were determined by PCR. Genotypic profiles were identified using ARMS-PCR. Logistic regression was used to assess the association of sub-microscopic asymptomatic P. falciparum with Schistosoma species and TNF (rs1800629) polymorphism. RESULTS: 17.2% of the children were infected with S. mansoni, and 27.4% were infected with S. haematobium. Microscopic examination of thick smears detected only one child infected with P. falciparum. Based on PCR results, 46.1% were infected with sub-microscopic asymptomatic P. falciparum. Children carrying heterozygous AG (OR: 16.964, 95% CI: 0.496-586.547) and homozygous GG (OR: 2.280, 95% CI: 0.111-46.796) genotypes of rs1800629 were associated with an increased likelihood of sub-microscopic asymptomatic P. falciparum infections compared with those carrying homozygous AA genotype. Children without S. haematobium infections (OR: 1.051, 95% CI: 0.146-8.985) and S. mansoni (OR: 2.658, 95% CI: 0.498-14.184) also had an increased likelihood (risk) of being infected with sub-microscopic asymptomatic P. falciparum compared with the Schistosoma-infected groups. However, all the associations observed were not statistical significant. CONCLUSION: No associations were observed between rs1800629 and schistosomiasis with sub-microscopic asymptomatic P. falciparum infections. This study also reports a high prevalence of sub-microscopic asymptomatic P. falciparum infection concomitant with low malaria transmission.

OBJECTIFS: L'infection par les parasites P. falciparum peut entraîner un large éventail de présentations allant d'asymptomatiques à bénignes ou sévères. Un certain nombre de facteurs sont associés à cette réaction hétérogène à l'infection à P. falciparum. Dans la présente étude, les associations entre la présentation asymptomatique sous-microscopique de P. falciparum avec les espèces de Schistosoma et le polymorphisme du TNF (rs1800629) ont été investiguées. MÉTHODES: 364 écoliers du primaire en bonne santé clinique ont subi microscopique pour S. haematobium, S. mansoni et P. falciparum. Les infections asymptomatiques sous-microscopiques à P. falciparum ont été déterminées par PCR. Les profils génotypiques ont été identifiés en utilisant ARMS-PCR. La régression logistique a été utilisée pour évaluer l'association entre la présentation asymptomatique sous-microscopique de P. falciparum avec les espèces de Schistosoma et le polymorphisme du TNF (rs1800629). RÉSULTATS: Parmi les enfants, 17,2% étaient infectés par S. mansoni et 27,4% étaient infectés par S. haematobium. L'examen microscopique de frottis épais n'a détecté qu'un seul enfant infecté par P. falciparum. D'après les résultats de la PCR, 46,1% étaient infectés par P. falciparum asymptomatique sous-microscopique. Les enfants porteurs des génotypes hétérozygotes AG (OR: 16,964 ; IC95%: 0,496-586,547) et homozygotes GG (OR: 2,280 ; IC95%: 0,111-46,796) de rs1800629 étaient associés à une probabilité accrue d'infections asymptomatiques sous-microscopiques à P. falciparum par rapport à ceux porteurs du génotype homozygote AA. Les enfants sans infection à S. haematobium (OR: 1,051 ; IC95%: 0,146-8,985) et S. mansoni (OR: 2,658 ; IC95%: 0,498 à 14,184) présentaient également une probabilité (risque) accrue d'être infectés par P. falciparum asymptomatique sous-microscopique par rapport à ceux infectés par Schistosoma. Cependant, toutes les associations observées n'étaient pas statistiquement significatives. CONCLUSION: Aucune association n'a été observée entre le rs1800629 et la schistosomiase avec des infections asymptomatiques sous-microscopiques à P. falciparum. Cette étude rapporte une prévalence élevée d' infection asymptomatique sous-microscopique à P. falciparum concomitante à une faible transmission du paludisme.

Interleukin-10 and tumour necrosis factor alpha promoter region polymorphisms and susceptibility to urogenital schistosomiasis in young Zimbabwean children living in Schistosoma haematobium endemic regions.

BACKGROUND: Host genetic factors can influence susceptibility, morbidity and mortality from schistosomiasis. The study explored the association between single nucleotide polymorphisms (SNPs) in interleukin-10 (IL-10) and tumour necrosis factor alpha (TNF-α) promoter regions and susceptibility to Schistosoma haematobium infection. METHODS: Urine specimens were collected from 361 primary school children aged 5-15 years from schistosomiasis endemic areas of Manicaland and Mashonaland central provinces. Schistosoma haematobium was diagnosed using the urine filtration method. Only 272 participants provided adequate blood for genotyping. Genotyping was performed using the amplification refractory mutation system-polymerase chain reaction. The association between IL-10 and TNF-α SNPs and S. haematobium infection was analysed using the chi-square test. RESULTS: Schistosoma haematobium infection was confirmed in 26.8% of the participants. No significant difference in S. haematobium prevalence between men (51.6% of those infected) and women (48.4%) (χ2 = 0.008, df = 1, p = 0.928) was observed. The total IL-10 -1082 G, IL-10 -819 C and TNF-α -308G allele distribution between S. haematobium infected and uninfected participants was 50.7% and 51.5% (χ2 = 0.025, df = 1, p = 0.87), 54.3% and 60.6% (χ2 = 1.187, df = 1, p = 0.187) and 82.1% and 80.9% (χ2 = 0.099, df = 1, p = 0.753), respectively, and the differences were not significant. CONCLUSION: Interleukin-10 -1082 G/A, IL-10 -819 C/T and TNF-α -308 G/A SNPs were not significantly associated with susceptibility to S. haematobium infection. The prevalence of schistosomiasis is still in the moderate range and is similar in boys and girls.

Elevation of C-reactive protein, P-selectin and Resistin as potential inflammatory biomarkers of urogenital Schistosomiasis exposure in preschool children.

BACKGROUND: Schistosomiasis is known to induce inflammatory immune responses. C-reactive protein (CRP), resistin and P-selectin are serological inflammatory markers that rise during the acute stages of infection. Here, we propose such inflammatory biomarkers have a potential for use in urogenital schistosomiasis diagnostic screening for exposure and infection in preschool-aged children. METHODS: As part of a larger study on urogenital schistosomiasis, 299 preschool children aged 1-5 years were included in this cross-sectional study. Parasitological diagnosis was conducted using urine filtration for Schistosoma haemtobium infection, and Kato Katz for S. mansoni infection. Serum levels of P-selectin, resistin, CRP, and antibodies against S. haematobium cercarial antigen preparation (CAP) and soluble worm antigen preparation (SWAP) were measured by ELISA. RESULTS: Of the 299 participants, 14% were egg positive for S. haematobium. Serology showed 46 and 9% of the participants to have been exposed to S. haematobium cercarial antigens and adult worm antigens, respectively. Levels of P-selectin were significantly higher in participants infected with S. haematobium (egg-positive) than in uninfected participants (p = 0.001). Levels of P-selectin were also higher in those exposed to cercarial antigen than in unexposed participants (p = 0.019). There was a positive correlation between P-selectin and infection intensity (r = 0.172; p = 0.002), as well as with IgM responses to CAP and SWAP (r = 0.183; p = 0.001); (r = 0.333; p < 0.0001) respectively. CRP significantly correlated with IgM responses to CAP (r = 0.133; p = 0.029) while resistin correlated with IgM responses to CAP and SWAP (r = 0.127; p = 0.016); (r = 0.197; p = 0.0004). CRP levels were higher in those exposed to cercarial and adult worm antigens than unexposed participants (p = 0.035); (p = 0.002) respectively, while resistin was higher in participants exposed to cercarial antigen than unexposed participants (p = 0.024). CONCLUSION: In this preschool population, P-selectin is significantly associated with urogenital schistosome infection and intensity; hence a potential biomarker for infection diagnosis and disease monitoring. The inflammatory biomarkers (P-selectin, Resistin and CRP) were significantly higher in participants exposed to cercarial antigens than unexposed individuals indicating an underlying inflammatory environment.

Benefits of annual chemotherapeutic control of schistosomiasis on the development of protective immunity.

BACKGROUND: Schistosomiasis is a devastating parasitic disease. The mainstay of schistosomiasis control is by praziquantel treatment. The study aimed to determine benefits of annual chemotherapy of schistosomiasis on development of protective immunity in school children in a selected endemic rural area in Zimbabwe. METHODS: Urine specimens from 212 school children (7-13 years) were collected and examined to determine prevalence, intensity and reinfection of S.haematobium at baseline, 6 weeks and 2 years following annual rounds of praziquantel treatment. Blood samples from the participants were assayed for total and S. haematobium (Sh13)-specific antibodies before and 2 years after annual rounds of treatment. RESULTS: Annual treatment reduced the prevalence of S. haematobium infection (p < 0.05) from 23.1% at baseline to 0.47% after 2 years. Overall cure rate was 97.8%. Intensity of infection declined (p < 0.05) from 15.9 eggs/10 ml urine at baseline to 2 eggs/10 ml urine. After two years, overall rate of reinfection was 0.96%. At baseline, total IgG4 was higher in S. haematobium-infected children (p = 0.042) ,while all other immunoglobulins were within normal ranges. There was an increase in total IgG2 (p = 0.044) levels and a decrease in total IgG4 (p = 0.031) levels 2 years post-treatment; and no significant changes in other total immunoglobulins. Schistosoma-infected children at baseline showed an increase in anti-Sh13 IgG1 (p = 0.005) and a decrease in Sh13 IgG4 levels (p = 0.012) following treatment. CONCLUSION: Annual praziquantel treatment delivered to school children over 2 years significantly reduce prevalence, intensity of infection and reinfection of S. haematobium infection. Treatment was also observed to cause a reduction in schistosome-specific blocking IgG4 and an increase in Schistosoma-specific protecting IgG1.