Blood qPCR Research Articles

Toxoplasma qPCR kinetics to guide pre-emptive treatment of toxoplasmosis after allogeneic hematopoietic stem cell transplantation.

Recent ECIL-guidelines recommend a quantitative PCR (qPCR) guided pre-emptive treatment approach to toxoplasmosis in seropositive recipients of allogeneic hematopoietic cell transplantation (allo-HCT). While qPCR might serve as a sensitive tool for early Toxoplasma detection, its role in treatment follow-up remains unknown. We analyzed the qPCR kinetics of allo-HCT recipients experiencing either Toxoplasma infection (TI, n=71) or disease (TD, n=14) in relation to different parameters. We included 85 patients with available qPCR values expressed as quantitative cycle (Cq) from four large hematological centers from 2009 to 2023, and kinetic analysis was performed in a selection of 74 patients screened at least weekly with blood qPCR. Day 0 (D0) was the day of anti-Toxoplasma treatment start or (when untreated) day of diagnosis. Time to qPCR negativity was inversely proportional to the Cq value at D0 (p=0.0063). Not reaching negativity at D10 was associated with a significantly higher mortality at D30 (p=0.023). Patients with a high D0-parasitic load and patients with TD showed slower clearance (p<0.001, p=0.032). Time to negativity was not significantly different for patients started on prophylactic vs curative doses as first-line treatment regimen (p=0.16). This study underscores the predictive value of qPCR kinetics monitoring in allo-HCT patients with toxoplasmosis. With the aforementioned risk factors, clinicians can identify patients at high-risk for worse outcome. Our results support to consider a therapeutic change or reinforcement if the parasitic load does not decrease after 10 days, supplementing existing clinical guidelines.

Methylenetetrahydrofolate reductase levels and gene expression in leukemia

Abstract Leukemia is a neoplastic disease that affects the proliferation of white blood cells and their progenitors. Folic acid deficiency is well-known as a risk factor for leukemia. Methylenetetrahydrofolate reductase (MTHFR) enzyme functions in the folate metabolism route, DNA synthesis and methylation processes. Numerous research has been conducted to investigate the link between MTHFR and several human illnesses, including cancer, cardiovascular disease, psychiatric disorders and neurological issues. The current study aimed to examine MTHFR levels and gene expression in patients with leukemia. The research was carried out between February and October of 2022. There were 130 subjects in total, 80 with leukemia, 45 with AML (Female = 16, Male = 26) with a mean age of (32.32±2.69), and 35 with ALL (Female = 16, Male = 19) with a mean age of (35.794±0.63). The study included 50 healthy subjects as a healthy control group (Female = 28, Male = 22), with an average age of (41.8±1.57) years. MTHFR and Folic acid were measured using ELISA, while MTHFR mRNA was assessed using qPCR in blood and plasma. Folic acid and MTHFR levels were found to be lower in patients with AML and ALL compared to controls (p &lt;0.01). MTHFR gene expression was found to be downregulated in leukemia patients (p &lt;0.01). The findings of the study give support for future research into the effect of folic acid level and supplementation on leukemia-associated pathological outcomes. Folic acid deficiency may affect the folate mediate-one carbon metabolism pathway, as evidenced by changes in the expression of the mRNA MTHFR gene. As a result, more research into the effects of folate status and folic acid supplementation on leukemia is needed to investigate potential therapeutic strategies.

Standardization of Semi-Quantitative Dot Blotting Assay-Application in the Diagnosis, Follow-Up, and Relapse of Paracoccidioidomycosis.

This study standardized a semi-quantitative dot blotting assay (DB) and a quantitative real-time polymerase chain reaction (qPCR) to detect specific antibodies for Paracoccidioides brasiliensis and its DNA in PCM patients. We evaluated 42 confirmed PCM patients upon admission using a serological double agar gel immunodiffusion test (DID), DB, and molecular tests (qPCR in total blood). The control groups included 42 healthy individuals and 37 patients with other infectious diseases. The serological progress during treatment was evaluated in eight patients, and there was a relapse diagnosis in ten patients using the Pb B.339 strain antigen. The cut-off points for the serological tests were determined by a receiver operator characteristic curve. The DB and DID tests showed similar accuracy, but the DB identified lower antibody concentrations. Cross-reactions were absent in the DB assay. In the relapse diagnoses, DB exhibited much higher sensitivity (90%) than DID (30%). A DB assay is easier and faster than a DID test to be performed; DB and DID tests show the same accuracy, while blood qPCR is not recommended in the diagnosis at the time of admission; cross-reactions were not observed with other systemic diseases; DB and DID tests are useful for treatment monitoring PCM patients; and a DB assay is the choice for diagnosing relapse. These findings support the introduction of semi-quantitative DB assays in clinical laboratories.

Efficacy of three benznidazole dosing strategies for adults living with chronic Chagas disease (MULTIBENZ): an international, randomised, double-blind, phase 2b trial

BackgroundTreatment with benznidazole for chronic Chagas disease is associated with low cure rates and substantial toxicity. We aimed to compare the parasitological efficacy and safety of 3 different benznidazole regimens in adult patients with chronic Chagas disease. MethodsThe MULTIBENZ trial was an international, randomised, double-blind, phase 2b trial performed in Argentina, Brazil, Colombia, and Spain. We included participants aged 18 years and older diagnosed with Chagas disease with two different serological tests and detectable T cruzi DNA by qPCR in blood. Previously treated people, pregnant women, and people with severe cardiac forms were excluded. Participants were randomly assigned 1:1:1, using a balanced block randomisation scheme stratified by country, to receive benznidazole at three different doses: 300 mg/day for 60 days (control group), 150 mg/day for 60 days (low dose group), or 400 mg/day for 15 days (short treatment group). The primary outcome was the proportion of patients with a sustained parasitological negativity by qPCR during a follow-up period of 12 months. The primary safety outcome was the proportion of people who permanently discontinued the treatment. Both primary efficacy analysis and primary safety analysis were done in the intention-to-treat population. The trial is registered with EudraCT, 2016-003789-21, and ClinicalTrials.gov, NCT03191162, and is completed. FindingsFrom April 20, 2017, to Sept 20, 2020, 245 people were enrolled, and 234 were randomly assigned: 78 to the control group, 77 to the low dose group, and 79 to the short treatment group. Sustained parasitological negativity was observed in 42 (54%) of 78 participants in the control group, 47 (61%) of 77 in the low dose group, and 46 (58%) of 79 in the short treatment group. Odds ratios were 1·41 (95% CI 0·69–2·88; p=0·34) when comparing the low dose and control groups and 1·23 (0·61–2·50; p=0·55) when comparing short treatment and control groups. 177 participants (76%) had an adverse event: 62 (79%) in the control group, 56 (73%) in the low dose group, and 59 (77%) in the short treatment group. However, discontinuations were less frequent in the short treatment group compared with the control group (2 [2%] vs 11 [14%]; OR 0·20, 95% CI 0·04–0·95; p=0·044). InterpretationParticipants had a similar parasitological responses. However, reducing the usual treatment from 8 weeks to 2 weeks might maintain the same response while facilitating adherence and increasing treatment coverage. These findings should be confirmed in a phase 3 clinical trial. FundingEuropean Community's 7th Framework Programme.

Bioinformatics analysis of primary biliary cholangitis key genes and molecular mechanisms

Objective: To extract the differentially expressed key genes of primary biliary cholangitis (PBC) using bioinformatics methods, so as to provide information for further study into the mechanism. Methods: The GSE119600 dataset was downloaded from the GEO database to obtain differentially expressed genes. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed for differentially expressed genes. Protein-protein interaction (PPI) network reconstruction, Cytoscape software visualization, and core gene screening were performed. The area under the receiver operating characteristic curve (ROC AUC) was used to assess the diagnostic effectiveness of genes and plot the pROC software package. The x-Cell software was used to calculate the enrichment score of 34 immune cells in each sample. Finally, four key genes (PSMA4, PSMA1, PSMB1, and PSMA3) were selected. Blood samples were analyzed using the qPCR method. Results:: A total of 373 immune-related differentially expressed genes were identified. Eight genes (PSMC6, PSMB2, PSMB1, PSMA3, PSMA4, PSMA1, PSMD7, and PSMB5) were screened from the 178 nodes and 596 edges as hub genes of the PPI network, which were significantly related to amino acid metabolism, hematopoietic stem cell differentiation, cell cycle, and immune processes. PSMA4, PSMA1, PSMB1, and PSMA3 were defined as immunological biomarkers for PBC with an AUC value of the ROC curve > 0.7. Immunoinfiltrating cell analysis showed that the proportion of eosinophils was significantly higher in PBC patients compared to the control group, whereas the proportion of CD4+ memory T cells, plasma cells, Th2 cells, and cDC cells was significantly lower in PBC patients than the control group. Plasma cells were associated with all four immunological biomarkers. Seven PBC patients and seven healthy subjects were selected for peripheral blood qPCR validation, which demonstrates that PSMB1, PSMA3, PSMA1, and PSMA4 levels were significantly lower in PBC patients than healthy subjects, with a statistically significant difference. Conclusion:: Bioinformatics screened eight key genes, of which four were key immunological markers and may serve as a basis for clinical diagnosis and mechanism exploration.

17th International Conference on Malignant Lymphoma, Palazzo dei Congressi, Lugano, Switzerland, 13 - 17 June, 2023.

17th International Conference on Malignant Lymphoma, Palazzo dei Congressi, Lugano, Switzerland, 13 - 17 June, 2023.

Lisocabtagene maraleucel (liso-cel) in R/R chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL): Primary analysis of TRANSCEND CLL 004.

7501 Background: In patients (pts) with R/R CLL/SLL that progressed on BTKi and failed venetoclax (ven)-based regimens, achieving CR with current treatment is uncommon. New therapies that achieve deep and durable responses are needed. We report the primary analysis of the phase 1/2, single-arm, multicenter TRANSCEND CLL 004 (NCT03331198) study evaluating liso-cel in pts with R/R CLL/SLL. Methods: Pts must have received at least 2 prior lines of therapy, including a BTKi. Eligible pts received liso-cel at a target dose of either 50 (DL1) or 100 (DL2) × 106 CAR+ T cells. The primary endpoint was rate of CR and CR with incomplete marrow recovery (CRi) by IRC per 2018 iwCLL criteria in the prespecified subset of efficacy-evaluable pts with disease progression on BTKi and ven failure (primary efficacy analysis set [PEAS]) at DL2 (null hypothesis [H0]: ≤ 5%). Key secondary endpoints were ORR (H0: ≤ 40%) and rate of undetectable minimal residual disease (uMRD; 10−4) in blood (H0: ≤ 5%). Results: Of 137 leukapheresed pts, 117 received liso-cel (safety set), 96 (DL1 = 9; DL2 = 87) were efficacy evaluable, and 53 (DL1 = 4; DL2 = 49) were in the PEAS. In the safety set, median (range) age was 65 y (49–82), 83% had high-risk features, median (range) lines of prior therapy was 5 (2–12), and all pts had prior BTKi. Median (range) on-study follow-up was 21.1 mo (0.4–55.6) for the safety set. In the PEAS at DL2, the primary endpoint of CR/CRi rate was met at 18.4% (95% CI, 8.8–32.0; 1-sided P = 0.0006; Table). ORR was 42.9% and was not statistically significant (95% CI, 28.8–57.8; 1-sided P = 0.3931). The uMRD rate was 63.3% in blood and 59.2% in marrow. Median (95% CI) DOR was 35.3 mo (11.01–not reached [NR]) with a median follow-up of 19.7 mo. Median duration of CR/CRi was NR. In the safety set, rate of any-grade CRS was 84.6% (gr 3, 8.5%; no gr 4/5) and neurological events (NE) was 45.3% (gr 3, 17.9%; gr 4, 0.9%; no gr 5); 69.2% received tocilizumab and/or corticosteroids for CRS/NEs. Rate of gr ≥ 3 infections, hypogammaglobulinemia, and prolonged cytopenia was 17.1%, 15.4%, and 53.8%, respectively. One death related to liso-cel was due to hemophagocytic lymphohistiocytosis. Liso-cel exhibited rapid in vivo expansion and was detected by qPCR in blood up to 36 mo after infusion. Conclusions: Liso-cel demonstrated durable CR/CRi, high uMRD rates, and a manageable safety profile in pts with heavily pretreated, high-risk R/R CLL/SLL and high unmet need. Clinical trial information: NCT03331198 . [Table: see text]

A 10-year retrospective analysis of Toxoplasma gondii qPCR screening in allogeneic hematopoietic stem cell transplantation recipients.

Weekly blood Toxoplasma gondii DNA screening using real-time quantitative polymerase chain reaction (qPCR) has been implemented in all allogeneic hematopoietic stem cell transplantation (alloHSCT) recipients at our hospital. We retrospectively analyzed the consequences of a positive blood qPCR in the management of Toxoplasma infection (TI) and disease (TD).From 2011 to 2020, 52 (4.13%) of 1 257 alloHSCT recipients had at least one positive qPCR, 45 (3.5%) with TI and seven (0.56%) with TD (central nervous system involvement). Forty-four patients were qPCR-positive before day 100, 30 without and 14 with anti-Toxoplasma prophylaxis. Twenty-five of them (56.8%) started or continued prophylactic dosage treatment: all became qPCR-negative, including 20 (80%) receiving only prophylactic dosage treatment. Twenty-four of them (54.5%) received non-prophylactic dosage treatment: qPCR became negative in 22/24 (91.7%), while TI contributed to death in two cases. Six of the eight patients diagnosed after D100 had breakthrough TI or TD. No death was attributable to TI or TD. qPCR kinetics available for 24 patients increased until anti-Toxoplasma treatment began, then decreased with all treatment regimens.Clinical follow-up and qPCR monitoring with quantification of the parasitic load appears a reasonable strategy to avoid TD and to use minimal effective dosage of anti-Toxoplasma treatments.

Hepadnavirus DNA Is Detected in Canine Blood Samples in Hong Kong but Not in Liver Biopsies of Chronic Hepatitis or Hepatocellular Carcinoma.

Chronic hepatitis and hepatocellular carcinoma (HCC) caused by the hepadnavirus hepatitis B virus (HBV) are significant causes of human mortality. A hepatitis-B-like virus infecting cats, domestic cat hepadnavirus (DCH), was reported in 2018. DCH DNA is hepatotropic and detectable in feline blood or serum (3.2 to 12.3%). Detection of HBV DNA has been reported in sera from 10% of free-roaming dogs in Brazil, whereas 6.3% of sera from dogs in Italy tested positive for DCH DNA by real-time quantitative PCR (qPCR). If DCH, HBV, or another hepadnavirus is hepatotropic in dogs, a role for such a virus in the etiology of canine idiopathic chronic hepatitis (CH) or HCC warrants investigation. This study investigated whether DCH DNA could be detected via qPCR in blood from dogs in Hong Kong and also whether liver biopsies from dogs with confirmed idiopathic CH or HCC contained hepadnaviral DNA using two panhepadnavirus conventional PCRs (cPCR) and a DCH-specific cPCR. DCH DNA was amplified from 2 of 501 (0.4%) canine whole-blood DNA samples. A second sample taken 6 or 7 months later from each dog tested negative in DCH qPCR. DNA extracted from 101 liver biopsies from dogs in Hong Kong or the USA, diagnosed by board-certified pathologists as idiopathic CH (n = 47) or HCC (n = 54), tested negative for DCH DNA and also tested negative using panhepadnavirus cPCRs. This study confirms that DCH DNA can be detected in canine blood by qPCR, although at a much lower prevalence than that reported previously. We identified no evidence to support a pathogenic role for a hepadnavirus in canine idiopathic CH or HCC.

Conjunctival Swab Real Time-PCR in Leishmania infantum Seropositive Dogs: Diagnostic and Prognostic Values.

Conjunctival swabs (CS) are the most promising non-invasive samples for the diagnosis and the regular screening of Leishmania infantum infection in dogs although knowledge on their diagnostic performance is still inconclusive. This study evaluates CS real time-PCR (qPCR) analysis for the diagnosis of canine leishmaniosis (CanL) and its prognostic value in seropositive dogs from an endemic area. In October 2020 (T0), 26 dogs were enrolled, divided in two groups according to anti-L. infantum antibody titres (n = 13, group low titre (LT) and n = 13, group high titre (HT)), and followed-up in August 2021. At both timepoints, animals underwent clinical examination, complete blood count and biochemical analyses, and serological (indirect fluorescent antibody test) and molecular (CS and peripheral blood qPCR) testing. At T0, 10 out of 26 enrolled dogs were positive at CS qPCR, with the number of positive animals significantly higher in group HT than in LT. After 10 months, only 5 out of 21 dogs that completed the trial still tested CS qPCR positive, and none of them developed an active CanL based on clinical score and antibody titre. None of the dogs required any leishmanicidal and/or leishmaniostatic treatments. This prospective study showed unsatisfying diagnostic and prognostic performances of CS qPCR analysis in L. infantum seropositive asymptomatic dogs from an endemic area.

Detection of Pathogens of Acute Febrile Illness Using Polymerase Chain Reaction from Dried Blood Spots.

ABSTRACT.Quantitative polymerase chain reaction (qPCR) of dried blood spots (DBS) for pathogen detection is a potentially convenient method for infectious disease diagnosis. This study tested 115 DBS samples paired with whole blood specimens of children and adolescent from Burkina Faso, Sudan, and Madagascar by qPCR for a wide range of pathogens, including protozoans, helminths, fungi, bacteria, and viruses. Plasmodium spp. was consistently detected from DBS but yielded a mean cycle threshold (Ct) 5.7 ± 1.6 higher than that from whole blood samples. A DBS qPCR Ct cutoff of 27 yielded 94.1% sensitivity and 95.1% specificity against the whole blood qPCR cutoff of 21 that has been previously suggested for malaria diagnosis. For other pathogens investigated, DBS testing yielded a sensitivity of only 8.5% but a specificity of 98.6% compared with whole blood qPCR. In sum, direct PCR of DBS had reasonable performance for Plasmodium but requires further investigation for the other pathogens assessed in this study.

P062 Effects of exposure to steroids on the PredictSURE whole blood prognostic assay in Inflammatory Bowel Disease

Abstract Background Accurately predicting disease course at diagnosis is critical to facilitate personalized therapy in inflammatory bowel disease (IBD). PredictSURE IBDTM is a whole blood qPCR assay that was developed to predict prognosis in newly diagnosed, treatment-naïve IBD patients – classifying them into IBDhi (high-risk) or IBDlo (low-risk). The current recommendation is that PredictSURE IBDTM should not be used in those who have commenced steroids. In this study, we aimed to determine the impact of steroid therapy on the performance of PredictSURE IBDTM. Methods Whole blood was serially taken from patients admitted with severe IBD requiring intravenous (IV) steroids (pre-steroid, day 3, day 5; n=10, cohort 1) and from patients receiving oral steroids as outpatients (pre-steroid, week 1, week 6; n=10, cohort 2). An independent cohort of 43 IBD patients, all within 3 months of diagnosis and on corticosteroid treatment (41 systemic and 2 topical, cohort 3) was recruited. RNA was extracted and analyzed with PredictSURE IBDTM (PredictImmune, UK). Patients were prospectively followed and treated according to routine clinical management by physicians blinded to the test results, and clinically stratified according to one of the original definitions used to construct and validate the test (need for step up to immunosuppressive or biological therapy or surgery). Results In cohorts 1 and 2, both oral and intravenous steroids affected the PredictSURE IBDTM result: misclassification as IBDlo occurred in 5/8 IBDhi patients receiving oral, and 5/7 IBDhi patients receiving IV, steroids. In 60% this change was detectable early (within 1 week of oral steroids and 3 days of IV steroids). Steroids did not affect the classification of IBDlo patients. Consistently, the prognostic accuracy was limited in patients already receiving steroids (cohort 3). After a median follow-up of 31.8 [IQR 18.7 - 42.1] months, 35 (81%) patients required step-up therapy. PredictSure IBDTM correctly classified only 23 (54%) patients with accuracy of 0.53 (sensitivity: 0.51, specificity: 0.63, positive likelihood ratio: 1.38, negative likelihood ratio: 0.77). Seventeen (80%) of the misclassifications were clinically high-risk patients who were predicted as IBDlo. Time to treatment escalation was similar between patients classified as IBDhi or IBDlo after starting steroid therapy (p= 0.47) (Figure 1). Conclusion The prognostic accuracy of PredictSURE IBDTM is limited if performed after steroid therapy has begun, most likely because of the misclassification of high-risk patients as low risk. Therefore, the test should only be performed in patients with active disease who are not receiving steroid therapy, as currently recommended.

A cross-sectional study of Leishmania infantum infection in stray cats in the city of Zaragoza (Spain) using serology and PCR

BackgroundFeline leishmaniosis is a vector-borne parasitic disease caused by Leishmania spp. Leishmania infection in dogs is prevalent in the Mediterranean basin, but in other animals, such as cats, it could also play a role in the epidemiology of the disease. Information on the geographical distribution and epidemiological features of L. infantum infection in cats is scarce, particularly in urban stray cats living in regions where canine leishmaniosis is endemic. As diagnosis can be challenging, combining different serological and molecular methods is a useful approach. Our aim was to investigate the prevalence of infection of L. infantum in apparently healthy stray cats in an endemic region of Spain (Zaragoza city) using serological and molecular methods, and to compare the results of the different techniques.MethodsThe prevalence of Leishmania infection was studied in stray cats captured in urban and peri-urban areas of Zaragoza. Blood was collected from each animal for serology and molecular analysis. Three serological methods, namely the immunofluorescent antibody test (IFAT), enzyme-linked immunosorbent assay (ELISA) and western blot (WB), were used to detect L. infantum antibodies and a real-time PCR (qPCR) assay was used to detect L. infantum DNA. The results were analyzed by Fisher’s exact test and Cohen’s kappa statistic (κ) to assess the level of agreement between the diagnostic techniques.ResultsSerological analysis of blood samples from 180 stray cats revealed 2.2% (4/179) Leishmania infection positivity by IFAT, 2.8% (5/179) by ELISA and 14.5% (26/179) by WB. Leishmania DNA was detected by qPCR in 5.6% (10/179) of the cats. Sixteen cats (8.9%) tested positive by only one serological technique and four tested positive by all three serological methods used. The overall rate of infected cats (calculated as the number of cats seropositive and/or qPCR positive) was 15.6%, and only two cats tested positive by all the diagnostic methods. A significant association was found between male cats and a positive qPCR result. Comparison of the techniques revealed a fair agreement in seropositivity between blood qPCR and IFAT (κ = 0.26), blood qPCR and ELISA (κ = 0.24), WB and ELISA (κ = 0.37) and WB and IFAT (κ = 0.40). The highest agreement between seropositive results was between IFAT and ELISA (κ = 0.89), and the lowest was between blood qPCR and WB (κ = 0.19). The prevalence of the feline leukemia virus antigen was 4.49% (8/178 cats) and that of the feline immunodeficiency virus (FIV) antibody was 6.74% (12/178), while co-infection with both retroviruses was observed in one female cat (1/178). Leishmania ELISA and IFAT seropositivity were statistically associated with FIV status by the chi-square test.ConclusionsThe results obtained in this study, using serological tests and qPCR, indicate the existence of L. infantum asymptomatic infection in apparently healthy stray cats in the city of Zaragoza, an endemic area in Spain.Graphical

Detection of toxoplasmic encephalitis in HIV positive patients in urine with hydrogel nanoparticles.

Diagnosis of toxoplasmic encephalitis (TE) is challenging under the best clinical circumstances. The poor clinical sensitivity of quantitative polymerase chain reaction (qPCR) for Toxoplasma in blood and CSF and the limited availability of molecular diagnostics and imaging technology leaves clinicians in resource-limited settings with few options other than empiric treatment. Here we describe proof of concept for a novel urine diagnostics for TE using Poly-N-Isopropylacrylamide nanoparticles dyed with Reactive Blue-221 to concentrate antigens, substantially increasing the limit of detection. After nanoparticle-concentration, a standard western blotting technique with a monoclonal antibody was used for antigen detection. Limit of detection was 7.8pg/ml and 31.3pg/ml of T. gondii antigens GRA1 and SAG1, respectively. To characterize this diagnostic approach, 164 hospitalized HIV-infected patients with neurological symptoms compatible with TE were tested for 1) T. gondii serology (121/147, positive samples/total samples tested), 2) qPCR in cerebrospinal fluid (11/41), 3) qPCR in blood (10/112), and 4) urinary GRA1 (30/164) and SAG1 (12/164). GRA1 appears to be superior to SAG1 for detection of TE antigens in urine. Fifty-one HIV-infected, T. gondii seropositive but asymptomatic persons all tested negative by nanoparticle western blot and blood qPCR, suggesting the test has good specificity for TE for both GRA1 and SAG1. In a subgroup of 44 patients, urine samples were assayed with mass spectrometry parallel-reaction-monitoring (PRM) for the presence of T. gondii antigens. PRM identified antigens in 8 samples, 6 of which were concordant with the urine diagnostic. Our results demonstrate nanoparticle technology's potential for a noninvasive diagnostic test for TE. Moving forward, GRA1 is a promising target for antigen based diagnostics for TE.

686. Elevations in TNFα and IL-18 are Associated with Increased Risk of Probable Cytomegalovirus Tissue Invasive Disease in Solid Organ Transplant Recipients

BackgroundHuman cytomegalovirus (CMV) continues to cause significant morbidity and mortality in solid organ transplant (SOT) recipients despite prophylaxis. Tissue invasive CMV disease (TI-CMV) can lead to end-organ damage and graft loss. Diagnosing TI-CMV can be challenging as CMV viral load in the blood does not always correlate with episodes of TI-CMV and therefore definitive diagnosis often requires an invasive procedure such as bronchoscopy or colonoscopy. The purpose of this study was to determine if proinflammatory cytokines, including IL-18, are elevated in SOT recipients with probably TI-CMV as a way to identify patients at risk for this severe form of CMV disease.MethodsThe electronic medical record was searched for adult SOT recipients who were tested for CMV via blood qPCR during an 11-month period.Twenty-nine SOT recipients were identified that had episodes of CMV DNAemia without other concomitant infections during this time period. Patients were divided into those that had probable TI-CMV and those with CMV DNAemia alone, by chart review. Inflammatory cytokines (IFNγ, TNFα, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, IL-18, and IL-1RA) were measured in residual plasma from these patients using a commercially available multiplex assay for at least two time points during the study period. Wilcoxon-Rank-Sum, logistic regression, and principal component analysis was performed comparing patients with and without probable TI-CMV.ResultsPatients with probable TI-CMV had significantly higher IL-18, TNFα, and IL-1β than patients with CMV DNAemia alone (p < 0.001, < 0.001, and < 0.05 respectively). When adjusting for transplant type and CMV recipient serostatus, elevations in TNFα (OR 1.43, 95% CI 1.07-1.92) and IL-18 (OR 2.00, 95% CI 1.06-3.75) were associated with increased odds of having probable TI-CMV. In principal component analysis the combination of CMV viral load, IL-18, TNFa, and IL-1β accounted for 80% of the variance in the data.ConclusionTNFα and IL-18 in combination with CMV viral load may be useful in predicting likelihood of TI-CMV. This is important in situations where tissue biopsies are not feasible, and adds to our diagnostic capability for TI-CMV in SOT recipients.Disclosures Stuart C. Ray, MD, miDiagnostics, Inc. (Board Member, Research Grant or Support) Robin K. Avery, MD, Aicuris (Scientific Research Study Investigator)Astellas (Scientific Research Study Investigator)Chimerix (Scientific Research Study Investigator)Merck (Grant/Research Support, Scientific Research Study Investigator)Oxford Immunotec (Scientific Research Study Investigator)Qiagen (Scientific Research Study Investigator)Takeda/Shire (Scientific Research Study Investigator)

Evaluation of the anti-Trypanosoma cruzi activity in vitro and in vivo of silibinin and silibinin in association to benznidazole.

Chagas disease (CD) is endemic in Latin America. Drugs available for its treatment are benznidazole (BZ)/nifurtimox (NF), both with low efficacy in the late infection and responsible forseveral side effects. Studies of new drugs for CD among natural products, and using drug combinations with BZ/NF are recommended. Silibinin (SLB) is a natural compound that inhibits the efflux pump (Pgp) of drugs in host cell membranes, causes death of trypanosomatids, has anti-inflammatory activity, and was never assayed against T. cruzi. Here, in vitro and in vivo activities of SLB, SLB+BZ, and BZ against T. cruzi Y strain were evaluated. Cytotoxicity of SLB in VERO cells by the MTT method revealed IC50 of 250.22 μM. The trypanocidal activity evaluated by resazurin method in epimastigotes showed that SLB 25 μM inhibited parasite growth. SLB IC50 and selectivity index (SI) for amastigote were 79.81 μM and 3.13, respectively. SLB100+BZ10 showed higher parasite inhibition (91.44%) than SLB or BZ. Swiss mice infected with Y strain were treated with SLB, SLB+BZ, and BZ. Parasitemia was evaluated daily and 90, 180, and 240 days after treatment in surviving animals by hemoculture, blood qPCR, and after euthanasia, by qPCR inheart tissue. SLBmonotherapy was not able to control the parasitemia/mortality of the animals. Parasitological negativation of 85.7-100% was observed in the experimental groups treated with SLB+BZ. Although SLB had shown activity against T. cruzi in vitro, it was not active in mice. Thus, the results of the therapeutic effect observed with SLB+BZ may be interpreted as a result from BZ action.

Blood viral load in the diagnostic workup of congenital cytomegalovirus infection

BackgroundThere is limited data on the role of cytomegalovirus (CMV) blood quantitative polymerase chain reaction (qPCR) in the diagnostic workup of congenital CMV (cCMV) infection. ObjectivesThe objective of this study was to determine if CMV blood qPCR at the time diagnosis could differentiate between symptomatic and asymptomatic infants according to the recent consensus classification. Study designRetrospective study of children diagnosed with cCMV infection at CHU Sainte-Justine, Montreal, Canada, between 2008 and 2016.Cases for whom qPCR was done at baseline (<4 weeks of age) alongside a complete diagnostic workup were included. The association between CMV blood viral load (VL) and clinical severity group was determined. The probability of having moderate to severe symptoms was assessed using univariate logistic regression analysis. ResultsForty-seven patients were included in the analysis. Median VL was significantly higher among infants with moderate to severely symptomatic disease vs. those asymptomatic or asymptomatic with isolated sensorineural hearing loss (SNHL) (13 736 vs. 1876 copies/ml, p = 0.004), infants with moderate to severe disease or asymptomatic with isolated SNHL vs. asymptomatic (17 736 vs. 1496 copies/ml, p < 0.001), and in infants with baseline neurological involvement vs. those without (17 317 vs. 2641 copies/ml, p = 0.03). Using logistic regression, an infant would have a >75 % probability of being moderate to severely symptomatic above 18 770 copies/ml, with a threshold of 100 000 copies/ml approaching a 100 % probability. ConclusionsOur baseline assessment of CMV blood VL suggests that that the level of CMV viremia correlates with symptom severity.

Selection of Reference Genes for Normalization of Gene Expression Data in Blood of Machado-Joseph Disease/Spinocerebellar Ataxia Type 3 (MJD/SCA3) Subjects.

Alongside with the emergent clinical trials for Machado-Joseph disease/Spinocerebellar ataxia type 3 (MJD/SCA3) comes the need to identify molecular biomarkers of disease that can be tracked throughout the trial. MJD is an autosomal dominant neurodegenerative disorder caused by expansion of a CAG repeat in the coding region of the ATXN3 gene. Previous findings indicate the potential of transcriptional alterations in blood of MJD patients as biomarkers of disease. Accurate quantification of gene expression levels by quantitative real-time PCR (qPCR) depends on data normalization, usually performed using reference genes. Because the expression level of routinely used housekeeping genes may vary in multiple biological and experimental conditions, reference gene controls should be validated in each specific experimental design. Here, we aimed to evaluate the expression behavior of five housekeeping genes previously reported as stably expressed in peripheral blood of patients from several disorders-peptidylprolyl isomerase B (PPIB), TNF receptor associated protein 1 (TRAP1), beta-2-microglobulin (B2M), 2,4-dienoyl-CoA reductase 1 (DECR1), and folylpolyglutamate synthase (FPGS). Expression levels of these five genes were assessed by qPCR in blood from MJD subjects (preataxic and patients) and matched controls. While all housekeeping genes, here studied, were stably expressed in our sets of samples, TRAP1 showed to be the most stable gene by NormFinder and BestKeeper. We, therefore, conclude that any of these genes could be used as reference gene in future qPCR studies using blood samples from MJD subjects.

P028 A BLOOD-BASED PROGNOSTIC BIOMARKER IN INFLAMMATORY BOWEL DISEASE; TOWARDS PERSONALISED MEDICINE IN IBD.

The course of Inflammatory Bowel Disease (IBD incorporating both Crohn’s Disease and ulcerative colitis) varies substantially between affected individuals, but reliable prognostic markers are not available in clinical practice. This hinders disease management because patients with aggressive disease will be undertreated by conventional “step-up” therapy, while those with indolent disease would be exposed to the risks and side-effects of unnecessary immunosuppression if a “top-down” approach was indiscriminately used. We have described, initially in ANCA-associated vasculitis and SLE (McKinney et al. Nat Med 2010) and then in IBD (Lee et al. JCL 2011), a transcriptional signature detectable within peripheral blood CD8+ T cells at diagnosis which correlates with subsequent disease course. To overcome the technical challenges of separating cell populations, which would not be possible in a routine clinical setting, we sought to develop a whole blood qPCR-based biomarker that can re-capitulate the CD8+ subgroups without the need for cell separation. Here we describe the development and validation of this biomarker and a biomarker-stratified trial that will test whether it can deliver personalised medicine in IBD. From a training cohort of 69 newly diagnosed IBD patients, we simultaneously obtained a whole blood PAXgene RNA tube and peripheral blood CD8+ T cell sample. Gene expression in both samples was measured by microarray. After confirming that the CD8+ transcriptional signature was detectable and correlated with prognosis, we used machine learning to identify a transcriptional classifier in whole blood gene expression data that would re-capitulate the CD8+ transcriptional subgroups. This was initially trained using leave-one-out cross-validation, and the genes identified were subsequently tested by qPCR and an optimized qPCR assay developed. Independent validation of this biomarker was established using a second, independent cohort of 84 newly diagnosed patients with IBD from 4 sites around the United Kingdom. This validated the biomarker and confirmed that the subgroups it identified had significantly different disease courses (analogous to those observed with the CD8+ T cell subgroups). We have now embarked on the PROFILE trial: PRedicting Outcomes For Crohn’s dIsease using a moLecular biomarkEr; the first ever biomarker-stratified trial in any inflammatory disease, to determine whether this biomarker can deliver personalised medicine in CD. We have developed, optimised and validated a whole blood qPCR classifier that is able to predict disease course from diagnosis in IBD patients. This represents a major step towards personalised therapy in IBD, and is currently being used investigate whether this could make personalised medicine a reality in CD.

P028 A BLOOD-BASED PROGNOSTIC BIOMARKER IN INFLAMMATORY BOWEL DISEASE; TOWARDS PERSONALISED MEDICINE IN IBD

The course of Inflammatory Bowel Disease (IBD incorporating both Crohn’s Disease and ulcerative colitis) varies substantially between affected individuals, but reliable prognostic markers are not available in clinical practice. This hinders disease management because patients with aggressive disease will be undertreated by conventional “step-up” therapy, while those with indolent disease would be exposed to the risks and side-effects of unnecessary immunosuppression if a “top-down” approach was indiscriminately used. We have described, initially in ANCA-associated vasculitis and SLE (McKinney et al. Nat Med 2010) and then in IBD (Lee et al. JCL 2011), a transcriptional signature detectable within peripheral blood CD8+ T cells at diagnosis which correlates with subsequent disease course. To overcome the technical challenges of separating cell populations, which would not be possible in a routine clinical setting, we sought to develop a whole blood qPCR-based biomarker that can re-capitulate the CD8+ subgroups without the need for cell separation. Here we describe the development and validation of this biomarker and a biomarker-stratified trial that will test whether it can deliver personalised medicine in IBD. From a training cohort of 69 newly diagnosed IBD patients, we simultaneously obtained a whole blood PAXgene RNA tube and peripheral blood CD8+ T cell sample. Gene expression in both samples was measured by microarray. After confirming that the CD8+ transcriptional signature was detectable and correlated with prognosis, we used machine learning to identify a transcriptional classifier in whole blood gene expression data that would re-capitulate the CD8+ transcriptional subgroups. This was initially trained using leave-one-out cross-validation, and the genes identified were subsequently tested by qPCR and an optimized qPCR assay developed. Independent validation of this biomarker was established using a second, independent cohort of 84 newly diagnosed patients with IBD from 4 sites around the United Kingdom. This validated the biomarker and confirmed that the subgroups it identified had significantly different disease courses (analogous to those observed with the CD8+ T cell subgroups). We have now embarked on the PROFILE trial: PRedicting Outcomes For Crohn’s dIsease using a moLecular biomarkEr; the first ever biomarker-stratified trial in any inflammatory disease, to determine whether this biomarker can deliver personalised medicine in CD. We have developed, optimised and validated a whole blood qPCR classifier that is able to predict disease course from diagnosis in IBD patients. This represents a major step towards personalised therapy in IBD, and is currently being used investigate whether this could make personalised medicine a reality in CD.