Evaluation of assays for nucleic acid testing for the prevention of chikungunya and dengue virus transmission by blood transfusion.

BACKGROUND: The large dengue (DENV) and chikungunya (CHIKV) outbreaks observed during the last decade across the world, as well as local transmissions in non-endemic areas are a growing concern for blood safety. The aim of this study was to evaluate and compare the sensitivity of nucleic acid tests (NAT) detecting DENV and CHIKV RNA. MATERIALS AND METHODS: Using DENV 1 to 4 International Standards, the limits of detection (LODs) calculated by probit analysis of two NAT assays; the cobas CHIKV/DENV assay (Roche Diagnostics) and the Procleix Dengue Virus Assay (Grifols) were compared. In addition, CHIKV-RNA LOD of the cobas CHIKV/DENV assay was evaluated. RESULTS: For dengue, the 95% LOD of the cobas assay ranged between 4.10 [CI95%: 2.70-8.19] IU/mL (DENV-2) and 7.07 [CI95%: 4.34-14.89] IU/mL (DENV-4), and between 2.19 [CI95%: 1.53-3.83] IU/mL (DENV-3) and 5.84 [CI95%: 3.84-10.77] IU/mL (DENV-1) for Procleix assay. The Procleix assay had a significant lower LOD for DENV-3 (2.19 vs. 5.89 IU/mL) when compared to the cobas assay (p = 0.005). The 95% LOD for CHIKV-RNA detection of the cobas assay was 4.76 [CI95%: 3.08-8.94] IU/mL. DISCUSSION: The two NAT assays developed for blood donor screening evaluated in this study demonstrated high and similar analytical performance. Subject to an appropriate risk-benefit assessment, they can be used to support blood safety during outbreaks in endemic areas or in non-endemic areas as an alternative to deferring blood donors during local transmission likely to affect the blood supply. The development of multiplex assays is expected to optimize laboratory organization.

Seven years (2015-2021) of blood donor screening for HEV-RNA in France: lessons and perspectives.

BACKGROUND: The French health authorities are considering expanding the current selective hepatitis E virus (HEV)-RNA testing procedure to include all donations in order to further reduce transfusion-transmitted HEV infection. Data obtained from blood donors (BDs) tested for HEV-RNA between 2015 and 2021 were used to assess the most efficient nucleic acid testing (NAT) strategy. MATERIALS AND METHODS: Viral loads (VLs) and the plasma volume of blood components, as well as an HEV-RNA dose of 3.85 log IU as the infectious threshold and an assay with a 95% limit of detection (LOD) at 17 IU/mL, were used to assess the proportion of: (i) HEV-RNA-positive BDs that would remain undetected; and (ii) blood components associated with these undetected BDs with an HEV-RNA dose >3.85 log IU, considering 4 NAT options (Individual testing [ID], MP-6, MP-12, and MP-24). RESULTS: Of the 510,118 BDs collected during the study period, 510 (0.10%) were HEV-RNA-positive. Based on measurable VLs available in 388 cases, 1%, 15.2%, 21.8%, and 32.6% of BDs would theoretically pass undetected due to a VL below the LOD of ID, MP-6, MP-12, and MP-24 testing, respectively. All BDs associated with a potentially infectious blood component would be detected with ID-NAT while 13% of them would be undetected with MP-6, 19.6% with MP-12, and 30.4% with MP-24 depending on the plasma volume. No red blood cell (RBC) components with an HEV-RNA dose >3.85 log IU would enter the blood supply, regardless of the NAT strategy used. DISCUSSION: A highly sensitive ID-NAT would ensure maximum safety. However, an MP-based strategy can be considered given that: (i) the risk of transmission is closely related to the plasma volume of blood components; (ii) RBC are the most commonly transfused components and have a low plasma content; and (iii) HEV-RNA doses transmitting infection exceed 4 log IU. To minimise the potential risk associated with apheresis platelet components and fresh frozen plasma, less than 12 donations should be pooled using an NAT assay with a LOD of approximately 20 IU/mL.

Incidence and risk factors of anti-HLA immunization after pregnancy.

Pregnancy is the only natural source of anti-HLA immunization. The exact frequency of this immunization remains undetermined as prior studies either used methods with a low sensitivity or were performed late after delivery. We present here the first study on women at delivery evaluating anti-HLA immunization by Luminex. We also attempted to isolate factors influencing immunization, such as soluble HLA-G (sHLA-G) levels and genetic polymorphisms. With Luminex, anti-HLA immunization was observed in 54.4% of the women. As expected, immunization frequency increased with the number of children, reaching 74% in women with >2 deliveries. Among immunized women, strong cytotoxic Ab (as detected by Complement Dependent Cytotoxicity) were associated with a lower level of sHLA-G. None of the studied polymorphisms influenced immunization rate in the whole cohort. Among 94 first pregnant women with no history of miscarriage, the -174 IL-6 gene promoter mutation (G/C) appeared more frequently in non immunized women (69% vs. 45% in immunized ones, p=0.02). Lastly, the occurrence of a miscarriage before the first live delivery significantly decreased immunization. These results may help to understand mechanisms of pregnancy induced immunization. They also have an impact in the management of previous pregnant women requiring organ or hematopoietic stem cell transplantation.

A convenient qualitative and quantitative method to investigate RHD-RHCE hybrid genes.

BACKGROUND: Molecular biology techniques, such as single specific-primer polymerase chain reaction (PCR), denaturing-high performance liquid chromatography, direct sequencing, next-generation sequencing, and microarray platforms, contribute to the efficient genotyping of the human blood group RHD gene. However, some alleles remain undetermined in rare cases in DNA samples carrying two copies of the RHD gene, which challenge the identification of D-CE hybrid genes. STUDY DESIGN AND METHODS: We set up, in a single-tube format, a qualitative and quantitative assay based on multiplex PCR of short fluorescent fragments (QMPSF) to simultaneously amplify all 10 RHD exons on the one hand and all 10 RHCE exons on the other hand. RESULTS: The test proved to be useful to rapidly identify hybrid genes in hemizygous RHD samples carrying a hybrid D-CE gene and to resolve unknown genotypes by quantifying individual exons in compound heterozygous samples, but also unexpectedly helped to redefine the RHDΨ haplotype. While validating the test, two novel single-point variants, c.648G>C (p.L216F) and c.1048G>C (p.D350H), were found. CONCLUSION: For the first time, a QMPSF-based method is reliable to individually quantify the exons of both RH genes, including hybrid D-CE genes in compound heterozygous samples and may help to investigate samples with unknown RHD and/or RHCE status.

Small deletions within the RHD coding sequence: a report of two novel mutational events and a survey of the underlying pathophysiologic mechanisms.

BACKGROUND: Some 270 variants in the RHD gene have so far been identified. Of these, approximately 6% (n = 17) are small (≤20 bp) deletions occurring within the gene's coding sequence. Fourteen of these small deletions disrupted the reading frame of the RHD gene, resulting almost invariably in a D- phenotype. STUDY DESIGN AND METHODS: Two subjects who displayed D phenotype ambiguity or a genotype-phenotype discrepancy were referred to our laboratory for RHD genetic analysis. Hemizygosity for the most common 70-kb RHD deletion was first determined in both subjects by long-range polymerase chain reaction (PCR) followed by PCR amplification and sequencing of all 10 exons of the RHD gene in the nondeleted allele individually. RESULTS: Two novel lesions in the RHD gene were identified on the nondeleted alleles, a 14-bp frameshifting deletion within Exon 1 (i.e., c.29_42delGGCGCTGCCTGCCC) and an 11-bp frameshifting deletion within Exon 3 (i.e., c.361_371delTTGTCGGTGCT), in Subjects 1 and 2, respectively. CONCLUSION: By reference to previously reported small deletions in the RHD gene, the 11-bp deletion in Exon 3 may be safely regarded as a bona fide D- variant. Although the association of the 14-bp deletion in Exon 1 with a weak D phenotype appears to be genuine, the underlying molecular mechanism still remains to be clarified. Evaluation of all known small RHD deletions points to slippage mutagenesis as the major underlying mutational mechanism. [Correction statement added after online publication 21-May2012: The spelling of bona has been updated.].

Establishment of a medium-throughput approach for the genotyping of RHD variants and report of nine novel rare alleles.

BACKGROUND: The routinely used serologic methods are robust in accurately typing standard D- or D+ blood. However, they result in discrepancy in weak or partial D blood, which requires genetic analysis. We have previously used denaturing high-performance liquid chromatography (DHPLC) to screen the entire RHD-coding sequence. However, DHPLC is technically challenging, labor-intensive, and time-consuming. To overcome these inconveniences, we sought to develop a new two-step approach. STUDY DESIGN AND METHODS: A total of 430 blood samples with D phenotype ambiguity were recruited for this study. The three most frequent weak D alleles (i.e., weak D, Type 1; weak D, Type 2; and weak D, Type 3), which altogether account for 60% to 90% of the atypical RHD alleles in the Caucasian population, were first identified by Tm-shift genotyping. The remaining unidentified samples were then subjected to a single-tube multiplex polymerase chain reaction (PCR) amplification of all 10 RHD exons followed by direct sequencing. RESULTS: Optimal conditions for efficient and reliable identification of the three most common weak D variants by Tm-shift genotyping were established. All 10 RHD exons were successfully amplified in a single-multiplex PCR procedure. Employment of the two-step analysis identified RHD variants in 91.6% of the 430 studied samples. Two of the nine previously undescribed variants, c.335G>T and c.939G>A, were found to cause aberrant mRNA splicing by means of a splicing minigene assay. CONCLUSION: The new two-step analysis proved to be much easier and cheaper than the DHPLC method and therefore is convenient to be used as a routine, medium-throughput approach for RHD genotyping.

Anti-inflammatory effect and modulation of cytochrome P450 activities by Artemisia annua tea infusions in human intestinal Caco-2 cells.

In an attempt to understand the beneficial health effects of Artemisia annua other than its anti-malaria properties, extracts from different cultivars prepared as tea infusions were investigated using Caco-2 cells on the intestinal inflammation and cytochrome P450 (CYP) activities. The characterisation of their phenolic compound (PC) profile revealed rosmarinic and chlorogenic acids as the main PCs. The extracts, assayed on Caco-2 cells at a plausible intestinal concentration, significantly decreased the secretion of pro-inflammatory cytokines, IL-8 and IL-6. This effect could be attributable at least to their content in rosmarinic acid, detected as a potent anti-inflammatory compound. The extracts also inhibited the activity of CYP3A4, whose expression was induced by 1,25-dihydroxyvitamin D(3), and of CYP1A1, induced by benzo(a)pyrene. Our results highlight the advantage of drinking A. annua infusions for their potent anti-inflammatory effect, linked to PC content, which could synergise their antimalarial activity.

Weak D caused by a founder deletion in the RHD gene.

BACKGROUND: The RhD blood group system exemplifies a genotype-phenotype correlation by virtue of its highly polymorphic and immunogenic nature. Weak D phenotypes are generally thought to result from missense mutations leading to quantitative change of the D antigen in the red blood cell membrane or intracellularly. STUDY DESIGN AND METHODS: Different sets of polymerase chain reaction primers were designed to map and clone a deletion involving RHD Exon 10, which was found in approximately 3% of approximately 2000 RHD hemizygous subjects with D phenotype ambiguity. D antigen density was measured by flow cytometry. Transcript analysis was carried out by 3'-rapid amplification of complementary DNA ends. Haplotype analysis was performed by microsatellite genotyping. RESULTS: A 5405-bp deletion that removed nearly two-thirds of Intron 9 and almost all of Exon 10 of the RHD gene was characterized. It is predicted to result in the replacement of the last eight amino acids of the wild-type RhD protein by another four amino acids. The mean RhD antigen density from two deletion carriers was determined to be only 30. A consensus haplotype could be deduced from the deletion carriers based on the microsatellite genotyping data. CONCLUSION: The currently reported deletion was derived from a common founder. This deletion appears to represent not only the first large deletion associated with weak D but also the weakest of weak D alleles so far reported. This highly unusual genotype-phenotype relationship may be attributable to the additive effect of three distinct mechanisms that affect mRNA formation, mRNA stability, and RhD/ankyrin-R interaction, respectively.

Variant screening of the RHD gene in a large cohort of subjects with D phenotype ambiguity: report of 17 novel rare alleles.

BACKGROUND: A considerable number of RHD alleles responsible for weak and partial D phenotypes have been identified over the past decade. Two particular concerns, namely, 1) that red blood cells of these phenotypes may cause anti-D immunization when transfused to D- recipients and 2) that serologic determination of these phenotypes is often doubtful, make genetic analysis of the RHD gene highly desirable. STUDY DESIGN AND METHODS: Blood samples that displayed D phenotype ambiguity (as determined by serologic analyses) were collected from several sites of the Etablissement Français du Sang and subjected to RHD variant screening by means of a previously established denaturing high-performance liquid chromatography method followed by direct sequencing. RESULTS: Systematic screening of the RHD coding sequences as well as the exon-intron boundaries identified DNA variants in 755 of the 806 samples analyzed. In particular, this resulted in the identification of 10 novel single-nucleotide substitutions and seven novel complex alleles. CONCLUSION: This study further increased the already large repertoire of RHD allelic variants. Whereas most of the newly found variants are putative weak or partial D alleles, most of the complex alleles are readily understandable in the present phylogenetic model of RHD.

Identification of a novel series of potent RON receptor tyrosine kinase inhibitors.

A novel series of N-(3-fluoro-4-(2-substituted-thieno[3,2-b]pyridin-7-yloxy)phenyl)-1-phenyl-5-(trifluoromethyl)-1H-pyrazole-4-carboxamides targeting RON receptor tyrosine kinase was designed and synthesized. SAR study of the series allowed us to identify compounds possessing either inhibitory activity of RON kinase enzyme in the low nanomolar range with low residual activity against the closely related c-Met or potent dual inhibitory activity against RON and c-Met, with no significant activity against VEGFR2 in both cases.

Rapid cellular enrichment of eicosapentaenoate after a single intravenous injection of a novel medium-chain triacylglycerol:fish-oil emulsion in humans.

BACKGROUND: Dietary deficiency in n-3 (omega-3) polyunsaturated fatty acids (PUFAs) prevails in Western populations and potentially results in adverse health outcomes. To circumvent the slow n-3 PUFA incorporation in phospholipids of key cells after oral supplementation, a new preparation for intravenous bolus injection was developed with 20 g triacylglycerols/100 mL of a mixture of 80% medium-chain triacylglycerols (MCTs) and 20% fish oil (FO) (wt:wt), and 0.4 g alpha-tocopherol/100 mL of the same mixture. OBJECTIVE: Our objective was to document the enrichment of n-3 PUFAs in leukocyte and platelet phospholipids after a bolus intravenous injection of MCT:FO in men. DESIGN: Twelve healthy male subjects received injections over a 5-min period of 50 mL of either MCT:FO or a control MCT:long-chain triacylglycerol (MCT:LCT) emulsion containing 20 g triacylglycerols/100 mL with equal amounts (wt:wt) of MCT and soybean triacylglycerols (LCT) and containing 0.02 g alpha-tocopherol/100 mL; after an 8-wk interval, the subjects received injections of the other preparation. RESULTS: Clinical and biological variables that assessed tolerance and safety remained unchanged. Plasma elimination was faster for MCT:FO than for MCT:LCT (half-life: 24.5 +/- 3.5 min compared with 32.9 +/- 3.0 min; P < 0.025). This was associated with a greater increase in the plasma nonesterified fatty acid concentration. The content of n-3 PUFAs, specifically eicosapentaenoic acid (20:5n-3), increased in leukocyte and platelet phospholipids within 60 min and > or =24 h after MCT:FO injection. CONCLUSION: Bolus intravenous injection of a novel MCT:FO emulsion allows rapid enrichment of cells with n-3 PUFAs.

Identification of potent and selective VEGFR receptor tyrosine kinase inhibitors having new amide isostere headgroups.

A novel series of malonamide-type dual VEGFR2/c-Met inhibitors in which one of the amide bonds was replaced by an amide isostere-a trifluoroethylamine unit, was designed, synthesized, and evaluated for their enzymatic and cellular inhibition of VEGFR2 and c-Met enzymes. Optimization of these molecular entities resulted in identification of potent and selective inhibitors of VEGFR2 enzyme.

N3-arylmalonamides: a new series of thieno[3,2-b]pyridine based inhibitors of c-Met and VEGFR2 tyrosine kinases.

A family of thieno[3,2-b]pyridine based small molecule inhibitors of c-Met and VEGFR2 were designed based on lead structure 2. These compounds were shown to have IC(50) values in the low nanomolar range in vitro and were efficacious in human tumor xenograft models in mice in vivo.

N-(4-(6,7-Disubstituted-quinolin-4-yloxy)-3-fluorophenyl)-2-oxo-3-phenylimidazolidine-1-carboxamides: a novel series of dual c-Met/VEGFR2 receptor tyrosine kinase inhibitors.

A series of N-(4-(6,7-disubstituted-quinolin-4-yloxy)-3-fluorophenyl)-2-oxo-3-phenylimidazolidine-1-carboxamides targeting c-Met and VEGFR2 tyrosine kinases was designed and synthesized. The compounds were potent against these two enzymes with IC(50) values in the low nanomolar range in vitro, possessed favorable pharmacokinetic profiles and showed high efficacy in vivo in several human tumor xenograft models in mice.

CYP1A1 and CYP3A4 modulation by dietary flavonoids in human intestinal Caco-2 cells.

Flavonoids have been proposed to exert beneficial effects in a multitude of disease states. However, evidence of potential toxic actions has also emerged. Since large doses of flavonoids can be encountered in the intestine simultaneously with ingested drugs and pollutants, this study aimed at investigating nine individual flavonoid compounds and their interactions with the major intestinal isoforms of cytochrome P450, i.e. CYPs 1A1 and 3A4, using human intestinal Caco-2 cells cultivated in a serum-free medium. Genistein, quercetin and chrysin provoked a dose-dependent inducing effect on the CYP1A1 activity, measured with the EROD assay. However, they did not affect the CYP1A1 mRNA expression, suggesting they are not aryl hydrocarbon receptor-ligands in intestinal cells and act at a post-transcriptional level. Chrysin, at 50 microM, was detected as a potent inhibitor of the TCDD-induced CYP1A1 activity, leading the activity to ca. 10% of the TCDD-control value (n=3), this effect involving, at least partly, direct interactions at the enzyme level. Quercetin was also shown to significantly inhibit the constitutive CYP3A4 activity, measured by the 6beta-(OH)-testosterone assay, and to impair its induction by 1,25-vitamin D(3). Chrysin, quercetin and genistein, were detected as significant inhibitors of the 1,25-vitamin D(3)-induced CYP3A4 activity. In vivo, these effects could result in reduced activation of procarcinogens and/or in drug bioavailability limitation. They underline the importance of intestinal studies to assess food safety and health risks linked to the ingestion of flavonoid-enriched supplements or functional foods.

Sensitivity of two hepatitis B virus, hepatitis C virus (HCV), and human immunodeficiency virus (HIV) nucleic acid test systems relative to hepatitis B surface antigen, anti-HCV, anti-HIV, and p24/anti-HIV combination assays in seroconversion panels.

BACKGROUND: Accurate determination of the infectious window period (IWP) that remains with individual-donation (ID) or minipool (MP) NAT compared to those with serology assays is essential for residual risk estimations. STUDY DESIGN AND METHODS: The relative sensitivity of the Procleix Tigris system (Gen-Probe/Chiron) used in ID-NAT format and cobas s 201 (Roche Molecular Systems) applied in 1:6 diluted samples to mimic six-minipool (MP6) nucleic acid test (NAT) was assessed by quadruplicate testing of five seroconversion panels per marker. A mathematical analysis based on the log-linear increase of viremia in the ramp-up phase, as established with bDNA 3.0 assays enabled estimation of the IWP for human immunodeficiency virus (HIV) and hepatitis B virus (HBV) assays. RESULTS: The mean IWPs were Tigris HIV RNA 5.5 days, s 201 (1:6) HIV RNA 7.4 days, GenScreen Plus p24/anti-HIV 17.8 days, PRISM anti-HIV 19.0 days, Tigris HBV DNA 20.6 days, s 201 (1:6) HBV DNA 22.6 days, Bio-Rad hepatitis B surface antigen (HBsAg) 37.8 days, and PRISM HBsAg 35.5 days. At estimated 50 percent NAT seroconversion rates, s 201 (1:6) and Tigris showed mean window-period reduction times (WPRTs) of 30.5 to 35.5 days to hepatitis C virus antibody (anti-HCV) assays, 10.4 to 13.5 days to anti-HIV, or combination p24/anti-HIV assays and 12.8 to 17.2 days to HBsAg assays. CONCLUSIONS: Tigris ID-NAT detected HIV RNA 2 days earlier than s 201 MP6-NAT, but the difference in sensitivity between the two NAT systems was not significant in HBV seroconversion panels. Insufficient seroconversion samples were available for reliable modeling of WPRT in early HCV infection, but 1.4 to 2.0 days could be predicted by translating analytical sensitivity data. Both multiplex NAT systems demonstrate significant WPRTs compared to (combined) antigen and antibody assays.

N-(3-fluoro-4-(2-arylthieno[3,2-b]pyridin-7-yloxy)phenyl)-2-oxo-3-phenylimidazolidine-1-carboxamides: a novel series of dual c-Met/VEGFR2 receptor tyrosine kinase inhibitors.

A series of N-(3-fluoro-4-(2-arylthieno[3,2-b]pyridin-7-yloxy)phenyl)-2-oxo-3-phenylimidazolidine-1-carboxamides targeting c-Met and VEGFR2 tyrosine kinases was designed and synthesized. The compounds were potent against these two enzymes with IC(50) values in the low nanomolar range in vitro, possessed favorable pharmacokinetic profiles and showed high efficacy in vivo in several human tumor xenograft models in mice.

Comparison of the analytical and operational performance of two viral nucleic acid test blood screening systems: Procleix Tigris and cobas s 201.

BACKGROUND: The operational and analytical performance of two automated triplex hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) nucleic acid test (NAT) systems were compared in four screening laboratories of the French Blood Service. STUDY DESIGN AND METHODS: Two laboratories evaluated the Procleix Tigris system (Chiron/Gen-Probe) in individual donation (ID) format and two sites used the cobas s 201 system (Roche Molecular Systems) on minipools (MPs) of six donations. The analytical sensitivity, the specificity, and operational performance were compared. RESULTS: The ID to MP-NAT relative sensitivity factors in standard dilution panels of different genotypes varied between 8.7 and 21.9 for HCV RNA, 6.7 and 14.8 for HIV RNA, and 0.71 and 11.6 for HBV DNA. Tigris was 800-fold more sensitive than cobas s 201 (1:6) for a HIV group O sample, but did not detect the HIV-2 sample picked up by cobas s 201 with equal sensitivity as the HIV-1 group M samples. The specificity of both NAT systems after initial screening of 10,520 donations with Tigris and 1444 test pools on s 201 was 99.9 percent for both systems, but reached 100 percent after the repeat and pool resolution test algorithms. A higher throughput of the pool test protocol on cobas s 201 became apparent when the daily workload was more than 400 donations. CONCLUSIONS: Tigris ID-NAT format was significantly more sensitive than cobas s 201 MP-NAT in detecting HCV RNA and HIV RNA dilution panels, but despite the 1:6 dilution factor in s 201 the difference in sensitivity was not significant for some of the HBV genotype panels. Both NAT systems demonstrated acceptable operational performance, but for routine use further improvement in system reliability is desirable.