Analysis of factors affecting the variability of a quantitative suspension bead array assay measuring IgG to multiple Plasmodium antigens.

Reducing variability of quantitative suspension array assays is key for multi-center and large sero-epidemiological studies. To maximize precision and robustness of an in-house IgG multiplex assay, we analyzed the effect of several conditions on variability to find the best combination. The following assay conditions were studied through a fractional factorial design: antigen-bead coupling (stock vs. several), sample predilution (stock vs. daily), temperature of incubation of sample with antigen-bead (22°C vs. 37°C), plate washing (manual vs. automatic) and operator expertise (expert vs. apprentice). IgG levels against seven P. falciparum antigens with heterogeneous immunogenicities were measured in test samples, in a positive control and in blanks. We assessed the variability and MFI quantification range associated to each combination of conditions, and their interactions, and evaluated the minimum number of samples and blank replicates to achieve good replicability. Results showed that antigen immunogenicity and sample seroreactivity defined the optimal dilution to assess the effect of assay conditions on variability. We found that a unique antigen-bead coupling, samples prediluted daily, incubation at 22°C, and automatic washing, had lower variability. However, variability increased when performing several couplings and incubating at 22°C vs. 37°C. In addition, no effect of temperature was seen with a unique coupling. The expertise of the operator had no effect on assay variability but reduced the MFI quantification range. Finally, differences between sample replicates were minimal, and two blanks were sufficient to capture assay variability, as suggested by the constant Intraclass Correlation Coefficient of three and two blanks. To conclude, a single coupling was the variable that most consistently reduced assay variability, being clearly advisable. In addition, we suggest having more sample dilutions instead of replicates to increase the likelihood of sample MFIs falling in the linear part of the antigen-specific curve, thus increasing precision.

Identifying Immune Correlates of Protection Against Plasmodium falciparum Through a Novel Approach to Account for Heterogeneity in Malaria Exposure.

Background: A main criterion to identify malaria vaccine candidates is the proof that acquired immunity against them is associated with protection from disease. The age of the studied individuals, heterogeneous malaria exposure, and assumption of the maintenance of a baseline immune response can confound these associations. Methods: Immunoglobulin G/immunoglobulin M (IgG/ IgM) levels were measured by Luminex® in Mozambican children monitored for clinical malaria from birth until 3 years of age, together with functional antibodies. Studied candidates were pre-erythrocytic and erythrocytic antigens, including EBAs/PfRhs, MSPs, DBLs, and novel antigens merely or not previously studied in malaria-exposed populations. Cox regression models were estimated at 9 and 24 months of age, accounting for heterogeneous malaria exposure or limiting follow-up according to the antibody's decay. Results: Associations of antibody responses with higher clinical malaria risk were avoided when accounting for heterogeneous malaria exposure or when limiting the follow-up time in the analyses. Associations with reduced risk of clinical malaria were found only at 24 months old, but not younger children, for IgG breadth and levels of IgG targeting EBA140III-V, CyRPA, DBL5ε and DBL3x, together with C1q-fixation activity by antibodies targeting MSP119. Conclusions: Malaria protection correlates were identified, only in children aged 24 months old when accounting for heterogeneous malaria exposure. These results highlight the relevance of considering age and malaria exposure, as well as the importance of not assuming the maintenance of a baseline immune response throughout the follow-up. Results may be misleading if these factors are not considered.

Host age and expression of genes involved in red blood cell invasion in Plasmodium falciparum field isolates.

Plasmodium falciparum proteins involved in erythrocyte invasion are main targets of acquired immunity and important vaccine candidates. We hypothesized that anti-parasite immunity acquired upon exposure would limit invasion-related gene (IRG) expression and affect the clinical impact of the infection. 11 IRG transcript levels were measured in P. falciparum isolates by RT-PCR, and IgG/IgM against invasion ligands by Luminex®, in 50 Mozambican adults, 25 children with severe malaria (SM) and 25 with uncomplicated malaria (UM). IRG expression differences among groups and associations between IRG expression and clinical/immunologic parameters were assessed. IRG expression diversity was higher in parasites infecting children than adults (p = 0.022). eba140 and ptramp expression decreased with age (p = 0.003 and 0.007, respectively) whereas p41 expression increased (p = 0.022). pfrh5 reduction in expression was abrupt early in life. Parasite density decreased with increasing pfrh5 expression (p < 0.001) and, only in children, parasite density increased with p41 expression (p = 0.007), and decreased with eba175 (p = 0.013). Antibody responses and IRG expression were not associated. In conclusion, IRG expression is associated with age and parasite density, but not with specific antibody responses in the acute phase of infection. Our results confirm the importance of multi-antigen vaccines development to avoid parasite immune escape when tested in malaria-exposed individuals.

Cytoadhesion to gC1qR through Plasmodium falciparum Erythrocyte Membrane Protein 1 in Severe Malaria.

Cytoadhesion of Plasmodium falciparum infected erythrocytes to gC1qR has been associated with severe malaria, but the parasite ligand involved is currently unknown. To assess if binding to gC1qR is mediated through the P. falciparum erythrocyte membrane protein 1 (PfEMP1) family, we analyzed by static binding assays and qPCR the cytoadhesion and var gene transcriptional profile of 86 P. falciparum isolates from Mozambican children with severe and uncomplicated malaria, as well as of a P. falciparum 3D7 line selected for binding to gC1qR (Pf3D7gC1qR). Transcript levels of DC8 correlated positively with cytoadhesion to gC1qR (rho = 0.287, P = 0.007), were higher in isolates from children with severe anemia than with uncomplicated malaria, as well as in isolates from Europeans presenting a first episode of malaria (n = 21) than Mozambican adults (n = 25), and were associated with an increased IgG recognition of infected erythrocytes by flow cytometry. Pf3D7gC1qR overexpressed the DC8 type PFD0020c (5.3-fold transcript levels relative to Seryl-tRNA-synthetase gene) compared to the unselected line (0.001-fold). DBLß12 from PFD0020c bound to gC1qR in ELISA-based binding assays and polyclonal antibodies against this domain were able to inhibit binding to gC1qR of Pf3D7gC1qR and four Mozambican P. falciparum isolates by 50%. Our results show that DC8-type PfEMP1s mediate binding to gC1qR through conserved surface epitopes in DBLß12 domain which can be inhibited by strain-transcending functional antibodies. This study supports a key role for gC1qR in malaria-associated endovascular pathogenesis and suggests the feasibility of designing interventions against severe malaria targeting this specific interaction.

[Duration of the Reimbursement Process in Spain for Innovative Drugs Approved by the European Medicines Agency during the Period 2008-2013]. / Duración del proceso de financiación en España de los fármacos innovadores aprobados por la Agencia Europea del Medicamento: 2008-2013.

BACKGROUND: In Spain, the decision of Price and Reimbursement (P&R) of a new drug must be taken between 180-270 days. The objective of this study was to assess the reimbursement timing in Spain for innovative drugs approved by the European Medicines Agency (EMA) between January 2008 and December 2013 and to explore the potential impact of drug's price on this time. METHODS: Drugs approved were extracted from EMA's website, authorization dates in Spain from the Spanish Agency (AEMPS) and, P&R dates and prices from Nomenclátor and BotPlus. Depending on days from approval to reimbursement, drugs were quick (<180), on time (180-270) and delayed (>270). Depending on posology: chronic or acute. Depending on dispensing conditions: retail or hospital drugs. It was calculated: median, maximum, minimum, first, and third quartiles of time until reimbursement. RESULTS: 431 drugs were approved by EMA; 285 were innovative, from them 147 were approved by the AEMPS and reimbursed: 103 chronic and 44 acute. Median price/day was €2.44 for chronic and €21 for acute. From 2008-2011, 80% of drugs were reimbursed, in 2012 21% and in 2013 17%. Time from approval to reimbursement move from 230 days in 2009 to 431 days in 2013. From the 139 drugs with reimbursement date 33 were quick, 44 on time and 62 delayed. CONCLUSIONS: The median time from approval by the EMA of innovative drugs since the reimbursement in Spain in 2013 is double that of 2008. The main driver of delays in the process of P&R seems to be the budget impact of the drug instead of its unit price.

Duración del proceso de financiación en España de los fármacos innovadores aprobados por la Agencia Europea del Medicamento. 2008-2013 / Duration of the reimbursement process in Spain for innovative drugs approved by the European Medicines Agency during the period 2008-2013

Fundamentos: En España la decisión de precio y financiación (PyF) de un nuevo medicamento debe tomarse entre 180 y 270 días. El objetivo de este estudio fue valorar el tiempo hasta la financiación en España de los medicamentos innovadores aprobados por la Agencia Europea de Medicamentos (EMA) entre enero 2008 y diciembre 2013 y explorar el impacto potencial del precio del fármaco sobre este tiempo. Métodos: Los medicamentos aprobados se obtuvieron de la web de la EMA, las fechas de autorización de la Agencia Española del Medicamento (AEMPS) y las fechas del PyF y los precios del Nomenclátor y BotPlus. Según los días desde la aprobación hasta la financiación se clasificó a los medicamentos en rápidos (<180), en plazo (180-270) y con demora (>270). Según la duración del tratamiento en crónicos o agudos. Y según las condiciones de dispensación: de farmacia u hospital. Del tiempo transcurrido hasta la financiación, se calculó la mediana, el máximo, el mínimo así como el primer y tercer cuartiles. Resultados: Durante el período de estudio fueron aprobados por la EMA 431 medicamentos, de los cuales 285 eran innovadores. De estos 147 fueron aprobados por la AEMPS y financiados: 103 para tratamientos crónicos y 44 para agudos. La mediana del precio/día fue de 2,44€ para crónicos y 21€ para agudos. De 2008-2011 fueron financiados el 80% , en 2012 el 21% y en 2013 el 17%. El tiempo hasta la financiación pasó de 230 días en 2009 a 431 en 2013. Los 139 medicamentos con fecha de financiación fueron: 33 rápidos, 44 en plazo y 62 con demora. Conclusiones: La mediana del tiempo desde la aprobación por la EMA de los medicamentos innovadores hasta su financiación en España en 2013 es el doble que en 2008. El motor principal de los retrasos en el proceso de PyF parece ser el impacto presupuestario del fármaco más que su precio unitario (AU)

Background: In Spain, the decision of Price and Reimbursement (P&R) of a new drug must be taken between 180-270 days. The objective of this study was to assess the reimbursement timing in Spain for innovative drugs approved by the European Medicines Agency (EMA) between January 2008 and December 2013 and to explore the potential impact of drug’s price on this time. Methods: Drugs approved were extracted from EMA’s website, authorization dates in Spain from the Spanish Agency (AEMPS) and, P&R dates and prices from Nomenclátor and BotPlus. Depending on days from approval to reimbursement, drugs were quick (<180), on time (180-270) and delayed (>270). Depending on posology: chronic or acute. Depending on dispensing conditions: retail or hospital drugs. It was calculated: median, maximum, minimum, first, and third quartiles of time until reimbursement. Results: 431 drugs were approved by EMA; 285 were innovative, from them 147 were approved by the AEMPS and reimbursed: 103 chronic and 44 acute. Median price/day was €2.44 for chronic and €21 for acute. From 2008-2011, 80% of drugs were reimbursed, in 2012 21% and in 2013 17%. Time from approval to reimbursement move from 230 days in 2009 to 431 days in 2013. From the 139 drugs with reimbursement date 33 were quick, 44 on time and 62 delayed. Conclusions: The median time from approval by the EMA of innovative drugs since the reimbursement in Spain in 2013 is double that of 2008. The main driver of delays in the process of P&R seems to be the budget impact of the drug instead of its unit price (AU)

Protein kinase Cε-calcineurin cosignaling downstream of toll-like receptor 4 downregulates fibrosis and induces wound healing gene expression in cardiac myofibroblasts.

The pathways which regulate resolution of inflammation and contribute to positive remodeling of the myocardium following injury are poorly understood. Here we show that protein kinase C epsilon (PKCε) cooperates with the phosphatase calcineurin (CN) to potentiate induction of cardioprotective gene expression while suppressing expression of fibrosis markers. This was achieved by detailed analysis of the regulation of cyclooxygenase 2 (COX-2) expression as a marker gene and by using gene expression profiling to identify genes regulated by coexpression of CN-Aα/PKCε in adult rat cardiac myofibroblasts (ARVFs) on a larger scale. GeneChip analysis of CN-Aα/PKCε-coexpressing ARVFs showed that COX-2 provides a signature for wound healing and is associated with downregulation of fibrosis markers, including connective tissue growth factor (CTGF), fibronectin, and collagens Col1a1, Col3a1, Col6a3, Col11a1, Col12a1, and Col14a1, with concomitant upregulation of cardioprotection markers, including COX-2 itself, lipocalin 2 (LCN2), tissue inhibitor of metalloproteinase 1 (TIMP-1), interleukin-6 (IL-6), and inducible nitric oxide synthase (iNOS). In primary rat cardiomyocyte cultures Toll-like receptor 4 (TLR4) agonist- or PKCε/CN-dependent COX-2 induction occurred in coresident fibroblasts and was blocked by selective inhibition of CN or PKC α/ε or elimination of fibroblasts. Furthermore, ectopic expression of PKCε and CN in ARVFs showed that the effects on COX-2 expression are mediated by specific NFAT sites within the COX-2 promoter as confirmed by site-directed mutagenesis and chromatin immunoprecipitation (ChIP). Therefore, PKCε may negatively regulate adverse myocardial remodeling by cooperating with CN to downregulate fibrosis and induce transcription of cardioprotective wound healing genes, including COX-2.