Common genetic variants do not predict recurrent events in coronary heart disease patients.

BACKGROUND: It is unclear whether genetic variants identified from single nucleotide polymorphisms (SNPs) strongly associated with coronary heart disease (CHD) in genome-wide association studies (GWAS), or a genetic risk score (GRS) derived from them, can help stratify risk of recurrent events in patients with CHD. METHODS: Study subjects were enrolled at the close-out of the LIPID randomised controlled trial of pravastatin vs placebo. Entry to the trial had required a history of acute coronary syndrome 3-36 months previously, and patients were in the trial for a mean of 36 months. Patients who consented to a blood sample were genotyped with a custom designed array chip with SNPs chosen from known CHD-associated loci identified in previous GWAS. We evaluated outcomes in these patients over the following 10 years. RESULTS: Over the 10-year follow-up of the cohort of 4932 patients, 1558 deaths, 898 cardiovascular deaths, 727 CHD deaths and 375 cancer deaths occurred. There were no significant associations between individual SNPs and outcomes before or after adjustment for confounding variables and for multiple testing. A previously validated 27 SNP GRS derived from SNPs with the strongest associations with CHD also did not show any independent association with recurrent major cardiovascular events. CONCLUSIONS: Genetic variants based on individual single nucleotide polymorphisms strongly associated with coronary heart disease in genome wide association studies or an abbreviated genetic risk score derived from them did not help risk profiling in this well-characterised cohort with 10-year follow-up. Other approaches will be needed to incorporate genetic profiling into clinically relevant stratification of long-term risk of recurrent events in CHD patients.

Enlargement of the WHO international repository for platelet transfusion-relevant bacteria reference strains.

BACKGROUND AND OBJECTIVES: Interventions to prevent and detect bacterial contamination of platelet concentrates (PCs) have reduced, but not eliminated the sepsis risk. Standardized bacterial strains are needed to validate detection and pathogen reduction technologies in PCs. Following the establishment of the First International Reference Repository of Platelet Transfusion-Relevant Bacterial Reference Strains (the 'repository'), the World Health Organization (WHO) Expert Committee on Biological Standardisation (ECBS) endorsed further repository expansion. MATERIALS AND METHODS: Sixteen bacterial strains, including the four repository strains, were distributed from the Paul-Ehrlich-Institut (PEI) to 14 laboratories in 10 countries for enumeration, identification and growth measurement on days 2, 4 and 7 after low spiking levels [10-25 colony-forming units (CFU)/PC bag]. Spore-forming (Bacillus cereusPEI-B-P-07-S, Bacillus thuringiensisPEI-B-P-57-S), Gram-negative (Enterobacter cloacaePEI-B-P-43, Morganella morganiiPEI-B-P-74, PEI-B-P-91, Proteus mirabilisPEI-B-P-55, Pseudomonas fluorescensPEI-B-P-77, Salmonella choleraesuisPEI-B-P-78, Serratia marcescensPEI-B-P-56) and Gram-positive (Staphylococcus aureusPEI-B-P-63, Streptococcus dysgalactiaePEI-B-P-71, Streptococcus bovisPEI-B-P-61) strains were evaluated. RESULTS: Bacterial viability was conserved after transport to the participating laboratories with one exception (M. morganiiPEI-B-P-74). All other strains showed moderate-to-excellent growth. Bacillus cereus, B. thuringiensis, E. coli, K. pneumoniae, P. fluorescens, S. marcescens, S. aureus and S. dysgalactiae grew to >106 CFU/ml by day 2. Enterobacter cloacae, P. mirabilis, S. epidermidis, S. bovis and S. pyogenes achieved >106 CFU/ml at day 4. Growth of S. choleraesuis was lower and highly variable. CONCLUSION: The WHO ECBS approved all bacterial strains (except M. morganiiPEI-B-P-74 and S. choleraesuisPEI-B-P-78) for repository enlargement. The strains were stable, suitable for spiking with low CFU numbers, and proliferation was independent of the PC donor.

Development of a mitochondrial DNA real-time polymerase chain reaction assay for quality control of pathogen reduction with riboflavin and ultraviolet light.

BACKGROUND AND OBJECTIVES: Transfusion is associated with a risk of infection and alloimmunization. Pathogen reduction using riboflavin and UV light (Mirasol treatment) inactivates pathogens and leucocytes. With increasing adoption of the technology in clinical use, regulatory agencies have recommended the introduction of quality control measures to monitor pathogen reduction efficacy. We sought to develop a real-time PCR-based assay to document the impact of pathogen reduction on the mitochondrial genome in blood components. MATERIALS AND METHODS: DNA was extracted from platelet and plasma components before and after treatment with riboflavin and UV light. Inhibition of PCR amplification of mitochondrial DNA (mtDNA) in short- and long-amplicon target regions, ranging from under 200 base pairs (bp) to over 1800 bp, was measured in treated relative to untreated components. RESULTS: Pathogen reduction of platelets using riboflavin and UV light resulted in inhibition of PCR amplification of long-amplicon mtDNA targets, demonstrating approximately 1 log reduction of amplification relative to untreated products. Amplification of short-amplicon mtDNA targets was not affected by treatment. Evaluation of 110 blinded platelet samples from the PREPAReS clinical trial resulted in prediction of treatment status with 100% accuracy. Pathogen reduction of plasma components resulted in similar levels of PCR inhibition, while testing of 30 blinded plasma samples resulted in prediction of treatment status with 93% accuracy. CONCLUSION: A differential sized amplicon real-time PCR assay of mitochondrial DNA effectively documents nucleic acid damage induced by Mirasol treatment of platelets. The use of the assay for plasma product pathogen reduction requires further investigation.

Establishment of the first international repository for transfusion-relevant bacteria reference strains: ISBT working party transfusion-transmitted infectious diseases (WP-TTID), subgroup on bacteria.

BACKGROUND: Bacterial contamination of platelet concentrates (PCs) still remains a significant problem in transfusion with potential important clinical consequences, including death. The International Society of Blood Transfusion Working Party on Transfusion-Transmitted Infectious Diseases, Subgroup on Bacteria, organised an international study on Transfusion-Relevant Bacteria References to be used as a tool for development, validation and comparison of both bacterial screening and pathogen reduction methods. MATERIAL AND METHODS: Four Bacteria References (Staphylococcus epidermidis PEI-B-06, Streptococcus pyogenes PEI-B-20, Klebsiella pneumoniae PEI-B-08 and Escherichia coli PEI-B-19) were selected regarding their ability to proliferate to high counts in PCs and distributed anonymised to 14 laboratories in 10 countries for identification, enumeration and bacterial proliferation in PCs after low spiking (0·3 and 0·03 CFU/ml), to simulate contamination occurring during blood donation. RESULTS: Bacteria References were correctly identified in 98% of all 52 identifications. S. pyogenes and E. coli grew in PCs in 11 out of 12 laboratories, and K. pneumoniae and S. epidermidis replicated in all participating laboratories. The results of bacterial counts were very consistent between laboratories: the 95% confidence intervals were for S. epidermidis: 1·19-1·32 × 10(7) CFU/ml, S. pyogenes: 0·58-0·69 × 10(7) CFU/ml, K. pneumoniae: 18·71-20·26 × 10(7) CFU/ml and E. coli: 1·78-2·10 × 10(7) CFU/ml. CONCLUSION: The study was undertaken as a proof of principle with the aim to demonstrate (i) the quality, stability and suitability of the bacterial strains for low-titre spiking of blood components, (ii) the property of donor-independent proliferation in PCs, and (iii) their suitability for worldwide shipping of deep frozen, blinded pathogenic bacteria. These aims were successfully fulfilled. The WHO Expert Committee Biological Standardisation has approved the adoption of these four bacteria strains as the first Repository for Transfusion-Relevant Bacteria Reference Strains and, additionally, endorsed as a project the addition of six further bacteria strain preparations suitable for control of platelet contamination as the next step of enlargement of the repository.

The effect of pathogen reduction technology (Mirasol) on platelet quality when treated in additive solution with low plasma carryover.

BACKGROUND AND OBJECTIVES: Pathogen reduction technologies (PRT) for platelets are now compatible with both plasma and platelet additive solutions (PAS). The aim of this study was to examine the effect of PRT on the platelet storage lesion, in the presence of PAS with low plasma carryover. MATERIALS AND METHODS: PRT-treated (Mirasol) and untreated buffy coat-derived platelet concentrates prepared in 28% plasma/PAS-IIIM were evaluated using in vitro cell quality parameters on days 1, 2, 5, and 7 post-collection. RESULTS: At day 5, there were no significant differences between control and PRT treated platelets for swirl, viability, pO(2) , pCO(2) , mean platelet volume and adenosine diphosphate-induced aggregation. PRT treatment did not affect the functional integrity of the mitochondria. However, PRT resulted in a decrease in pH and enhancement of platelet glycolysis and activation, evidenced by increased glucose consumption and lactate production rates, increased expression of CD62P, CD63, annexin V staining and increased secretion of cytokines (P < 0.05). Hypotonic shock response and aggregation in response to collagen were also significantly reduced in PRT treated platelets (P < 0.05). CONCLUSION: Despite the observed differences in platelet metabolism and activation observed following PRT treatment in PAS and low plasma carryover, the results suggest that treatment and storage of platelets in PAS is no more detrimental to platelets than treatment and storage in plasma.

Mirasol Pathogen Reduction Technology treatment does not affect acute lung injury in a two-event in vivo model caused by stored blood components.

INTRODUCTION: Mirasol Pathogen Reduction Technology (PRT) treatment uses riboflavin and UV light to inactivate pathogens in blood components. Neutrophil [polymorphonuclear cells (PMN)] priming activity accumulates during routine storage of cellular blood components, and this activity has been implicated in transfusion-related acute lung injury (TRALI). We hypothesize that PRT-treatment of blood components affects the priming activity generated during storage of packed RBCs (PRBCs) or platelet concentrates (PCs), which can elicit ALI in vivo. METHODS: Plasma, PRBCs and PCs were isolated from healthy donor's whole blood or by apheresis. Half of a collected unit was treated with PRT treatment and the remainder was left as an unmodified control. Supernatant was collected during storage of PCs and PRBCs and assayed for PMN priming activity and used as the second event in a two-event in vivo model of TRALI. RESULTS: PRT treatment did not induce priming activity in plasma or affect the priming activity generated during storage of PCs or PRBCs as compared with the unmodified controls. The supernatants from stored, but not fresh, PCs and PRBCs did cause ALI as the second event in a two-event animal model of TRALI, which was unaffected by PRT treatment. We conclude that the PRT treatment does not induce priming activity in plasma nor does it affect the priming activity generated during storage of PCs or PRBCs or their ability to cause ALI as the second event in a two-event in vivo model of TRALI. Moreover, the amount of priming activity in TRIMA-isolated PCs was significantly less than SPECTRA-isolated PCs.

Recent advances of PET imaging in clinical radiation oncology.

Radiotherapy and radiation oncology play a key role in the clinical management of patients suffering from oncological diseases. In clinical routine, anatomic imaging such as contrast-enhanced CT and MRI are widely available and are usually used to improve the target volume delineation for subsequent radiotherapy. Moreover, these modalities are also used for treatment monitoring after radiotherapy. However, some diagnostic questions cannot be sufficiently addressed by the mere use standard morphological imaging. Therefore, positron emission tomography (PET) imaging gains increasing clinical significance in the management of oncological patients undergoing radiotherapy, as PET allows the visualization and quantification of tumoral features on a molecular level beyond the mere morphological extent shown by conventional imaging, such as tumor metabolism or receptor expression. The tumor metabolism or receptor expression information derived from PET can be used as tool for visualization of tumor extent, for assessing response during and after therapy, for prediction of patterns of failure and for definition of the volume in need of dose-escalation. This review focuses on recent and current advances of PET imaging within the field of clinical radiotherapy / radiation oncology in several oncological entities (neuro-oncology, head & neck cancer, lung cancer, gastrointestinal tumors and prostate cancer) with particular emphasis on radiotherapy planning, response assessment after radiotherapy and prognostication.

Pathogen reduction technology (Mirasol) treated single-donor platelets resuspended in a mixture of autologous plasma and PAS.

BACKGROUND AND OBJECTIVES: Mirasol pathogen reduction technology (PRT) for platelet concentrates uses riboflavin and ultraviolet light. Previously, we described increased metabolism and activation for PRT platelets stored in 100% plasma. To improve platelet quality, we resuspended platelets in a mixture of plasma and platelet additive solution (PAS). MATERIALS AND METHODS: Single-donor platelets were resuspended in plasma and split into an untreated control and a PRT-treated single product. One hundred and fifty millilitre PAS (SSP+) was added to both. Over 7 days, we assayed pH, glucose consumption-, lactate production rate and CD62p with and without TRAP. RESULTS: On day 5, PRT units showed a significantly lower pH (7.087 +/- 0.105 vs. 7.288 +/- 0.200) accompanied by a higher lactate production (0.104 +/- 0014 vs. 0.063 +/- 0.017 mmol/10(12)/h) and glucose consumption rate (0.039 +/- 0005 vs. 0.028 +/- 0.009 mmol/10(12) platelets/h). CD62p expression was higher in treated units (44.5 +/- 13.0 vs. 16.5 +/- 7.6%). CONCLUSION: In comparison to PRT platelets resuspended in 100% plasma, a mixture of plasma and PAS improves pH and platelet metabolism but not platelet activation. Prolonged shelf-life for up to 7 days may be possible

Ligation of the CD4 receptor induces activation-independent down-regulation of L-selectin.

Lymphocyte circulation plays an important role in the generation of a specific immune response. Mature lymphocytes continuously circulate between blood and lymph, entering the lymphoid tissue via high endothelial venules. Trafficking across high endothelial venules of peripheral lymph nodes (PLN) depends on the expression of L-selectin. It has been shown that L-selectin is rapidly cleaved from the surface by a metalloproteinase after in vitro activation. Here, we show that ligation of CD4, without ligation of the T cell receptor for antigen, causes down-regulation of L-selectin on T helper cells. This down-regulation is caused by proteolytic cleavage by a metalloproteinase and is reversible by the addition of hydroxamic acid-based metalloproteinase inhibitors. We show that in vivo down-regulation of L-selectin in huCD4tg mice by mAb reduces the homing of lymphocytes to PLN in adoptive transfer experiments. Because CD4 is a coreceptor for HIV-1, the down-regulation of L-selectin induced by CD4 ligation could play a role in the pathogenesis of AIDS. We provide evidence that CD4 ligation by HIV-1 induces metalloproteinase-dependent L-selectin down-regulation. Reduced levels of L-selectin expression might contribute to immune deficiency in individuals infected with HIV by inhibiting T cell redistribution and decreasing the probability of an encounter between specific lymphocytes and viral antigens in PLN.

Image-based bidirectional reflectance distribution function measurement.

We present a new image-based process for measuring a surface's bidirectional reflectance rapidly, completely, and accurately. Requiring only two cameras, a light source, and a test sample of known shape, our method generates densely spaced samples covering a large domain of illumination and reflection directions. We verified our measurements both by tests of internal consistency and by comparison against measurements made with a gonioreflectometer. The resulting data show accuracy rivaling that of custom-built dedicated instruments.

FcgammaRIIB-mediated inhibition of T-cell receptor signal transduction involves the phosphorylation of SH2-containing inositol 5-phosphatase (SHIP), dephosphorylation of the linker of activated T-cells (LAT) and inhibition of calcium mobilization.

The low-affinity receptor for immunoglobulin G, FcgammaRIIB, is expressed on most B-cells and on immature and activated mature T-cells. Co-aggregation of FcgammaRIIB with the B-cell antigen receptor (BCR) leads to attenuation of BCR-induced blastogenesis and cell proliferation via inhibition of p21(ras), phosphatidylinositol 3-kinase (PI3-K) and phospholipase Cgamma (PLCgamma) activation. These effects are mediated, at least in part, by the recruitment of SH2-containing protein tyrosine phosphatase-1 (SHP-1) and -2 (SHP-2) and SH2-containing inositol 5-phosphatase (SHIP). In this report, we demonstrate that FcgammaRIIB co-aggregation with the T-cell antigen receptor (TCR), which may occur when T-cells recognize antibody-coated target cells, leads to inhibition of TCR-induced phosphorylation of the linker of activated T-cells (LAT). When phosphorylated, LAT functions as an adapter molecule and recruits PI3-K. Additionally, we demonstrate that PI3-K is required for TCR-induced Ca(2+) mobilization. Together, these data suggest that FcgammaRIIB may inhibit TCR-mediated Ca(2+) mobilization, in part via inhibition of LAT phosphorylation and subsequent inhibition of PI3-K activation. A similar mechanism has been described in B-cells, where FcgammaRIIB co-aggregation with the BCR leads to inhibition of PI3-K activity via dephosphorylation of CD19. It is likely that, in both cell types, levels of PtdIns(3,4,5)P(3) are additionally modulated via the enzymic activity of SHIP.

Partially distinct molecular mechanisms mediate inhibitory FcgammaRIIB signaling in resting and activated B cells.

FcgammaRIIB functions as an inhibitory receptor to dampen B cell Ag receptor signals and immune responses. Accumulating evidence indicates that ex vivo B cells require the inositol 5-phosphatase, Src homology domain 2-containing inositol 5-phosphatase (SHIP), for FcgammaRIIB-mediated inhibitory signaling. However, we report here that LPS-activated primary B cells do not require SHIP and thus differ from resting B cells. SHIP-deficient B cell blasts display efficient FcgammaRIIB-dependent inhibition of calcium mobilization as well as Akt and extracellular signal-related protein kinase phosphorylation. Surprisingly, FcgammaRIIB-dependent degradation of phosphatidylinositol 3,4,5-trisphosphate and conversion into phosphatidylinositol 3,4-bisphosphate occur in SHIP-deficient B cell blasts, demonstrating the function of an additional inositol 5-phosphatase. Further analysis reveals that while resting cells express only SHIP, B cell blasts also express the recently described inositol 5-phosphatase, SHIP-2. Finally, data suggest that both SHIP-2 and SHIP can mediate downstream biologic consequences of FcgammaRIIB signaling, including inhibition of the proliferative response.

Apoptosis in HIV-1 Infection.

We have studied apoptosis in lymph node and peripheral blood mononuclear cells (PBMCs) from HIV-infected children and adults and SIV-infected rhesus macaques. In lymph nodes, we found that apoptosis and productive infection occurred only rarely in the same cell. There was, however, a direct correlation between the numbers of apoptotic and productively-infected cells. In HIV-infected children, we found a direct correlation between disease severity and percentage CD4+ T cell apoptosis (p = 0.001). Both CD4+ and CD8+ T cell apoptosis were directly related to CD4+ T cell depletion (p = 0.006 and p = 0.01, respectively). In addition, we found a trend towards diminished CD4+ T cell apoptosis on anti-retroviral agents. These findings suggest that apoptosis of uninfected cells may be important in HIV pathogenesis and that measurement of apoptosis may be a useful marker of disease activity.

Apoptosis of CD4+ and CD8+ T cells isolated immediately ex vivo correlates with disease severity in human immunodeficiency virus type 1 infection.

Apoptosis of CD4+ and CD8+ T cells has been shown in peripheral blood mononuclear cells (PBMCs) from HIV-infected adults analyzed after overnight culture. Because cell death may be an artifact of in vitro culture, and because there is little information on apoptosis in pediatric HIV disease, we undertook a cross-sectional analysis of apoptosis in PBMCs analyzed immediately ex vivo in HIV-infected children and adults. PBMCs from 22 children, four adolescents, and nine adults and seronegative age-matched control subjects were stained for CD4 and CD8 surface markers. Apoptotic cells were detected in a newly characterized flow cytometric assay by diminished forward and increased side scatter. Children with the most advanced disease had 9.9% (SEM 1.8) apoptotic CD4+ T cells above control, significantly higher than in asymptomatic patients [0.4% (SEM 2.3)], those with mild disease [2.2% (SEM 1.83)], and those with moderate disease [2.5 (SEM 3.6)] (p = 0.015). The percentages of both CD4+ and CD8+ T cell apoptosis were directly related to CD4+ T cell depletion (R2 = 0.23; p = 0.006; n = 32 and R2 = 0.2; p = 0.012; n = 30, respectively). Patients who responded to antiretroviral therapy with the greatest increase in CD4+ T cell percentage had the least CD4+ T cell apoptosis (R2 = 0.15; p = 0.1; n = 19). These findings show that the rate or extent of T cell death by apoptosis percentage of T cell apoptosis is significantly increased in HIV-infected children. The observed correlation of both CD4+ and CD8+ T cell apoptosis with CD4+ T cell depletion suggests that apoptosis plays a role in HIV pathogenesis and may be a useful marker of disease activity.