Precision Medicine in Hematology 2021: Definitions, Tools, Perspectives, and Open Questions

During the past few years, our understanding of molecular mechanisms and cellular interactions relevant to malignant blood cell disorders has improved substantially. New insights include a detailed knowledge about disease-initiating exogenous factors, endogenous (genetic, somatic, epigenetic) elicitors or facilitators of disease evolution, and drug actions and interactions that underlie efficacy and adverse event profiles in defined cohorts of patients. As a result, precision medicine and personalized medicine are rapidly growing new disciplines that support the clinician in making the correct diagnosis, in predicting outcomes, and in optimally selecting patients for interventional therapies. In addition, precision medicine tools are greatly facilitating the development of new drugs, therapeutic approaches, and new multiparametric prognostic scoring models. However, although the emerging roles of precision medicine and personalized medicine in hematology and oncology are clearly visible, several questions remain. For example, it remains unknown how precision medicine tools can be implemented in healthcare systems and whether all possible approaches are also affordable. In addition, there is a need to define terminologies and to relate these to specific and context-related tools and strategies in basic and applied science. To discuss these issues, a working conference was organized in September 2019. The outcomes of this conference are summarized herein and include a proposal for definitions, terminologies, and applications of precision and personalized medicine concepts and tools in hematologic neoplasms. We also provide proposals aimed at reducing costs, thereby making these applications affordable in daily practice.

Study of natural uranium fuel for a new reactor design TEPLATOR

The TEPLATOR is a new type of nuclear reactor which the main purpose is producing heat for district heating. It is designed as a special thermal reactor with 55 fuel channels for fuel assemblies, which is moderated and cooled by heavy water and operated around atmospheric pressure. The TEPLATOR DEMO is designed for the use of irradiated fuel from PWR or BWR reactors. Using heavy water as the moderator and coolant in this reactor concept allows to use natural uranium as an alternative fuel in case that the irradiated fuel is not available for some reason. This solution is suitable because of the price of natural uranium and the absence of costly fuel enrichment. This article is focused on deeper analyses of alternative suitable fuel for TEPLATOR based on natural uranium and new fuel geometries. This work builds on previous research on alternative fuel material and geometry for the TEPLATOR. It is mainly concerned with the neutronic development of fuel assemblies, the possibility of manufacturing of developed fuel types, and optimization of fuel management and uranium consumption. This article contains predetermined candidates for suitable fuel geometries and new untested fuel geometry types with some new advantages. Finally, optimization of the whole reactor core and number of fuel channels was made in terms of increased safety and higher fuel burn-up. Presented calculations were performed by Monte Carlo code Seprent.

Position evaluation of ex-core neutron flux measurement in new type graphite reactors

Several concepts of new reactors use graphite. Some of them use graphite as a moderator, some of them as a reflector. There are at least two concepts of these graphitetype reactors under development in the Czech Republic. Both reactors use graphite as the reflector. An in-core measurement might be impossible to use because of various reasons, for instance, high temperature or aggressive environment. Therefore, this article focuses on ex-core neutron flux measurement system placed in the graphite reflector and the optimization of ex-core detector position. A set of experiments were performed at LR-0 reactor. The LR-0 is a light water reactor with a well-defined neutron field, which can be used for different material insertion tests and testing of its influence on criticality. Several modifications of LR-0 cores were modelled in Monte Carlo codes Serpent and KENO. A set of calculations were performed for verification of the criticality and neutron flux course in the reactor core and graphite reflector. Further investigation was focused on the influence of the presence of a graphite reflector on the neutron distribution in the reactor core. The LR-0 graphite experiments were also used to verify the calculations. Based on the results of this article, the optimal position of ex-core detectors in the graphite reflector is proposed.

Diagnostic impact of early cardiac magnetic resonance imaging in patients with the working diagnosis of MINOCA. Does the final diagnosis affect patients outcome?

Introduction

The diagnostic value of cardiac magnetic resonance (CMR) imaging has been suggested in determination of the cause in patients with the working diagnosis of Myocardial Infarction with Non-obstructive Coronary Arteries (MINOCA). According to the current STEMI Guideline CMR is considered to have the best diagnostic performance, when CMR timing is within its optimal ≤2 weeks.

Aims

The aim of our study was to assess the diagnostic value of early (1–7 days) CMR examination in patients with signs of troponin positive acute coronary syndrome (ACS) but with nonobstructive coronary arteries. We also aimed to investigate how early CMR changes the provisional diagnosis. We investigated the mortality in each patient group.

Methods

273 consecutive patients (43±16 years, 64% male) with working diagnosis of MINOCA underwent CMR examination following coronary angiography in a mean length of time of 2.5 days between 2009–2020. Cine movie, T2-weighted and late gadolinium enhanced images (LGE) were performed. Left ventricular end-diastolic and end-systolic volumes (LVESVi), ejection fraction (LVEF), mass (LVM) and myocardial necrosis were evaluated. We analysed the risk factors and laboratory values of our patients. Patients were followed for all-cause mortality.

Results

CMR examination established a definitive diagnosis in 86% of the cases: acute myocardial infarction (MI) in 65 patients (47% male), acute myocarditis in 142 patients (87% male), Tako-Tsubo syndrome (TTS) in 27 woman, myocardial contusion in one case. The diagnosis of four patients remained inconclusive after CMR and in 34 pts (50% male) there was no CMR abnormality. CMR changed the provisional diagnosis in 53% of the patients. LVEF was lower, LVESVi was elevated in TTS patients compared to MI and myocarditis (LVEF: 43±9.5 vs 56±7.7 vs 54±6.7%; LVESVi: 52±12.8 vs 38±13.2 vs 42±9.1 ml/m2 p<0.001). Myocarditis patients were younger (myocarditis: 34±10 vs MI 47±14.8 vs TTS 66±10.7 years; p<0.001) and lower percentage had hypercholesterolaemia (myocarditis:18.8 vs MI: 40 vs TTS:54.5%, p<0.01) or hypertension (myocarditis: 20 vs MI: 49 vs TTS: 60%, p<0.001). Laboratory values showed significant elevation of hsTroponin and CKMB of MI and myocarditis patients compared to other groups (p<0.05), but there was no difference between these two groups. During the median follow-up of 3-years 13 patients died. Mortality rate in deaths per patient-year was as follows: MI 2.6 vs Myocarditis 0.4 vs TTS 7.4%. We found a strong association between CMR diagnosis and mortality (logrank 22.3 p<0.001).

Conclusion

Our study demonstrates the diagnostic value of early CMR in patients with the working diagnosis of MINOCA. It established a definite diagnosis in 86% of our patients and changed the provisional diagnosis in 53%. According to our results there is an association between CMR diagnosis and mortality.

Myocarditis, MI, TakoTsubo syndrome

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Project no. NVKP_16-1-2016-0017 has been implemented with the support provided from the National Research, Development and Innovation Fund of Hungary, financed under the NVKP_16 funding scheme. This project was supported by a grant from the National Research, Development and Innovation Office (NKFIH) of Hungary (K 120277).

P5485The impact of meteorological parameters on the incidence of myocardial infarction

Introduction

The changing of some meteorological parameters have major burden on the human body. That's why it became necessary to adopt to the altering conditions. The air temperature, atmospheric pressure have a significant influence on the patient's physical shape, blood pressure and response to stress.

The aim of our study was to assess the impact of the fronts and all the factors forming the weather at the same time on the incidence of myocardial infarction and its prognosis.

Methods

We performed a retrospective analysis on the data of 11820 consecutive patients surviving acute myocardial infarction between 2005 and 2014. We used to scales applied in meteorology to characterise the days (Péczely Scale, Front Scale). We studied the incidence of the values of the different scales 2 days before and after the infarction.

Results

We had a database of 11820 patients, STEMI (n=5183) and NSTEMI (n=6004). We created different subgroups (age, 30-day mortality, occurrence of primary ventricle fibrillation) to make our estimation. Considering non VF patients the effect of Front 3 whereas among VF positive patients Front 5 is more significant. The incidence rates of Front 3 one day before and on the day of the infarction in the non-VF and NSTEMI group is 0.2041 and 0.1735, in the non-VF and STEMI group it is 0.1939 two days before the event. The incidence rate of Front 5 on the 2nd day in the NSTEMI and VF positive group is 0.0357, it is 0.0714 among STEMI and VF positive patients on the day of the event. The influence of the approaching warm front is significant (p<0.05).

Conclusion

The influence of the weather is not irrelevant in the occurrence of MI. The mortality rates are higher in several subgroups on days having a Péczely Scale 3. The different fronts have a major impact on the severity of the infarction. The Front 5 causes higher incidence of VF due to MI. We proved that warm fronts have a significant effect on patients dying within 30 days.

In vitro biomimetic engineering of a human hematopoietic niche with functional properties

In adults, human hematopoietic stem and progenitor cells (HSPCs) reside in the bone marrow (BM) microenvironment. Our understanding of human hematopoiesis and the associated niche biology remains limited, due to human material accessibility and limits of existing in vitro culture models. The establishment of an in vitro BM system would offer an experimentally accessible and tunable platform to study human hematopoiesis. Here, we develop a 3D engineered human BM analog by recapitulating some of the hematopoietic niche elements. This includes a bone-like scaffold, functionalized by human stromal and osteoblastic cells and by the extracellular matrix they deposited during perfusion culture in bioreactors. The resulting tissue exhibited compositional and structural features of human BM while supporting the maintenance of HSPCs. This was associated with a compartmentalization of phenotypes in the bioreactor system, where committed blood cells are released into the liquid phase and HSPCs preferentially reside within the engineered BM tissue, establishing physical interactions with the stromal compartment. Finally, we demonstrate the possibility to perturb HSPCs' behavior within our 3D niches by molecular customization or injury simulation. The developed system enables the design of advanced, tunable in vitro BM proxies for the study of human hematopoiesis.

Bone marrow microvessel density and plasma angiogenic factors in myeloproliferative neoplasms: clinicopathological and molecular correlations

Increased angiogenesis in BCR-ABL1 negative myeloproliferative neoplasms (MPNs) has been recognized, but its connection with clinical and molecular markers needs to be defined. The aims of study were to (1) assess bone marrow (BM) angiogenesis measured by microvessel density (MVD) using CD34 and CD105 antibodies; (2) analyze correlation of MVD with plasma angiogenic factors including vascular endothelial growth factor, basic fibroblast growth factor, and interleukin-8; (3) examine the association of MVD with clinicopathological and molecular markers. We examined 90 de novo MPN patients (30 polycythemia vera (PV), primary myelofibrosis (PMF), essential thrombocythemia (ET)) and 10 age-matched controls. MVD was analyzed by immunohistochemistry "hot spot" method, angiogenic factors by immunoassay and JAK2V617F, and CALR mutations by DNA sequencing and allelic PCR. MVD was significantly increased in MPNs compared to controls (PMF > PV > ET). Correlation between MVD and plasma angiogenic factors was found in MPNs. MVD was significantly increased in patients with JAK2V617F mutation and correlated with JAK2 mutant allele burden (CD34-MVD: ρ = 0.491, p < 0.001; CD105-MVD: ρ = 0.276, p = 0.02) but not with CALR mutation. MVD correlated with leukocyte count, serum lactate dehydrogenase, hepatomegaly, and splenomegaly. BM fibrosis was significantly associated with CD34-MVD, CD105-MVD, interleukin-8, and JAK2 mutant allele burden. JAK2 homozygote status had positive predictive value (100%) for BM fibrosis. Patients with prefibrotic PMF had significantly higher MVD than patients with ET, and we could recommend MVD to be additional histopathological marker to distinguish these two entities. This study also highlights the strong correlation of MVD with plasma angiogenic factors, JAK2 mutant allele burden, and BM fibrosis in MPNs.

Layer Protecting the Surface of Zirconium Used in Nuclear Reactors

BACKGROUND

Zirconium alloys have very useful properties for nuclear facilities applications having low absorption cross-section of thermal electrons, high ductility, hardness and corrosion resistance. However, there is also a significant disadvantage: it reacts with water steam and during this (oxidative) reaction it releases hydrogen gas, which partly diffuses into the alloy forming zirconium hydrides. A new strategy for surface protection of zirconium alloys against undesirable oxidation in nuclear reactors by polycrystalline diamond film has been patented- Czech patent 305059: Layer protecting the surface of zirconium alloys used in nuclear reactors and PCT patent: Layer for protecting surface of zirconium alloys (Patent Number: WO2015039636-A1). The zirconium alloy surface was covered by polycrystalline diamond layer grown in plasma enhanced chemical vapor deposition apparatus with linear antenna delivery system. Substantial progress in the description and understanding of the polycrystalline diamond/ zirconium alloys interface and material properties under standard and nuclear reactors conditions (irradiation, hot steam oxidation experiments and heating-quenching cycles) was made. In addition, process technology for the deposition of protective polycrystalline diamond films onto the surface of zirconium alloys was optimized.

RESULTS

Zircaloy2 nuclear fuel pins were covered by 300 nm thick protective polycrystalline diamond layer (PCD) using plasma enhanced chemical vapor deposition apparatus with linear antenna delivery system. The polycrystalline diamond layer protects the zirconium alloy surface against undesirable oxidation and consolidates its chemical stability while preserving its functionality. PCD covered Zircaloy2 and standard Zircaloy2 pins were for 30 min. oxidized in 1100°C hot steam. Under these conditions α phase of zirconium changes to β phase (more opened for oxygen/hydrogen diffusion). PCD anticorrosion protection of Zircaloy nuclear fuel assemblies can significantly prolong lifetime of Zirconium alloy in nuclear reactors even above Zirconium phase transition temperatures. Even after ion beam irradiation (10 dpa, 3 MeV Fe(2+)) the diamond film still shows satisfactory structural integrity with both sp(3) and sp(2) carbon phases. Zircaloy2 under the carbon-based protective layer after hot steam oxidation test differed from the original Zircaloy2 material composition only very slightly, proving that the diamond coating increases the material resistance to high temperature oxidation.

CONCLUSIONS

Zirconium alloys nuclear fuel pins' surfaces were covered by compact and homogeneous polycrystalline diamond layers consisting of sp(3) and sp(2) carbon phases with a high crystalline diamond content and low roughness. Diamond withstands very high temperatures, has excellent thermal conductivity and low chemical reactivity, it does not degrade over time and (important for the nuclear fuel cladding) being pure carbon, it has perfect neutron cross-section properties. Moreover, polycrystalline diamond layers consisting of crystalline (sp(3)) and amorphous (sp(2)) carbon phases could have suitable thermal expansion. Zirconium alloys coated with polycrystalline diamond film are protected against undesirable changes and processes. Further, the polycrystalline diamond layer prevents the reaction between the alloy surface and water vapor. During such reaction, water molecules dissociate and initiate formation of zirconium dioxide and hydrogen, accompanied by the release of large amount of heat. Thus the protective layer prevents the formation of hydrogen and the release of reaction heat. Few relevant patents to the topic have been reviewed and cited.

Dkk3 levels in patients with myeloproliferative neoplasms

INTRODUCTION

Dickkopf-3 (Dkk3) has been proposed as tumor suppressor gene and a marker for tumor blood vessels and has pro-angiogenic properties. Dkk3 is expressed in platelets and megakaryocytes from healthy controls and patients with BCR-ABL1-negative myeloproliferative neoplasms (MPN). The aim of this study is, to find out whether patients with MPN have higher Dkk3 serum levels than normal controls.

MATERIAL & METHODS

We analyzed Dkk3 serum levels with ELISA in patients with newly diagnosed and untreated MPN, including 10 essential thrombocythemia (ET), 10 polycythemia vera (PV), 10 primary meylofibrosis (PMF) and 10 healthy blood donors and correlated these findings with biological and clinical key data and the JAK2-V617F status. Dkk3 levels were corrected to platelet count, Dkk3c, as patients with MPN have higher platelet counts than controls.

RESULTS

As expected, patients with MPN have higher platelet counts than normal controls. Dkk3 serum levels of patients with MPN (5.4 ± 6.1 ng/ml) showed no significant difference compared to normal controls (4.4 ± 3.8 ng/ml). Regarding Dkk3c, a significant difference to controls was found in PV (8.5 ± 8.7 ng/ml; p=0.04), but not in ET and PMF (5.7 ± 3.8 ng/ml; p=0.07 and 2.7 ± 3.6 ng/ml; p=0.9; respectively. Dkk3c correlated with the JAK2-V617F mutational burden (p=0.014, Rho=0.445).

CONCLUSION

Dkk3 levels corrected to platelet count showed higher levels in PV than normal controls. Elevated Dkk3c level could possibly correlate to platelet activation in PV patients and increased Dkk3 release. Whether this remains a surrogate marker of platelet release or it contributes to the thrombophilic state through its pro-angiogenic properties remains to be shown.

Hematology Testing in Mice

The mouse is an increasingly important system for the study of both normal and aberrant hematopoiesis. As a model organism, the mouse recapitulates much of human hematopoiesis; however, there are some important differences. Here, the basic approaches for analyzing hematopoiesis in mice are described. In particular, methods are provided for the collection and analysis of peripheral blood, flow cytometry analysis of peripheral blood, bone marrow, and spleen cells, and isolation and transplantation of bone marrow stem cells. Curr. Protoc. Mouse Biol. 1:323-346 © 2011 by John Wiley & Sons, Inc.

Chronic myeloproliferative diseases with and without the Ph chromosome: some unresolved issues

Ph-positive chronic myeloid leukemia (CML) and Ph-negative chronic myeloproliferative diseases (MPDs), characterized in many cases by the presence of the JAK2(V617F) mutation, have many features in common and yet also show fundamental differences. In this review, we pose five discrete and related questions relevant to both categories of hematological malignancy, namely: What are the mechanisms that underlie disease progression from a relatively benign or chronic phase? By what therapeutic methods might one target residual leukemia stem cells in CML? Is JAK2(V617F) the original molecular event in MPD? What epigenetic events must have a role in dictating disease phenotype in MPDs? And finally, Will the benefits conferred by current or future JAK2(V617F) inhibitors equal or even surpass the clinical success that has resulted from the use of tyrosine kinase inhibitors in CML? These and others questions must be addressed and in some cases should be answered in the foreseeable future.

Angiogenesis and vascular endothelial growth factor-/receptor expression in myeloproliferative neoplasms: correlation with clinical parameters and JAK2-V617F mutational status

Data on angiogenesis in the bone marrow of BCR-ABL1-negative myeloproliferative neoplasm (MPN) patients suggest an increase of the microvessel density (MVD) and vascular endothelial growth factor (VEGF) expression, but relations to the JAK2-V617F status remain controversial. We performed immunohistochemical studies of MVD and VEGF-expression in 100 MPN, including 24 essential thrombocythemia- (ET), 46 polycythemia vera- (PV), 26 primary myelofibrosis- (PMF), four myelodysplastic (MDS)/MPN- and 20 control reactive bone marrow cases, and correlated these findings with biological and clinical key data and the JAK2-V617F status. We found significantly increased MVD, particularly that assessed by CD105, and VEGF expression in MPN compared to controls (PMF > PV > MDS/MPN > ET). We observed stronger association between CD105-MVD and VEGF expression, fibrosis, and JAK2-V617F mutant allele burden, compared to CD34-MVD. MVD was strongly increased in MPN with high JAK2-V617F mutant allele burden. Our study highlights the importance of newly formed CD105+ vessels in the bone marrow of MPN patients, and indicates that assessment of CD105-MVD better reflects angiogenic activity in MPN. In addition, it provides evidence that despite the fact that angiogenesis is generally independent of the JAK2-V617F status in MPN, new vessel formation might be linked to Jak2 effects in some cases with high JAK2-V617F mutant allele burden.

Megakaryocyte-restricted MYH9 inactivation dramatically affects hemostasis while preserving platelet aggregation and secretion

Mutations in the MYH9 gene encoding the nonmuscle myosin heavy chain IIA result in bleeding disorders characterized by a macrothrombocytopenia. To understand the role of myosin in normal platelet functions and in pathology, we generated mice with disruption of MYH9 in megakaryocytes. MYH9Δ mice displayed macrothrombocytopenia with a strong increase in bleeding time and absence of clot retraction. However, platelet aggregation and secretion in response to any agonist were near normal despite absence of initial platelet contraction. By contrast, integrin outside-in signaling was impaired, as observed by a decrease in integrin β3 phosphorylation and PtdIns(3,4)P2 accumulation following stimulation. Upon adhesion on a fibrinogen-coated surface, MYH9Δ platelets were still able to extend lamellipodia but without stress fiber–like formation. As a consequence, thrombus growth and organization, investigated under flow by perfusing whole blood over collagen, were strongly impaired. Thrombus stability was also decreased in vivo in a model of FeCl3-induced injury of carotid arteries. Overall, these results demonstrate that while myosin seems dispensable for aggregation and secretion in suspension, it plays a key role in platelet contractile phenomena and outside-in signaling. These roles of myosin in platelet functions, in addition to thrombocytopenia, account for the strong hemostatic defects observed in MYH9Δ mice.

The genetic basis of myeloproliferative disorders

For many decades, myeloproliferative disorders (MPD) were largely neglected orphan diseases. The conceptual work of William Dameshek in 1951 provided the basis for understanding MPD as a continuum of related syndromes, possibly with a common pathogenetic cause. Recognition of the clonal origin of peripheral blood cells in MPD in 1976 and the ability to grow erythroid colonies in vitro in the absence of added growth factors in 1974 initiated the search for genetic alterations that might be responsible for myeloproliferation. Mutations in the genes for the erythropoietin receptor, thrombopoietin and the von Hippel-Lindau protein were found to cause familial syndromes resembling MPD, but despite their phenotypic similarities, none of these mutations were later found in patients with the sporadic form of MPD. The discovery of activating mutations in the Janus kinase 2 (JAK2) in most patients with MPD has fully transformed and energized the MPD field. Sensitive assays for detecting the JAK2-V617F mutation have become an essential part of the diagnostic work-up, and JAK2 now constitutes a prime target for developing specific inhibitors for the treatment of patients with MPD. Despite this progress, many questions remain unsolved, including how a single JAK2 mutation causes three different MPD phenotypes, what other genes might be involved in the pathogenesis, and what are the factors determining the progression to acute leukemia.

Adaptive functional differentiation of dendritic cells: integrating the network of extra- and intracellular signals

Phenotypic maturation, cytokine secretion, and migration are distinct functional characteristics of dendritic cells (DCs). These functions are independently regulated by a number of extracellular variables, such as type, strength, and persistence of an array of soluble and membrane-bound mediators. Since the exact composition of these variables in response to infection may differ between individuals, the intracellular signaling pathways activated by these extracellular networks may more closely correlate with DC function and predict the course of adaptive immunity. We found that activation of p38 kinase (p38K), extracellular signal-related kinase 1/2 (ERK1/2), and phosphatidylcholine-specific phospholipase C (PC-PLC) enhanced cytokine secretion, whereas p38K, cyclic adenosine monophosphate (cAMP), and PC-PLC enhanced migration. In contrast, phosphatidylinositol 3-kinase (PI3K)/Akt-1 and cAMP inhibited cytokine secretion while ERK1/2 inhibited migration. Migration and cytokine secretion further differed in their sensitivity to inhibition over time. However, although DCs could be manipulated to express migration, cytokine secretion, or both, the level of activation or persistence of intracellular pathway signaling was not predictive. Our results suggest a modular organization of function. We hypothesize that the expression of specific DC functions integrates a large variety of activating and inhibitory variables, and is represented by the formation of a functional unit of molecular networks-the signal response module (SRM). The combined activities of these modules define the functional outcome of DC activation.

Lessons from familial myeloproliferative disorders

By definition, myeloproliferative disorders (MPDs) are caused by an acquired somatic mutation of a hematopoietic progenitor/stem cell and have sporadic occurrence. However, well-documented families exist with first-degree relatives acquiring one or several MPDs. It is reasonable to assume that the germ-line mutation(s) or genetic background must facilitate or predispose for one or several somatic mutation(s) that lead to the MPD that is indistinguishable from the sporadic form. This is best documented in familial polycythemia vera (PV), which appears to be inherited as an autosomal dominant disorder with incomplete penetrance. However, there are also families wherein members develop any combination of MPDs, including PV, essential thrombocythemia (ET), chronic myelocytic leukemia (CML), and idiopathic myelofibrosis (IMF). A separate group of familial diseases is the familial thrombocythemias, wherein germ-line mutations in the genes for thrombopoietin or its receptor, MPL, cause polyclonal hereditary thrombocythemia, which may be clinically indistinguishable from ET. Patients with the congenital polycythemic condition "primary familial and congenital polycythemia" (PFCP) have characteristically decreased erythropoietin (Epo) levels similar to PV, hypersensitive erythroid progenitors, and low Epo levels; as such, this condition is often confused with PV. Therefore, PFCP will also be discussed here, while other congenital polycythemic states such as the Chuvash polycythemia that have elevated or inappropriately normal Epo levels will be omitted from this review in view of their distinct phenotype and unique laboratory features.

Tuning the volume of the immune response: strength and persistence of stimulation determine migration and cytokine secretion of dendritic cells

Migration to lymph nodes and secretion of cytokines are critical functions of mature dendritic cells (DCs); however, these 2 functions are not necessarily linked. This is the first report showing that quantitative differences in identical signaling pathways determine DC migration and cytokine secretion. Using different polymerized forms of CD40 ligand, we demonstrate that the strength and persistence of CD40 signaling can induce either function. Induction of monocyte-derived DC (MoDC) migration required a weak and transient CD40 signal, whereas strong and persistent CD40 signaling blocked migration and biased toward cytokine secretion. In contrast to MoDCs, CD40 activation of CD1c+ peripheral blood DCs (PBDCs) induced a nonpersistent, intracellular signaling profile resulting in migratory-type DCs unable to secrete interleukin-12p70 (IL-12p70). Extracellular signal-regulated kinase 1/2 (ERK1/2) and p38K activation synergistically mediated cytokine secretion, whereas migration was enhanced by p38K activation but reduced by persistent ERK1/2 activity. This model of signal strength and persistence also applied when stimulating DCs with intact microbes. Thus, a novel concept emerges in which the type of immune response induced by DCs is tuned by the strength and persistence of DC activating signals.

Genomic organisation of the human chordin gene and mutation screening of candidate Cornelia de Lange syndrome genes

We have determined the genomic organisation of the human chordin gene, CHRD, and have shown that it maps within a gene cluster at 3q27 containing THPO (thrombopoietin), CLCN2 (a voltage-gated chloride-channel gene) and EIF4G1 (a eukaryotic translation-initiation-factor-gamma gene). The CHRD and THPO genes are very close neighbours and are transcribed from opposing DNA strands from promoters that are spaced less than 2 kb apart. We considered that the CHRD gene and the chordin-regulating GSC (goosecoid) gene could be candidate genes for Cornelia de Lange syndrome (CDLS), a developmental malformation syndrome which is primarily characterised by mental handicap, growth retardation, distinctive facial features and limb-reduction defects. CDLS patients typically occur as sporadic cases, but several reports have suggested dominant inheritance. The candidacy of the CHRD and GSC genes was supported by several lines of evidence: prior evidence for a CDLS gene at 3q26.3-q27; a report suggesting a significant association between CDLS and thrombocytopenia; suspected genetic heterogeneity in CDLS; location of the GSC gene in close proximity to a 14q32 breakpoint detected in a CDLS patient with a balanced de novo translocation; known regulation of chordin expression by goosecoid; and the pattern of embryonic expression of the mouse GSC gene. Another candidate gene at 3q27, SOX2, was also considered because of its suspected role as a transcription factor in early development and because of known examples of SOX genes that are loci for dominantly inherited developmental disorders. However, mutation screening failed to identify CDLS patient-specific mutations in CHRD, GSC or SOX2.

Human leukocyte and fibroblast interferon in a combination therapy of dendritic keratitis

Thirty-eight patients with virologically proven dendritic keratitis were treated using either debridement plus human leukocyte interferon (HLI) or debridement plus human fibroblast interferon (HFI) in a randomized, double-blind study. We administered one drop of HLI or HFI (1 X 10(6) reference units/ml) daily and found no significant difference in the action of either type of interferon.

Comparative evaluation of human leukocyte and fibroblast interferon in the prevention of herpes simplex virus keratitis in a monkey model

The prophylactic potency of topically applied human leukocyte interferon and human fibroblast interferon was compared in a monkey model with herpes simplex virus type 1-induced keratitis. Both interferons effectively prevented keratitis at 1.9 X 10(6) U of activity per ml but were ineffective at 1.9 X 10(3) U/ml. Slight differences between human leukocyte interferon and human fibroblast interferon observed at the level of 1.9 X 10(5) U/ml were not statistically significant.

Experimental infection of weanling pigs with A-swine influenza virus. I. Epidemiology and serological response

Naturally occurring swine influenza is caused by a strain of virus closely related to influenza strains isolated from man in 1918 and later. Information is lacking on certain aspects of the epidemiology of swine influenza that, if obtained, might shed some light on the epidemiology of human influenza, particularly with respect to inter-epidemic reservoirs and shedders of the virus. In a first series of experiments undertaken by the authors pigs were experimentally infected intranasally with swine influenza virus and the course of clinical infection, spread by contact, and the serological response of infected animals were studied. Observations were also made on persons in contact with the infected swine to determine whether cross-transmission occurred. Respiratory and feverish clinical signs of the disease were observed in infected animals. Contact infection of several animals in the same piggery occurred, as revealed by serological tests, although the contact-infected pigs showed no clinical signs. There was some but not highly significant serological evidence of human infection in laboratory workers and animal handlers exposed to swine influenza virus. Some pigs infected as weanlings developed specific antibodies that lasted for 1(1/2) years of observation. Antibody titres decreased markedly towards the end of 1 year in animals of a lower age at the time of infection (42 days old), as compared with older animals (52-77 days) in which there were lesser decreases in titre.