A dynamic transmission model to calculate vaccination coverage needed to control COVID-19 in Germany

Background

Control of the 2019 coronavirus disease (COVID-19) pandemic in Germany and return to pre-pandemic behaviour can only be achieved through natural or vaccine-induced immunity. Sufficient vaccine capacity promotes interest in the necessary and feasible target vaccination coverage.

Methods

An age and risk group stratified SEIR transmission model was used to assess the impact of vaccination coverage ranging 65%-95% for 12-59-year-olds and 90%-95% for ≥ 60-year-olds on COVID-19 incidence and intensive care unit (ICU) utilization between 01.07.2021-31.03.2022. Separate implementation of licensed vaccines allows to consider different efficacies, delivery rates and age-specific national vaccination recommendations. The analysis was conducted under different assumptions about contact behaviour during summer, reduction of daily contacts with increasing number of cases, daily vaccination uptake and the dominant variant. Data from the COVIMO study (N = 3004, data collection: 17.05.-09.06.2021) were used to define the population percentage willing to be vaccinated.

Results

The COVIMO study indicates an achievable vaccination compliance rate of 83.9% among 12-59-year-olds and 94.8% among those ≥ 60-year-olds. Maximum incidence or ICU utilization during observation period decreases from 385 to 61 and 6220 to 2800, respectively, with an increase in vaccination coverage from 65% to 95% of 12-59-year-olds, 90% vaccination rate among ≥ 60-year-olds, compared to pre-pandemic reduced contact behaviour in summer and reduction of contacts as case numbers increase.

Conclusions

The vaccination campaign should be continued at high intensity until at least 85% of 12-59-year-olds or 90% of ≥ 60-year-olds are fully vaccinated against COVID-19. Based on the population's willingness to be vaccinated, this goal seemed feasible.

Key messages

• Mathematical modeling was used to determine an evidence-based target vaccination coverage of ≥ 85%.

• Expertise in modeling should be further strengthened.

Ventricular tachycardia mechanisms and prevention in patients with severe heart failure and left ventricular assist device

 

Terminal Heart Failure with reduced Ejection Fraction (HFrEF) is associated with severe morbidity and mortality. Mechanical Left Ventricular Assist Devices (LVAD) are often used to provide these patients with a last resort therapy and as bridge to transplant. However, HFrEF patients with LVAD have significant myocardial substrate for ventricular arrhythmias and the LVAD itself might be regarded as pro-arrhythmogenic. Aim of the current study was to investigate the mechanism of ventricular arrhythmias in LVAD patients and to provide evidence for the hypothesis that ad-hoc ablation/substrate modification during surgical LVAD implantation might reduce the risk of VT.

We retrospectively analyzed invasive ablation procedures in patients with VT±LVAD and determined the mechanism of arrhythmia during electrophysiological examination (using 3D electroanatomical and local activation time mapping; Carto; Biosense Webster) in LVAD (n=17) and non-LVAD (n=12) subgroups. Mean age of the predominantly male (97%) patients was 60±2 years. VTs were directly LVAD associated (i.e. focal, adjacent to LVAD insertion or macro-reentry, around LVAD) in almost half of the LVAD patients. Number of radiofrequency ablation (RF) lesions and RF time were not significantly different between LVAD associated VT and non-LVAD associated VT patients. Within the LVAD patient group, freedom from VT (mean follow-up 40±6 months) was 50% upon ablation in patients with VTs originating from the LVAD region and 70% if ablation was conducted in non-LVAD regions. None of the LVAD associated and 22% of non-LVAD associated VT patients died during follow-up of these critically ill patients. Moreover, to reduce LVAD related arrhythmias and based on additional ex-vivo/in-silico derived data, we propose a distinctive (i.e. “star” shaped, LVAD encirclement) epicardial substrate modification during surgical LVAD implantation.

In summary, a significant percentage of patients with LVAD exhibit LVAD-associated focal/macro-reentry VT and recurrence rates are high. VT likelihood is reduced ex-vivo/in-silico upon substrate modification targeting myocardium adjacent to a possible LVAD implantation site. Epicardial RF ablation during surgical LVAD implantation might allow prevention of LVAD-associated focal/macro-reentry VT.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): DFG

0750 Nocturnal Sleep Stability and Cerebrospinal Fluid Orexin-A Levels: Sleep and Wake Bouts

Introduction

The orexin (ORX)/hypocretin system stabilizes sleep-wake regulation by sustaining long periods of wakefulness in humans and animals. We aimed to evaluate the relationships between cerebrospinal fluid (CSF) ORX levels and markers of nocturnal sleep stability assessed by polysomnography (PSG) in humans.

Methods

Nocturnal PSG data and CSF ORX levels of 300 drug-free subjects (55% men, 29.9±15.5 years old, mean ORX levels 155.1±153.7 pg/mL) with a complaint of hypersomnolence were collected in the National Reference Center for Narcolepsy, France. Several markers of nocturnal sleep stability were analyzed: wake (WB), sleep bouts (SB), and sleep/wake transitions. Groups were categorized according to ORX levels: two categories (≤110, >110 pg/mL, the current established threshold of ORX-deficiency), and tertiles (≤26,]26;254], >254 pg/mL); and were compared using logistic regression models. Results were adjusted for age, gender and body mass index.

Results

ORX-deficient subjects had more WB, SB, and sleep-wake transitions than the others. The WB duration was longer and the SB duration shorter in ORX-deficient category. The proportion of the shortest WB (30 sec) was lower in the ORX-deficient category whereas the proportion of WB above 1 min 30 sec was higher. The proportion of SB ≤ 14min was higher among ORX-deficient patients, with opposite results for longer SB. Subsequent analyses performed in the population categorized according to tertiles of CSF ORX-A confirmed all these findings, with a strong dose-response effect of ORX levels in post-hoc comparisons. All results remained highly significant in adjusted statistical models.

Conclusion

This study provides a strong evidence of the direct effect of ORX on nocturnal sleep stabilization in humans. WB and SB are reliable markers of nighttime sleep stability, strongly correlated to CSF ORX-A levels in a dose dependent way. These PSG biomarkers are promising to be applied in clinical and research settings.

Support

none

1420Peripheral edema and headache associated with amlodipine treatment: a meta-analysis of randomized, placebo-controlled trials

Background

Use of amlodipine for treatment of arterial hypertension (AH) and stabile angina pectoris (SAP) is sometimes limited by occurrence of peripheral edema and headache.

Purpose

As these side effects (SE) occur also on placebo in clinical trials, we aimed to explore the true magnitude of this phenomenon by determining the rate and placebo-adjusted rate of these SE.

Methods

We performed a meta-analysis by including all randomized, placebo-controlled trials reporting edema and headache with amlodipine in patients with AH and SAP. Placebo-adjusted rate (%) was determined as follows: (SE amlodipine % − SE placebo %)/SE amlodipine %. Electronic databases PubMed, Web of Science, and Cochrane library were systematically searched for eligible trials published until July 2018. Diseases such as heart failure, severe renal or hepatic disease were not considered. Furthermore, in most of the trials, a wash-out period took place before the study medication was given.

Results

Data from 7,226 patients of 22 trials were analyzed. In most of the analyzed trials, duration of follow up was comparable, and lasted about 8 weeks. All studies were graded as high quality according to Jadad score. Rate of edema was higher on amlodipine compared with placebo (16.6 vs 6.2%, RR: 2.9, 95% CI: 2.5–3.36, p<0.0001). The placebo-adjusted rate was 63%, indicating that 37% of edema cases were unrelated to amlodipine. Treatment with low/medium doses (2.5–5 mg) resulted in lower rates of edema (RR: 2.01, 95% CI: 1.41–2.88, p=0.0001) compared with high dose (10 mg) (RR: 3.08, 95% CI 2.62–3.6, p<0.0001, p for interaction=0.03). For each 5-mmHg reduction in BP one could expect lower rates of edema using a low/medium compared with high dose of amlodipine (3.2 vs. 12.2%). Headache was reduced using amlodipine compared with placebo (7.9 vs 10.9%, RR: 0.77, 95% CI: 0.65–0.90, p=0.002) and was driven by use of low/medium doses (RR: 0.52, 95% CI: 0.40–0.69, p<0.ehz748.00661 versus RR: 0.92, 95%-CI: 0.74–1.15, p=0.45, for high doses, p for interaction =0.002). According to a data from six studies administration of renin-angiotensin-inhibitors as add-on therapy to low/medium dose of amlodipine, resulted in higher BP reduction with equivalent rates of edema in comparison with amlodipine monotherapy (p for interaction = 0.23), which may be advantageous in obtaining guideline-recommended target BP values.

Conclusion

Patients on amlodipine exhibit a dose-dependent 3-fold increased risk of peripheral edema compared with placebo. Of note, up to one third of edema cases on amlodipine might not be induced by amlodipine. Headache is reduced on amlodipine treatment, mainly driven by use of this drug at low/medium doses potentially related to better blood pressure control. Amlodipine used at appropriate doses express the best risk-benefit ratio concerning edema and prevention of headache, thus maintaining treatment adherence, alone or in combination with other drugs.

Acknowledgement/Funding

None

Species-specific developmental toxicity in rats and rabbits: Generation of a reference compound list for development of alternative testing approaches

For regulatory information requirements, developmental toxicity testing is often conducted in two mammalian species. In order to provide a set of reference compounds that could be used to explore alternative approaches to supersede testing in a second species, a retrospective data analysis was conducted. The aim was to identify compounds for which species sensitivity differences between rats and rabbits are not caused by maternal toxicity or toxicokinetic differences. A total of 330 compounds were analysed and classified according to their species-specific differences. A lack of concordance between rat and rabbit was observed in 24% of the compounds, of which 10% were found to be selective developmental toxicants in one of the species. In contrast to previously published analyses the presented comparison is based entirely on publically data allowing validating and comparing alternative approaches for developmental toxicity testing. Furthermore, this list could be useful to identify mechanisms leading to species differences.

An ecotoxicological view on neurotoxicity assessment

The numbers of potential neurotoxicants in the environment are raising and pose a great risk for humans and the environment. Currently neurotoxicity assessment is mostly performed to predict and prevent harm to human populations. Despite all the efforts invested in the last years in developing novel in vitro or in silico test systems, in vivo tests with rodents are still the only accepted test for neurotoxicity risk assessment in Europe. Despite an increasing number of reports of species showing altered behaviour, neurotoxicity assessment for species in the environment is not required and therefore mostly not performed. Considering the increasing numbers of environmental contaminants with potential neurotoxic potential, eco-neurotoxicity should be also considered in risk assessment. In order to do so novel test systems are needed that can cope with species differences within ecosystems. In the field, online-biomonitoring systems using behavioural information could be used to detect neurotoxic effects and effect-directed analyses could be applied to identify the neurotoxicants causing the effect. Additionally, toxic pressure calculations in combination with mixture modelling could use environmental chemical monitoring data to predict adverse effects and prioritize pollutants for laboratory testing. Cheminformatics based on computational toxicological data from in vitro and in vivo studies could help to identify potential neurotoxicants. An array of in vitro assays covering different modes of action could be applied to screen compounds for neurotoxicity. The selection of in vitro assays could be guided by AOPs relevant for eco-neurotoxicity. In order to be able to perform risk assessment for eco-neurotoxicity, methods need to focus on the most sensitive species in an ecosystem. A test battery using species from different trophic levels might be the best approach. To implement eco-neurotoxicity assessment into European risk assessment, cheminformatics and in vitro screening tests could be used as first approach to identify eco-neurotoxic pollutants. In a second step, a small species test battery could be applied to assess the risks of ecosystems.

Fe-Catalyzed reductive NO-bond cleavage – a route to the diastereoselective 1,4-aminohydroxylation of 1,3-dienes

We describe the iron-catalyzed reductive cleavage of N–O-bonds in oxazines using malononitrile as reductant, which – in sequence with a [4 + 2]-cycloaddition – can be considered as an efficient way for the diastereoselective 1,4-aminohydroxylation of 1,3-dienes.

Optical properties of strain-compensated CdSe/ZnSe/(Zn,Mg)Se quantum well microdisks

Strain-compensated CdSe/ZnSe/(Zn,Mg)Se quantum well structures that were grown on (In,Ga)As allow for efficient room-temperature photoluminescence and spectral tuning over the whole visible range. We fabricated microdisk cavities from these samples by making use of a challenging chemical structuring technique for selective and homogeneous removal of the (In,Ga)As sacrificial layer below the quantum structure. The observed whispering gallery modes in our microdisks are mainly visible up to photon energies of ~ 2.3 eV due to strong self-absorption. As extinction coefficients and effective refractive indices are dominated by the quantum well material CdSe, thick quantum wells (> 3 monolayer) are necessary to observe resonances in the corresponding quantum well emission.

The role of chemical speciation, chemical fractionation and calcium disruption in manganese-induced developmental toxicity in zebrafish (Danio rerio) embryos

Manganese (Mn) is an essential nutrient that can be toxic in excess concentrations, especially during early development stages. The mechanisms of Mn toxicity is still unclear, and little information is available regarding the role of Mn speciation and fractionation in toxicology. We aimed to investigate the toxic effects of several chemical forms of Mn in embryos of Danio rerio exposed during different development stages, between 2 and 122h post fertilization. We found a stage-specific increase of lethality associated with hatching and removal of the chorion. Mn(II), ([Mn(H2O)6](2+)) appeared to be the most toxic species to embryos exposed for 48h, and Mn(II) citrate was most toxic to embryos exposed for 72 and/or 120h. Manganese toxicity was associated with calcium disruption, manganese speciation and metal fractionation, including bioaccumulation in tissue, granule fractions, organelles and denaturated proteins.

Filtration effects of zebra mussels on pathogens and total bacterial burden in the Odra Lagoon (South Baltic)

As a result of their mode of filter feeding, zebra mussels (Dreissena polymorpha Pall.) have been observed to purify natural water bodies and in vitro. Therefore, the possibility of using zebra mussels for water purification was investigated in a slightly brackish water body of a large lagoon. In this study, water samples were taken above, near and at distance from zebra mussel beds (MB) in the Odra Lagoon in North East Germany. Near typical bacterial species like Aeromonas spp. pathogenic bacteria with potential relation to hospital wastewater pollution (Burkholderia cepacia, Staphylococcus aureus, Weeksella spp.) were detected. There were no correlations found between either total bacteria or pathogens and distance to MB and no antimicrobial effect of the mussels could be deduced. For bioremediation in larger water bodies like lagoons, natural zebra MB do not seem to play a major antimicrobial role and the effect of artificial mussel grids especially against hospital pathogens should be investigated.

TERT promoter mutations in ocular melanoma distinguish between conjunctival and uveal tumours

BACKGROUND

Recently, activating mutations in the TERT promoter were identified in cutaneous melanoma. We tested a cohort of ocular melanoma samples for similar mutations.

METHODS

The TERT promoter region was analysed by Sanger sequencing in 47 uveal (ciliary body or choroidal) melanomas and 38 conjunctival melanomas.

RESULTS

Mutations of the TERT promoter were not identified in uveal melanomas, but were detected in 12 (32%) conjunctival melanomas. Mutations had a UV signature and were identical to those found in cutaneous melanoma.

CONCLUSION

Mutations of TERT promoter with UV signatures are frequent in conjunctival melanomas and favour a pathogenetic kinship with cutaneous melanomas. Absence of these mutations in uveal melanomas emphasises their genetic distinction from cutaneous and conjunctival melanomas.

Alternatives to in vivo tests to detect endocrine disrupting chemicals (EDCs) in fish and amphibians--screening for estrogen, androgen and thyroid hormone disruption

Endocrine disruption is considered a highly relevant hazard for environmental risk assessment of chemicals, plant protection products, biocides and pharmaceuticals. Therefore, screening tests with a focus on interference with estrogen, androgen, and thyroid hormone pathways in fish and amphibians have been developed. However, they use a large number of animals and short-term alternatives to animal tests would be advantageous. Therefore, the status of alternative assays for endocrine disruption in fish and frogs was assessed by a detailed literature analysis. The aim was to (i) determine the strengths and limitations of alternative assays and (ii) present conclusions regarding chemical specificity, sensitivity, and correlation with in vivo data. Data from 1995 to present were collected related to the detection/testing of estrogen-, androgen-, and thyroid-active chemicals in the following test systems: cell lines, primary cells, fish/frog embryos, yeast and cell-free systems. The review shows that the majority of alternative assays measure effects directly mediated by receptor binding or resulting from interference with hormone synthesis. Other mechanisms were rarely analysed. A database was established and used for a quantitative and comparative analysis. For example, a high correlation was observed between cell-free ligand binding and cell-based reporter cell assays, between fish and frog estrogenic data and between fish embryo tests and in vivo reproductive effects. It was concluded that there is a need for a more systematic study of the predictive capacity of alternative tests and ways to reduce inter- and intra-assay variability.

Variation of the intercalating proline in artificial peptides mimicking the DNA binding and bending IHF protein

The integration host factor (IHF) is a protein which sequence specifically induces a bend of double-stranded DNA by more than 160°. Based on IHF as lead structure, a peptide mimic was introduced resembling the positively charged body of the protein by a lysine dendrimer and the minor groove recognition loop by a cyclopeptide. The proline located close to the tip of the recognition loop intercalates between the base pair plane. It was modified in order to evaluate the influence of the side chain residue with respect to size (1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid), aromaticity (phenylalanine), conformation of the five-membered ring [(4R)-fluoroproline, (4S)-fluoroproline, 3,4-dehydroproline], and the peptide backbone conformation (α-methylproline) on binding dsDNA and bending the double strand. Binding and bending studies were carried out by fluorescence resonance energy transfer experiments and gel electrophoresis using DNA sequences prepared by PCR with the IHF binding site in central or terminal position. Whereas aromatic residues and α-methylproline were not tolerated as proline substitute, incorporation of (4S)-fluoroproline and 3,4-dehydroproline provided enhanced binding.

[Usage of drugs with potential adverse effects on cognition in a memory-clinic]

Cognitive decline is a frequent clinical symptom in elderly patients. In particular, memory disturbances are an early sign and a risk factor for subsequent development of neurodegenerative dementia. At the same time, elderly patients often receive multiple medications due to an increasing number of acquired diseases. Certain drugs have adverse side effects on cognition due to interference with the cholinergic or GABA-ergic system. This could lead to underestimation of the actual cognitive status at initial clinical presentation. In the present study we included 221 patients (mean age 68,5 years) who presented for the first time in a specialized memory-clinic and who had or developed dementia during follow up. Most patients had mixed vascular-degenerative dementia (57 %). On average, patients took 2.1 drugs. 19.9 % of the patients had medications with potential adverse effects on cognition. Patients with medication affecting cognition had a worse cognitive performance than patients with a medication not influencing cognitive functioning (Mini-Mental vs. 18.8. 22.01, p = 0.01) in univariate analysis. Psychotropic drugs were used less frequently (38 %) than primary non-CNS medication. The results remained unchanged even after performing a case-control study with the mixed dementia population with age and gender matched patients. However, in multivariate analysis, only the absolute number of medication taken remained as an independent factor. Our data highlight the clinical importance of medication history in the diagnostic work-up of cognitive impairment. The absolute number of medication taken seems to be more important than medication with possible adverse side effects on cognition.

Cationic Starches as Substitute for Synthetic Cationic Flocculants in Solid−Liquid Separation of Harbor Sludge

Harbor sludge (about 25% total solid) has to be dredged to keep the waterways free. Thus, annually 1.2 million m3 of dredged material has to be cleaned. For this process, three different synthetic flocculants with optimal molar masses, ionogenities, and concentrations are added in order to get a good dewatering efficiency and shear strength of the flocs. But as synthetic flocculants bring about unwanted fish toxicity and insufficient biodegradability, this study intends to check whether these flocculants can successively be substituted by cationic starches which have already been proven to be less toxic than synthetic flocculants. Five different starch derivatives with an average degree of substitution higher than 0.5 were characterized, especially in terms of the molar mass and coil size distribution, and flocculation tests, zeta potential measurements and filtrate turbidity tests were carried out in order to create optimum flocculation conditions. The flocculation and dewatering measurements clearly show that the synthetic cationic flocculant PA (0.2 kg/tTS) can be best substituted by cationic starch KS 2 (c = 0.1 kg/tTS, Mw = 1.1 e+08). For substitution of PTAC (c = 0.3 kg/tTS) by cationic starches, we observed that a maximal dewatering efficiency is reached with an approximately 3-fold dose of KS 1 (1 kg/tTS, Mw = 8.1 e+07).

Routine HLA sequence-specific-oligonucleotide typing and confirming sequence-based typing of a prospective bone marrow donor identified a novel B*27 allele, HLA-B*2734

In this study, we report the identification of a new human leukocyte antigen-B allele in a sample that was tested in our routine typing for volunteer bone marrow donors. This novel allele officially named B*2734 was found in a female donor of Caucasoid origin (laboratory code 158567). The search for unrelated bone marrow donors was initiated by the Aktion Knochenmarkspende Bayern. In comparison with the closest related allele B*2707, B*2734 differs at two nucleotide positions, all located in exon 3, at position 412, 'A' in B*2707 is replaced by 'G' and at position 486, 'G' is replaced by 'A' in the novel allele. The single nucleotide polymorphism at position 412 results in an amino acid substitution at codon 138. The amino acid asparagine is changed to aspartic acid in B*2734 allele. The second nucleotide exchange is a silent mutation and codon 163 remains unaffected as ACG-->ACA, still codes for alanine.

LRRK2 mutations in a clinic-based cohort of Parkinson's disease

In the last decade, major breakthroughs in the understanding of genetic contributions to Parkinson's disease (PD) have been achieved. Recently, mutations in LRRK2, encoding dardarin, have been found to be responsible for an autosomal dominant parkinsonism (OMIM 607060). We screened 311 subjects (cases: n = 202, controls: n = 109) for the three previously reported LRRK2 mutations. Our investigation revealed a sporadic case of PD with a heterozygous mutation G2019S (c.6055G>A). Here, we present the clinical phenotype of this patient and discuss the implications of genetic testing for the G2019S mutation in patients with sporadic PD.

The nasal airflow in noses with septal perforation: a model study

BACKGROUND

Septal perforation is a common clinical problem in rhinology. Affected patients suffer from a dry nose, crusts as well as recurrent epistaxis and sometimes an inspiratory whistle. The aim of this study was to investigate the underlying flow dynamic mechanisms.

METHODS

The physical flow effects of such pathologies were examined in functional nose models (box models) and anatomically exact models of the nose. Therefore, septal perforations of different sizes and localisations were studied in straight and deviated nasal septa.

RESULTS AND CONCLUSIONS

It could be seen that the localisation of the perforation has no impact on the flow pattern. In large septal perforations, the air jet collides with the posterior edge of the perforation and disintegrates turbulently. Since airflow is physiologically turbulent in the posterior part of the nose, posterior perforations do not cause clinical complaints. The inspiratory whistling sound during respiration is based on the principle of a lip whistle. Large perforations do not cause a whistling sound. The necessary high flow velocity needed in large perforations is usually not achievable.

Physical interaction of apoptosis-inducing factor with DNA and RNA

Apoptosis-inducing factor (AIF) is a mitochondrial flavoprotein, which upon apoptosis induction translocates to the nucleus where it interacts with DNA by virtue of positive charges clustered on the AIF surface. Here we show that the AIF interactome, as determined by mass spectroscopy, contains a large panel of ribonucleoproteins, which apparently bind to AIF through the RNA moiety. However, AIF is devoid of any detectable RNAse activity both in vitro and in vivo. Recombinant AIF can directly bind to DNA as well as to RNA. This binding can be visualized by electron microscopy, revealing that AIF can condense DNA, showing a preferential binding to single-stranded over double-stranded DNA. AIF also binds and aggregates single-stranded and structured RNA in vitro. Single-stranded poly A, poly G and poly C, as well double-stranded A/T and G/C RNA competed with DNA for AIF binding with a similar efficiency, thus corroborating a computer-calculated molecular model in which the binding site within AIF is the same for distinct nucleic acid species, without a clear sequence specificity. Among the preferred electron donors and acceptors of AIF, nicotine adenine dinucleotide phosphate (NADP) was particularly efficient in enhancing the generation of higher-order AIF/DNA and AIF/RNA complexes. Altogether, these data support a model in which a direct interaction of AIF contributes to the compaction of nucleic acids within apoptotic cells.

Penetration of piperacillin and tazobactam into inflamed soft tissue of patients with diabetic foot infection

We investigated the pharmacokinetics of piperacillin and tazobactam in the extracellular space fluid of inflamed soft tissues of six patients with diabetic foot infection using in vivo microdialysis and found similar penetration for piperacillin but not for tazobactam into inflamed and noninflamed soft tissue.

[When the tongue impairs breathing]

Ätiologisch ist im vorliegenden Fall ein Angioödem mit Mastzelldegranulation unwahrscheinlich. Einerseits wegen fehlendem Exanthem und Pruritus und andererseits fehlte ein suffizientes Ansprechen auf hochdosierte Steroidgabe oder Adrenalin. Der wiederholt normale Wert von C1-INH im Serum sowohl quantitativ und auch qualitativ spricht gegen das Vorliegen eines C1-Esteraseinhibitor-Mangel. Aufgrund der Anamnese und des klinischen Verlaufs bleibt als wahrscheinlichste Ursache für das Angioödem die bereits lange Jahre etablierte und in der Dosierung unveränderte ACE-Hemmer-Therapie, obwohl eine derartige Manifestation nach langjährigem ACE Hemmer Einsatz sehr selten ist.

Minimal T-cell-stimulatory sequences and spectrum of HLA restriction of immunodominant CD4+ T-cell epitopes within hepatitis C virus NS3 and NS4 proteins

The hepatitis C virus (HCV)-specific CD4+ T-cell response against nonstructural proteins is strongly associated with successful viral clearance during acute hepatitis C. To further develop these observations into peptide-based vaccines and clinical immunomonitoring tools like HLA class II tetramers, a detailed characterization of immunodominant CD4+ T-cell epitopes is required. We studied peripheral blood mononuclear cells from 20 patients with acute hepatitis C using 83 overlapping 20-mer peptides covering the NS3 helicase and NS4. Eight peptides were recognized by > or = 40% of patients, and specific CD4+ T-cell clones were obtained for seven of these and three additional, subdominant epitopes. Mapping of minimal stimulatory sequences defined epitopes of 8 to 13 amino acids in length, but optimal T-cell stimulation was observed with 10- to 15-mers. While some epitopes were presented by different HLA molecules, others were presented by only a single HLA class II molecule, which has implications for patient selection in clinical trials of peptide-based immunotherapies. In conclusion, using two different approaches we identified and characterized a set of CD4+ T-cell epitopes in the HCV NS3-NS4 region which are immunodominant in patients achieving transient or persistent viral control. This information allows the construction of a valuable panel of HCV-specific HLA class II tetramers for further study of CD4+ T-cell responses in chronic hepatitis C. The finding of immunodominant epitopes with very constrained HLA restriction has implications for patient selection in clinical trials of peptide-based immunotherapies.