Effective high-throughput RT-qPCR screening for SARS-CoV-2 infections in children

Systematic SARS-CoV-2 testing is a valuable tool for infection control and surveillance. However, broad application of high sensitive RT-qPCR testing in children is often hampered due to unpleasant sample collection, limited RT-qPCR capacities and high costs. Here, we developed a high-throughput approach (‘Lolli-Method’) for SARS-CoV-2 detection in children, combining non-invasive sample collection with an RT-qPCR-pool testing strategy. SARS-CoV-2 infections were diagnosed with sensitivities of 100% and 93.9% when viral loads were >10⁶ copies/ml and >10³ copies/ml in corresponding Naso-/Oropharyngeal-swabs, respectively. For effective application of the Lolli-Method in schools and daycare facilities, SEIR-modeling indicated a preferred frequency of two tests per week. The developed test strategy was implemented in 3,700 schools and 698 daycare facilities in Germany, screening over 800,000 individuals twice per week. In a period of 3 months, 6,364 pool-RT-qPCRs tested positive (0.64%), ranging from 0.05% to 2.61% per week. Notably, infections correlated with local SARS-CoV-2 incidences and with a school social deprivation index. Moreover, in comparison with the alpha variant, statistical modeling revealed a 36.8% increase for multiple (≥2 children) infections per class following infections with the delta variant. We conclude that the Lolli-Method is a powerful tool for SARS-CoV-2 surveillance and can support infection control in schools and daycare facilities.

Dewald et al. combine a non-invasive sampling approach (Lolli-Test) with an RT qPCR-pool testing strategy to screen for SARS-CoV-2 infections in children and use the method for surveillance and infection control in > 4000 school and daycare settings.

Discovery of ultrapotent broadly neutralizing antibodies from SARS-CoV-2 elite neutralizers

A fraction of COVID-19 convalescent individuals mount a potent antibody response to SARS-CoV-2 with cross-reactivity to SARS-CoV-1. To uncover their humoral response in detail, we performed single B cell analysis from 10 SARS-CoV-2 elite neutralizers. We isolated and analyzed 126 monoclonal antibodies, many of which were sarbecovirus cross-reactive, with some displaying merbecovirus- and embecovirus-reactivity. Several isolated broadly neutralizing antibodies were effective against B.1.1.7, B.1.351, B.1.429, B.1.617, and B.1.617.2 variants and 19 prominent potential escape sites. Furthermore, assembly of 716,806 SARS-CoV-2 sequences predicted emerging escape variants, which were also effectively neutralized. One of these broadly neutralizing potent antibodies, R40-1G8, is a IGHV3-53 RBD-class-1 antibody. Remarkably, cryo-EM analysis revealed that R40-1G8 has a flexible binding mode, targeting both "up" and "down" conformations of the RBD. Given the threat of emerging SARS-CoV-2 variants, we demonstrate that elite neutralizers are a valuable source for isolating ultrapotent antibody candidates to prevent and treat SARS-CoV-2 infection.

Safe and effective pool testing for SARS-CoV-2 detection

Objectives

The global spread of SARS-CoV-2 is a serious public health issue. Large-scale surveillance screenings are crucial but can exceed test capacities. We (A) optimized test conditions and (B) implemented pool testing of respiratory swabs into SARS-CoV-2 diagnostics.

Study design

(A) We determined the optimal pooling strategy and pool size. In addition, we measured the impact of vortexing prior to sample processing, compared a pipette-pooling method (by combining transport medium of several specimens) and a swab-pooling method (by combining several swabs into a test tube filled with PBS) as well as determined the sensitivities of three PCR assays. (B) Finally, we applied high-throughput pool testing for diagnostics.

Results

(A) In a low prevalence setting, we defined a preferable pool size of ten in a two-stage hierarchical pool testing strategy. Vortexing of swabs (n = 33) increased cellular yield by a factor of 2.34. By comparing Ct-values of 16 pools generated with two different pooling strategies, pipette-pooling was more efficient compared to swab-pooling. Measuring dilution series of 20 SARS-CoV-2 positive samples in three PCR assays simultaneously revealed detection rates of 85% (assay I), 50% (assay II), and 95% (assay III) at a 1:100 dilution. (B) We systematically pooled 55,690 samples in a period of 44 weeks resulting in a reduction of 47,369 PCR reactions.

Conclusions

For implementing pooling strategies into high-throughput diagnostics, we recommend utilizing a pipette-pooling method, performing sensitivity validation of the PCR assays used, and vortexing swabs prior to analyses. Pool testing for SARS-CoV-2 detection is feasible and effective in a low prevalence setting.

The enteric nervous system is a potential autoimmune target in multiple sclerosis

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system (CNS) in young adults that has serious negative socioeconomic effects. In addition to symptoms caused by CNS pathology, the majority of MS patients frequently exhibit gastrointestinal dysfunction, which was previously either explained by the presence of spinal cord lesions or not directly linked to the autoimmune etiology of the disease. Here, we studied the enteric nervous system (ENS) in a B cell- and antibody-dependent mouse model of MS by immunohistochemistry and electron microscopy at different stages of the disease. ENS degeneration was evident prior to the development of CNS lesions and the onset of neurological deficits in mice. The pathology was antibody mediated and caused a significant decrease in gastrointestinal motility, which was associated with ENS gliosis and neuronal loss. We identified autoantibodies against four potential target antigens derived from enteric glia and/or neurons by immunoprecipitation and mass spectrometry. Antibodies against three of the target antigens were also present in the plasma of MS patients as confirmed by ELISA. The analysis of human colon resectates provided evidence of gliosis and ENS degeneration in MS patients compared to non-MS controls. For the first time, this study establishes a pathomechanistic link between the well-established autoimmune attack on the CNS and ENS pathology in MS, which might provide a paradigm shift in our current understanding of the immunopathogenesis of the disease with broad diagnostic and therapeutic implications.

Differential effects of FTY720 on the B cell compartment in a mouse model of multiple sclerosis

Background

MP4-induced experimental autoimmune encephalomyelitis (EAE) is a mouse model of multiple sclerosis (MS), which enables targeted research on B cells, currently much discussed protagonists in MS pathogenesis. Here, we used this model to study the impact of the S1P₁ receptor modulator FTY720 (fingolimod) on the autoreactive B cell and antibody response both in the periphery and the central nervous system (CNS).

Methods

MP4-immunized mice were treated orally with FTY720 for 30 days at the peak of disease or 50 days after EAE onset. The subsequent disease course was monitored and the MP4-specific B cell/antibody response was measured by ELISPOT and ELISA. RNA sequencing was performed to determine any effects on B cell-relevant gene expression. S1P₁ receptor expression by peripheral T and B cells, B cell subset distribution in the spleen and B cell infiltration into the CNS were studied by flow cytometry. The formation of B cell aggregates and of tertiary lymphoid organs (TLOs) was evaluated by histology and immunohistochemistry. Potential direct effects of FTY720 on B cell aggregation were studied in vitro.

Results

FTY720 significantly attenuated clinical EAE when treatment was initiated at the peak of EAE. While there was a significant reduction in the number of T cells in the blood after FTY720 treatment, B cells were only slightly diminished. Yet, there was evidence for the modulation of B cell receptor-mediated signaling upon FTY720 treatment. In addition, we detected a significant increase in the percentage of B220⁺ B cells in the spleen both in acute and chronic EAE. Whereas acute treatment completely abrogated B cell aggregate formation in the CNS, the numbers of infiltrating B cells and plasma cells were comparable between vehicle- and FTY720-treated mice. In addition, there was no effect on already developed aggregates in chronic EAE. In vitro B cell aggregation assays suggested the absence of a direct effect of FTY720 on B cell aggregation. However, FTY720 impacted the evolution of B cell aggregates into TLOs.

Conclusions

The data suggest differential effects of FTY720 on the B cell compartment in MP4-induced EAE.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-017-0924-4) contains supplementary material, which is available to authorized users.

Nimodipine fosters remyelination in a mouse model of multiple sclerosis and induces microglia-specific apoptosis

Despite continuous interest in multiple sclerosis (MS) research, there is still a lack of neuroprotective strategies, because the main focus has remained on modulating the immune response. Here we performed in-depth analysis of neurodegeneration in experimental autoimmune encephalomyelitis (EAE) and in in vitro studies regarding the effect of the well-established L-type calcium channel antagonist nimodipine. Nimodipine treatment attenuated clinical EAE and spinal cord degeneration and promoted remyelination. Surprisingly, we observed calcium channel-independent effects on microglia, resulting in apoptosis. These effects were cell-type specific and irrespective of microglia polarization. Apoptosis was accompanied by decreased levels of nitric oxide (NO) and inducible NO synthase (iNOS) in cell culture as well as decreased iNOS and reactive oxygen species levels in EAE. In addition, increased numbers of Olig2+APC+ oligodendrocytes were detected. Overall, nimodipine application seems to generate a favorable environment for regenerative processes and therefore could be a treatment option for MS, because it combines features of immunomodulation with beneficial effects on neuroregeneration.

CEACAM1 mediates B cell aggregation in central nervous system autoimmunity

B cell aggregates in the central nervous system (CNS) have been associated with rapid disease progression in patients with multiple sclerosis (MS). Here we demonstrate a key role of carcinoembryogenic antigen-related cell adhesion molecule1 (CEACAM1) in B cell aggregate formation in MS patients and a B cell-dependent mouse model of MS. CEACAM1 expression was increased on peripheral blood B cells and CEACAM1⁺ B cells were present in brain infiltrates of MS patients. Administration of the anti-CEACAM1 antibody T84.1 was efficient in blocking aggregation of B cells derived from MS patients. Along these lines, application of the monoclonal anti-CEACAM1 antibody mCC1 was able to inhibit CNS B cell aggregate formation and significantly attenuated established MS-like disease in mice in the absence of any adverse effects. CEACAM1 was co-expressed with the regulator molecule T cell immunoglobulin and mucin domain −3 (TIM-3) on B cells, a novel molecule that has recently been described to induce anergy in T cells. Interestingly, elevated coexpression on B cells coincided with an autoreactive T helper cell phenotype in MS patients. Overall, these data identify CEACAM1 as a clinically highly interesting target in MS pathogenesis and open new therapeutic avenues for the treatment of the disease.

The Correlation between the Virus- and Brain Antigen-Specific B Cell Response in the Blood of Patients with Multiple Sclerosis

There is a largely divergent body of literature regarding the relationship between Epstein-Barr virus (EBV) infection and brain inflammation in multiple sclerosis (MS). Here, we tested MS patients during relapse (n = 11) and in remission (n = 19) in addition to n = 22 healthy controls to study the correlation between the EBV- and brain-specific B cell response in the blood by enzyme-linked immunospot (ELISPOT) and enzyme-linked immunosorbent assay (ELISA). Cytomegalovirus (CMV) was used as a control antigen tested in n = 16 MS patients during relapse and in n = 35 patients in remission. Over the course of the study, n = 16 patients were untreated, while n = 33 patients received immunomodulatory therapy. The data show that there was a moderate correlation between the frequencies of EBV- and brain-reactive B cells in MS patients in remission. In addition we could detect a correlation between the B cell response to EBV and disease activity. There was no evidence of an EBV reactivation. Interestingly, there was also a correlation between the frequencies of CMV- and brain-specific B cells in MS patients experiencing an acute relapse and an elevated B cell response to CMV was associated with higher disease activity. The trend remained when excluding seronegative subjects but was non-significant. These data underline that viral infections might impact the immunopathology of MS, but the exact link between the two entities remains subject of controversy.

Central nervous system infiltrates are characterized by features of ongoing B cell-related immune activity in MP4-induced experimental autoimmune encephalomyelitis

In multiple sclerosis (MS) lymphoid follicle-like aggregates have been reported in the meninges of patients. Here we investigated the functional relevance of B cell infiltration into the central nervous system (CNS) in MP4-induced experimental autoimmune encephalomyelitis (EAE), a B cell-dependent mouse model of MS. In chronic EAE, B cell aggregates were characterized by the presence of CXCL13(+) and germinal center CD10(+) B cells. Germline transcripts were expressed in the CNS and particularly related to TH17-associated isotypes. We also observed B cells with restricted VH gene usage that differed from clones found in the spleen. Finally, we detected CNS-restricted spreading of the antigen-specific B cell response towards a myelin and a neuronal autoantigen. These data imply the development of autonomous B cell-mediated autoimmunity in the CNS in EAE - a concept that might also apply to MS itself.

Identification of a B cell-dependent subpopulation of multiple sclerosis by measurements of brain-reactive B cells in the blood

B cells are increasingly coming into play in the pathogenesis of multiple sclerosis (MS). Here, we screened peripheral blood mononuclear cells (PBMC) from patients with clinically isolated syndrome (CIS), MS, other non-inflammatory neurological, inflammatory neurological or autoimmune diseases, and healthy donors for their B cell reactivity to CNS antigen using the enzyme-linked immunospot technique (ELISPOT) after 96 h of polyclonal stimulation. Our data show that nine of 15 patients with CIS (60.0%) and 53 of 67 patients with definite MS (79.1%) displayed CNS-reactive B cells, compared to none of the control donors. The presence of CNS-reactive B cells in the blood of the majority of patients with MS or at risk to develop MS along with their absence in control subjects suggests that they might be indicative of a B cell-dependent subpopulation of the disease.

The complement system contributes to the pathology of experimental autoimmune encephalomyelitis by triggering demyelination and modifying the antigen-specific T and B cell response

So far, studies of the human autoimmune disease multiple sclerosis (MS) have largely been hampered by the absence of a pathogenic B cell component in its animal model, experimental autoimmune encephalomyelitis (EAE). To overcome this shortcoming, we have previously introduced the myelin basic protein (MBP)-proteolipid protein (PLP) MP4-induced EAE, which is B cell and autoantibody-dependent. Here we show that MP4-immunized wild-type C57BL/6 mice displayed a significantly lower disease incidence when their complement system was transiently depleted by a single injection of cobra venom factor (CVF) prior to immunization. Considering the underlying pathomechanism, our data suggest that the complement system is crucial for MP4-specific antibodies to trigger CNS pathology. Demyelinated lesions in the CNS were colocalized with complement depositions. In addition, B cell deficient JHT mice reconstituted with MP4-reactive serum showed significantly attenuated clinical and histological EAE after depletion of complement by CVF. The complement system was also critically involved in the generation of the MP4-specific T and B cell response: in MP4-immunized wild-type mice treated with CVF the MP4-specific cytokine and antibody response was significantly attenuated compared to untreated wild-type mice. Taken together, we propose two independent mechanisms by which the complement system can contribute to the pathology of autoimmune encephalomyelitis. Our data corroborate the role of complement in triggering antibody-dependent demyelination and antigen-specific T cell immunity and also provide first evidence that the complement system can modify the antigen-specific B cell response in EAE and possibly MS.

Radiofrequenzablation von Lebertumoren mittels 4 cm Schirmelektrode

BACKGROUND

The purpose of this study was to evaluate safety and efficacy of a radiofrequency ablation system in clinical practice.

METHODS

In 35 patients (age 63,9 +/- 12,6 years, range 22 - 83) a total of 65 liver tumors were percutaneously treated using a 200 watt radiofrequency generator and a LeVeen 4 cm array probe (RF3000, Boston Scientific). The interventions were performed under CT guidance in local anaesthesia and sedation. Adapted to the tumor size, the LeVeen Probe was repositioned during the procedure with an additional safety margin of 1 cm. Primary tumors were colorectal in 22, and mamma tumors (n = 4), zystic pancreas tumors (n = 2), gastric cancer (n = 1), zystadenocarcinoma of the liver (n = 1), lung cancer (n = 1), gastrointestinal stroma tumor (n = 1), duodenal carcinoma (n = 1), cholangiocellular carcinoma (n = 1) and hepatocellular carcinoma (n = 1). Post interventional control and follow-up was performed with multislice-CT (collimation 2.5 mm, unenhanced and contrast enhanced, arterial and portal filling) at 4 weeks, and every three months.

RESULTS

One to 4 metastases were treated per patient during one or up to 4 procedure sessions. Mean lesion size was 2,3 +/- 1,2 cm (range 0,2 to 7,0). The corresponding size of the necrosis achieved was 4,6 +/- 1,4 cm (range 2,0 - 8,2). Primary technical success with complete tumor ablation was reached in 60 of 65 lesions. In 4 cases two treatment sessions were necessary in order to achieve the intended results. In one case the procedure was aborted because of a close relationship between lesion and right colon. 63 tumors were treated in sedation and local anesthesia. General anesthesia was necessary in two cases, in one who refused intervention in sedation, and in another case with insufficient analgetic effect. Morbidity was 9.2 %: Bleeding complications (n = 3, one arterial bleeding from the ablation tract, two intrahepatic bleedings with extrahepatic hematoma) were confirmed by selective angiography of the hepatic artery and were treated with coil embolisation of the respective segmental arteries. One case with subcapsular tumor ablation suffered from a large subcapsular hematoma requiring a blood transfusion. In one case with a subphrenic location of the metastasis, the needle electrode had passed the costophrenic recessus and resulted in an hematothorax. This patient was treated by pleural drainage for two days. One patient suffered from fever up to 39 degrees C and inflammation of the biliary tract and received a cholecystectomy 22 days post interventionally. There was no peri interventional mortality. Mean follow-up is 5,6 +/- 3,3 months (range 0 to 13). 21 of 35 patients showed no evidence of tumor recurrence. One case is scheduled for a second treatment session for complete tumor ablation. 13 of 35 patients suffered from tumor recurrence, either local recurrences and/or new metastases. At the sites of prior RF-ablation 9 local recurrences were detected in 7 patients, two cases with isolated local recurrences and 5 cases with local recurrences and new metastases. 6 Patients showed no evidence for local recurrences but new metastases. In these 11 cases a total of 37 metastases were found at new locations. In three patients tumor recurrence was treated by means of a second RF-ablation. The remaining 10 patients received chemotherapy.

CONCLUSION

RF-ablation can be performed in local anaesthesia and sedation with low peri interventional morbidity and mortality. Using the LeVeen probe and a 200 watt generator, appropriate necroses can be achieved. CT follow-up is required every three months because of the tumor recurrence rate and reinterventions may be required.

Endoscopic exploration of Red Sea coral reefs reveals dense populations of cavity-dwelling sponges

Framework cavities are the largest but least explored coral reef habitat. Previous dive studies of caverns, spaces below plate corals, rubble and artificial cavities suggest that cavity-dwelling (coelobite) filter-feeders are important in the trophodynamics of reefs. Quantitative community data are lacking, however, as the bulk of the narrow crevices interlacing the reef framework are inaccessible to conventional analysis methods. Here we have developed endoscopic techniques to explore Red Sea framework crevices up to 4 m into the carbonate rock, revealing a large internal surface (2.5-7.4 m2 per projected m2 reef) dominated by encrusting filter-feeders. Sponges alone provided up to 60% of coelobite cover, outweighing epi-reefal filter-feeder biomass by two orders of magnitude. Coelobite community filtration removed more than 60% of the phytoplankton in the course of its less than 5-minute passage through the crevices, corresponding to an uptake of roughly 0.9 g carbon m-2 d-1. Mineralization of the largely allochthonous organic material is a principal source of nutrients supporting coral and algal growth. The supply of new material by coelobites may provide a key to understanding the 'coral reef paradox'-a rich ecosystem thriving in nutrient-poor water.

Biomechanical studies of transthoracic vertebral body replacement with autologous bone grafts (fibula and rib)

Thoracic processes which destroy vertebral bodies leave gaps which usually have to be bridged. The aim of our experiments was to find out whether rib and fibula grafts are suitable vertebral body substitutes from the biomechanical point of view. Therefore, we examined characteristics of vertebral body/bone graft/vertebral body arrangements under the influence of pulsating compression forces in a testing machine. The deformation of the rib graft alone was 0.78 mm under a preselected peak load of 1010 Newton. When the rib graft was placed between two vertebral bodies, the deformation (creeping) was 6 mm under a peak load of 1010 Newton. The deformation of the fibula graft alone was 0.41 mm, and when placed between vertebral bodies maximally 3 mm. The results of our experiments lead to the conclusion that ribs modified according to our design are prinzipally suitable for vertebral body replacement in the thoracic region as far as primary stress resistance is concerned. Characteristics of these bone grafts in the human body are being followed-up.

Prevalence of cardiovascular disease risk factors in a southwestern Native American tribe

A cross-sectional study was conducted among the Pascua Yaqui Indian tribe in Tucson, AZ, in 1990 to document the prevalence of cardiovascular disease risk factors. Cardiovascular disease is the leading cause of mortality for Native Americans and for members of the Pascua Yaqui tribe specifically. A total of 230 randomly selected adults, ages 25-65 years, who were listed as members on the tribal roll, participated, resulting in a 73-percent participation rate for those contacted. The five risk factors studied included diabetes, hypertension, hypercholesterolemia, obesity, and smoking. Only 14 percent of participants had none of the risk factors; 52 percent had two or more factors. Obesity was the most prevalent, being present in 69 percent of the women and 40 percent of the men, followed by diabetes, 35 percent of men and 39 percent of women. Twenty-six percent of the population had hypertension, and 43 percent of men were smokers, compared with 24 percent of women. Hypercholesterolemia was present in 19 percent of men and 14 percent of women. The rates of diabetes, obesity, hypertension, and smoking documented in this tribe are relatively high and can serve as a baseline for evaluating future prevention efforts.

Junior and senior faculty women: commonalities and differences in perceptions of academic life

The purpose of this study was to explore the commonalities and differences in the perceptions of senior and junior faculty women regarding the barriers to success experienced early in academic careers. The population consisted of 22 pairs of junior and senior faculty women who participated in a mentoring program at a major public research university. Descriptive data indicate close agreement among junior and senior women faculty regarding the importance of the majority of potential barriers. Nonetheless, important differences exist. An exploratory factor analysis identified four underlying dimensions: personal security, work priorities, sense of belonging, and scholarly accomplishment. There was a significant difference between the two groups in their perceptions of personal security.

[Intrauterine cerebral hemorrhage as a cause of hydrocephalus]

Intracranial haemorrhages in before-term children and risk newborn are a well-known problem, hydrocephalus being one of the possible posthaemorrhagic complications. In most cases intrapartal and postpartal complications will be responsible for the occurrence of haemorrhages. However, in this regard it is difficult to assess the ranking of individual factors such as acidosis, birth trauma, postpartal care and infusion therapy or postpartal complications. The following case report concerns a rare case of prepartal intraventricular bleeding resulting in hydrocephalus in an otherwise uneventful pregnancy course. Whereas in the 32nd pregnancy week both the cerebral ventricular system and the dimensions of the head had been normal, development of hydrocephalus was discovered at random in the 36th week during a screening procedure.

[Bilateral pneumothorax following laparoscopy]

A case of laparoscopy is presented with postoperative large subcutaneous emphysema and bilateral pneumothorax. As a result of careful control, conservative treatment, and consequent oxygen administration, this life-threatening phenomena disappeared within a short time. Preventive measures for complications of diagnostic laparoscopy are discussed and established to lower the anaesthetic risk of this widely practised procedure.

[Sonographic diagnosis of a large placental tumour in late pregnancy - case and consequences for delivery]

The article deals with the sonographic diagnosis of a large chorioangioma in the 34th week of pregnancy. In consequence of the fast growth of the tumour and development of an oligohydramnios a Caesarian section was carried out in the 36th week. The infant suffered with anaemia. We summarize the current literature and discuss the differential diagnosis as well as the consequences for delivery in conclusion of the diagnosis "placental tumour".

Inhibitory effect of antiproteoglycan serum on the biosynthesis of proteochondroitin sulfate in calf rib cartilage in vitro

Incubation of calf rib cartilage slices with antiproteoglycan serum elevates CO2-production, but inhibits biosynthesis of proteochondroitinsulfate and of total protein. Absorbing antiserum with proteoglycan abolishes these effects.