Antibody responses elicited by mRNA vaccination in firefighters persist six months and correlate inversely with age and directly with BMI

Knowledge regarding the sustainability of immune responses after COVID-19 vaccination is important, e.g., to decide whom and when to booster. Thus, we analyzed antibody titers in firefighters six months after vaccination with the mRNA-based vaccine Comirnaty. SARS-CoV-2 spike-binding antibodies (bAb) were quantified and compared to peak responses determined in healthcare workers (HCW). For the firefighters, neutralizing antibodies (nAb) were also analyzed. Six months after the second vaccine dose, all analyzed firefighters had detectable bAb, and 91% exhibited nAb titers above 1:16. However, actual titers six months after vaccination were over 12-fold lower than in the HCW control group four weeks after vaccination. bAb and nAb responses showed a significant correlation, and age correlated inversely with antibody responses. Unexpectedly, participants with a body mass index over 25 had higher neutralization titers after six months. All participants with very low neutralization titers were offered booster vaccination. The booster vaccination improved the extent and sustainability of antibody responses.

Midazolam impacts acetyl-And butyrylcholinesterase genes: An epigenetic explanation for postoperative delirium?

Midazolam is a widely used short-acting benzodiazepine. However, midazolam is also criticized for its deliriogenic potential. Since delirium is associated with a malfunction of the neurotransmitter acetylcholine, midazolam appears to interfere with its proper metabolism, which can be triggered by epigenetic modifications. Consequently, we tested the hypothesis that midazolam indeed changes the expression and activity of cholinergic genes by acetylcholinesterase assay and qPCR. Furthermore, we investigated the occurrence of changes in the epigenetic landscape by methylation specific PCR, ChiP-Assay and histone ELISA. In an in-vitro model containing SH-SY5Y neuroblastoma cells, U343 glioblastoma cells, and human peripheral blood mononuclear cells, we found that midazolam altered the activity of acetylcholinesterase /buturylcholinesterase (AChE / BChE). Interestingly, the increased expression of the buturylcholinesterase evoked by midazolam was accompanied by a reduced methylation of the BCHE gene and the di-methylation of histone 3 lysine 4 and came along with an increased expression of the lysine specific demethylase KDM1A. Last, inflammatory cytokines were not induced by midazolam. In conclusion, we found a promising mechanistic link between midazolam treatment and delirium, due to a significant disruption in cholinesterase homeostasis. In addition, midazolam seems to provoke profound changes in the epigenetic landscape. Therefore, our results can contribute to a better understanding of the hitherto poorly understood interactions and risk factors of midazolam on delirium.

Acquired aplastic anemia following SARS-CoV-2 vaccination

COVID‐19 is a potential life‐threatening viral disease caused by SARS‐CoV‐2 and was declared a pandemic by the WHO in March 2020. mRNA‐based SARS‐CoV‐2 vaccines are routinely recommended in immune‐compromised patients, including patients with AA, as these patients are at increased risk of contracting COVID‐19 and developing a more severe course of disease. Between March 2021 and November 2021 relapse of AA occurred in four (age [median]: 53 years, range 30–84 years) out of 135 patients currently registered at our department and two de novo cases of AA in temporal context to vaccination against SARS‐CoV‐2, were documented. Median time after first COVID‐19 vaccination and relapse of AA was 77 days. All relapsed patients were vaccinated with the mRNA‐based vaccine Comirnaty®. Relapse in two out of the four patients was refractory to CsA/eltrombopag, favoring IST with hATG/CsA or BMT, respectively. Our observations should prompt clinicians to take vaccine‐induced relapse of AA or de novo AA after SARS‐CoV‐2 vaccination into account. Furthermore, careful clinical monitoring and vigilance for signs or symptoms that may indicate relapse of AA (e.g., bleeding complications) are indicated.

Performance of the LIAISON® SARS-CoV-2 Antigen Assay vs. SARS-CoV-2-RT-PCR

We aimed to evaluate the LIAISON® SARS-CoV-2 antigen assay (DiaSorin), comparing its performance to real-time polymerase chain reaction (RT-PCR) for the detection of SARS-CoV-2 RNA. 182 (110 PCR-positive and 72 PCR-negative) nasopharyngeal swab samples were taken for the detection of SARS-CoV-2. RT-PCR and antigen assay were performed using the same material. The sensitivity and specificity of the antigen assay were calculated for different cut-offs, with RT-PCR serving as the reference method. Stored clinical samples that were positive for other respiratory viruses were tested to evaluate cross-reactivity. One third (33/110, 30%) were falsely classified as negative, while no false positives were found using the 200 TCID50/mL cut-off for the SARS-CoV-2 antigen as proposed by the manufacturer. This corresponded to a sensitivity of 70% (60-78%) and a specificity of 100% (94-100%). Lowering the cut-off for positivity of the antigen assay to 22.79 or 57.68 TCID50/mL increased the sensitivity of the method, reaching a sensitivity of 92% (85-96%) vs. 79% (70-86%) and a specificity of 81% (69-89%) vs. 99% (91-100%), respectively. The antigen assay reliably detected samples with high SARS-CoV-2 viral loads (≥106 copies SARS-CoV-2/mL), while it cannot differentiate between negative and low positive samples. Cross-reactivity toward other respiratory viruses was not detected.

Fast Detection of SARS-CoV-2 RNA Directly from Respiratory Samples Using a Loop-Mediated Isothermal Amplification (LAMP) Test

The availability of simple SARS-CoV-2 detection methods is crucial to contain the COVID-19 pandemic. This study examined whether a commercial LAMP assay can reliably detect SARS-CoV-2 genomes directly in respiratory samples without having to extract nucleic acids (NA) beforehand. Nasopharyngeal swabs (NPS, n = 220) were tested by real-time reverse transcription (RT)-PCR and with the LAMP assay. For RT-PCR, NA were investigated. For LAMP, NA from 26 NPS in viral transport medium (VTM) were tested. The other 194 NPS were analyzed directly without prior NA extraction (140 samples in VTM; 54 dry swab samples stirred in phosphate buffered saline). Ten NPS were tested directly by LAMP using a sous-vide cooking unit. The isothermal assay demonstrated excellent specificity (100%) but moderate sensitivity (68.8%), with a positive predictive value of 1 and a negative predictive value of 0.65 for direct testing of NPS in VTM. The use of dry swabs, even without NA extraction, improved the analytical sensitivity; up to 6% of samples showed signs of inhibition. LAMP could be performed successfully with a sous-vide cooking unit. This technique is very fast, requires little laboratory resources, and can replace rapid antigen tests or verify reactive rapid tests on-site.

LPS-Induced Endotoxemia Evokes Epigenetic Alterations in Mitochondrial DNA That Impacts Inflammatory Response

Mitochondrial DNA (mtDNA) plays a vital role as a damage-associated molecular pattern in sepsis being able to shape the immune response. Since pathogen recognition receptors of innate immune cells are activated by demethylated DNA only, we set out to investigate the amount of DNA methyltransferase 1 (DNMT1) in mitochondria and the extent of mtDNA methylation in a human endotoxin model. Peripheral blood mononuclear cells of 20 healthy individuals were isolated from whole blood and stimulated with lipopolysaccharide (LPS) for 48 h. Subsequently, DNMT1 protein abundance was assessed in whole cells and a mitochondrial fraction. At the same time, methylation levels of mtDNA were quantified, and cytokine expression in the supernatant was measured. Despite increased cellular expression of DNMT1 after LPS stimulation, the degree of mtDNA methylation slightly decreased. Strikingly the mitochondrial protein abundance of DNMT1 was reduced by 50% in line with the lower degree of mtDNA methylation. Although only modest alterations were seen in the degree of mtDNA methylation, these strongly correlated with IL-6 and IL-10 expression. Our data may hint at a protein import problem for DNMT1 into the mitochondria under LPS stimulation and suggest a role of demethylated mtDNA in the regulation of the inflammatory immune response.

A novel understanding of postoperative complications: In vitro study of the impact of propofol on epigenetic modifications in cholinergic genes

Background

Propofol is a widely used anaesthetic drug with advantageous operating conditions and recovery profile. However, propofol could have long term effects on neuronal cells and is associated with post-operative delirium (POD). In this context, one of the contributing factors to the pathogenesis of POD is a reduction of cholinesterase activity. Accordingly, we investigated the effects of propofol on the methylation, expression and activity of cholinergic genes and proteins in an in-vitro model.

Results

We found that propofol indeed reduced the activity of AChE / BChE in our in-vitro model, without affecting the protein levels. Furthermore, we could show that propofol reduced the methylation of a repressor region of the CHRNA7 gene without changing the secretion of pro–or anti-inflammatory cytokines. Lastly, propofol changed the expression patterns of genes responsible for maintaining the epigenetic status of the cell and accordingly reduced the tri-methylation of H3 K27.

Conclusion

In conclusion we found a possible functional link between propofol treatment and POD, due to a reduced cholinergic activity. In addition to this, propofol changed the expression of different maintenance genes of the epigenome that also affected histone methylation. Thus, propofol treatment may also induce strong, long lasting changes in the brain by potentially altering the epigenetic landscape.

Hyperactivity in patients with anorexia nervosa and in semistarved rats: evidence for a pivotal role of hypoleptinemia

Patients with anorexia nervosa (AN) often show normal to elevated physical activity levels despite severe weight loss and emaciation. This is seemingly in contrast to the loss of energy and fatigue characteristic of other starvation states associated with weight loss. Despite the fact that historical accounts and clinical case studies of AN have regularly commented on the elevated activity levels, the behavior has become only recently the subject of systematic study. Because rodents and other species increase their activity upon food restriction leading to weight loss when given access to an activity wheel--a phenomenon referred to as activity-based anorexia or semi-starvation-induced hyperactivity (SIH)-it has been proposed that the hyperactivity in AN patients may reflect the mobilization of phylogenetically old pathways in individuals predisposed to AN. Exogeneous application of leptin in this animal model of AN has recently been shown to suppress completely the development of SIH. Hypoleptinemia, as a result of the food restriction, may represent the initial trigger for the increased activity levels in AN patients and in food-restricted rats. In the first and second parts of our review, we will summarize the relevant findings pertaining to hyperactivity in AN patients and in the rat model, respectively. We conclude with a synopsis and implications for future research.

Invasive pneumococcal infections in children infected with HIV are not associated with splenic dysfunction

OBJECTIVES

Children infected with HIV-1 are more likely to acquire infections associated with the encapsulated bacterial pathogens of childhood than their non-HIV-infected peers. The goal of the current study was to determine what proportion of community-acquired, invasive pneumococcal disease in HIV-infected children could be attributed to splenic dysfunction, as measured by enumerating the number of pocked red blood cells (RBCs) in peripheral blood.

METHODS

Splenic reticuloendothelial function was assessed semiquantitatively by examining the morphology of the RBCs of 84 children born to HIV-infected mothers using phase interference microscopy. Surveillance of medical records, and a review of the Yale-New Haven Hospital Clinical Microbiology computerized database, revealed that all of the bacterial cultures of blood and cerebrospinal fluid from these patients were positive.

RESULTS

Of the 84 children assessed, 70 were infected with HIV (median age 66 months) and 14 were uninfected seroreverters (controls). Sixty-one of the 70 HIV-infected children met the CDC criteria for moderate or severe immunodeficiency and/or moderate or severe symptomatic conditions. Seventeen of the 70 HIV-infected children experienced 23 invasive bacterial infections. Streptococcus pneumoniae was responsible for all 23 infections. The median age at the time of first infection among these 17 subjects was 20 months (range, 10-58 months). There were no episodes of invasive bacterial infections in the remaining 53 HIV-infected children nor among the 14 controls. All 84 children studied, including those with invasive pneumococcal disease, had normal proportions (i.e., < 2%) of pocked erythrocytes in peripheral blood.

CONCLUSION

Splenic dysfunction, as measured by the pocked RBC count, does not account for the increased occurrence of invasive pneumococcal disease found in children infected with HIV.

Characterization of autoantibodies against the platelet glycoprotein antigens IIb/IIIa in childhood idiopathic thrombocytopenia purpura

The majority of children with idiopathic thrombocytopenia (ITP) have an acute self-limiting course and no diagnostic test has been identified which will predict the course of thrombocytopenia and detect those with the chronic autoimmune form. The detection of autoantibodies directed against the platelet glycoprotein complex IIB/IIIa, may identify patients with chronic ITP. Serum anti-GP IIb/IIIa antibodies were assessed by the indirect MAIPA assay in 54 children with immune thrompocytopenia at initial presentation along with an additional 7 children previously diagnosed with chronic ITP, to determine if there was a difference in antibody positivity between acute and chronic ITP patients, and whether the identification of antibodies could be used as a predictive test at diagnosis. There was no significant difference in the percentage of antibodies detected in children classified with acute ITP (27/40-68%) compared to children with chronic ITP (13/21-62%, P > 0.05). Patients with acute ITP had significantly lower mean platelet counts at diagnosis compared to the chronic ITP group (16,225/mm3 vs 32,250/mm3, P < 0.05), though there was no significant difference in the bleeding manifestations between the acute and chronic ITP groups. Serum anti-GP IIb/IIIa antibodies are detected in a high percentage of children with ITP and autoantibodies appear to be involved in the pathogenesis of both acute and chronic ITP. The detection of anti-GP IIb/IIIa antibodies at diagnosis, however, does not appear to be a useful prognostic test in childhood ITP.