The likeliest explanation is that wasp venom extract is a mix of different Vespula species and Ves v 5 is likely to be underrepresented in the venom mix. ...it is important to consider determining ...rVes v 5 in patients with a clear history of wasp venom allergy and negative sIgE to wasp venom, which could enhance the general sensitivity of this test. ...despite considerable progress by the introduction of recombinant allergens, larger studies to determine individual sensitization patterns of patients from different regions with the whole panel of venom components (when available) are needed.
Background Anaphylaxis after Hymenoptera stings has been reported in subjects with mastocytosis, but few data exist regarding disease prevalence in populations allergic to these insects. Objective ...The incidence of clonal mast cell (MC) disorders in subjects with both systemic reactions to Hymenoptera stings and increased serum baseline tryptase (sBT) levels was assessed by using bone marrow (BM) aspirates and biopsy specimens. Methods Subjects with a history of a systemic reaction caused by a Hymenoptera sting underwent the standard diagnostic work-up for Hymenoptera allergy, and sBT levels were measured. Subjects with an increased sBT level had BM evaluation that included histology/cytology, flow cytometry, and detection of KIT mutations. Results Forty-four (11.6%) of 379 subjects with systemic reactions had increased sBT levels (>11.4 ng/mL), and 31 (70.5%) of these had a history of anaphylaxis. Thirty-four subjects with increased sBT levels underwent a BM analysis. Histology detected diagnostic or subdiagnostic MC infiltrates in 22 (65%) of 34 patients. Abnormal MCs were identified by means of flow cytometry and cytology in 26 (78.8%) of 33 and 20 (58.8%) of 34 subjects, respectively. A KIT mutation was detected in 17 (54.8%) of 31 subjects. The diagnosis was indolent systemic mastocytosis in 21 (61.7%) of 34 subjects and monoclonal MC activation syndrome in 9 (26.5%) of 34 subjects. All subjects with anaphylaxis had one of those 2 disorders. Conclusion The concomitant presence of systemic reactions (especially anaphylaxis) after Hymenoptera stings and increased sBT levels strongly suggests that a BM examination is indicated for the diagnosis of clonal MC disease.
Epstein-Barr Virus (EBV) is a human gamma-herpesvirus that is widespread worldwide. To this day, about 200,000 cancer cases per year are attributed to EBV infection. EBV is capable of infecting both ...B cells and epithelial cells. Upon entry, viral DNA reaches the nucleus and undergoes a process of circularization and chromatinization and establishes a latent lifelong infection in host cells. There are different types of latency all characterized by different expressions of latent viral genes correlated with a different three-dimensional architecture of the viral genome. There are multiple factors involved in the regulation and maintenance of this three-dimensional organization, such as CTCF, PARP1, MYC and Nuclear Lamina, emphasizing its central role in latency maintenance.
Epstein-Barr virus (EBV) persists in human B-cells by maintaining its chromatinized episomes within the nucleus. We have previously shown that cellular factor Poly ADP-ribose polymerase 1 (PARP1) ...binds the EBV genome, stabilizes CTCF binding at specific loci, and that PARP1 enzymatic activity correlates with maintaining a transcriptionally active latency program. To better understand PARP1's role in regulating EBV latency, here we functionally characterize the effect of PARP enzymatic inhibition on episomal structure through in situ HiC mapping, generating a complete 3D structure of the EBV genome. We also map intragenomic contact changes after PARP inhibition to global binding of chromatin looping factors CTCF and cohesin across the EBV genome. We find that PARP inhibition leads to fewer total unique intragenomic interactions within the EBV episome, yet new chromatin loops distinct from the untreated episome are also formed. This study also illustrates that PARP inhibition alters gene expression at the regions where chromatin looping is most effected. We observe that PARP1 inhibition does not alter cohesin binding sites but does increase its frequency of binding at those sites. Taken together, these findings demonstrate that PARP has an essential role in regulating global EBV chromatin structure and latent gene expression.
A systematic comparison with the Wild-Type (WT) of one-point mutants of bacteriophage T4 lysozyme was carried out using as difference markers the topological parameters of the protein contact ...networks corresponding to each crystallographic structure. The investigation concerned changes at the resolution level of single residue along the protein sequence. The results were correlated with (reported) changes in functional properties and (observed) changes in the information provided by the energy dissipation algorithm of the "Turbine" software simulation tool. The critical factor leading to significant difference among mutants and WT is in most cases associated to the sensitivity towards mutation of relatively short windows in the amino acidic sequence not necessarily contiguous to the active site.
The Epstein Barr virus (EBV) infects almost 95% of the population worldwide. While typically asymptomatic, EBV latent infection is associated with several malignancies of epithelial and lymphoid ...origin in immunocompromised individuals. In latently infected cells, the EBV genome persists as a chromatinized episome that expresses a limited set of viral genes in different patterns, referred to as latency types, which coincide with varying stages of infection and various malignancies. We have previously demonstrated that latency types correlate with differences in the composition and structure of the EBV episome. Several cellular factors, including the nuclear lamina, regulate chromatin composition and architecture. While the interaction of the viral genome with the nuclear lamina has been studied in the context of EBV lytic reactivation, the role of the nuclear lamina in controlling EBV latency has not been investigated. Here, we report that the nuclear lamina is an essential epigenetic regulator of the EBV episome. We observed that in B cells, EBV infection affects the composition of the nuclear lamina by inducing the expression of lamin A/C, but only in EBV+ cells expressing the Type III latency program. Using ChIP-Seq, we determined that lamin B1 and lamin A/C bind the EBV genome, and their binding correlates with deposition of the histone repressive mark H3K9me2. By RNA-Seq, we observed that knock-out of lamin A/C in B cells alters EBV gene expression. Our data indicate that the interaction between lamins and the EBV episome contributes to the epigenetic control of viral gene expression during latency, suggesting a restrictive function of the nuclear lamina as part of the host response against viral DNA entry into the nucleus.
Epstein-Barr virus (EBV) latency is controlled by epigenetic silencing by DNA methylation 5-methyl cytosine (5mC), histone modifications, and chromatin looping. However, how they dictate the ...transcriptional program in EBV-associated gastric cancers remains incompletely understood. EBV-associated gastric cancer displays a 5mC hypermethylated phenotype. A potential treatment for this cancer subtype is the DNA hypomethylating agent, which induces EBV lytic reactivation and targets hypermethylation of the cellular DNA. In this study, we identified a heterogeneous pool of EBV epialleles within two tumor-derived gastric cancer cell lines that are disrupted with a hypomethylating agent. Stochastic DNA methylation patterning at critical regulatory regions may be an underlying mechanism for spontaneous reactivation. Our results highlight the critical role of epigenetic modulation on EBV latency and life cycle, which is maintained through the interaction between 5mC and the host protein CCCTC-binding factor.
Synthetic lethality triggered by PARP inhibitor (PARPi) yields promising therapeutic results. Unfortunately, tumor cells acquire PARPi resistance, which is usually associated with the restoration of ...homologous recombination, loss of PARP1 expression, and/or loss of DNA double-strand break (DSB) end resection regulation. Here, we identify a constitutive mechanism of resistance to PARPi. We report that the bone marrow microenvironment (BMM) facilitates DSB repair activity in leukemia cells to protect them against PARPi-mediated synthetic lethality. This effect depends on the hypoxia-induced overexpression of transforming growth factor beta receptor (TGFβR) kinase on malignant cells, which is activated by bone marrow stromal cells-derived transforming growth factor beta 1 (TGF-β1). Genetic and/or pharmacological targeting of the TGF-β1-TGFβR kinase axis results in the restoration of the sensitivity of malignant cells to PARPi in BMM and prolongs the survival of leukemia-bearing mice. Our finding may lead to the therapeutic application of the TGFβR inhibitor in patients receiving PARPis.
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•Bone marrow microenvironment (BMM) facilitates DSB repair activity in leukemia cells•BMM protects leukemia cells from PARP inhibitor (PARPi)-induced synthetic lethality•TGF-β1-TGFβR kinase-SMAD3 pathway is responsible for PARPi resistance•Sensitivity of leukemia cells to PARPi is restored by the targeting of the TGF-β1 axis
Le et al. show that the TGF-β1-TGFβR kinase-SMAD3 pathway protects leukemia cells from PARP inhibitor (PARPi)-mediated synthetic lethality in the bone marrow microenvironment. The targeting of the TGF-β1 axis restored the sensitivity of leukemia cells to PARPi and prolonged survival of leukemia-bearing mice.
On the basis of these considerations and previous clinical observations,6 we vaccinated several patients with SM without observing important side effects. ...almost all of them achieved a relevant ...protection and decreased their grade of reaction from IV to I. The 2 patients who maintained a grade IV reaction on maintenance SIT could achieve a benefit by increasing the maintenance dose.8 We are aware that the population evaluated in our study is small, but if we take into account the rarity of SM and the low frequency of severe HVA, this study includes the largest cohorts of patients with HVA and SM treated with SIT. An accessory observation is that SM was indeed diagnosed in 16 of 121 patients with severe HVA. ...it can be supposed that severe HVA could be a clinical manifestation of underlying SM, as reported with idiopathic anaphylaxis.9 This would support the usefulness of tryptase assay screening in patients with Hymenoptera-induced anaphylaxis.
To assess the safety and efficacy of convalescent plasma (CP) transfusion in elderly people with moderate to severe coronavirus disease 2019 (COVID-19) living in a long-term care facility (LTCF).
...Twenty-two consecutive elderly patients with COVID-19 infection living in an LTCF in Lombardy, Italy, who were given CP during May 15 to July 31, 2020, were enrolled in a prospective cohort study. Their clinical, instrumental, and laboratory parameters were assessed following the CP treatment. The overall mortality rate in this group was compared with that recorded in other LTCFs in Lombardy during the 3-month period from March to May 2020.
Of the 22 patients enrolled, 68.2% (n=15) received 1 CP unit, 27.3% (n=6) received 2 units, and 4.5% (n=1) received 3 units. Of the CP units transfused, 76.7% (23/30) had a neutralizing antibody titer of 1:160 or greater. No adverse reactions were recorded during or after CP administration. Improvements in clinical, functional, radiologic, and laboratory parameters during the 14 days after CP transfusion were observed in all 19 patients who survived. Viral clearance was achieved in all patients by the end of follow-up (median, 66 days; interquartile range, 48-80 days). The overall mortality rate was 13.6% (3/22), which compared favorably with that in the control group (38.3% 281/733; P=.02) and corresponded to a 65% reduction in mortality risk.
Early administration of CP with an adequate anti–severe acute respiratory syndrome coronavirus 2 antibody titer to elderly symptomatic patients with COVID-19 infection in an LTCF was safe and effective in eliminating the virus, restoring patients’ immunity, and blocking the progression of COVID-19 infection, thereby improving patients’ survival.
ClinicalTrials.gov: NCT04569188.
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