Dedicated team to ambulatory care for patients with COVID-19 requiring oxygen: Low rate of hospital readmission

OBJECTIVES

We aimed to determine the impact of a dedicated medical team (DMT) on ambulatory care for patients requiring oxygen.

METHODS

The DMT selected patients requiring oxygen for less than 5 l/min in the emergency department (ED). The rate of ED readmission was compared in patients managed by the DMT and those managed by the ED physicians (EDPs). Consensual treatment for COVID-19 pneumonia with oxygen requirement was steroids + preventive anticoagulation.

RESULTS

A total of 1397 patients with COVID-19 came to our ED from the first to the 31^st of August, 2021, among whom 580 (41%) had ambulatory care. A total of 82 (14.1%) patients were managed by the DMT, with a rate of ED readmission of 4.8% (4/82), compared with 13.6% (68/498) for those managed by EDPs (P <0.001). Focusing on the 45/498 (9.0%) patients requiring oxygen and managed by EDPs, the rate of ED readmission was 20%, P = 0.017. Prescription of the consensual treatment concerned 96% versus 40% for those patients requiring oxygen for the DMT and the EDP, respectively (P <0.001).

CONCLUSION

A DMT for ambulatory care of patients with COVID-19 requiring oxygen was associated with less return to the ED than usual practices.

Food poisoning due to a TSST1-producing Staphylococcus aureus

Toxic Shock Syndrome (TSS) is a very rare and severe complication of Staphylococcus aureus infections. However, bacteremia is very uncommon in this disease. We present here the case of a healthy 15-year old boy who presented septic shock and diffuse exanthema four hours after eating in a fast food restaurant. Blood cultures were positive for a TSST-1 producing Staphylococcus aureus. The patient was treated with antibiotics and fully recovered.

Microelimination or Not? The Changing Epidemiology of Human Immunodeficiency Virus-Hepatitis C Virus Coinfection in France 2012–2018

Background

The arrival of highly effective, well-tolerated, direct-acting antiviral agents (DAA) led to a dramatic decrease in hepatitis C virus (HCV) prevalence. Human immunodeficiency virus (HIV)-HCV–coinfected patients are deemed a priority population for HCV elimination, while a rise in recently acquired HCV infections in men who have sex with men (MSM) has been described. We describe the variations in HIV-HCV epidemiology in the French Dat’AIDS cohort.

Methods

This was a retrospective analysis of a prospective cohort of persons living with HIV (PLWH) from 2012 to 2018. We determined HCV prevalence, HCV incidence, proportion of viremic patients, treatment uptake, and mortality rate in the full cohort and by HIV risk factors.

Results

From 2012 to 2018, 50 861 PLWH with a known HCV status were followed up. During the period, HCV prevalence decreased from 15.4% to 13.5%. HCV prevalence among new HIV cases increased from 1.9% to 3.5% in MSM but remained stable in other groups. Recently acquired HCV incidence increased from 0.36/100 person-years to 1.25/100 person-years in MSM. The proportion of viremic patients decreased from 67.0% to 8.9%. MSM became the first group of viremic patients in 2018 (37.9%). Recently acquired hepatitis represented 59.2% of viremic MSM in 2018. DAA treatment uptake increased from 11.4% to 61.5%. More treatments were initiated in MSM in 2018 (41.2%) than in intravenous drug users (35.6%). In MSM, treatment at the acute phase represented 30.0% of treatments in 2018.

Conclusions

A major shift in HCV epidemiology was observed in PLWH in France from 2012 to 2018, leading to a unique situation in which the major group of HCV transmission in 2018 was MSM.

Clinical Trials Registration. NCT02898987.

Infectious Mononucleosis Resulting in Acute Necrotizing Mediastinitis: A Case Report and Literature Review

The serological prevalence of Epstein-Barr virus (EBV) among young adults exceeds 90% worldwide. Even though EBV primary infection is usually benign, severe complications can occur in adolescents and young adults and so the disease must be promptly diagnosed. The development of an oropharyngeal abscess leading to a descending necrotizing mediastinitis (DNM) is exceptional and potentially lethal, so early diagnosis with a CT scan, appropriate antibiotics and surgery are essential. The authors present a case where DNM was associated with reactive hemophagocytic syndrome as a result of infectious mononucleosis, as well as a review of similar cases in the English literature.

LEARNING POINTS

The incidence of serious complications in Epstein-Barr virus (EBV) primary infection increases with age.Respiratory symptoms (e.g., pleuritic pain, dyspnoea) and unusually prolonged fever (>10 days) in patients with infectious mononucleosis could be 'red flags' for life-threatening complications such as empyema and descending necrotizing mediastinitis.The threshold for performing cervical and chest computed tomography in septic patients with infectious mononucleosis should be low.

FOXO1 is a TXN- and p300-dependent sensor and effector of oxidative stress in diffuse large B-cell lymphomas characterized by increased oxidative metabolism

Molecular profiling has led to identification of subtypes of diffuse large B-cell lymphomas (DLBCLs) differing in terms of oncogenic signaling and metabolic programs. The OxPhos-DLBCL subtype is characterized by enhanced mitochondrial oxidative phosphorylation. As increased oxidative metabolism leads to overproduction of potentially toxic reactive oxygen species (ROS), we sought to identify mechanisms responsible for adaptation of OxPhos cells to these conditions. Herein, we describe a mechanism involving the FOXO1-TXN-p300 redox-dependent circuit protecting OxPhos-DLBCL cells from ROS toxicity. We identify a BCL6-dependent transcriptional mechanism leading to relative TXN overexpression in OxPhos cells. We found that OxPhos cells lacking TXN were uniformly more sensitive to ROS and doxorubicin than control cells. Consistent with this, the overall survival of patients with high TXN mRNA expression, treated with doxorubicin-containing regimens, is significantly shorter than of those with low TXN mRNA expression. TXN overexpression curtails p300-mediated FOXO1 acetylation and its nuclear translocation in response to oxidative stress, thus attenuating FOXO1 transcriptional activity toward genes involved in apoptosis and cell cycle inhibition. We also demonstrate that FOXO1 knockdown in cells with silenced TXN expression markedly reduces ROS-induced apoptosis, indicating that FOXO1 is the major sensor and effector of oxidative stress in OxPhos-DLBCLs. These data highlight dynamic, context-dependent modulation of FOXO1 tumor-suppressor functions via acetylation and reveal potentially targetable vulnerabilities in these DLBCLs.

Adjuvant vaccination with melanoma antigen pulsed dendritic cells (DCs) in stage III melanoma patients

9039

Background: This is a pilot study evaluating of high-risk melanoma patients (pts) treated with peptide-DC vaccine after lymphadenectomy (LND). DC vaccination was designed to induce the immune response against melanoma antigens in melanoma pts who remain at high risk of dissemination after LND. Methods: DCs were generated from the bone marrow with the use GM-CSF, SCF, FLT3-L and TNFa or from peripheral blood adherent monocytes with GM-CSF and IL-4. DCs pulsed with HLA-A2-binding TYR, MART-1 and gp100 peptides and/or HLA-A1-binding MAGE-1, MAGE-3 peptides, tumor lysate if available, or with tracer antigen keyhole limpet hemocyanin (KLH), were injected sc 9 times within 8 months (mos). Boost injections were performed after 12 and 24 mos. Vaccinated pts were matched to unvaccinated controls (22 of 587) by sex, number of metastatic lymph nodes, extracapsular involvement, completion or therapeutic LND, Breslow stage (T), and ulceration. Results: HLA-A2+, -A1+ or -A3+ melanoma pts (n=22), stage III, N1b-N3, enrolled between Sept. 2002 and Apr. 2004, received 5–16 vaccinations (median: 11) within 2 yrs. Cutaneous delayed type hypersensitivity (DTH) to melanoma peptides was induced in 12 of 22 pts. Peptide-specific IFNg producing CD8+ cells were detected in peripheral blood of 13 of 19 pts after vaccination. At least one of these responses to melanoma antigens was elicited in 17 of 22 pts. DTH to KLH was positive in 15 of 22 pts. Nine vaccinated pts are free of disease, and 1 is stable by Dec. 2008 (follow up is 58–76 mos after LND). Survival analysis for vaccinated pts and matched controls is presented in the Table . Conclusions: The DC/peptide vaccine elicited immune responses to melanoma antigens. Vaccinated pts had clinically substantially longer overall survival (OS) and disease free survival (DFS) than matched control. OS was associated with the immune responsiveness to melanoma antigens and to KLH.

[Table: see text]

No significant financial relationships to disclose.

HER2+ circulating tumor cells (CTCs): a more sensitive and specific marker for CTCs positivity than total CTCs count in early breast cancer

Abstract #5023

Background: CTCs have been detected using the CellSearch System in early and metastatic breast cancer (BC). However, no studies have been reported for the detection of HER2+ CTCs using the CellSearch System. In this study we aimed to analyze CTCs for HER2 expression in different stages of BC progression from ductal/lobular carcinoma in situ (DCIS/LCIS) to early and metastatic BC. Patients and Methods: 20ml of peripheral blood per woman was analyzed from healthy women, DCIS/LCIS or early BC patients, whereas 7.5ml of blood was analyzed from metastatic BC patients. The presence of CTCs as well as HER2 expression was assessed with the CellSearchSystem (Veridex, USA). After immunomagnetic enrichment with an anti-Epcam-antibody, cells were labeled with anti-cytokeratin (8,18,19), anti-HER2 and anti-CD45 antibodies. CTCs were defined as Cytokeratin-positive/CD45-negative cells, whereas HER2+ CTCs were defined as Cytokeratin-positive/CD45-negative/HER2-positive cells. Results: The presence of CTCs and HER2+ CTCs in healthy women, DCIS/LCIS, early and metastatic BC is depicted in table.&#x2028; &#x2028; Since 1 and 2 CTCs were detected in 7 (14.8%) and 4 (8.5%) of 47 healthy women, respectively, &gt;1CTC or &gt;2CTCs were selected as cutoffs for further analysis. Using the above cutoffs, 7 (18.9%) and 5 (13.5%) of 37 patients with early BC were considered CTC-positive, respectively. Since no HER2+ CTCs were detected in any of the 47 healthy women, a cutoff of ≥1 HER2+ CTCs was chosen. With this cutoff, more women with early BC [11 (29.7%) of 37 women] were considered CTC-positive. Conclusion: HER2+ CTCs seems to be a more sensitive and specific marker for CTCs' positivity than total CTCs counts in early breast cancer. Clinical relevance of the above cutoff for CTCs positivity using HER2+ CTCs detection will be performed in ongoing clinical trials of HER2 positive early breast cancer.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5023.

Recovery of dendritic cell counts and function in peripheral blood of cancer patients after chemotherapy

Dendritic cell (DC) counts and function were assayed in peripheral blood of lymphoma and solid tumor patients before and after chemotherapy. The DC counts declined significantly within the first week from the start of chemotherapy, recovered in the second week, and exceeded the baseline values in the third week. DC recovery was usually similar after the first and after the last cycle of chemotherapy. DC1 and DC2 subsets followed the pattern of reconstitution found for the DC population as a whole. Monocytes and granulocytes recovered 1-2 weeks later than DC. The primary proliferative response to keyhole lympet hemocyanin (KLH), totally DC-dependent, declined within the first week from the start of chemotherapy, and in the majority of patients (including those initially unresponsive) recovered along with DC counts. The recovered responsiveness to KLH, but not to anti-CD3 antibody, disappeared at the end of chemotherapy in lymphoma and some solid tumor patients. Prolonged depletion of CD4+ T cells could contribute to the loss of responsiveness in lymphoma patients receiving multiple cycles of chemotherapy. However, in some solid tumor patients, the reactivity to KLH was absent, despite the reconstitution of both DC and CD4+ T-cell counts. Our data show that numerical reconstitution of DC is not necessarily accompanied by functional recovery. The early recovery of DC should be considered while designing protocols for DC collection for immunotherapy.

A method for directly determining the number of dendritic cells and for evaluation of their function in small amounts of human peripheral blood

Bone marrow-derived dendritic cells (DC) are highly potent antigen-presenting cells (APC) capable of initiating primary responses of naive T lymphocytes to antigen. Studies on DC in disease have been impeded by the lack of a defined method for accurate DC counting and for evaluation of their function in a small amount of blood. In order to detect and enumerate DC in whole peripheral blood preparations, we applied a direct two-color immunofluorescence method. Blood from healthy donors was stained with a mixture of fluorescein isothiocyanate (FITC)-conjugated monoclonal antibodies (mAbs) recognizing lineage-associated molecules (CD3, CD14, CD16, CD20, CD57) and phycoerythrin (PE)-conjugated anti-HLA-DR mAb. DC were identified as lineage marker negative (lin-), HLA-DR highly positive cells. The mean percentage of these cells present in peripheral blood leukocytes (PBL) was 0.54%, and the mean absolute DC count was 31.4 x 10(6)/l of blood. DC stained directly in whole blood were heterogeneous with regard to their expression of CD2 and CD4 molecules, and did not express CD80 and CD83 molecules. Expression of CD80 and CD83 on DC was induced following a multistep isolation procedure, including overnight culture. We demonstrated a significant primary proliferative response to keyhole limpet hemocyanin (KLH) in cultures of peripheral blood mononuclear cells (PBMNC). Since primary proliferative response to neoantigens is entirely dependent on DC as APC, the cultures of unseparated PBMNC stimulated with KLH can be used to evaluate DC function in a relatively simple test. This test does not require previous isolation of DC and T lymphocytes and, therefore, can be performed on a small amount of blood. The elaborated flow cytometric method of DC counting in blood and the proliferative test of DC-dependent primary response to neoantigen are currently being applied in an ongoing study on the effect of chemotherapy on DC number and function in cancer patients.

Generation of antigen-specific CD4+ T cell lines from naive precursors

The conditions required for sensitizing naive T cells to nominal antigen are poorly understood. In this report we describe an in vitro system for generating antigen-specific CD4+ T cells from previously unprimed individuals. Freshly isolated CD4+ T cells were cultured with keyhole limpet hemocyanin (KLH), sperm whale myoglobin (SWM), or human immunodeficiency virus (HIV) gp160, antigens to which most persons have not been sensitized, in the presence of either dendritic cells (DC) or macrophages (M phi). In short-term (< 8 days) cultures, CD4+ T cells or their CD4+, CD45RA (naive) subpopulation mounted significant proliferative responses to KLH, SWM, and HIV gp160, but only if the antigens were presented by DC. In contrast, CD4+, CD45RO (memory) T cells responded poorly to these antigens, although they responded vigorously to tetanus toxoid, a recall antigen, presented by either DC or M phi. KLH- and SWM-specific CD4+ T cell lines were established from the starting population that had been sensitized in vitro, following repeated stimulation with antigen and M phi in medium supplemented with interleukin-2 and interleukin-4. Despite the continued presence of these cytokines during T cell expansion, the expanded lines retained their ability to respond to the priming antigen in the absence of exogenous cytokines. When the CD45RA and CD45RO subpopulations were sensitized and expanded separately, the CD45RA cells alone gave rise to antigen-specific T cell lines, while the CD45RO cells proliferated nonspecifically. These results demonstrate that human naive CD4+ T cells can be sensitized in vitro to nominal antigens presented by DC and that the sensitized cells can be expanded into long-term lines that retain their antigen specificity.

Generation of antigen-specific CD8+ CTLs from naive precursors

Class I MHC-restricted CTLs are an important component of the host immune response against viral infections, and CTL effectors can often be isolated from infected individuals. However, the mechanism responsible for the induction of CTLs is incompletely understood because, in part, of the difficulty in generating such cells in vitro from naive precursors. In the present study we have used human peripheral blood dendritic cells (DCs), devoid of CD4+ T cells, to sensitize naive CD8+ T cells to exogenous Ags, resulting in the generation of Ag specific CTL effectors. With this system, Ag-specific CTL lines were generated to a complex glycoprotein, keyhole limpet hemocyanin, and to multiple small (9-15 amino acids) synthetic peptides derived from conserved regions of the HIV-1 gag and envelope proteins. The HIV-1-specific CTLs demonstrated potent HLA class I restricted killing of both Ag pulsed and virally infected target cells. In contrast to Ag-pulsed DCs, Ag-pulsed monocytes failed to sensitize CTL precursors although they could be used as feeders for purposes of CTL expansion and as target cells in cytolytic assays. With the use of the system described herein, a detailed analysis of the primary human T cell response to foreign Ags is now feasible, and CTL of desired specificity can be generated for potential clinical use in adoptive immunotherapy protocols.

Generation of antigen-specific CD8+ CTLs from naive precursors

Class I MHC-restricted CTLs are an important component of the host immune response against viral infections, and CTL effectors can often be isolated from infected individuals. However, the mechanism responsible for the induction of CTLs is incompletely understood because, in part, of the difficulty in generating such cells in vitro from naive precursors. In the present study we have used human peripheral blood dendritic cells (DCs), devoid of CD4+ T cells, to sensitize naive CD8+ T cells to exogenous Ags, resulting in the generation of Ag specific CTL effectors. With this system, Ag-specific CTL lines were generated to a complex glycoprotein, keyhole limpet hemocyanin, and to multiple small (9-15 amino acids) synthetic peptides derived from conserved regions of the HIV-1 gag and envelope proteins. The HIV-1-specific CTLs demonstrated potent HLA class I restricted killing of both Ag pulsed and virally infected target cells. In contrast to Ag-pulsed DCs, Ag-pulsed monocytes failed to sensitize CTL precursors although they could be used as feeders for purposes of CTL expansion and as target cells in cytolytic assays. With the use of the system described herein, a detailed analysis of the primary human T cell response to foreign Ags is now feasible, and CTL of desired specificity can be generated for potential clinical use in adoptive immunotherapy protocols.

Granulocyte-macrophage colony-stimulating factor promotes differentiation and survival of human peripheral blood dendritic cells in vitro

Interest in human dendritic cells (DC) has been heightened recently by the discovery that this cell type is a primary target of the human immunodeficiency virus, the causative agent of AIDS. DC are bone marrow-derived cells with an extraordinarily potent ability to promote the immunological activity of T lymphocytes. Unfortunately, since DC constitute less than 0.5% of peripheral blood mononuclear cells and die within a few days of their isolation, they are not readily accessible to study. We report here that granulocyte-macrophage colony-stimulating factor (GM-CSF), a cytokine with well-recognized effects on granulocyte and macrophage maturation, profoundly affects the morphology and viability of DC isolated from peripheral blood. GM-CSF not only promotes DC survival but also induces DC differentiation to mobile, reversibly adherent cells with long-branched projections. DC cultured in GM-CSF survive for up to 6 wk and retain their ability to stimulate the proliferation of T cells in allogeneic and autologous mixed leukocyte reactions.