Longitudinal changes in global structural brain connectivity and cognitive performance in former hospitalized COVID-19 survivors: an exploratory study.

BACKGROUND: Long-term sequelae of COVID-19 can result in reduced functionality of the central nervous system and substandard quality of life. Gaining insight into the recovery trajectory of admitted COVID-19 patients on their cognitive performance and global structural brain connectivity may allow a better understanding of the diseases' relevance. OBJECTIVES: To assess whole-brain structural connectivity in former non-intensive-care unit (ICU)- and ICU-admitted COVID-19 survivors over 2 months following hospital discharge and correlate structural connectivity measures to cognitive performance. METHODS: Participants underwent Magnetic Resonance Imaging brain scans and a cognitive test battery after hospital discharge to evaluate structural connectivity and cognitive performance. Multilevel models were constructed for each graph measure and cognitive test, assessing the groups' influence, time since discharge, and interactions. Linear regression models estimated whether the graph measurements affected cognitive measures and whether they differed between ICU and non-ICU patients. RESULTS: Six former ICU and six non-ICU patients completed the study. Across the various graph measures, the characteristic path length decreased over time (ß = 0.97, p = 0.006). We detected no group-level effects (ß = 1.07, p = 0.442) nor interaction effects (ß = 1.02, p = 0.220). Cognitive performance improved for both non-ICU and ICU COVID-19 survivors on four out of seven cognitive tests 2 months later (p < 0.05). CONCLUSION: Adverse effects of COVID-19 on brain functioning and structure abate over time. These results should be supported by future research including larger sample sizes, matched control groups of healthy non-infected individuals, and more extended follow-up periods.

Late presentation to HIV testing is overestimated when based on the consensus definition.

OBJECTIVES: In 2011, a consensus was reached defining "late presenters" (LPs) as individuals presenting for care with a CD4 count < 350 cells/µL or with an AIDS-defining event, regardless of CD4 count. However, a transient low CD4 count is not uncommon in recent infections. The objective of this study was to investigate how measurements of late presentation change if the clinical stage at the time of diagnosis is taken into account. METHODS: Case surveillance data for newly diagnosed patients in Belgium in 1998-2012 were analysed, including CD4 count at diagnosis, the presence of AIDS-defining events, and recent infections (< 6 months) as reported by clinicians in the case of acute illness or a recent negative test. First, proportions of LPs were calculated according to the consensus definition. Secondly, LPs were reclassified as "nonlate" if infections were reported as recent. RESULTS: A total of 7949 HIV diagnoses were included in the study. Recent infections were increasingly reported over time, accounting for 8.2% of new infections in 1998 and 37.5% in 2012. The consideration of clinical stage significantly modified the proportion of LPs: 18.2% of men who have sex with men (MSM) diagnosed in 2012 would be classified as LPs instead of 30.9% using the consensus definition (P < 0.001). The proportion of patients misclassified as LPs increased significantly over time: 5% in MSM in 1998 vs. 41% in 2012. CONCLUSIONS: This study suggests that low CD4 counts in recent infections may lead to overestimation of late presentation when applying the consensus definition. The impact of transient CD4 count on late presentation estimates should be assessed and, if relevant, the introduction of clinical stage in the definition of late presentation should be considered.

Good continuum of HIV care in Belgium despite weaknesses in retention and linkage to care among migrants.

BACKGROUND: The Belgian HIV epidemic is largely concentrated among men who have sex with men and Sub-Saharan Africans. We studied the continuum of HIV care of those diagnosed with HIV living in Belgium and its associated factors. METHODS: Data on new HIV diagnoses 2007-2010 and HIV-infected patients in care in 2010-2011 were analysed. Proportions were estimated for each sequential stage of the continuum of HIV care and factors associated with attrition at each stage were studied. RESULTS: Of all HIV diagnosed patients living in Belgium in 2011, an estimated 98.2% were linked to HIV care, 90.8% were retained in care, 83.3% received antiretroviral therapy and 69.5% had an undetectable viral load (<50 copies/ml). After adjustment for sex, age at diagnosis, nationality and mode of transmission, we found lower entry into care in non-Belgians and after preoperative HIV diagnoses; lower retention in non-Belgians and injecting drug users; higher retention in men who have sex with men and among those on ART. Younger patients had lower antiretroviral therapy uptake and less viral suppression; those with longer time from diagnosis had higher ART uptake and more viral suppression; Sub-Saharan Africans on ART had slightly less viral suppression. CONCLUSIONS: The continuum of HIV care in Belgium presents low attrition rates over all stages. The undiagnosed HIV-infected population, although not precisely estimated, but probably close to 20% based on available survey and surveillance results, could be the weakest stage of the continuum of HIV care. Its identification is a priority along with improving the HIV care continuum of migrants.

Sequence evolution and escape from specific immune pressure of an HIV-1 Rev epitope with extensive sequence similarity to human nucleolar protein 6.

Antigen-specific immunity is crucially important for containing viral replication in human immunodeficiency virus (HIV)-1-infected hosts. Several epitopes have been predicted for the early expressed HIV-1 proteins Tat and Rev, but few have been studied in detail. We characterized the human leukocyte antigen (HLA)-B44-restricted Rev epitope EELLKTVRL (EL9) in an HIV-1-infected subject treated with antiretroviral therapy. Interestingly, a high sequence similarity was found between the EL9 epitope and the human nucleolar protein 6 (NOL6). However, this similarity does not seem to impede immunogenicity as CD8(+) T-cells, previously stimulated with EL9-pulsed dendritic cells, were able to specifically recognize the HIV-1 Rev epitope without cross-recognizing the human self-antigen NOL6. After the subject interrupted antiretroviral therapy and virus rebounded, mutations within the EL9 epitope were identified. Although the emerging mutations resulted in decreased or abolished T-cell recognition, they did not impair Rev protein function. Mutations leading to escape from T-cell recognition persisted for up to 124 weeks following treatment interruption. This study shows that the HLA-B44-restricted Rev CD8(+) T-cell epitope EL9 is immunogenic notwithstanding its close resemblance to a human peptide. The epitope mutates as a consequence of dynamic interaction between T-cells and HIV-1. Clinical status, CD4(+) T-cell count and viral load remained stable despite escape from T-cell recognition.

Antibiotic prescriptions in the context of suspected bacterial respiratory tract superinfections in the COVID-19 era: a retrospective quantitative analysis of antibiotic consumption and identification of antibiotic prescription drivers.

This study aims to quantify antibiotic consumption for suspected respiratory tract superinfections in COVID-19 patients, while investigating the associated drivers of antibiotic prescribing in light of the current signs of antibiotic overuse. Adult patients with a positive COVID-19 diagnosis admitted to a Belgian 721-bed university hospital were analyzed retrospectively (March 11th-May 4th, 2020), excluding short-term admissions (< 24 h). Antibiotic prescriptions were analyzed and quantified, using Defined Daily Doses (DDD) per admission and per 100 bed days. Possible drivers of antibiotic prescribing were identified by means of mixed effects logistic modelling analysis with backwards selection. Of all included admissions (n = 429), 39% (n = 171) were prescribed antibiotics for (presumed) respiratory tract superinfection (3.6 DDD/admission; 31.5 DDD/100 bed days). Consumption of beta-lactamase inhibitor-penicillin combinations was the highest (2.55 DDD/admission; 23.3 DDD/100 bed days). Four drivers were identified: fever on admission (OR 2.97; 95% CI 1.42-6.22), lower SpO2/FiO2 ratio on admission (OR 0.96; 95% CI 0.92-0.99), underlying pulmonary disease (OR 3.04; 95% CI 1.12-8.27) and longer hospital stay (OR 1.09; 95% CI 1.03-1.16). We present detailed quantitative antibiotic data for presumed respiratory tract superinfections in hospitalized COVID-19 patients. In addition to knowledge on antibiotic consumption, we hope antimicrobial stewardship programs will be able to use the drivers identified in this study to optimize their interventions in COVID-19 wards.

Outbreak of multidrug-resistant Acinetobacter baumannii in a Belgian university hospital after transfer of patients from Greece.

Multidrug-resistant (MDR) Acinetobacter baumannii are emerging as important nosocomial pathogens. These organisms have a capacity for long-term survival in the hospital environment. The purpose of this study was to describe the course and control of an outbreak with MDR A. baumannii in a Belgian university hospital after transfer of two trauma patients from Greece. Wounds in both patients were colonised with MDR A. baumannii. Over an 11 month period from September 2004 to July 2005, carbapenem-non-susceptible A. baumannii (producing carbapenem-hydrolysing oxacillinase OXA-58) were isolated from 28 patients, despite early implementation of contact precautions. MDR A. baumannii was detected in routine clinical diagnostic samples from 26 patients and in screening specimens from an additional two patients. Twenty patients (71.4%) were colonised or infected during their stay in intensive care. Twenty-four (85.7%) respiratory samples were positive for MDR A. baumannii. Careful review of all procedures related to the respiratory tract did not identify a common route of transmission. Outbreak control required multiple interventions, including contact isolation of colonised and infected patients, monitoring the practice of personnel, screening of asymptomatic patients, use of isolation rooms and enhanced environmental disinfection. Introduction of single-use ventilator circuits was considered but the outbreak was controlled before implementation.

Establishment and characterization of a human stroma-dependent myeloma cell line (MM5.1) and its stroma-independent variant (MM5.2).

Although IL-6 has been identified as a major growth factor in multiple myeloma (MM), it is believed that maintenance of tumor growth in vivo depends on one or more additional stroma-derived factors. We describe a new human myeloma cell line (MM5.1) that can be maintained in the presence of bone marrow-derived stromal cell layers, and not only when cultured with exogeneous IL-6. This cell line expresses the same immunoglobulin kappa light chain RNA sequence as the patient's original tumor cells, has a plasma cell morphology and expresses plasma cell antigens (cytoplasmic kappa light chain, CD38, BB4). Without the presence of stromal factors, MM5.1 cells become apoptotic. A low proliferative effect was observed in the presence of oncostatin M (OSM) but other cytokines (IL-10, IL-11, stem cell factor (SCF) and leukemia inhibitory factor (LIF)) had no effect at all. We observed that MM5.1 cells also grow when physically separated from stromal cell layers by a 0.45 microm microporous membrane or when cultured in conditioned medium from stromal marrow cells. Unexpectedly, the growth in stromal supernatants was markedly inhibited by an anti-IL-6 antiserum and an anti-IL-6 receptor transducer chain (gp130) mAb in a dose-dependent manner. This implies that MM5.1 cells are IL-6 responsive only when exposed to one or more additional soluble factor(s) derived from bone marrow stroma. Coculturing MM5.1 cells with IL-6 and cytokines that were described to increase the IL-6 responsiveness of myeloma cells (G-CSF, GM-CSF and IL-3) had no effect on the growth or survival. A strong proliferative effect was observed when MM5.1 cells were cultured with IL-6 and soluble IL-6 receptor (sgp80). However no sgp80 could be detected in stromal supernatants using a sensitive immunoassay. This indicates that sustained proliferation of the MM5.1 cell line depends on a combination of IL6 and at least one, thus far unidentified, stroma-derived factor. After more than 1 year in continuous culture, we could obtain a variant of the line (MM5.2) that shows an improved growth rate and grows stroma independently. Molecular analysis revealed clonal identity with the early passage form and Epstein-Barr virus antigen expression was negative. The two variants of this cell line offer a useful model to identify molecular mechanisms involved in clonal evolution towards stroma-independent growth of myeloma cells.

Monitoring of C-reactive protein after allogeneic bone marrow transplantation identifies patients at risk of severe transplant-related complications and mortality.

Patterns of C-reactive protein (CRP) release were derived from frequent CRP measurements in a cohort of 66 consecutive patients receiving allogeneic bone marrow transplants (BMT) in our unit. Based on a retrospective study of clinical events occurring within the first 40 days after BMT, patients with major transplant-related complications (MTC+ group, n = 22) could be separated from those with fever or mild complications only (MTC- group, n = 44). Treatment-related mortality in the MTC+ group was significantly higher: 32 vs 0% (P < 0.001). Major complications included veno-occlusive liver disease (VOD), severe endothelial leakage syndrome (ELS), pneumonitis and acute GVHD >II. The severity of complications was reflected by the patterns of CRP release with continuously high levels preceding the maximal signs and symptoms of MTC. Univariate analysis showed that, among other variables (sex, age, disease status at transplant, +/- TBI in the conditioning regimen, +/- use of myeloid growth factors after BMT, time to reach PN >200/mm3), three factors were significantly associated with MTC: maximal levels of CRP during the post-transplant episode (CRPmax) (296.6 +/- 91.8 vs 88.9 +/- 55.8 mg/100 ml, P < 0.001), the use of unmanipulated graft (no T depletion) (46.9 vs 12.5%, P < 0.009) and the CRP level on the day of BMT (CRPo) (42.7 +/- 55.4 vs 18.2 +/- 19.5, P = 0.045). In multivariate analysis, using a stepwise logistic regression model including the same variables, CRPmax appeared to be the strongest independent variable (P < 0.001) and a reliable (94% accuracy) parameter to assess the risk of MTC. Based on this model, CRP levels of 200 and 300 mg/100 ml are associated with a risk of 48 and 94% of developing MTC, respectively. We conclude that CRP monitoring after BMT identifies patients at risk of severe transplant-related complications and mortality.

The absolute number of circulating CD34+ cells predicts the number of hematopoietic stem cells that can be collected by apheresis.

We report our single institution's effort to standardize the method of collecting peripheral blood progenitor cells (PBPC) used for autologous transplantation. PBPC were mobilized by different types of chemotherapy followed by G-CSF (24 patients) or G-CSF alone (six patients) in 30 patients with various underlying neoplastic diseases. A median of three aphereses (range: 2-7), using the CS3000 cell separator was performed and a blood volume of 101 was processed. We studied the relationship between the absolute numbers of circulating leukocytes, mononuclear cells and CD34+ cells and the amount of PBPC collected during a single apheresis procedure. CD34+ cells were quantified by leukocyte subset analysis based on flow cytometry. Both CFU-GM and CD34+ cell contents of the apheresis products (69 procedures analyzed) correlated strongly: rho = 0.936, P = 0.0001). Regression analysis showed that the total number of CD34+ cells or CFU-GM content of the apheresis products could be predicted (r = 0.915, P = 0.0001) from the absolute number of CD34+ cells in the blood. A number of 10 circulating CD34+ cells per mm3 blood ensured a minimum of 0.5 x 10(6) CD34+ cells per kg, collected on the same day. Of the 30 patients, 17 received an autologous graft that contained only PBPC in 13. Long-term and complete hematological reconstitution was observed in all patients who had a minimum of 2 x 10(6) CD34+ cells per kg reinfused.

Diagnostic and prognostic value of the MB2 monoclonal antibody in paraffin-embedded bone marrow sections of patients with multiple myeloma and monoclonal gammopathy of undetermined significance.

Routinely processed bone marrow biopsies of 59 patients with untreated multiple myeloma (MM) and of 41 patients with monoclonal gammopathies of undetermined significance (MGUS) were immunocytochemically studied with the MB2 monoclonal antibody. In 54 of 59 biopsies of patients with MM, most neoplastic plasma cells showed strong cytoplasmic positivity to MB2. In contrast, only three biopsies of patients with MGUS contained highly MB2-positive plasma cells, whereas the plasma cells in the remaining biopsies were either negative (18 of 41) or revealed a weak dot-like staining of the cytoplasm (20 of 41). Plasma cells in tonsillar tissue, gastric and duodenal mucosae, and bone marrow with reactive plasmacytosis were not stained with MB2. These findings suggest that MB2 helps to distinguish between MM and MGUS. Because the five MB2-negative patients with MM were all in stage III and had very short survival time, neoplastic plasma cell staining with MB2 could also have a prognostic significance.

Regulation of the expression of peripheral benzodiazepine receptors and their endogenous ligands during rat sciatic nerve degeneration and regeneration: a role for PBR in neurosteroidogenesis.

Peripheral benzodiazepine receptors (PBR) and their endogenous ligands, the diazepam-binding inhibitor derived-peptides, are present in Schwann cells in the peripheral nervous system. The aim of this study was to determine the influence of reversible (freeze-injury) and permanent (transection and ligature) nerve lesion on PBR density and on the levels of their endogenous ligands, by autoradiography (using [3H]PK11195) and radioimmunoassay (using antisera directed against the octadecaneuropeptide (ODN), a diazepam-binding inhibitor fragment). The potential role of PBR on peripheral nerve steroidogenesis, was studied by investigating the effect of specific PBR agonists and antagonists on pregnenolone levels in the sciatic nerve. Sixteen to 30 days after nerve lesion, PBR density and ODN-LI level were highly increased. Their expression returned to normal level when regeneration was completed 60 days after freeze-injury, but remained elevated when regeneration did not occur in transected distal stumps. Reverse-phase HPLC analysis of ODN-LI showed that in control nerve extracts, the major immunoreactive peak co-elutes with triakontatetraneuropeptide (TTN). After freeze-injury, intermediate molecular forms eluting between ODN and TTN were predominant and remained elevated at day 60. The greater accumulation of intermediate forms when regeneration is allowed to occur may indicate a particular role of these forms in axonal elongation and myelination. Ro5-4864, a high affinity PBR agonist increased pregnenolone concentration in the sciatic nerve. This effect was antagonised by PK11195, a high affinity PBR antagonist, which had no effect on pregnenolone basal level, indicating a specific action of PBR in neurosteroid production. These results suggest a role for PBR and their endogenous ligands in peripheral nerve regeneration. A trophic effect could be exerted via stimulation of steroid synthesis.

Enhanced expression of the peripheral benzodiazepine receptor (PBR) and its endogenous ligand octadecaneuropeptide (ODN) in the regenerating adult rat sciatic nerve.

In this study we have investigated the expression of the peripheral benzodiazepine receptor (PBR) and its endogenous ligand octadecaneuropeptide (ODN) in the sciatic nerve of the adult rat by immunohistochemistry. We have also determined the effect of nerve freezing lesion or chronic denervation on PBR and ODN expression. In the sciatic nerve of control rats PBR- and ODN-immunoreactivities (IR) were associated to Schwann cells. Ten days after nerve injury, PBR- and ODN-IR increased significantly in the distal stump. PBR-IR was associated to Schwann cells and macrophages, whereas ODN-IR was only detected in Schwann cells. Immunoreactivities returned to normal levels when axons were allowed to regenerate for 2 months after nerve freezing-injury. Under chronic denervation conditions, PBR- and ODN-IR remained elevated in the distal stump, at least for this period of time. These results suggest that PBR and ODN are regulated by signals from regenerating axons and that PBR and its endogenous ligand may play a role in peripheral nerve regeneration.

Immunogold-silver staining of cells recovered by bronchoalveolar lavage. A report of three cases demonstrating its value in the diagnosis of pulmonary involvement in hematologic malignancies.

BACKGROUND: The diagnosis of pulmonary involvement in hematologic malignancies (PHM) has traditionally necessitated large specimens (usually invasive or surgically obtained biopsies). The development of reliable immunocytologic identification techniques allows diagnosis on noninvasively obtained cellular material, including bronchoalveolar lavage (BAL) fluid. Since 1985, 12 such cases have been reported. CASES: Three cases of B-cell-related PHM were diagnosed by means of BAL fluid cellular analysis using the immunogold-silver staining technique. CONCLUSION: This is the first report showing immunogold-silver staining to be a reliable immunocytochemical identification technique for monoclonal B-cell populations recovered by BAL.

Infectious diseases, from HCV to cpe how susceptible are we?

Infectious diseases remain a leading cause of morbidity and mortality. Still, there is substantial variation in the individual outcome when humans are exposed to potentially pathogenic micro-organisms. At least, one of the factors involved in the individual susceptibility to infections, is the genetic diversity of the host's immune response. This article gives a concise overview of the actual knowledge on the genetic mechanisms underlying human susceptibility to infectious diseases and the methods that are used to investigate it.

Community associated methicillin-resistant Staphylococcus aureus.

Community associated methicillin resistant Staphylococcus aureus (CA-MRSA) is an emergent infectious pathogen that might become an important public-health problem. Indeed, unique strains of S. aureus that combine specific virulence factors with resistance against frequently used antibiotics have been associated with severe community acquired infections in otherwise healthy and often younger people. This is especially the case in the USA, were these strains now represent a major part of staphylococcal infections in the outpatient setting. But, severe infections with CA-MRSA strains have already been reported in Belgium as well. This article summarizes the current knowledge on CA-MRSA as an emergent pathogen and discusses its clinical management.

Systemic anaplastic large cell lymphoma presenting with cutaneous manifestations in a young man: a case report.

Skin lesions can be a sign of internal disease. When they are associated with persisting systemic signs, the possibility of an internal malignancy should always be considered. We describe a 25-year-old man who presented with weight loss, fatigue, subpyrexia, xerostomia and skin rash of 6 months duration. Physical examination showed a dry red skin, most prominent in the face, the palms of the hands and the soles of the feet. Laboratory investigations revealed signs of inflammation and a high level of antinuclear antibodies. Retroperitoneal lymph nodes were visualized on a CT scan of the abdomen. CT-guided biopsy of an abdominal lymph node revealed the presence of an anaplastic large cell lymphoma (ALCL), ALK-positive. A biopsy of the skin showed non-specific signs of inflammation.The patient underwent 8 cycles of chemotherapy according to the CHOP protocol. A complete remission was obtained. Non-Hodgkin lymphoma can indeed be associated with skin lesions. They result from direct invasion by malignant cells or are of paraneoplastic origin, as was the case in this patient.