Kinetics and ability of binding antibody and surrogate virus neutralization tests to predict neutralizing antibodies against the SARS-CoV-2 Omicron variant following BNT162b2 booster administration.

OBJECTIVES: To assess the long-term humoral immunity induced by booster administration, as well as the ability of binding antibody and surrogate virus neutralization tests (sVNT) to predict neutralizing antibodies (NAbs) against the SARS-CoV-2 Omicron variant. METHODS: A total of 269 sera samples were analyzed from 64 healthcare workers who had received a homologous booster dose of BNT162b2. Neutralizing antibodies assessed by sVNT and anti-RBD IgG measured with the sCOVG assay (Siemens Healthineers®) were analyzed at five timepoints; before and up to 6 months following the booster. Antibody titers were correlated with neutralizing antibodies against the Omicron BA.1 variant obtained by pseudovirus neutralization test (pVNT) as a reference method. RESULTS: While Wild-type sVNT percentage of inhibition (POI) remained above 98.6% throughout the follow-up period after booster administration, anti-RBD IgG and NAbs assessed by Omicron BA.1 pVNT showed respectively a 3.4-fold and 13.3-fold decrease after 6 months compared to the peak reached at day 14. NAbs assessed by Omicron sVNT followed a steady decline until reaching a POI of 53.4%. Anti-RBD IgG and Omicron sVNT assays were strongly correlated (r=0.90) and performed similarly to predict the presence of neutralizing antibodies with Omicron pVNT (area under the ROC: 0.82 for both assays). In addition, new adapted cut-off values of anti-RBD IgG (>1,276 BAU/mL) and Omicron sVNT (POI>46.6%) were found to be better predictors of neutralizing activity. CONCLUSIONS: This study showed a significant drop in humoral immunity 6 months after booster administration. Anti-RBD IgG and Omicron sVNT assays were highly correlated and could predict neutralizing activity with moderate performance.

Hypercalcemia Heralding Pneumocystis jirovecii Pneumonia in an HIV-Seronegative Patient with Diffuse Cutaneous Systemic Sclerosis.

Pneumocystis pneumonia (PCP) is a life-threatening fungal infection occurring in immunocompromised patients such as HIV-positive patients with low CD4 cell count or patients under heavy immunosuppressive therapy. We report the case of a 59-year-old male with severe diffuse cutaneous systemic sclerosis presenting with asthenia, dry cough and worsening shortness of breath for the last 15 days. Biological studies were remarkable for PTH-independent severe hypercalcemia with low 25-hydroxyvitamin D and a paradoxically elevated 1,25-dihydroxyvitamin D. Early bronchoalveolar lavage allowed for PCP diagnosis and targeted treatment. We discuss the underlying physiopathology and difficulties regarding prophylaxis and treatment.

Absence of recognition of common melanocytic antigens by T cells isolated from the cerebrospinal fluid of a Vogt-Koyanagi-Harada patient.

PURPOSE: Vogt-Koyanagi-Harada (VKH) syndrome is an autoimmune disease characterized by inaugural uveomeningitidis and hearing loss and at late stages a depigmentation in eyes and skin. Melanocytes are the cells common to the four affected tissues, namely eye, brain, inner ear, and skin. Melanocytes are therefore considered as the source of self-antigens. The melanocytic proteins tyrosinase-related protein-1 (TRP1), TRP2, tyrosinase, and gp100 have been proposed as the proteins targeted by autoreactive T cells from VKH patients bearing human leukocyte antigen (HLA)-DRB1*04:05, the HLA allele classically associated with VKH disease. The objective of this work was to determine the antigens recognized by a large number of potentially autoreactive CD4 T lymphocytes obtained from the cerebrospinal fluid of one VKH patient who did not express HLA-DRB1*04:05. METHODS: T cells were isolated from the cerebrospinal fluid of a newly diagnosed HLA-DRB1*14:01,*15:03;-DPB1*01:01,*04:02 patient in the acute phase of the VKH disease and cloned by limiting dilution. Each of the 107 T cell clones, of which 90% were CD4(+), was tested for its ability to secrete cytokines upon contact with autologous antigen-presenting cells loaded with either of the melanocytic proteins TRP1, TRP2, tyrosinase, gp100, Melan-A and KU-MEL-1. The sensitivity of our recombinant bacteria-based approach was validated with a CD4 T cell clone with known antigen specificity. The ability of each of the 107 clones to secrete cytokines upon nonspecific stimulation was verified. RESULTS: None of the 107 T cell clones was able to secrete tumor necrosis factor-α, interferon-γ, interleukin (IL)-5, or IL-17 upon contact with autologous B cells loaded with any of the six common melanocytic proteins. Nine clones secreted high-level IL-17 upon stimulation with beads coated with antibodies. CONCLUSIONS: The self-antigens that triggered the VKH disease in this patient probably derive from proteins other than the six melanocytic proteins mentioned above. Further study of antigens that are recognized by potential autoreactive T cells from VKH patients is likely to benefit from testing a broader set of melanocytic proteins.

Intravenous cefuroxime as a first-line treatment for women hospitalized for pyelonephritis.

Background: Empirical treatment of pyelonephritis in the emergency ward includes broad-spectrum antibiotics. Such a strategy favours broad-spectrum antibiotic overuse. Local antibiotic stewardship teams can propose local recommendations to adapt empirical antibiotic treatment devoted to spare precious molecules that remain active on MDR bacteria, such as fluoroquinolones or other broad-spectrum antibiotics. Objectives: We aimed to evaluate the incidence of urinary tract infection recurrence within 3 months after hospital discharge following empirical antibiotic therapy with cefuroxime in women with pyelonephritis in the emergency room. Patients and methods: We conducted a retrospective, single-centre study. We identified 109 women treated for pyelonephritis, 95 with cefuroxime at any time, and 14 with only other antibiotics, and divided them into subgroups based on antibiotic switch to other molecules. We compared the incidence of urinary tract infection recurrence in the subgroups. Results: In the group of patients treated with cefuroxime only, we identified five cases of recurrence (9.4%) in a total of 53 patients, but only 1 (1.9%) case of recurrence associated with the same uropathogen. No significant difference in clinical outcome, length of antibiotic treatment, or urinary tract infection recurrence was observed between the subgroups. Conclusions: Our study supports that a strategy elaborated by an antibiotic stewardship team based on local ecology and aimed at proposing the narrowest-spectrum antibiotic upon treatment initiation in the emergency room is safe.

Sniffing out safety: canine detection and identification of SARS-CoV-2 infection from armpit sweat.

Detection dogs were trained to detect SARS-CoV-2 infection based on armpit sweat odor. Sweat samples were collected using cotton pads under the armpits of negative and positive human patients, confirmed by qPCR, for periods of 15-30 min. Multiple hospitals and organizations throughout Belgium participated in this study. The sweat samples were stored at -20°C prior to being used for training purposes. Six dogs were trained under controlled atmosphere conditions for 2-3 months. After training, a 7-day validation period was conducted to assess the dogs' performances. The detection dogs exhibited an overall sensitivity of 81%, specificity of 98%, and an accuracy of 95%. After validation, training continued for 3 months, during which the dogs' performances remained the same. Gas chromatography/mass spectrometry (GC/MS) analysis revealed a unique sweat scent associated with SARS-CoV-2 positive sweat samples. This scent consisted of a wide variety of volatiles, including breakdown compounds of antiviral fatty acids, skin proteins and neurotransmitters/hormones. An acceptability survey conducted in Belgium demonstrated an overall high acceptability and enthusiasm toward the use of detection dogs for SARS-CoV-2 detection. Compared to qPCR and previous canine studies, the detection dogs have good performances in detecting SARS-CoV-2 infection in humans, using frozen sweat samples from the armpits. As a result, they can be used as an accurate pre-screening tool in various field settings alongside the PCR test.

Unplanned pregnancy in an HIV positive woman undergoing alectinib treatment for metastatic non-small-cell lung carcinoma.

We report an unplanned pregnancy in an HIV-positive woman in her 20s who was undergoing treatment for 6 months with alectinib (Alecensa) for stage IV non-small-cell lung carcinoma. Anaplastic lymphoma kinase (ALK)-tyrosine kinase inhibitor alectinib, a molecule that inhibits proteins involved in tumour cell growth, is the recommended first-line treatment option in case of ALK mutation. Although the patient was informed of the need for definitive contraception, she became pregnant during the treatment with alectinib. A complete tumour response was observed at the time the pregnancy was discovered. Treatment discontinuation was proposed as the patient wanted to keep the pregnancy. Alectinib was temporarily stopped throughout the remaining pregnancy period inline with the patient's wishes. The pregnancy was uncomplicated. She delivered a healthy female baby vaginally, with treatment being resumed after delivery. After 34 follow-up months, the patient remained in oncological remission and the child's physical development is normal.

Reversibility of valve regurgitation due to cancer-related non-bacterial thrombotic endocarditis after switching direct oral anticoagulation for heparin.

Non-bacterial thrombotic endocarditis (NBTE) is a rare condition related to a state of hypercoagulability in advanced neoplastic disease. Most of the time, arterial thromboembolic event precedes the diagnosis of NBTE. We report here a case of NBTE responsible for multiple ischaemic strokes, which leads to the diagnosis of metastatic pancreatic adenocarcinoma. Aortic and mitral valvular regurgitations secondary to NBTE appeared within 6 weeks despite therapeutic anticoagulation with direct oral anticoagulant (DOAC) in stroke prevention of paroxysmal atrial fibrillation. Bivalvular regurgitations resolved 8 weeks after therapeutic switch to low-molecular-weight heparin (LMWH) and chemotherapy. DOACs are a possible alternative to LMWH for the prevention of venous thromboembolism in patients with active neoplasia. There is a lack of evidence for a clinical efficiency for the prevention of arterial thromboembolism in NBTE. We propose here a short review of the efficacy of anticoagulant therapy for the prevention of arterial thromboembolism in NBTE.

Serum SARS-CoV-2 Antigens for the Determination of COVID-19 Severity.

The diagnostic of SARS-CoV-2 infection relies on reverse transcriptase polymerase chain reactions (RT-PCRs) performed on nasopharyngeal (NP) swabs. Nevertheless, false-negative results can be obtained with inadequate sampling procedures, making the use of other biological matrices worthy of investigation. This study aims to evaluate the kinetics of serum N antigens in severe and non-severe patients and compare the clinical performance of serum antigenic assays with NP RT-PCR. Ninety patients were included in the study and monitored for several days. Disease severity was determined according to the WHO clinical progression scale. Serum N antigen levels were measured with a chemiluminescent assay (CLIA) and the Single Molecular Array (Simoa) assay. Viremia thresholds for severity were determined and proposed. In severe patients, the peak antigen response was observed 7 days after the onset of symptoms, followed by a decline. No real peak response was observed in non-severe patients. Severity thresholds for the Simoa and the CLIA provided positive likelihood ratios of 30.0 and 10.9 for the timeframe between day 2 and day 14, respectively. Sensitive detection of N antigens in serum may thus provide a valuable new marker for COVID-19 diagnosis and evaluation of disease severity. When assessed during the first 2 weeks since the onset of symptoms, it may help in identifying patients at risk of developing severe COVID-19 to optimize better intensive care utilization.

Tumor-infiltrating lymphocytes: apparently good for melanoma patients. But why?

Tumor-infiltrating T lymphocytes (TILs) are observed in a number of human primary or metastatic tumors. Recently, gene expression profiling experiments suggested that the presence of T cells in metastatic melanomas before vaccinating the patients with tumor antigens could be a biomarker for clinical benefit from the vaccines. In this context, we review results pertaining to TILs in human melanomas, their prognostic value, and some possible reasons why their presence could help in selecting melanoma patients for vaccination against tumor-specific antigens.

Waning of IgG, Total and Neutralizing Antibodies 6 Months Post-Vaccination with BNT162b2 in Healthcare Workers.

Data about the long-term duration of antibodies after SARS-CoV-2 vaccination are still scarce and are important to design vaccination strategies. In this study, 231 healthcare professionals received the two-dose regimen of BNT162b2. Of these, 158 were seronegative and 73 were seropositive at baseline. Samples were collected at several time points. The neutralizing antibodies (NAbs) and antibodies against the nucleocapsid and the spike protein of SARS-CoV-2 were measured. At day 180, a significant antibody decline was observed in seronegative (-55.4% with total antibody assay; -89.6% with IgG assay) and seropositive individuals (-74.8% with total antibody assay; -79.4% with IgG assay). The estimated half-life of IgG from the peak humoral response was 21 days (95% CI: 13-65) in seronegative and 53 days (95% CI: 40-79) in seropositive individuals. The estimated half-life of total antibodies was longer and ranged from 68 days (95% CI: 54-90) to 114 days (95% CI: 87-167) in seropositive and seronegative individuals, respectively. The decline of NAbs was more pronounced (-98.6%) and around 45% of the subjects tested were negative at day 180. Whether this decrease correlates with an equivalent drop in the clinical effectiveness against the virus would require appropriate clinical studies.

Antibody titres decline 3-month post-vaccination with BNT162b2.

Several studies reported on the humoral response in subjects having received the BNT162b2 mRNA COVID-19 vaccine. However, data on the kinetics of antibodies 3 months post-vaccination are currently lacking and are important to drive the future vaccination strategy. The CRO-VAX HCP study is an ongoing multicentre, prospective and interventional study designed to assess the antibody response in a population of healthcare professionals who had received two doses of the BNT162b2 mRNA COVID-19 vaccine. Two hundred individuals underwent a blood drawn within 2 days before the first vaccine dose. One-hundred and forty-two persons (71%) were categorized as seronegative at baseline while 58 (29%) were seropositive. Samples were then collected after 14, 28, 42, 56, and 90 days. Antibodies against the SARS-CoV-2 nucleocapsid and the receptor binding domain of the S1 subunit of the spike protein were measured in all individuals at different time points. Using a one-compartment kinetics model, the time to maximum concentration was estimated at 36 ± 3 days after the first dose and the estimated half-life of antibodies was 55 days (95% CI: 37-107 days) in seronegative participants. In seropositive participants, the time to maximum concentration was estimated at 24 ± 4 days and the estimated half-life was 80 days (95% CI: 46-303 days). The antibody response was higher in seropositive compared to seronegative participants. In both seropositive and seronegative subjects, a significant antibody decline was observed at 3 months compared to the peak response. Nevertheless, the humoral response remained robust in all participants.

Confounding Factors Influencing the Kinetics and Magnitude of Serological Response Following Administration of BNT162b2.

BACKGROUND: Little is known about potential confounding factors influencing the humoral response in individuals having received the BNT162b2 vaccine. METHODS: Blood samples from 231 subjects were collected before and 14, 28, and 42 days following coronavirus disease 2019 (COVID-19) vaccination with BNT162b2. Anti-spike receptor-binding-domain protein (anti-Spike/RBD) immunoglobulin G (IgG) antibodies were measured at each time-point. Impact of age, sex, childbearing age status, hormonal therapy, blood group, body mass index and past-history of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection were assessed by multivariable analyses. RESULTS AND CONCLUSIONS: In naïve subjects, the level of anti-Spike/RBD antibodies gradually increased following administration of the first dose to reach the maximal response at day 28 and then plateauing at day 42. In vaccinated subjects with previous SARS-CoV-2 infection, the plateau was reached sooner (i.e., at day 14). In the naïve population, age had a significant negative impact on anti-Spike/RBD titers at days 14 and 28 while lower levels were observed for males at day 42, when corrected for other confounding factors. Body mass index (BMI) as well as B and AB blood groups had a significant impact in various subgroups on the early response at day 14 but no longer after. No significant confounding factors were highlighted in the previously infected group.

The Gut-Lung Axis in Health and Respiratory Diseases: A Place for Inter-Organ and Inter-Kingdom Crosstalks.

The gut and lungs are anatomically distinct, but potential anatomic communications and complex pathways involving their respective microbiota have reinforced the existence of a gut-lung axis (GLA). Compared to the better-studied gut microbiota, the lung microbiota, only considered in recent years, represents a more discreet part of the whole microbiota associated to human hosts. While the vast majority of studies focused on the bacterial component of the microbiota in healthy and pathological conditions, recent works have highlighted the contribution of fungal and viral kingdoms at both digestive and respiratory levels. Moreover, growing evidence indicates the key role of inter-kingdom crosstalks in maintaining host homeostasis and in disease evolution. In fact, the recently emerged GLA concept involves host-microbe as well as microbe-microbe interactions, based both on localized and long-reaching effects. GLA can shape immune responses and interfere with the course of respiratory diseases. In this review, we aim to analyze how the lung and gut microbiota influence each other and may impact on respiratory diseases. Due to the limited knowledge on the human virobiota, we focused on gut and lung bacteriobiota and mycobiota, with a specific attention on inter-kingdom microbial crosstalks which are able to shape local or long-reached host responses within the GLA.

Do Probiotics During In-Hospital Antibiotic Treatment Prevent Colonization of Gut Microbiota With Multi-Drug-Resistant Bacteria? A Randomized Placebo-Controlled Trial Comparing Saccharomyces to a Mixture of Lactobacillus, Bifidobacterium, and Saccharomyces.

Objective: Most infections with Enterobacteriaceae producing AmpC ß-lactamase (AmpC)-, extended-spectrum ß-lactamase (ESBL)-, and carbapenemase-producing bacteria, vancomycin-resistant Enterococcus as well as naturally resistant non-fermenting bacteria such as Pseudomonas aeruginosa, are related to a prior colonization of the gut microbiota. The objective of this study was to determine whether treatment with probiotics during an antibiotic treatment could prevent the colonization of the gut microbiota with multi-drug resistant bacteria. Method: In total, 120 patients treated for 10 days with amoxicillin-clavulanate antibiotics were included in a randomized, placebo-controlled, double-blinded trial, comparing the effects of a 30 days treatment with placebo Saccharomyces boulardii CNCM I-745® and a probiotic mixture containing Saccharomyces boulardii, Lactobacillus acidophilus NCFM, Lactobacillus paracasei Lpc-37, Bifidobacterium lactis Bl-04, and Bifidobacterium lactis Bi-07 (Bactiol duo®). Study treatment was initiated within 48 h of the antibiotic being initiated. Most of the patients included were elderly with a mean age of 78 years old with multiple comorbidities. Stools were collected at the time of inclusion in the trial, at the end of the antibiotic treatment, and the end of the study treatment. These were cultured on selective antibiotic media. Results: Treatment with the probiotic mixture led to a significant decline in colonization with Pseudomonas after antibiotic treatment from 25 to 8.3% (p = 0.041). Colonization with AmpC-producing enterobacteria was transiently increased after the antibiotic treatment (p = 0.027) and declined after the probiotic intervention (p= 0.041). No significant changes were observed in the placebo and Saccharomyces groups. Up to 2 years after the trial, no infection with ESBL-producing bacteria was observed in the probiotic mixture group. Conclusion: The association of Saccharomyces boulardii with specific strains of Lactobacillus and Bifidobacterium influences antibiotic treatment by counteracting the colonization of the colon microbiota with antibiotic-resistant pathogens.

How Probiotics Affect the Microbiota.

Probiotics have been used to treat a variety of diseases for decades; however, what is the rationale for their application? Such a treatment was first proposed in the early nineteenth century based on observations of decreased bifidobacterial populations in children suffering from diarrhea, suggesting that oral intake of bifidobacteria could replete this subpopulation of the microbiota and improve health. Since then, studies have shown modifications in the gut or skin microbiota in the course of a variety of diseases and suggested positive effects of certain probiotics. Most studies failed to report any impact on the microbiota. The impact of probiotics as well as of bacteria colonizing food does not reside in their ability to graft in the microbiota but rather in sharing genes and metabolites, supporting challenged microbiota, and directly influencing epithelial and immune cells. Such observations argue that probiotics could be associated with conventional drugs for insulin resistance, infectious diseases, inflammatory diseases, and psychiatric disorders and could also interfere with drug metabolism. Nevertheless, in the context of a plethora of probiotic strains and associations produced in conditions that do not allow direct comparisons, it remains difficult to know whether a patient would benefit from taking a particular probiotic. In other words, although several mechanisms are observed when studying a single probiotic strain, not all individual strains are expected to share the same effects. To clarify the role of probiotics in the clinic, we explored the relation between probiotics and the gut and skin microbiota.

Pre- and post-transplant monitoring of granzyme B enzyme-linked immunosorbent spot assay in pediatric liver recipients.

UNLABELLED: This study aims to investigate potential role of granzyme B enzyme-linked immunosorbent spot (GrB ELISPOT) for immunological monitoring in pediatric liver transplantation. PATIENTS AND METHODS: Peripheral blood mononuclear cells from 28 pediatric recipients were serially tested for GrB-producing donor-reactive cells at day 0 pre-transplantation (baseline) and days 7, 14, and 28 post-transplantation. RESULTS: At baseline, no difference of GrB value was found in acute rejection (14/28) compared to normal graft function patients (day 0: 4(3.9) spots versus 5(2.9) spots, respectively: p=0.65). At day 7 post-transplantation, acute rejection patients showed frequencies of GrB ELISPOT higher than those with normal graft function, but the differences observed were not statistically significant (day 7: 15(4.9) spots versus 10(4.0) spots, respectively: p=0.55). GrB increased significantly at day 7 from baseline in the rejection group (15(4.9) spots versus 4(3.9), respectively p=0.04), whereas corresponding changes were not significant in the group without rejection (10(4.0) versus 5(2.9), respectively: p=0.15). CONCLUSION: GrB ELISPOT pre-transplantation could not predict the occurrence of early post-transplant acute rejection; similarly frequencies at days 7, 14 and 28 could not be correlated with acute rejection in pediatric liver recipients. However, a kinetic study of GrB ELISPOT could be helpful to predict or confirm early rejection in the small group of liver allograft recipients analyzed in this study.

Monitoring tolerance after human liver transplantation.

The validation of reliable, non-invasive immunological assays evaluating anti-donor responsiveness in allograft recipients would provide a clinically relevant tool for the early detection of ongoing rejection process as well as for the identification of operational tolerance in the long term. A sequential approach towards immunological monitoring of allografts is proposed in this review: (i) investigations exploring the initial donor-recipient alloresponses, including the analysis of the cytokine network; (ii) investigations regarding graft acceptance and operational tolerance in long-term transplant patients, consisting in the analysis of regulatory T cells and of circulating precursors of dendritic cells, in the measurement of T cell alloreactivity as well as in the study of T cell receptor repertoires. Beside the conventional in vivo and in vitro immunological techniques, the potential applications of molecular imaging in transplantation also deserve further exploration, with particular respect to allograft immune monitoring. Enforced collaboration between transplant clinicians and immunologists will be required to develop the translational research protocols required for the development of immunological monitoring, within an international multicentric network.

Immunological monitoring after organ transplantation: potential role of soluble CD30 blood level measurement.

Analysing the relevance of soluble CD30 (sCD30) in the bloodstream before and after transplantation may be important for the monitoring of transplant recipients. In this study, 27 patients (15 pediatric liver and 12 adult kidney graft recipients) were investigated. In the liver graft group, the patients who developed acute rejection during the first month (n=9) had a slightly higher sCD30 value on pre-transplantation baseline (day 0) and post-transplantation day 7, when compared to patients with normal graft function (n=6) (day 0: 102(1.6) U/ml versus 118(1.5) U/ml, p=0.52) and (day 7: 69(1.5) U/ml versus 83(1.6) U/ml, p=0.47). Increased serum sCD30 was shown to correlate with increased interleukin-10 circulating levels between day 0 and day 7 (r=0.53; p=0.04), whereas, no correlation could be evidenced between interferon-gamma (IFN-gamma) and sCD30 (r=0.02; p=0.47). Similarly, in the kidney transplantation group, no significant difference was found in sCD30 levels at day 0 in both groups with graft rejection or normal graft function (n=6) (85(1.3) U/ml versus 77(1.6) U/ml, p=0.66), but sCD30 decreased significantly at day 7 post-transplantation from baseline value in the rejection group (n=6) (77(1.6) versus 35(1.4); p=0.02). We conclude that increased serum sCD30 was correlated with increased IL-10 (interleukin-10) circulating levels, but not with IFN-gamma levels in the post-transplantation period. Neither pre-transplantation sCD30 nor sCD30 at day 7 post-transplantation could be correlated with acute rejection in liver graft recipient. The monitoring of sCD30 might constitute a tool to assess the risk of acute rejection in renal transplant but did not appear as a valuable mean for early immunological monitoring in the small group of liver allograft recipients patients analysed in this study.

Fever, bone pain and erectile dysfunction. Where is the cat?

Cat-scratch disease is due to Bartonella henselae and commonly presents as a localised papular lesion with regional lymphadenopathy. We report the case of a young man suffering general symptoms and dysautonomy characterised by an erectile dysfunction due to an invasive cat-scratch disease. He was successfully treated by tetracyclines during 3 weeks.