Humoral immune responses are typically characterized by primary IgM antibody responses followed by secondary antibody responses associated with immune memory and composed of IgG, IgA, and IgE. Here, ...we measured acute humoral responses to SARS-CoV-2, including the frequency of antibody-secreting cells and the presence of SARS-CoV-2-specific neutralizing antibodies in the serum, saliva, and bronchoalveolar fluid of 159 patients with COVID-19. Early SARS-CoV-2-specific humoral responses were dominated by IgA antibodies. Peripheral expansion of IgA plasmablasts with mucosal homing potential was detected shortly after the onset of symptoms and peaked during the third week of the disease. The virus-specific antibody responses included IgG, IgM, and IgA, but IgA contributed to virus neutralization to a greater extent compared with IgG. Specific IgA serum concentrations decreased notably 1 month after the onset of symptoms, but neutralizing IgA remained detectable in saliva for a longer time (days 49 to 73 post-symptoms). These results represent a critical observation given the emerging information as to the types of antibodies associated with optimal protection against reinfection and whether vaccine regimens should consider targeting a potent but potentially short-lived IgA response.
Anecdotal evidence rapidly accumulated during March 2020 from sites around the world that sudden hyposmia and hypogeusia are significant symptoms associated with the SARS-CoV-2 pandemic. Our ...objective was to describe the prevalence of hyposmia and hypogeusia and compare it in hospitalized and non-hospitalized COVID-19 patients to evaluate an association of these symptoms with disease severity. We performed a cross-sectional survey during 5 consecutive days in March 2020, within a tertiary referral center, associated outpatient clinic, and two primary care outpatient facilities in Paris. All SARS-CoV-2-positive patients hospitalized during the study period and able to be interviewed (
n
= 198), hospital outpatients seen during the previous month (
n
= 129), and all COVID-19-highly suspect patients in two primary health centers (
n
= 63) were included. Hospitalized patients were significantly more often male (64 vs 40%) and older (66 vs 43 years old in median) and had significantly more comorbidities than outpatients. Hyposmia and hypogeusia were reported by 33% of patients and occurred significantly less frequently in hospitalized patients (12% and 13%, respectively) than in the health centers’ outpatients (33% and 43%, respectively) and in the hospital outpatients (65% and 60%, respectively). Hyposmia and hypogeusia appeared more frequently after other COVID-19 symptoms. Patients with hyposmia and/or hypogeusia were significantly younger and had significantly less respiratory severity criteria than patients without these symptoms. Olfactory and gustatory dysfunction occurs frequently in COVID-19, especially in young, non-severe patients. These symptoms might be a useful tool for initial diagnostic work-up in patients with suspected COVID-19.
Our aim was to evaluate systemic lupus erythematosus (SLE) disease activity and SARS-CoV-2-specific immune responses after BNT162b2 vaccination.
In this prospective study, disease activity and ...clinical assessments were recorded from the first dose of vaccine until day 15 after the second dose in 126 patients with SLE. SARS-CoV-2 antibody responses were measured against wild-type spike antigen, while serum-neutralising activity was assessed against the SARS-CoV-2 historical strain and variants of concerns (VOCs). Vaccine-specific T cell responses were quantified by interferon-γ release assay after the second dose.
BNT162b2 was well tolerated and no statistically significant variations of BILAG (British Isles Lupus Assessment Group) and SLEDAI (SLE Disease Activity Index) scores were observed throughout the study in patients with SLE with active and inactive disease at baseline. Mycophenolate mofetil (MMF) and methotrexate (MTX) treatments were associated with drastically reduced BNT162b2 antibody response (β=-78, p=0.007; β=-122, p<0.001, respectively). Anti-spike antibody response was positively associated with baseline total immunoglobulin G serum levels, naïve B cell frequencies (β=2, p=0.018; β=2.5, p=0.003) and SARS-CoV-2-specific T cell response (r=0.462, p=0.003). In responders, serum neutralisation activity decreased against VOCs bearing the E484K mutation but remained detectable in a majority of patients.
MMF, MTX and poor baseline humoral immune status, particularly low naïve B cell frequencies, are independently associated with impaired BNT162b2 mRNA antibody response, delineating patients with SLE who might need adapted vaccine regimens and follow-up.
CD4+CD25highCD127low/−FOXP3+ T regulatory cells are responsible for maintaining immune tolerance and controlling excessive immune responses. Treg cell use in pre‐clinical animal models showed the ...huge therapeutic potential of these cells in immune‐mediated diseases and laid the foundations for their applications in therapy in humans. Currently, there are several clinical trials utilizing the adoptive transfer of Treg cells to reduce the morbidity in autoimmune disorders, allogeneic HSC transplantation, and solid organ transplantation. However, a large part of them utilizes total Treg cells without distinction of their biological variability. Many studies on the heterogeneity of Treg cell population revealed distinct subsets with different functions in the control of the immune response and induction of peripheral tolerance. Some of these subsets also showed a role in controlling the general homeostasis of non‐lymphoid tissues. All these Treg cell subsets and their peculiar properties can be therefore exploited to develop novel therapeutic approaches. This review describes these functionally distinct subsets, their phenotype, homing properties and functions in lymphoid and non‐lymphoid tissues. In addition, we also discuss the limitations in using Treg cells as a cellular therapy and the strategies to enhance their efficacy.
The study of heterogeneity in Treg‐cell population reveals cell subsets with distinct phenotypes, homing abilities and functions. These cells have a role in maintaining homeostasis in lymphoid and non‐lymphoid tissues. This review describes the clinical potential of these cells and discuss strategies to enhance the efficacy of future Treg‐cell therapies.
Plasmodium falciparum immature gametocytes accumulate in the bone marrow, but their exact location in this tissue remains unclear.
The stage and deposition pattern of gametocytes was analysed on ...histological sections of a bone marrow sample collected in a patient with subacute P. falciparum malaria.
A majority (89%) of immature stages II to IV gametocytes and a minority (29%) of mature stage V gametocytes were observed in extravascular spaces.
These observations represent a valuable step towards understanding sequestration patterns of P. falciparum gametocytes and may ultimately lead to novel transmission-blocking interventions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract Relapsing polychondritis (RP) is a very rare autoimmune disease characterised by a relapsing inflammation of the cartilaginous tissues (joints, ears, nose, intervertebral discs, larynx, ...trachea and cartilaginous bronchi), which may progress to long-lasting atrophy and/or deformity of the cartilages. Non-cartilaginous tissues may also be affected, such as the eyes, heart, aorta, inner ear and skin. RP has a long and unpredictable course. Because no randomised therapeutic trials are available, the treatment of RP remains mainly empirical. Minor forms of the disease can be treated with non-steroidal anti-inflammatory drugs, whereas more severe forms are treated with systemic corticosteroids. Life-threatening diseases and corticosteroid-dependent or resistant diseases are an indication for immunosuppressant therapy such as methotrexate, azathioprine, mycophenolate mofetil and cyclophosphamide. Biologics could be given as second-line treatment in patients with an active disease despite the use of steroids and immunosuppressive drugs. Although the biologics represent new potential treatment for RP, very scarce information is available to draw any firm conclusion on their use in RP.
Langerhans cell histiocytosis (LCH) and the non-LCH neoplasm Erdheim-Chester disease (ECD) are heterogeneous neoplastic disorders marked by infiltration of pathologic macrophage-, dendritic cell–, or ...monocyte-derived cells in tissues driven by recurrent mutations activating MAPK signaling. Although recent data indicate that at least a proportion of LCH and ECD patients have detectable activating kinase mutations in circulating hematopoietic cells and bone marrow–based hematopoietic progenitors, functional evidence of the cell of origin of histiocytosis from actual patient materials has long been elusive. Here, we provide evidence for mutations in MAPK signaling intermediates in CD34+ cells from patients with ECD and LCH/ECD, including detection of shared origin of LCH and acute myelomonocytic leukemia driven by TET2-mutant CD34+ cell progenitors in one patient. We also demonstrate functional self-renewal capacity for CD34+ cells to drive the development of histiocytosis in xenotransplantation assays in vivo. These data indicate that the cell of origin of at least a proportion of patients with systemic histiocytoses resides in hematopoietic progenitor cells prior to committed monocyte/macrophage or dendritic cell differentiation and provide the first example of a patient-derived xenotransplantation model for a human histiocytic neoplasm.
•BRAFV600E mutations are detectable in hematopoietic stem and progenitors in adults with histiocytosis.•Transplantation of CD34+ cells from histiocytosis patients can give rise to genetically and phenotypically accurate xenografts.
The induction of graft tolerance remains the holy grail of transplantation. This is important as chronic allograft dysfunction and the side effects of immunosuppression regimens place a major burden ...on the lives of transplant patients and their healthcare systems. This has mandated the need to understand the immunobiology of graft rejection and identify novel therapeutics. Regulatory T (Treg) cells play an important role in modulating pro‐inflammatory microenvironments and maintaining tissue homeostasis. However, there are fundamental unanswered questions regarding Treg cell immunobiology. These cells are a heterogeneous entity with functionally diverse roles. Moreover, the adoption of novel deeper immunophenotyping and genomic sequencing technologies has identified this phenotype and function to be more complex than expected. Hence, a comprehensive understanding of Treg cell heterogeneity is needed to safely and effectively exploit their therapeutic potential. From a clinical perspective, the recent decade has seen different clinical teams commence and complete first‐in‐man clinical trials utilising Treg cells as an adoptive cellular therapy. In this review, we discuss these trials from a translational perspective with an important focus on safety. Finally, we identify crucial knowledge gaps for future study.
Treg cell therapy has the potential to revolutionise current post‐transplant immunosuppression protocols. Treg cells are presently undergoing early phase trials in solid organ transplantation. However, there are multiple questions regarding Treg cell immunobiology that need to be resolved.
Adults who have been infected with SARS-CoV-2 can develop a multisystem inflammatory syndrome (MIS-A), including fulminant myocarditis. Yet, several patients fail to meet MIS-A criteria, suggesting ...the existence of distinct phenotypes in fulminant COVID-19-related myocarditis.
This study sought to compare the characteristics and clinical outcome between patients with fulminant COVID-19-related myocarditis fulfilling MIS-A criteria (MIS-A
) or not (MIS-A
).
A monocentric retrospective analysis of consecutive fulminant COVID-19-related myocarditis in a 26-bed intensive care unit (ICU).
Between March 2020 and June 2021, 38 patients required ICU admission (male 66%; mean age 32 ± 15 years) for suspected fulminant COVID-19-related myocarditis. In-ICU treatment for organ failure included dobutamine 79%, norepinephrine 60%, mechanical ventilation 50%, venoarterial extracorporeal membrane oxygenation 42%, and renal replacement therapy 29%. In-hospital mortality was 13%. Twenty-five patients (66%) met the MIS-A criteria. MIS-A
patients compared with MIS-A
patients were characterized by a shorter delay between COVID-19 symptoms onset and myocarditis, a lower left ventricular ejection fraction, and a higher rate of in-ICU organ failure, and were more likely to require mechanical circulatory support with venoarterial extracorporeal membrane oxygenation (92% vs 16%; P < 0.0001). In-hospital mortality was higher in MIS-A
patients (31% vs 4%). MIS-A
had higher circulating levels of interleukin (IL)-22, IL-17, and tumor necrosis factor-α (TNF-α), whereas MIS-A
had higher interferon-α2 (IFN-α2) and IL-8 levels. RNA polymerase III autoantibodies were present in 7 of 13 MIS-A
patients (54%) but in none of the MIS-A
patients.
MIS-A
and MIS-A
fulminant COVID-19-related myocarditis patients have 2 distinct phenotypes with different clinical presentations, prognosis, and immunological profiles. Differentiating these 2 phenotypes is relevant for patients' management and further understanding of their pathophysiology.
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