Phenotype of BTK-lacking myeloid cells during prolonged COVID-19 and upon convalescent plasma.

XLA patient with 7-month course of COVID-19 with persistent plasma SARS-CoV-2 load revealed a sustained non-inflammatory profile of myeloid cells in association with contained severity of disease, arguing in favor of the use of BTK inhibitors in SARS-COV-2 infection.

SARS-CoV2 pneumonia recovery is linked to expansion of innate lymphoid cells type 2 expressing CCR10.

Accelerate lung repair in SARS-CoV-2 pneumonia is essential for pandemic handling. Innate lymphoid cells (ILCs) are likely players, given their role in mucosal protection and tissue homeostasis. We studied ILC subpopulations at two time points in a cohort of patients admitted in the hospital due to SARS-CoV-2 infection. COVID-19 patients with moderate/severe respiratory failure featured profound depletion of circulating ILCs at hospital admission, in agreement with overall lymphocyte depletion. However, ILCs recovered in direct correlation with lung function improvement as measured by oxygenation index and in negative association with inflammatory and lung/endothelial damage markers like RAGE. While both ILC1 and ILC2 expanded, ILC2 showed the most striking phenotype changes, with CCR10 upregulation in strong correlation with these parameters. Overall, CCR10+ ILC2 emerge as relevant contributors to SARS-CoV-2 pneumonia recovery.

Acute HIV-1 and SARS-CoV-2 Infections Share Slan+ Monocyte Depletion-Evidence from an Hyperacute HIV-1 Case Report.

Monocytes are key modulators in acute viral infections, determining both inflammation and development of specific B- and T-cell responses. Recently, these cells were shown to be associated to different SARS-CoV-2 infection outcome. However, their role in acute HIV-1 infection remains unclear. We had the opportunity to evaluate the mononuclear cell compartment in an early hyper-acute HIV-1 patient in comparison with an untreated chronic HIV-1 and a cohort of SARS-CoV-2 infected patients, by high dimensional flow cytometry using an unsupervised approach. A distinct polarization of the monocyte phenotype was observed in the two viral infections, with maintenance of pro-inflammatory M1-like profile in HIV-1, in contrast to the M2-like immunosuppressive shift in SARS-CoV-2. Noticeably, both acute infections had reduced CD14low/-CD16+ non-classical monocytes, with depletion of the population expressing Slan (6-sulfo LacNac), which is thought to contribute to immune surveillance through pro-inflammatory properties. This depletion indicates a potential role of these cells in acute viral infection, which has not previously been explored. The inflammatory state accompanied by the depletion of Slan+ monocytes may provide new insights on the critical events that determine the rate of viral set-point in acute HIV-1 infection and subsequent impact on transmission and reservoir establishment.

Severe COVID-19 Recovery Is Associated with Timely Acquisition of a Myeloid Cell Immune-Regulatory Phenotype.

After more than one year since the COVID-19 outbreak, patients with severe disease still constitute the bottleneck of the pandemic management. Aberrant inflammatory responses, ranging from cytokine storm to immune-suppression, were described in COVID-19 and no treatment was demonstrated to change the prognosis significantly. Therefore, there is an urgent need for understanding the underlying pathogenic mechanisms to guide therapeutic interventions. This study was designed to assess myeloid cell activation and phenotype leading to recovery in patients surviving severe COVID-19. We evaluated longitudinally patients with COVID-19 related respiratory insufficiency, stratified according to the need of intensive care unit admission (ICU, n = 11, and No-ICU, n = 9), and age and sex matched healthy controls (HCs, n = 11), by flow cytometry and a wide array of serum inflammatory/immune-regulatory mediators. All patients featured systemic immune-regulatory myeloid cell phenotype as assessed by both unsupervised and supervised analysis of circulating monocyte and dendritic cell subsets. Specifically, we observed a reduction of CD14lowCD16+ monocytes, and reduced expression of CD80, CD86, and Slan. Moreover, mDCs, pDCs, and basophils were significantly reduced, in comparison to healthy subjects. Contemporaneously, both monocytes and DCs showed increased expression of CD163, CD204, CD206, and PD-L1 immune-regulatory markers. The expansion of M2-like monocytes was significantly higher at admission in patients featuring detectable SARS-CoV-2 plasma viral load and it was positively correlated with the levels of specific antibodies. In No-ICU patients, we observed a peak of the alterations at admission and a progressive regression to a phenotype similar to HCs at discharge. Interestingly, in ICU patients, the expression of immuno-suppressive markers progressively increased until discharge. Notably, an increase of M2-like HLA-DRhighPD-L1+ cells in CD14++CD16- monocytes and in dendritic cell subsets was observed at ICU discharge. Furthermore, IFN-γ and IL-12p40 showed a decline over time in ICU patients, while high values of IL1RA and IL-10 were maintained. In conclusion, these results support that timely acquisition of a myeloid cell immune-regulatory phenotype might contribute to recovery in severe systemic SARS-CoV-2 infection and suggest that therapeutic agents favoring an innate immune system regulatory shift may represent the best strategy to be implemented at this stage.

Early ART in Acute HIV-1 Infection: Impact on the B-Cell Compartment.

HIV-1 infection induces B cell defects, not fully recovered upon antiretroviral therapy (ART). Acute infection and the early start of ART provide unique settings to address the impact of HIV on the B cell compartment. We took advantage of a cohort of 21 seroconverters, grouped according to the presence of severe manifestations likely mediated by antibodies or immune complexes, such as Guillain-Barré syndrome and autoimmune thrombocytopenic purpura, with a follow-up of 8 weeks upon effective ART. We combined B and T cell phenotyping with serum immunoglobulin level measurement and quantification of sj-KRECs and ΔB to estimate bone marrow output and peripheral proliferative history of B cells, respectively. We observed marked B cell disturbances, notably a significant expansion of cells expressing low levels of CD21, in parallel with markers of both impaired bone marrow output and increased peripheral B cell proliferation. This B cell dysregulation is likely to contribute to the severe immune-mediated conditions, as attested by the higher serum IgG and the reduced levels of sj-KRECs with increased ΔB in these individuals as compared to those patients with mild disease. Nevertheless, upon starting ART, the dynamic of B cell recovery was not distinct in the two groups, featuring both persistent alterations by week 8. Overall, we showed for the first time that acute HIV-1 infection is associated with decreased bone marrow B cell output assessed by sj-KRECs. Our study emphasizes the need to intervene in both bone marrow and peripheral responses to facilitate B cell recovery during acute HIV-1 infection.

Automated assessment of absolute nailfold capillary number on videocapillaroscopic images: Proof of principle and validation in systemic sclerosis.

BACKGROUND: Absolute nailfold capillary number should be a putative biomarker in selected rheumatic diseases but could be time-consuming and not highly repeatable. OBJECTIVE: To validate an automated software for absolute nailfold capillary number and density evaluation, on NVC images in SSc. METHODS: An automated software to count nailfold capillary number (AUTOCAPI) had been constructed, through an exploratory image set. Subsequently, application rules have been created to define the ROI in NVC images, through a training images set. The software reliability was assessed through calculation of the ICC between automatic and manual counting, by four independent observers, on the same NVC images. RESULTS: The following ICC's were obtained per observer, for the patients with SSc (40 images), the healthy (20 images), and the PRP subgroups (20 images), respectively: 0.94, 0.81, and 0.62 (observer 1); 0.94, 0.91, and 0.67 (observer 2); 0.88, 0.56, and 0.64 (observer 3); and 0.88, 0.85, and 0.85 (observer 4). CONCLUSIONS: The validation of an automated software for measuring absolute nailfold capillary number and density in SSc was achieved. The integration into the pre-existing imaging software should make the assessment of the capillary number in NVC easier, quicker, and standardized.

Nailfold Capillaroscopy and Clinical Applications in Systemic Sclerosis.

Capillary microscopy is a safe and non-invasive tool to evaluate the morphology of the microcirculation typically affected in SSc. Next to being paramount for the "(very) early" diagnosis of SSc eyes are also geared toward capillaroscopy with the aim to be able to use it as a biomarker, especially in the prediction of future occurrence of DU. The following review will explain what capillary microscopy is and will focus additionally on studies evaluating the association between capillaroscopy and DU.

Regression of systemic lupus erythematosus after development of an acquired toll-like receptor signaling defect and antibody deficiency.

Toll-like receptor 9 (TLR-9) and TLR-7 may have a role in the production of anti-DNA and anti-RNA autoantibodies, respectively, but murine models do not clearly demonstrate their contribution to the development of systemic lupus erythematosus (SLE). Herein we describe a patient with SLE who had long-lasting remission of her autoimmune disease after development of an antibody deficiency resembling common variable immunodeficiency (CVID). After CVID had developed, anti-double-stranded DNA antibodies disappeared, although antinuclear antibodies remained positive for >10 years. In vitro studies revealed that the patient's B cells proliferated poorly and failed to differentiate into plasmablasts after stimulation of either TLR-9 or TLR-7, providing evidence for an acquired defect of the signaling pathway downstream of these TLRs. These observations suggest, although indirectly, that signaling through TLR-9 and TLR-7 is important in the pathogenesis of human SLE, and indicate that investigation of potential treatment strategies with TLR antagonists is warranted.