Atoms to Phenotypes: Molecular Design Principles of Cellular Energy Metabolism.

We report a 100-million atom-scale model of an entire cell organelle, a photosynthetic chromatophore vesicle from a purple bacterium, that reveals the cascade of energy conversion steps culminating in the generation of ATP from sunlight. Molecular dynamics simulations of this vesicle elucidate how the integral membrane complexes influence local curvature to tune photoexcitation of pigments. Brownian dynamics of small molecules within the chromatophore probe the mechanisms of directional charge transport under various pH and salinity conditions. Reproducing phenotypic properties from atomistic details, a kinetic model evinces that low-light adaptations of the bacterium emerge as a spontaneous outcome of optimizing the balance between the chromatophore's structural integrity and robust energy conversion. Parallels are drawn with the more universal mitochondrial bioenergetic machinery, from whence molecular-scale insights into the mechanism of cellular aging are inferred. Together, our integrative method and spectroscopic experiments pave the way to first-principles modeling of whole living cells.

Diagnosis and management of ANCA-associated vasculitis.

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis consists of two main diseases, granulomatosis with polyangiitis and microscopic polyangiitis, and remains among the most devastating and potentially lethal forms of autoimmune inflammatory disease. Granulomatosis with polyangiitis and microscopic polyangiitis are characterised by a necrotising vasculitis that can involve almost any organ, and have generally been studied together. The diseases commonly affect the kidneys, lungs, upper respiratory tract, skin, eyes, and peripheral nerves. Granulomatous inflammation and multinucleated giant cells are key pathological hallmarks of granulomatosis with polyangiitis, but are absent in microscopic polyangiitis. Many immune system events are essential to disease aetiopathogenesis, such as activation of the alternative complement pathway, neutrophil activation via complement receptors, and the influx of inflammatory cells, including monocytes and macrophages. These cells perpetuate inflammation and lead to organ damage. During the 21st century, the management of ANCA-associated vasculitis has moved away from reliance on cytotoxic medications and towards targeted biological medications for both the induction and maintenance of disease remission. Earlier diagnosis, partly the result of more reliable ANCA testing, has led to improved patient outcomes and better survival. Reductions in acute disease-related mortality have now shifted focus to long-term morbidities related to ANCA-associated vasculitis and their treatments, such as chronic kidney disease and cardiovascular disease. Therapeutic approaches in both clinical trials and clinical practice still remain too reliant on glucocorticoids, and continued efforts to reduce toxicity from glucocorticoids remain a priority in the development of new treatment strategies.

Granzyme K- and amphiregulin-expressing cytotoxic T cells and activated extrafollicular B cells are potential drivers of IgG4-related disease.

BACKGROUND: IgG4-related disease (IgG4-RD), an example of a type I immune disease, is an immune-mediated fibrotic disorder characterized by dysregulated resolution of severe inflammation and wound healing. However, truly dominant or pathognomonic autoantibodies related to IgG4-RD are not identified. OBJECTIVE: We sought to perform single-cell RNA sequencing and T-cell receptor and B-cell receptor sequencing to obtain a comprehensive, unbiased view of tissue-infiltrating T and B cells. METHODS: We performed unbiased single-cell RNA-sequencing analysis for the transcriptome and T-cell receptor sequencing and B-cell receptor sequencing on sorted CD3+ T or CD19+ B cells from affected tissues of patients with IgG4-RD. We also conducted quantitative analyses of CD3+ T-cell and CD19+ B-cell subsets in 68 patients with IgG4-RD and 30 patients with Sjögren syndrome. RESULTS: Almost all clonally expanded T cells in these lesions were either Granzyme K (GZMK)-expressing CD4+ cytotoxic T cells or GZMK+CD8+ T cells. These GZMK-expressing cytotoxic T cells also expressed amphiregulin and TGF-ß but did not express immune checkpoints, and the tissue-infiltrating CD8+ T cells were phenotypically heterogeneous. MKI67+ B cells and IgD-CD27-CD11c-CXCR5- double-negative 3 B cells were clonally expanded and infiltrated affected tissue lesions. GZMK+CD4+ cytotoxic T cells colocalized with MKI67+ B cells in the extrafollicular area from affected tissue sites. CONCLUSIONS: The above-mentioned cells likely participate in T-B collaborative events, suggesting possible avenues for targeted therapies. Our findings were validated using orthogonal approaches, including multicolor immunofluorescence and the use of comparator disease groups, to support the central role of cytotoxic CD4+ and CD8+ T cells expressing GZMK, amphiregulin, and TGF-ß in the pathogenesis of inflammatory fibrotic disorders.

Clinical Perspectives on IgG4-Related Disease and Its Classification.

Immunoglobulin G4-related disease (IgG4-RD) is a systemic immune-mediated fibroinflammatory disease. Since its discovery nearly two decades ago, our understanding of its pathophysiology and clinical manifestations has grown substantially. Early diagnosis and treatment of this elusive disease can prevent substantial organ damage from end-stage fibrosis, emphasizing the need for prompt recognition and accurate characterization of IgG4-RD. The classification criteria endorsed by the American College of Rheumatology and the European Alliance of Associations for Rheumatology in 2019 provide a framework for establishing the diagnosis in the clinical setting. This process involves recognizing the typical manifestations of the disease and incorporating clinical, radiological, serological, and histopathological information as well as excluding disease mimickers. Glucocorticoids and rituximab are effective at inducing remission in IgG4-RD in most patients, but the optimal approach to long-term management of IgG4-RD remains an area of active clinical research.

Multiorgan involvement and circulating IgG1 predict hypocomplementaemia in IgG4-related disease.

OBJECTIVES: Hypocomplementaemia is common in patients with IgG4-related disease (IgG4-RD). We aimed to determine the IgG4-RD features associated with hypocomplementaemia and investigate mechanisms of complement activation in this disease. METHODS: We performed a single-centre cross-sectional study of 279 patients who fulfilled the IgG4-RD classification criteria, using unadjusted and multivariable-adjusted logistic regression to identify factors associated with hypocomplementaemia. RESULTS: Hypocomplementaemia was observed in 90 (32%) patients. In the unadjusted model, the number of organs involved (OR 1.42, 95% CI 1.23 to 1.63) and involvement of the lymph nodes (OR 3.87, 95% CI 2.19 to 6.86), lungs (OR 3.81, 95% CI 2.10 to 6.89), pancreas (OR 1.66, 95% CI 1.001 to 2.76), liver (OR 2.73, 95% CI 1.17 to 6.36) and kidneys (OR 2.48, 95% CI 1.47 to 4.18) were each associated with hypocomplementaemia. After adjusting for age, sex and number of organs involved, only lymph node (OR 2.59, 95% CI 1.36 to 4.91) and lung (OR 2.56, 95% CI 1.35 to 4.89) involvement remained associated with hypocomplementaemia while the association with renal involvement was attenuated (OR 1.6, 95% CI 0.92 to 2.98). Fibrotic disease manifestations (OR 0.43, 95% CI 0.21 to 0.87) and lacrimal gland involvement (OR 0.53, 95% CI 0.28 to 0.999) were inversely associated with hypocomplementaemia in the adjusted analysis. Hypocomplementaemia was associated with higher concentrations of all IgG subclasses and IgE (all p<0.05). After adjusting for serum IgG1 and IgG3, only IgG1 but not IgG4 remained strongly associated with hypocomplementaemia. CONCLUSIONS: Hypocomplementaemia in IgG4-RD is not unique to patients with renal involvement and may reflect the extent of disease. IgG1 independently correlates with hypocomplementaemia in IgG4-RD, but IgG4 does not. Complement activation is likely involved in IgG4-RD pathophysiology.

The clinical outcomes and healthcare resource utilization in IgG4-related disease: a claims-based analysis of commercially insured adults in the United States.

OBJECTIVES: IgG4-related disease (IgG4-RD) can affect nearly any organ and is often treated with glucocorticoids, which contribute to organ damage and toxicity. Comorbidities and healthcare utilization in IgG4-RD are poorly understood. METHODS: We conducted a cohort study using claims data from a US managed care organization. Incident IgG4-RD cases were identified using a validated algorithm; general population comparators were matched by age, sex, race/ethnicity and index date. The frequency of 21 expert-defined clinical outcomes associated with IgG4-RD or its treatment and healthcare-associated visits and costs were assessed 12 months before and 36 months after the index date (date of earliest IgG4-RD-related claim). RESULTS: There were 524 cases and 5240 comparators. Most cases received glucocorticoids prior to (64.0%) and after (85.1%) the index date. Nearly all outcomes, many being common glucocorticoid toxicities, occurred more frequently in cases vs comparators. During follow-up, the largest differences between cases and comparators were seen for gastroesophageal reflux disease (prevalence difference: +31.2%, P < 0.001), infections (+17.3%, P < 0.001), hypertension (+15.5%, P < 0.01) and diabetes mellitus (+15.0%, P < 0.001). The difference in malignancy increased during follow-up from +8.8% to +12.5% (P < 0.001). Some 17.4% of cases used pancreatic enzyme replacement therapy during follow-up. Over follow-up, cases were more often hospitalized (57.3% vs 17.2%, P < 0.01) and/or had an emergency room visit (72.0% vs 36.7%, P < 0.01); all costs were greater in cases than comparators. CONCLUSIONS: Patients with IgG4-RD are disproportionately affected by adverse outcomes, some of which may be preventable or modifiable with vigilant clinician monitoring. Glucocorticoid-sparing treatments may improve these outcomes.

Antisynthetase Syndrome Causing Necrotizing Myositis Involving Extraocular Muscles.

The authors describe the clinical, histologic, and serologic findings of a patient with necrotizing myositis of the extraocular muscles in the setting of antisynthetase syndrome, as well as subsequent management. This is the first case in the literature of a systemic necrotizing myositis to have associated ophthalmic findings.

Efficacy of Tocilizumab in Patients Hospitalized with Covid-19.

BACKGROUND: The efficacy of interleukin-6 receptor blockade in hospitalized patients with coronavirus disease 2019 (Covid-19) who are not receiving mechanical ventilation is unclear. METHODS: We performed a randomized, double-blind, placebo-controlled trial involving patients with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, hyperinflammatory states, and at least two of the following signs: fever (body temperature >38°C), pulmonary infiltrates, or the need for supplemental oxygen in order to maintain an oxygen saturation greater than 92%. Patients were randomly assigned in a 2:1 ratio to receive standard care plus a single dose of either tocilizumab (8 mg per kilogram of body weight) or placebo. The primary outcome was intubation or death, assessed in a time-to-event analysis. The secondary efficacy outcomes were clinical worsening and discontinuation of supplemental oxygen among patients who had been receiving it at baseline, both assessed in time-to-event analyses. RESULTS: We enrolled 243 patients; 141 (58%) were men, and 102 (42%) were women. The median age was 59.8 years (range, 21.7 to 85.4), and 45% of the patients were Hispanic or Latino. The hazard ratio for intubation or death in the tocilizumab group as compared with the placebo group was 0.83 (95% confidence interval [CI], 0.38 to 1.81; P = 0.64), and the hazard ratio for disease worsening was 1.11 (95% CI, 0.59 to 2.10; P = 0.73). At 14 days, 18.0% of the patients in the tocilizumab group and 14.9% of the patients in the placebo group had had worsening of disease. The median time to discontinuation of supplemental oxygen was 5.0 days (95% CI, 3.8 to 7.6) in the tocilizumab group and 4.9 days (95% CI, 3.8 to 7.8) in the placebo group (P = 0.69). At 14 days, 24.6% of the patients in the tocilizumab group and 21.2% of the patients in the placebo group were still receiving supplemental oxygen. Patients who received tocilizumab had fewer serious infections than patients who received placebo. CONCLUSIONS: Tocilizumab was not effective for preventing intubation or death in moderately ill hospitalized patients with Covid-19. Some benefit or harm cannot be ruled out, however, because the confidence intervals for efficacy comparisons were wide. (Funded by Genentech; ClinicalTrials.gov number, NCT04356937.).

Incidence, prevalence and mortality of IgG4-related disease in the USA: a claims-based analysis of commercially insured adults.

BACKGROUND: IgG4-related disease (IgG4-RD) is an immune-mediated condition that can affect nearly any organ or anatomic site. We sought to describe the epidemiology of IgG4-RD in the USA. METHODS: We used Optum's deidentified Clinformatics Data Mart Database from 1 January 2009 to 31 December 2021 to identify IgG4-RD cases using a validated algorithm. We estimated the incidence rate and prevalence between 2015 and 2019 (when rates stabilised), standardised to the US population by age and sex. We compared mortality rates among patients with IgG4-RD to the non-IgG4-RD population matched in a 1:10 ratio on age, sex, race/ethnicity and encounter date. We used Cox proportional hazards models to estimate HRs and 95% CIs. RESULTS: We identified 524 IgG4-RD cases. The mean age was 56.5 years with 57.6% female and 66% White. The incidence of IgG4-RD increased during the study period from 0.78 to 1.39 per 100 000 person-years in 2015 and 2019, respectively. The point prevalence on 1 Janury 2019 was 5.3/100 000 persons. During follow-up, there were 39 and 164 deaths among 515 IgG4-RD cases and 5160 comparators, resulting in a mortality rate of 3.42 and 1.46/100 person-years, respectively, and adjusted HR of 2.51 (95% CI 1.76 to 3.56). CONCLUSIONS: The incidence of IgG4-RD is similar to that of systemic rheumatic diseases such as ANCA-associated vasculitis and systemic sclerosis but may be increasing as familiarity with this diagnosis grows. Clinicians should be aware of this condition, especially given the excess risk of death. Identification of effective therapies is an important research agenda.

Risk factors for serious infections in ANCA-associated vasculitis.

OBJECTIVES: Severe infections contribute to morbidity and mortality in antineutrophil cytoplasm antibody-associated vasculitis (AAV). This study aimed to identify risk factors associated with severe infections in participants of the Rituximab versus Cyclophosphamide for ANCA-Associated Vasculitis (RAVE) trial. METHODS: Data on 197 patients recruited into the RAVE trial were analysed. Participants received either rituximab (RTX) or cyclophosphamide (CYC), followed by azathioprine (AZA). Clinical and laboratory data of patients with and without severe infections (≥grade 3, according to the Common Terminology Criteria for Adverse Events version 3.0) were compared. Risk factors for severe infections were investigated using Cox-regression models. RESULTS: Eighteen of 22 (82%) severe infections occurred within 6 months after trial entry, most commonly respiratory tract infections (15/22, 68%). At baseline, lower absolute numbers of CD19+ cells were observed in patients with severe infections either receiving RTX or CYC/AZA at baseline, while CD5+B and CD3+T cells did not differ between groups. In Cox-regression analysis, higher baseline serum immunoglobulin M levels were associated with the risk of severe infections, whereby a higher baseline total CD19+B cell number and prophylaxis against Pneumocystis jirovecii with trimethoprim-sulfamethoxazole (TMP/SMX) with decreased risk of severe infections. Use of TMP/SMX was associated with lower risk of severe infections in both groups, receiving either RTX or CYC/AZA. CONCLUSIONS: The use of low-dose TMP/SMX is associated with reduced risk of severe infections in patients with AAV treated with either RTX or CYC/AZA. Reduced B cell subpopulations at start of treatment might be a useful correlate of reduced immunocompetence.

Association of baseline soluble immune checkpoints with the risk of relapse in PR3-ANCA vasculitis following induction of remission.

OBJECTIVES: We investigated whether soluble immune checkpoints (sICPs) predict treatment resistance, relapse and infections in patients with antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV). METHODS: Plasma sICP concentrations from available samples obtained during conduct of the RAVE trial were measured by immunoabsorbent assays from patients with either proteinase 3 (PR3) or myeloperoxidase (MPO)-ANCA vasculitis and were correlated with clinical outcomes, a set of biomarkers and available flow cytometry analyses focusing on T cell subsets. Log-rank test was used to evaluate survival benefits, and optimal cut-off values of the marker molecules were calculated using Yeldons J. RESULTS: Analysis of 189 plasma samples at baseline revealed higher concentrations of sTim-3, sCD27, sLag-3, sPD-1 and sPD-L2 in patients with MPO-ANCA vasculitis (n=62) as compared with PR3-ANCA vasculitis (n=127). Among patients receiving rituximab induction therapy (n=95), the combination of lower soluble (s)Lag-3 (<90 pg/mL) and higher sCD27 (>3000 pg/mL) predicted therapy failure. Twenty-four out of 73 patients (32.9%) in the rituximab arm reaching remission at 6 months relapsed during follow-up. In this subgroup, high baseline values of sTim-3 (>1200 pg/mL), sCD27 (>1250 pg/mL) and sBTLA (>1000 pg/mL) were associated with both sustained remission and infectious complications. These findings could not be replicated in 94 patients randomised to receive cyclophosphamide/azathioprine. CONCLUSIONS: Patients with AAV treated with rituximab achieved remission less frequently when concentrations of sLag-3 were low and concentrations of sCD27 were high. Higher concentrations of sTim-3, sCD27 and sBTLA at baseline predicted relapse in patients treated with rituximab. These results require confirmation but may contribute to a personalised treatment approach of AAV.

The Positive Predictive Value of a Very High Serum IgG4 Concentration for the Diagnosis of IgG4-Related Disease.

OBJECTIVE: Serum IgG4 concentrations are used to evaluate a diagnosis of IgG4-related disease (IgG4-RD), but the positive predictive value (PPV) of a very high IgG4 level is uncertain. This study evaluated the PPV of a very high IgG4 concentration for diagnosing IgG4-RD. METHODS: The data warehouses of 2 large academic healthcare systems were queried for IgG4 concentration test results. Cases with serum IgG4 concentrations > 5× the upper limit of normal (ULN) were included. Cases of IgG4-RD were determined using the American College of Rheumatology/European Alliance of Associations for Rheumatology (ACR/EULAR) classification criteria. The PPV for IgG4-RD of an IgG4 concentration > 5× ULN was estimated. Other conditions associated with very high IgG4 concentrations and specific features of IgG4-RD cases were characterized. RESULTS: IgG4 concentrations were available in 32,206 cases. Of these, 3039 (9.4%) had elevated IgG4 concentrations, and a final cohort of 191 (0.6%) cases had IgG4 concentrations > 5× ULN (median age 66 yrs, 72% male). The PPV of an IgG4 concentration > 5× ULN for a diagnosis of IgG4-RD was 75.4% (95% CI 68.7-81.3). In the remaining cases, elevated IgG4 concentrations were observed among patients with malignancies, autoimmune diseases, and infections. CONCLUSION: The majority of cases with serum IgG4 concentrations > 5× ULN in this study had IgG4-RD. These data support the high weight placed on very high serum IgG4 concentrations in the ACR/EULAR classification criteria. However, 25% of cases with very high IgG4 concentrations had an alternative diagnosis, underscoring the importance of considering the broad differential of etiologies associated with an elevated IgG4 concentration when evaluating a patient.

VMD as a Platform for Interactive Small Molecule Preparation and Visualization in Quantum and Classical Simulations.

Modeling and simulation of small molecules such as drugs and biological cofactors have been both a major focus of computational chemistry for decades and a growing need among computational biophysicists who seek to investigate the interaction of different types of ligands with biomolecules. Of particular interest in this regard are quantum mechanical (QM) calculations that are used to more accurately describe such small molecules, which can be of heterogeneous structures and chemistry, either in purely QM calculations or in hybrid QM/molecular mechanics (MM) simulations. QM programs are also used to develop MM force field parameters for small molecules to be used along with established force fields for biomolecules in classical simulations. With this growing need in mind, here we report a set of software tools developed and closely integrated within the broadly used molecular visualization/analysis program, VMD, that allow the user to construct, modify, and parametrize small molecules and prepare them for QM, hybrid QM/MM, or classical simulations. The tools also provide interactive analysis and visualization capabilities in an easy-to-use and integrated environment. In this paper, we briefly report on these tools and their major features and capabilities, along with examples of how they can facilitate molecular research in computational biophysics that might be otherwise prohibitively complex.

Distinct disease-specific Tfh cell populations in 2 different fibrotic diseases: IgG4-related disease and Kimura disease.

BACKGROUND: How T follicular (Tfh) cells contribute to many different B-cell class-switching events during T-cell-dependent immune responses has been unclear. Diseases with polarized isotype switching offer a unique opportunity for the exploration of Tfh subsets. Secondary and tertiary lymphoid organs in patients with elevated tissue expression levels of IgE (Kimura disease, KD) and those of IgG4 (IgG4-related disease, IgG4-RD) can provide important insights regarding cytokine expression by Tfh cells. OBJECTIVE: We sought to identify disease-specific Tfh cell subsets in secondary and tertiary lymphoid organs expressing IL-10 or IL-13 and thus identify different cellular drivers of class switching in 2 distinct types of fibrotic disorders: allergic fibrosis (driven by type 2 immune cells) and inflammatory fibrosis (driven by cytotoxic T lymphocytes). METHODS: Single-cell RNA sequencing, in situ sequencing, and multicolor immunofluorescence analysis were used to investigate B cells, Tfh cells, and infiltrating type 2 cells in lesion tissues from patients with KD or IgG4-RD. RESULTS: Infiltrating Tfh cells in tertiary lymphoid organs from IgG4-RD were divided into 6 main clusters. We encountered abundant infiltrating IL-10-expressing LAG3+ Tfh cells in patients with IgG4-RD. Furthermore, we found that infiltrating AICDA+CD19+ B cells expressing IL-4, IL-10, and IL-21 receptors correlated with IgG4 expression. In contrast, we found that infiltrating IL-13-expressing Tfh cells were abundant in affected tissues from patients with KD. Moreover, we observed few infiltrating IL-13-expressing Tfh cells in tissues from patients with IgG4-RD, despite high serum levels of IgE (but low IgE in the disease lesions). Cytotoxic T cells were abundant in IgG4-RD; in contrast, type 2 immune cells were abundant in KD. CONCLUSIONS: Our analysis revealed a novel subset of IL-10+LAG3+ Tfh cells infiltrating the affected organs of IgG4-RD patients. In contrast, IL-13+ Tfh cells and type 2 immune cells infiltrated those of KD patients.

Neutralizing anti-IL-1 receptor antagonist autoantibodies induce inflammatory and fibrotic mediators in IgG4-related disease.

BACKGROUND: IgG4-related disease (IgG4-RD) is a fibroinflammatory condition involving loss of B-cell tolerance and production of autoantibodies. However, the relevant targets and role of these aberrant humoral immune responses are not defined. OBJECTIVE: Our aim was to identify novel autoantibodies and autoantigen targets that promote pathogenic responses in IgG4-RD. METHODS: We sequenced plasmablast antibody repertoires in patients with IgG4-RD. Representative mAbs were expressed and their specificities characterized by using cytokine microarrays. The role of anti-IL-1 receptor antagonist (IL-1RA) autoantibodies was investigated by using in vitro assays. RESULTS: We identified strong reactivity against human IL-1RA by using a clonally expanded plasmablast-derived mAb from a patient with IgG4-RD. Plasma from patients with IgG4-RD exhibited elevated levels of reactivity against IL-1RA compared with plasma from the controls and neutralized IL-1RA activity, resulting in inflammatory and fibrotic mediator production in vitro. IL-1RA was detected in lesional tissues from patients with IgG4-RD. Patients with anti-IL-1RA autoantibodies of the IgG4 subclass had greater numbers of organs affected than did those without anti-IL-1RA autoantibodies. Peptide analyses identified IL-1RA epitopes targeted by anti-IL-1RA antibodies at sites near the IL-1RA/IL-1R interface. Serum from patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) also had elevated levels of anti-IL-1RA autoantibodies compared with those of the controls. CONCLUSION: A subset of patients with IgG4-RD have anti-IL-1RA autoantibodies, which promote proinflammatory and profibrotic meditator production via IL-1RA neutralization. These findings support a novel immunologic mechanism underlying the pathogenesis of IgG4-RD. Anti-IL-1RA autoantibodies are also present in a subset of patients with SLE and RA, suggesting a potential common pathway in multiple autoimmune diseases.

Perspectives on current and emerging therapies for immunoglobulin G4-related disease.

Understanding of the pathophysiology of immunoglobulin G4-related disease (IgG4-RD) over the last dozen years has opened the door to a variety of targeted treatment approaches. Glucocorticoids are an effective treatment for IgG4-RD if used at a sufficiently high dose, but disease flares are common during or after glucocorticoid tapers and these medications seldom lead to long-term, treatment-free remissions. Moreover, their long-term use in a disease that frequently affects middle-aged to elderly individuals and often causes major pancreatic damage leads to a narrow therapeutic index. Biological therapies offer the possibility of effective disease control with fewer treatment-associated side effects. Promising avenues of investigation include B-cell depletion, immunomodulation of B-cell subsets, interference with co-stimulation, Bruton's tyrosine kinase inhibition, and Signaling lymphocytic activation molecule F7-directed treatment.

B-Cell depletion therapy in IgG4-related disease: State of the art and future perspectives.

IgG4-related disease (IgG4-RD) is an increasingly recognized immune-mediated fibroinflammatory disorder that promptly responds to glucocorticoids but commonly relapses during steroid tapering or after discontinuation. In the last few years, B-cell depletion therapy with rituximab (RTX) proved to be effective in the induction of remission and maintenance treatment of IgG4-RD, providing a new powerful tool in the management of this emerging condition. In this review, we outline the pathogenetic rationale for using B-cell depleting agents in IgG4-RD, we summarize available clinical experience with RTX in this disease, and we describe future possible therapies targeting B-lymphocytes that are now in the pipeline.

#COVIDisAirborne: AI-enabled multiscale computational microscopy of delta SARS-CoV-2 in a respiratory aerosol.

We seek to completely revise current models of airborne transmission of respiratory viruses by providing never-before-seen atomic-level views of the SARS-CoV-2 virus within a respiratory aerosol. Our work dramatically extends the capabilities of multiscale computational microscopy to address the significant gaps that exist in current experimental methods, which are limited in their ability to interrogate aerosols at the atomic/molecular level and thus obscure our understanding of airborne transmission. We demonstrate how our integrated data-driven platform provides a new way of exploring the composition, structure, and dynamics of aerosols and aerosolized viruses, while driving simulation method development along several important axes. We present a series of initial scientific discoveries for the SARS-CoV-2 Delta variant, noting that the full scientific impact of this work has yet to be realized.

Glucocorticoid toxicity reduction with mepolizumab using the Glucocorticoid Toxicity Index.

BACKGROUND: Reduction in glucocorticoid exposure is the primary benefit of new biologic treatments in severe asthma, but there is currently no evidence that reduction in glucocorticoid exposure corresponds to a proportionate reduction in associated toxicity. OBJECTIVES: To use the validated Glucocorticoid Toxicity Index (GTI) to assess change in glucocorticoid toxicity after 12 months treatment with mepolizumab, and compare toxicity change to glucocorticoid reduction and change in patient-reported outcome measures (PROMs). METHODS: A longitudinal, real-world prospective cohort of 101 consecutive patients with severe asthma commenced on mepolizumab in a specialist UK regional severe asthma clinic. GTI toxicity assessment, cumulative glucocorticoid exposure and PROMs were recorded on commencing mepolizumab (V1), and after 12 months treatment (V2). RESULTS: There was significant reduction in oral glucocorticoid exposure (V1 median 4280 mg prednisolone per year (interquartile range 3083-5475 mg) versus V2 2450 mg prednisolone per year (1243-3360 mg), p<0.001). Substantial improvements in individual toxicities were observed, but did not correlate with oral glucocorticoid reduction. Mean±sd GTI aggregate improvement score (AIS) was -35.7±57.8 with a wide range in toxicity change at individual patient level (AIS range -165 to +130); 70% (71 out of 101) had a reduction in toxicity (AIS <0); 3% (three out of 101) had no change (AIS=0); and 27% (27 out of 101) an increase in overall toxicity. 62% (62 out of 101) of patients met the AIS minimally clinically important difference of ≤-10, but AIS did not correlate with glucocorticoid reduction or change in PROMs. CONCLUSION: Mepolizumab resulted in substantial oral glucocorticoid reduction, but this did not correlate with reduction in oral glucocorticoid toxicity, which varies widely at the individual patient level. Oral glucocorticoid reduction is not a comprehensive measure of response to mepolizumab.