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Objectives: The evolution of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) necessitates rapid methods for assessing monoclonal antibody (mAb) potency against emerging variants. Authentic virus neutralisation assays are considered the gold standard for measuring virus‐neutralising antibody (nAb) titres in serum. However, authentic virus‐based assays pose inherent practical challenges for measuring nAb titres against emerging SARS‐CoV‐2 variants (e.g. storing infectious viruses and testing at biosafety level‐3 facilities). Here, we demonstrate the utility of pseudovirus neutralisation assay data in conjunction with serum mAb concentrations to robustly predict nAb titres in serum. Methods: SARS‐CoV‐2 nAb titres were determined via authentic‐ and lentiviral pseudovirus‐based neutralisation assays using serological data from three AZD7442 (tixagevimab–cilgavimab) studies: PROVENT (NCT04625725), TACKLE (NCT04723394) and a phase 1 dose‐ranging study (NCT04507256). AZD7442 serum concentrations were assessed using immunocapture. Serum‐based half‐maximal inhibitory concentration (IC50) values were derived from pseudovirus nAb titres and serum mAb concentrations, and compared with in vitro IC50 measurements. Results: nAb titres measured via authentic‐ and lentiviral pseudovirus‐based neutralisation assays were strongly correlated for the ancestral SARS‐CoV‐2 virus and SARS‐CoV‐2 Alpha. Serum AZD7442 concentrations and pseudovirus nAb titres were strongly correlated for multiple SARS‐CoV‐2 variants with all Spearman correlation coefficients ≥ 0.78. Serum‐based IC50 values were similar to in vitro IC50 values for AZD7442, for ancestral SARS‐CoV‐2 and Alpha, Delta, Omicron BA.2 and Omicron BA.4/5 variants. Conclusions: These data highlight that serum mAb concentrations and pseudovirus in vitro IC50 values can be used to rapidly predict nAb titres in serum for emerging and historical SARS‐CoV‐2 variants. [ABSTRACT FROM AUTHOR]

This study aimed to elucidate the pharmacokinetic/pharmacodynamic and pharmacodynamic/efficacy relationships of anifrolumab, a type I interferon receptor antibody, in patients with moderate to severe systemic lupus erythematosus. Data were pooled from the randomized, 52‐week, placebo‐controlled TULIP‐1 and TULIP‐2 trials of intravenous anifrolumab (150 mg/300 mg, every 4 weeks for 48 weeks). Pharmacodynamic neutralization was measured with a 21‐gene type I interferon gene signature (21‐IFNGS) in patients with high IFNGS. The pharmacokinetic/pharmacodynamic relationship was analyzed graphically and modeled with a nonlinear mixed‐effects model. British Isles Lupus Assessment Group–based Composite Lupus Assessment (BICLA) response rates were compared across 21‐IFNGS neutralization quartiles. Overall, 819 patients received ≥1 dose of anifrolumab or placebo, of whom 676 were IFNGS high. Over 52 weeks, higher average anifrolumab serum concentrations were associated with increased median 21‐IFNGS neutralization, which was rapid and sustained with anifrolumab 300 mg (>80%, weeks 12‐52), lower and delayed with anifrolumab 150 mg (>50%, week 52), and minimal with placebo. The proportion of patients with week 24 anifrolumab trough concentration exceeding the IC80 (3.88 μg/mL) was greater with anifrolumab 300 mg vs anifrolumab 150 mg (≈83% vs ≈27%), owing to the higher estimated median trough concentration (15.6 vs 0.2 μg/mL). BICLA response rates increased with 21‐IFNGS neutralization; more patients had a BICLA response in the highest vs lowest neutralization quartiles at week 52 (58.1% vs 37.6%). In conclusion, anifrolumab 300 mg every 4 weeks rapidly, substantially, and sustainably neutralized the 21‐IFNGS and was associated with clinical efficacy, supporting this dosing regimen in patients with systemic lupus erythematosus. [ABSTRACT FROM AUTHOR]

Objective: B cells impact the progression of systemic sclerosis (SSc; scleroderma) through multiple pathogenic mechanisms. CD19 inhibition in mice reduced skin thickness, collagen production, and autoantibody levels, consistent with CD19 expression on plasma cells (PCs), the source of antibody production. PC depletion could effectively reduce collagen deposition and inflammation in SSc; therefore, we investigated the effects of PC depletion on SSc disease activity. Methods: A PC gene signature was evaluated in SSc skin biopsy samples in 2 phase I clinical trials. We assessed microarray data from tissue from public studies of chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), dermatomyositis (DM), systemic lupus erythematosus (SLE), and atopic dermatitis, as well as blood from a phase IIb clinical trial in SLE. Results: The PC signature was elevated in SSc skin specimens compared to healthy donor skin (P = 2.28 × 10−6) and correlated with the baseline modified Rodnan skin thickness score (MRSS) (r = 0.64, P = 0.0004). Patients with a high PC signature at baseline showed greater improvement in the MRSS (mean ± SD change 35 ± 16%; P = 6.30 × 10−4) following anti‐CD19 treatment with inebilizumab (MEDI‐551) than did patients with a low PC signature at baseline (mean ± SD change 8 ± 12%; P = 0.104). The PC signature was overexpressed in tissue from patients with SLE, DM, COPD, interstitial lung disease, and IPF relative to controls (all fold change >2; P < 0.001). The PC signature also differed significantly between SLE patients with mild‐to‐moderate disease and those with severe disease (SLE Disease Activity Index cutoff at 10) (fold change 1.44; P = 3.90 × 10−3) and correlated significantly with the degree of emphysema in COPD (r = 0.53, P = 7.55 × 10−8). Conclusion: Our results support the notion that PCs have a role in the pathogenesis of SSc and other autoimmune or pulmonary indications. An elevated pretreatment PC signature was associated with increased benefit from MEDI‐551 in SSc. [ABSTRACT FROM AUTHOR]

Objective The molecular basis of inflammatory myopathies such as dermatomyositis (DM), polymyositis, and inclusion body myositis, which share the characteristics of chronic muscle inflammation and skeletal muscle wasting, are poorly understood. As such, effective targeted treatments for these diseases are lacking, resulting in critical unmet medical needs for these devastating diseases. The purpose of this study was to identify possible new targets for drug development by exploring the mechanism by which inflammation may play a role in the pathology of the inflammatory myopathies. Methods We compared expression levels of inflammatory cytokines and microRNAs (miRNAs) between muscle biopsy samples from patients with inflammatory myopathies and those from donors without myositis. In vitro human and mouse model systems were then used to characterize the role of these cytokines and microRNAs on myoblast-to-myocyte differentiation. Results We observed increased expression of inflammatory cytokines, including tumor necrosis factor α (TNFα), interferon-α (IFNα), IFNβ, and interleukin-1β, in different subtypes of inflammatory myopathies. We observed decreased expression of microRNA-1 (miR-1), miR-133a, and miR-133b in all of the inflammatory myopathy subtypes we evaluated, as well as decreased expression of miR-206 in DM; these miRNAs are essential for adult skeletal muscle differentiation and maintenance. TNFα was significantly inversely correlated with decreased myogenic miRNA expression in the inflammatory myopathy subtypes. In mechanistic studies, TNFα inhibited the expression of myogenic miRNAs and suppressed the differentiation of C2C12 myoblasts to myocytes/myotubes in an NF-κB-dependent manner. This block in differentiation by TNFα was relieved by overexpression of miR-1, miR-206, or miR-133a/b. Conclusion Taken together, these results provide a new mechanistic link between the action of proinflammatory cytokines and the degenerative pathology of inflammatory myopathies, and suggest therapeutic approaches for these diseases. [ABSTRACT FROM AUTHOR]

Expression profiling of micro RNAs in melanoma lesional skin biopsies compared with normal donor skin biopsies, as well as melanoma cell lines compared with normal melanocytes, revealed that hsa-mi R-206 was down-regulated in melanoma (−75.4-fold, P = 1.7 × 10−4). Mi R-206 has been implicated in a large number of cancers, including breast, lung, colorectal, ovarian, and prostate cancers; however, its role in tumor development remains largely unknown, its biologic function is poorly characterized, and its targets affecting cancer cells are largely unknown. Mi R-206 reduced growth and migration/invasion of multiple melanoma cell lines. Bioinformatics identified cell cycle genes CDK2, CDK4, Cyclin C, and Cyclin D1 as strong candidate targets. Western blots and 3′ UTR reporter gene assays revealed that mi R-206 inhibited translation of CDK4, Cyclin D1, and Cyclin C. Additionally, hsa-mi R-206 transfection induced G1 arrest in multiple melanoma cell lines. These observations support hsa-mi R-206 as a tumor suppressor in melanoma and identify Cyclin C, Cyclin D1, and CDK4 as mi R-206 targets. [ABSTRACT FROM AUTHOR]

Little information is available regarding the impact of cytochrome P450 ( CYP) 3A5 on the metabolism of TAC in infant LTx. Therefore, the CYP3A5 genotype of Chinese pediatric recipients (intestine) as well as donors (graft liver) was performed for the purpose of establishing an optimal dosage regimen in children. Sixty-four patients were divided according to CYP3A5 genotype (expression of *1 allele: EX and NEX) for each recipient (R) and donor (D), EX-R/ EX-D (n = 21), EX-R/ NEX-D (n = 8), NEX-R/ EX-D (n = 8) and NEX-R/ NEX-D (n = 27). Results indicated that initial TAC daily dose requirement was higher among EX-R/ EX-D children compared with those who did not express CYP3A5 (0.28 ± 0.10 vs. 0.19 ± 0.08 mg/kg/day, p < 0.01). CYP3A5 expression contributed an overall of 38.35% to its C/D ratios, and graft liver was a key determinant. Additionally, the EX-R/ EX-D group showed significantly higher incidence of infectious complications, lower immune response and was an independent risk factor for the development of infections (odds ratio 3.86, p = 0.025). Donor CYP3A5 expression partially explains TAC dose requirement, the effect of CYP3A5 variation may influence clinical outcomes; therefore, monitoring immune response may be important for preventing risks associated with under- and over-immunosuppression. [ABSTRACT FROM AUTHOR]

Objective Production of pathogenic autoantibodies by self-reactive plasma cells (PCs) is a hallmark of autoimmune diseases. We undertook this study to investigate the prevalence of PCs and their relationship to known pathogenic pathways to increase our understanding of the role of PCs in disease progression and treatment response. Methods We developed a sensitive gene expression-based method to overcome the challenges of measuring PCs using flow cytometry. Whole-genome microarray analysis of sorted cellular fractions identified a panel of genes, IGHA1, IGJ, IGKC, IGKV4-1, and TNFRSF17, expressed predominantly in PCs. The sensitivity of the PC signature score created from the combined expression levels of these genes was assessed through ex vivo experiments with sorted cells. This PC gene expression signature was used for monitoring changes in PC levels following anti-CD19 therapy, for evaluating the relationship between PCs and other autoimmune disease-related genes, and for estimating PC levels in affected blood and tissue from patients with multiple autoimmune diseases. Results The PC signature was highly sensitive and capable of detecting a change in as few as 360 PCs. The PC signature was reduced more than 90% in scleroderma patients following anti-CD19 treatment, and this reduction was highly correlated (r = 0.80) with inhibition of collagen gene expression. Evaluation of multiple autoimmune diseases revealed that 30-35% of lupus and rheumatoid arthritis patients had increased levels of PCs. Conclusion This newly developed PC signature provides a robust and accurate method of measuring PC levels in the clinic. Our results highlight subsets of patients across multiple autoimmune diseases who may benefit from PC-depleting therapy. [ABSTRACT FROM AUTHOR]