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Efficient phagocytosis of pathogens is a key effector function of the innate immune system. Impaired phagocytic activity can result in uncontrolled pathogen proliferation and life-threatening infections. However, reliable methods to detect early dysfunction of the phagocytic system in vivo are limited. Here, we used a mouse model of Listeria monocytogenes infection to determine blood parameters which correlate with limited macrophage function. We found that lack of macrophages led to accumulation of nuclei in the blood. Further analysis of nuclei revealed that these nuclei were released from bone marrow-derived cells. Macrophage-depleted mice and interferon-gamma-deficient mice, which are known to have reduced phagocytotic capacity, showed increased amounts of free nuclei. This was associated with lethal outcome and occurrence of acute hepatopathy in these mice after Listeria monocytogenes infection. Our findings highlight a simple and noninvasive method to assess macrophage phagocytic function in vivo , which should be assessed in further murine and human studies as a tool for predicting host vulnerability to infection.

Neutralizing antibodies (nAbs) are pivotal in developing fast, broadly protective therapeutics against novel pandemic viruses. Despite their well-known direct neutralization capacity, their effector mechanisms via Fc receptors remain poorly understood. Identifying the types of effector cells engaged in antibody-mediated effector functions is essential for regulating their activities. Using the lymphocytic choriomeningitis virus (LCMV), we show that nAbs obtained from immune sera or monoclonal LCMV-specific nAbs show dependency on Fc receptors. We demonstrate that therapy with nAbs is highly protective in the presence of patrolling monocytes. These monocytes bind nAbs primarily via FcγRIV, targeting virus-infected cells, and thereby limiting virus propagation. Depleting patrolling monocytes or blocking FcγRIV resulted in a substantial loss of virus control by nAbs, indicating the pivotal role of patrolling monocytes in the antiviral activity of these antibodies. In conclusion, our findings highlight that, alongside direct neutralization, nAbs primarily exert their effects through the involvement of patrolling monocytes.

Besides its robust antiviral activity, type I interferon (IFN-I) also exerts immunomodulatory effects and can even drive pathology during chronic viral infections. Mechanisms that regulate IFN-I induction during virus infection, thus strongly affecting the outcome of disease, remain to be defined. Here, using the lymphocytic choriomeningitis virus (LCMV) Docile strain, we identified acid ceramidase (aCDase, ) as a critical lipid-metabolic regulator of endosomal, nucleic acid-driven IFN-I responses and disease outcome during chronic virus infection. aCDase is highly expressed in plasmacytoid dendritic cells (pDCs) and required for robust early IFN-I production. aCDase deficiency resulted in ceramide accumulation, blunting IFN-α/β induction, impairing IFN-I-dependent upregulation of programmed death-ligand 1 (PD-L1) on antigen-presenting cells and preventing the exhaustion of virus-specific CD8 T cells, leading to severe immunopathology. This pathology is abrogated by CD8 T-cell depletion or by adoptive transfer of IFN-I-induced PD-L1-expressing macrophages. Conversely, limiting ceramide production in acid sphingomyelinase (Asm)-deficient mice prevented ceramide accumulation, and pDCs showed accelerated IFN-I induction. Mechanistically, ceramide abundance regulated IFN-I production by altering endosomal signaling microdomains. Collectively, our findings reveal ceramide homeostasis as a key determinant of IFN-I-driven CD8 T-cell exhaustion and immunopathology during chronic viral infection and highlight aCDase as a potential therapeutic target.

Objective To determine the early treatment response after microwave ablation (MWA) of inoperable lung neoplasms using the apparent diffusion coefficient (ADC) value calculated 24 h after the ablation. Materials and methods This retrospective study included 47 patients with 68 lung lesions, who underwent percutaneous MWA from January 2008 to December 2017. Evaluation of the lesions was done using MRI including DWI sequence with ADC value calculation pre-ablation and 24 h post-ablation. DWI-MR was performed with b values (50, 400, 800 mm 2 /s). The post-ablation follow-up was performed using chest CT and/or MRI within 24 h following the procedure; after 3, 6, 9, and 12 months; and every 6 months onwards to determine the local tumor response. The post-ablation ADC value changes were compared to the end response of the lesions. Results Forty-seven patients (mean age: 63.8 ± 14.2 years, 25 women) with 68 lesions having a mean tumor size of 1.5 ± 0.9 cm (range: 0.7–5 cm) were evaluated. Sixty-one lesions (89.7%) showed a complete treatment response, and the remaining 7 lesions (10.3%) showed a local progression (residual activity). There was a statistically significant difference regarding the ADC value measured 24 h after the ablation between the responding (1.7 ± 0.3 × 10 −3 mm 2 /s) and non-responding groups (1.4 ± 0.3 × 10 −3 mm 2 /s) with significantly higher values in the responding group ( p = 0.001). A suggested ADC cut-off value of 1.42 could be used as a reference point for the post-ablation response prediction (sensitivity: 66.67%, specificity: 84.21%, PPV: 66.7%, and NPV: 84.2%). No significant difference was reported regarding the ADC value performed before the ablation as a factor for the prognosis of treatment response ( p = 0.86). Conclusion ADC value assessment following ablation may allow the early prediction of treatment efficacy after MWA of inoperable lung neoplasms. Key Points • ADC value calculated 24 h post-treatment may allow the early prediction of MWA efficacy as a treatment of pulmonary tumors and can be used in the early immediate post-ablation imaging follow-up. • The pre-treatment ADC value of lung neoplasms is not different between the responding and non-responding tumors.

Ubiquitin-specific peptidase 22 (Usp22) cleaves ubiquitin moieties from numerous proteins, including histone H2B and transcription factors. Recently, it was reported that Usp22 acts as a negative regulator of interferon-dependent responses. In the current study, we investigated the role of Usp22 deficiency in acute viral infection with lymphocytic choriomeningitis virus (LCMV). We found that the lack of Usp22 on bone marrow-derived cells (Usp22fl/fl Vav1-Cre mice) reduced the induction of type I and II interferons. A limited type I interferon response did not influence virus replication. However, restricted expression of PD-L1 led to increased frequencies of functional virus-specific CD8+ T cells and rapid death of Usp22-deficient mice. CD8+ T cell depletion experiments revealed that accelerated CD8+ T cells were responsible for enhanced lethality in Usp22 deficient mice. In conclusion, we found that the lack of Usp22 generated a pathological CD8+ T cell response, which gave rise to severe disease in mice.

The aim of the study was to investigate the possible association of Alu I and Rsa I polymorphisms of estrogen receptor β (ER-β) gene and 23-bp nucleotide repeat polymorphism of estrogen-related receptor α (ERRα) gene with bone mineral density (BMD) in postmenopausal Egyptian women. Two-hundred postmenopausal osteoporotic women as cases and 180 healthy age-matched postmenopausal women as controls were genotyped by PCR fragment length polymorphism for Alu I, allele-specific PCR for Rsa I, and by sizing of PCR products on agarose gels for ERRα repeats. sRANKL levels were estimated by ELISA. BMD measurements for spine and femoral neck were performed by dual energy X-ray absorptiometry. A significant difference between women with osteoporosis and controls regarding allele and genotype distributions of Alu I G/A (OR 2.37, 95 % CI 1.77–3.18 and p  < 0.001 for A allele) and ERRα polymorphisms (for the two repeats allele OR 2.08, 95 % CI 1.09–4.00, and p  = 0.02). Osteoporotic women with the Alu I AA + GA genotype or with the EERα 2,2 genotype had significantly lower BMD than did women with the other genotypes. Moreover, there was a significant increase of the mean values of sRANKL in carriers of Alu I A, Rsa I A alleles and in patients having 2,2 genotypes of ERRα ( p  < 0.001, p  < 0.001, p  = 0.02, respectively). We demonstrated an association of ER-β Alu I G/A and ERRα 23-repeats polymorphisms with BMD in postmenopausal Egyptian women. A possible effect of ER-β and ERRα polymorphisms on the levels of sRANKL was estimated.

Background This systematic review investigates the effect of small interfering RNA (siRNA) therapies on lipoprotein(a) [Lp(a)] levels. The purpose is to evaluate the outcomes of recent randomized controlled trials (RCTs) involving siRNA treatments aimed at lowering Lp(a) levels, a known cardiovascular risk factor. Methods A comprehensive search across multiple databases was conducted, identifying 20 published and ongoing RCTs that examined the effects of siRNA therapies such as inclisiran, olpasiran, and SLN360 on Lp(a) levels. The included studies were analyzed to assess Lp(a) reductions and other lipid-related outcomes. Results The RCTs demonstrated significant reductions in Lp(a) levels following siRNA therapy. Additional reductions were noted in LDL-c and apolipoprotein B levels. Side effects were typically mild, including injection site reactions. Conclusions siRNA therapies show promise in effectively lowering Lp(a) levels, with minimal adverse effects. However, further research is required to establish their long-term safety and efficacy. Highlights The review evaluates the efficacy of SiRNA therapies, including inclisiran, SLN360, and olpasiran, in effectively lowering Lp(a) and LDL-C levels, which are critical in reducing the risk of cardiovascular diseases. Olpasiran is more effective in lowering Lp(a) more than inclisiran and SLN360, while inclisiran is more effective in lowering LDL-C more than olpasiran and SLN360. It assesses the safety profiles of these SiRNA drugs, finding them generally favorable across the studies analyzed, with injection site pain being the most reported side effect. Long-term safety profiles yet to be determined. The analysis spans various SiRNA medications, providing a comparative insight into their performance, dose-responsiveness, and the potential for personalized treatment approaches in lipid management. The call for further research is emphasized, particularly the need for more extensive and rigorous randomized controlled trials. These future studies are crucial for validating the long-term benefits, safety, and efficacy of SiRNA therapies in a diverse patient demographic. Additionally, there is advocacy for studies focusing specifically on the reduction of cardiac risk factors. Understanding SiRNA therapies' impact on cardiovascular risk factors beyond Lp(a) and LDL-C could revolutionize preventive strategies in cardiovascular health.

The aim of the study was to investigate the possible association of AluI and RsaI polymorphisms of estrogen receptor [beta] (ER-[beta]) gene and 23-bp nucleotide repeat polymorphism of estrogen-related receptor [alpha] (ERR[alpha]) gene with bone mineral density (BMD) in postmenopausal Egyptian women. Two-hundred postmenopausal osteoporotic women as cases and 180 healthy age-matched postmenopausal women as controls were genotyped by PCR fragment length polymorphism for AluI, allele-specific PCR for RsaI, and by sizing of PCR products on agarose gels for ERR[alpha] repeats. sRANKL levels were estimated by ELISA. BMD measurements for spine and femoral neck were performed by dual energy X-ray absorptiometry. A significant difference between women with osteoporosis and controls regarding allele and genotype distributions of AluI G/A (OR 2.37, 95 % CI 1.77-3.18 and p < 0.001 for A allele) and ERR[alpha] polymorphisms (for the two repeats allele OR 2.08, 95 % CI 1.09-4.00, and p = 0.02). Osteoporotic women with the AluI AA + GA genotype or with the EER[alpha] 2,2 genotype had significantly lower BMD than did women with the other genotypes. Moreover, there was a significant increase of the mean values of sRANKL in carriers of AluI A, RsaI A alleles and in patients having 2,2 genotypes of ERR[alpha] (p < 0.001, p < 0.001, p = 0.02, respectively). We demonstrated an association of ER-[beta] AluI G/A and ERR[alpha] 23-repeats polymorphisms with BMD in postmenopausal Egyptian women. A possible effect of ER-[beta] and ERR[alpha] polymorphisms on the levels of sRANKL was estimated.

Anaphylaxis is a life-threatening hypersensitivity reaction. Clinical observations suggest heightened susceptibility during viral infections, yet the mechanisms remain poorly defined. Here, we show that both active and passive IgG-mediated anaphylaxis were exacerbated in the setting of acute viral infection. In mice, this enhancement was driven predominantly by FcγRIV, the homolog of human FcγRIIIa. FcγRIV crosslinking induced anaphylactic symptoms selectively in infected animals, with no effect in naive conditions. Among leukocytes, inflammatory monocytes emerged as the principal drivers of this lethal reaction. Viral infection triggered a strong upregulation of FcγRIV on inflammatory monocytes, an effect absent in type I IFN receptor–deficient ( Ifnar1 -deficient) mice. Extending these findings, we observed increased frequencies of CD16-expressing classical monocytes in patients with acute COVID-19, and murine SARS-CoV-2 infection recapitulated this phenotype. Mechanistically, FcγRIV crosslinking during infection promoted the production of platelet-activating factor, the key mediator of mortality, in a type I IFN–dependent (IFN-I–dependent) manner. Together, these findings indicate that viral infection creates an immune milieu that heightens monocyte sensitivity to Fcγ receptor engagement, positioning these cells as major effectors of IgG-mediated hypersensitivity in the infected host. They further suggest that Fc receptor pathway modulation merits further investigation in contexts with heightened IFN-I responses, such as in systemic lupus erythematosus.

Anaphylaxis is a life-threatening hypersensitivity reaction. Clinical observations suggest heightened susceptibility during viral infections, yet the mechanisms remain poorly defined. Here, we show that both active and passive IgG-mediated anaphylaxis were exacerbated in the setting of acute viral infection. In mice, this enhancement was driven predominantly by Fc[gamma]RIV, the homolog of human Fc[gamma]RIIIa. Fc[gamma]RIV crosslinking induced anaphylactic symptoms selectively in infected animals, with no effect in naive conditions. Among leukocytes, inflammatory monocytes emerged as the principal drivers of this lethal reaction. Viral infection triggered a strong upregulation of Fc[gamma]RIV on inflammatory monocytes, an effect absent in type I IFN receptor-deficient (Ifnar1-deficient) mice. Extending these findings, we observed increased frequencies of CD16-expressing classical monocytes in patients with acute COVID-19, and murine SARS-CoV-2 infection recapitulated this phenotype. Mechanistically, Fc[gamma]RIV crosslinking during infection promoted the production of platelet-activating factor, the key mediator of mortality, in a type I IFN-dependent (IFN-I-dependent) manner. Together, these findings indicate that viral infection creates an immune milieu that heightens monocyte sensitivity to Fc[gamma] receptor engagement, positioning these cells as major effectors of IgG-mediated hypersensitivity in the infected host. They further suggest that Fc receptor pathway modulation merits further investigation in contexts with heightened IFN-I responses, such as in systemic lupus erythematosus.