Clinical and experimental immunology最新文献

Chronic prostatitis and chronic pelvic pain syndrome (CP/CPPS) are diagnosed in patients with various pelvic or genitourinary symptoms irrespective of the presence of a tender prostate. The etiology of chronic nonbacterial prostatitis remains unclear. Current treatments such as alpha-blockers, neuroleptics, anti-inflammatory, medications, and physical therapy, are often unsatisfactory. New treatments, as well as an improved knowledge of the underlying CP/CPPS pathogenesis, are thus needed. Sulforaphane (SFN), an isothiocyanate found in large quantities in Brassica species, has shown therapeutic effects on inflammation and cancer, and can protect against DNA damage and modulate the cell cycle to control apoptosis, angiogenesis, and metastasis. At the molecular level, SFN modulates cell homeostasis by activating the transcription factor Nrf2. However, its effect on CP/CPPS is not clear. Here, SFN was found to alleviate inflammation by suppressing NLRP3 inflammasomes via the Nrf2/HO-1 axis, as demonstrated in both animal and cellular analyses.

Introduction: Cladribine is a deoxyadenosine analogue that can penetrate the blood-brain barrier. It is used to treat multiple sclerosis (MS). However, the mechanistic understanding of the effect of this highly effective therapy on B cells and plasma cells in the central nervous system compartment is limited. The CLADRIPLAS study examined the effect of cladribine on peripheral and intrathecal B and plasma cell biology in people with MS.

Methods: Thirty-eight people with progressive MS ineligible for- or rejecting-treatment with licenced therapies were recruited and supplied a baseline lumbar puncture. Those exhibiting gadolinium-enhancing or new/enlarging T2 magnetic resonance imaging lesions and/or elevated neurofilament levels were offered subcutaneous cladribine (Litak®). Seven people were eligible; one person died before treatment, and only five completed the first year of treatment. Twenty-two ineligible people were willing to provide a repeat lumbar puncture 12 months later.

Results: The CLADRIPLAS study found no evidence of a difference in the odds of a positive cerebrospinal fluid oligoclonal band result between the cladribine-treated and untreated group. This is probably explained by microarray and in vitro studies, which demonstrated that plasmablasts and notably long-lived plasma cells are relatively resistant to the cytotoxic effect of cladribine compared with memory B cells at physiological concentrations. This was consistent with the loss of intracellular deoxycytidine kinase during antibody-secreting cell differentiation.

Conclusion: CLADRIPLAS indicates that cerebrospinal fluid oligoclonal bands are not rapidly eliminated in most people with MS. This may be explained by the relative lack of direct cytotoxic action of cladribine on long-lived plasma cells.

Neutrophils are key effector leukocytes of the innate immune system and play a pivotal role in defending the host against microbial infections. Recent studies have identified a crucial link between glycolysis and neutrophil cellular functions. Using human neutrophils, we have investigated the intricate relationship between glycolysis, extracellular glucose availability, and the enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3), in the regulation of reactive oxygen species (ROS) and neutrophil extracellular trap (NET) production. We have identified that PFKFB3 is elevated in rheumatoid arthritis (RA) neutrophils and that the small molecule PFKFB3 inhibitor 3PO is a key regulator of neutrophil ROS and NET production. 3PO blocked the production of ROS and NETs in a dose-dependent manner in both RA and healthy neutrophils (P < 0.01), and RA neutrophils were more sensitive to lower concentrations of 3PO. Bacterial killing was only partially inhibited by 3PO, and the proportion of live neutrophils after 24 h incubation was unchanged. Using NMR metabolomics, we identified that 3PO increases the concentration of lactate, phenylalanine, and L-glutamine in neutrophils, as well as significantly decreasing intracellular glutathione (adj. P-value < 0.05). We also demonstrated that RA neutrophils produce ROS and NETs in culture conditions which mimic the low glucose environments encountered in RA synovial joints. Our results also suggest that 3PO may have molecular targets beyond PFKFB3. By dissecting the intricate interplay between metabolism and neutrophil effector functions, this study advances the understanding of the molecular mechanisms governing pro-inflammatory neutrophil responses and identifies 3PO as a potential therapeutic for conditions characterized by dysregulated neutrophil activation.

Introduction: Specific granule deficiency (SGD)-a rare innate immune disorder-is classified into types 1 and 2 (SGD-1 and -2). SGD-1 is caused by variants of the CCAAT/enhancer-binding protein epsilon (C/EBPε) gene.

Methods: We assessed the molecular mechanisms underlying C/EBPε dysfunction in SGD-1, caused by the frameshift variant (c.655_665del; del11) that we previously reported. We compared the functions of del11 with those of the previously reported p.Arg247_Ser248del (ΔRS) variant and wild-type (WT) C/EBPε.

Results: Forced expression in embryonic stem cells revealed that both the del11 and ΔRS variants inhibited C/EBPε-mediated target gene induction, indicating a loss of transcriptional activity. In NIH3T3 cells, WT and ΔRS C/EBPε were localized to the nucleus, whereas del11 C/EBPε showed cytoplasmic retention and induced morphological changes in expressing cells. Protein-protein interaction analyses demonstrated that both mutants failed to interact with the transcription factors GATA-binding protein 1 and purine-rich box-1. DNA-binding assays revealed that del11 C/EBPε completely lost its ability to bind to target DNA sequences, whereas WT and ΔRS C/EBPε retained binding capacity. Thus, del11 disrupts multiple C/EBPε functions, including nuclear localization, DNA-binding, and protein interactions.

Conclusion: Based on these functional differences, we propose a novel classification of SGD-1 into types 1a and 1b (SGD-1a and -1b). Patients with SGD-1b,-associated with nonsense and frameshift variants, such as del11,-exhibit more severe clinical phenotypes than those with SGD-1a,-associated with missense variants and in-frame deletions. This study offers novel insights into the pathogenesis of SGD and genotype-phenotype correlations, potentially informing the development of future therapeutic strategies.

Introduction: Signal transducer and activator of transcription 3 (STAT3) orchestrates crucial immune responses through its pleiotropic functions as a transcription factor. Patients with germline monoallelic dominant negative or hypermorphic STAT3 variants, who present with immunodeficiency and/or immune dysregulation, have revealed the importance of balanced STAT3 signaling in lymphocyte differentiation and function, and immune homeostasis. Here, we report a novel missense variant of unknown significance in the DNA-binding domain of STAT3 in a patient who experienced hypogammaglobulinemia, lymphadenopathy, hepatosplenomegaly, immune thrombocytopenia, eczema, and enteropathy over a 35-year period.

Methods: In vitro demonstration of prolonged STAT3 activation due to delayed dephosphorylation, and enhanced transcriptional activity, confirmed this to be a novel pathogenic STAT3 gain-of-function variant. Peripheral blood lymphocytes from this patient, and patients with confirmed STAT3 Gain-of-function Syndrome, were collected to investigate mechanisms of disease pathogenesis.

Results: B cell dysregulation was evidenced by a loss of class-switched memory B cells and a significantly expanded CD19hiCD21lo B cell population, likely influenced by a skewed CXCR3+ TFH population. Interestingly, unlike STAT3 dominant negative variants, cytokine secretion by activated peripheral blood STAT3 GOF CD4+ T cells and frequencies of Treg cells were intact, suggesting CD4+ T cell dysregulation likely occurs at sites of disease rather than the periphery.

Conclusion: This study provides an in-depth case study in confirming a STAT3 gain-of-function variant and identifies lymphocyte dysregulation in the peripheral blood of patients with STAT3 gain-of-function syndrome. Identifying cellular biomarkers of disease provides a flow cytometric-based screen to guide validation of additional novel STAT3 gain-of-function variants as well as provide insights into putative mechanisms of disease pathogenesis.

Increasing evidence supports the involvement of inborn errors of immunity in severe infections, but little is known about the prevalence of these genetic defects in children with sepsis. Due to the limited understanding of the molecular and immunological mechanisms driving sepsis, genetic testing is rarely used in routine diagnostics to identify genetic susceptibility to the condition. We performed a prospective observational study on previously healthy children hospitalized for severe infections, including sepsis. Patients underwent immunophenotyping and whole-exome sequencing, followed by in silico analysis to identify potentially causal variants. We assembled a cohort of 194 previously healthy children, including 149 (77%) patients with severe infection and 45 (23%) with sepsis. Our cohort was marked by a high frequency of respiratory tract infections (35%), bloodstream infections (20%), and central nervous system infections (16%). The genetic investigation identified 28 potentially causal variants, 18 (64%) are classified as variants with uncertain significance, and 10 (36%) are likely pathogenic variants. Of 45 patients with sepsis, 6 (13%) had potentially causal genetic variants. Similarly, 22/149 (15%) patients with severe infection presented potentially causal genetic variants. Whole-exome sequencing predicted the impairment of various immune mechanistic pathways such as immune dysregulation defects, antibody deficiencies, and combined immunodeficiencies (18% each). We found no clear association between genetic variants and the studied parameters: organ failure, microbe identification, immunoglobulin levels, and lymphocyte subset numbers. Although whole-exome sequencing is a valuable tool for detecting inborn errors of immunity underlying sepsis and unexplained severe infections, it could be selectively recommended for patients with a strong clinical suspicion of genetic abnormalities, balancing its diagnostic value with its cost and complexity.

Fc receptors (FcR) play a key role in coordinating responses from both the innate and adaptive immune system. The inhibitory Fc gamma receptor (FcγRIIB/CD32B; referred to as FcγRII/CD32 in mice) restrains the immune response, specifically through regulating immunoglobulin G (IgG) effector functions. FcγRII-deficient mice demonstrate elevated incidence and severity of autoimmunity and increased responses to immunization and infections. To explore the potential of FcγRIIB as a target for augmenting vaccines, we tested the ability of monoclonal antibodies (mAb) against mouse FcγRII and human FcγRIIB to enhance humoral responses in preclinical models. We used wild-type (WT), FcγR-deficient, and human FcγRIIB transgenic (Tg) mice with either a functional intracellular domain (hFcγRIIB Tg) or lacking immunoreceptor tyrosine-based inhibitory motif (ITIM) signalling capacity (NoTIM). Targeting mouse FcγRII and human FcγRIIB with antibodies significantly augmented humoral immune responses against experimental antigens and enhanced tumour clearance in vivo. Surprisingly, mAbs without a functional Fc (N297Q; referred to as Fc-null) lacked efficacy. Similarly, blocking FcγRII in mice lacking activating FcγRs failed to enhance immune responses. Conversely, blocking both signalling-competent and signalling-defective (NoTIM) FcγRIIB in Tg mice with a WT, but not Fc-null, FcγRIIB mAb equally enhanced immunity. These data indicate the redundancy of inhibitory signalling in potentiating immune responses in vivo. Collectively, our data suggest that mAb-targeting of FcγRIIB stabilizes mAb Fc and enhances immune responses via Fc-mediated crosslinking of activating FcγRs, irrespective of the inhibitory function of FcγRIIB. These findings support a strategy to boost immune responses in immunization protocols.

Granulomatosis with polyangiitis (GPA) is a B-cell-mediated, relapsing, autoimmune disease. There is a need for novel therapeutic approaches and relapse markers to achieve durable remission. B cells express immune regulatory molecules that modulate their activation and maintain tolerance. While recent studies show dysregulation of these molecules in other autoimmune diseases, data on their expression in GPA are limited. This study aimed to map the expression of surface immune regulatory molecules on circulating B-cell subsets in GPA and correlate their expression with clinical parameters. Immune regulatory molecule expression on circulating B-cell subsets was comprehensively examined in active GPA (n = 16), GPA in remission (n = 16), and healthy controls (n = 16) cross-sectionally using a 35-color B-cell-specific spectral flow cytometry panel. Our supervised and unsupervised in-depth analysis revealed differential expression of inhibitory and stimulatory immune molecules on distinct B-cell populations in GPA, with the most notable differences observed in active GPA. These differences include the upregulation of FcγRIIB on nonmature B cells, downregulation of CD21 and upregulation of CD86 on antigen-experienced B cells, and elevated CD22 expression on various populations. Additionally, we found a strong association between FcγRIIB, BTLA, and CD21 expression on specific B-cell populations and disease activity in GPA. Together, these findings provide novel insights into the immune regulatory molecule expression profile of B cells in GPA and could potentially form the foundation for new therapeutic approaches and disease monitoring markers.

Potent inflammatory responses stemming from innate and T cell activation are initiated during acute human immunodeficiency virus infection. Suppression of the virus replication by antiretroviral therapy reduces but does not normalize immune activation. By now, it is clear that residual immune activation can persist even after years of antiretroviral therapy and associates with increased risks for co-morbidities, thereby raising interest for strategies that can resolve the residual immune activation in people with human immunodeficiency virus on antiretrovirals. This brief review reports the human studies with various drugs with anti-inflammatory properties and their effects on measures of systemic immune activation on people with human immunodeficiency virus. Along with the possible reasons for conflicting outcomes, considerations for ongoing and future approaches are outlined.