Neutrophil extracellular trap-induced intermediate monocytes trigger macrophage activation syndrome in adult-onset Still's disease

Toward a personalized therapy of still's disease based on immunologic endotypes: a narrative review

INTRODUCTION

Accumulative evidence indicates that both innate and adaptive immunity are involved in pathogenesis of Still's disease, an autoinflammatory disease. With Increasing insights into the pathogenesis of Still's disease coupled with the availability of emerging targeted therapeutics, it may be the unmet need for personalizing therapy and achieving a treat-to-target goal. We aim to summarize the available evidence regarding immunopathogenesis of Still's disease and therapeutic strategies based on immunologic endotypes.

AREAS COVERED

We searched MEDLINE database using the PubMed interface and reviewed relevant English-language literature from 1971 to 2024. This review focuses on the existing evidence on pathophysiology and immunological endotypes of Still's disease and their implications for personalized strategies for patients with this disease.

EXPERT OPINION

Targeting the complex immunopathogenesis of Still's disease, emerging new agents are available for treatment, including biologic disease-modifying anti-rheumatic drugs (bDMARDs) and targeted synthetic DMARDs (tsDMARDs) such as Janus kinase inhibitors (JAKi). According to the updated evidence, meta-analyses, and recommendations, we propose a flow chart emphasizing personalized therapeutic strategies based on immunological endotypes. Hopefully, the therapeutic strategy might help guide the optimal selection of b/tsDMARDs to achieve a 'treat-to-target' goal in Still's disease. This proposed flow chart will be updated as newer evidence emerges.

High Neutrophil Alkaline Phosphatase Activity in Adult-Onset Still's Disease

INTRODUCTION

Adult-onset Still's disease (AOSD) is an autoinflammatory disorder characterized by reactive neutrophilia and dysregulated cytokine release. Mature neutrophils exhibit increased alkaline phosphatase enzyme activity within cytoplasmic granules, particularly in response to inflammation or acute infection. However, whether neutrophil alkaline phosphatase (NAP) activity is elevated in active AOSD, a hyperinflammatory state, remains unclear.

METHODS

We enrolled 114 patients diagnosed with AOSD, 47 patients with diffuse large B-cell lymphoma (DLBCL), 25 patients with antiphospholipid syndrome (APS), 25 patients with systemic lupus erythematosus (SLE), and 30 healthy controls. Blood samples were collected and smears were prepared, stained, and analyzed to calculate the NAP score.

RESULTS

Our findings demonstrated that NAP scores were significantly elevated in patients with active AOSD compared to those with inactive disease, other rheumatic diseases, and healthy controls (HCs). Further analysis revealed strong positive correlations between the NAP score and white blood cell (WBC) count, neutrophil ratio (NE%), absolute neutrophil count (ANC), ferritin, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), alkaline phosphatase (ALP), and systemic disease activity score. Additionally, among patients with AOSD-pre-macrophage activation syndrome (MAS), NAP scores were significantly higher than in those with active AOSD without MAS. Receiver operating characteristic (ROC) curves showed that NAP scores were more effective than other clinical features in distinguishing active AOSD without MAS from patients with AOSD-pre-MAS. Unexpectedly, in patients with AOSD-MAS, NAP scores were significantly reduced compared to those with active AOSD without MAS, likely due to leukopenia.

CONCLUSIONS

Our findings revealed that NAP scores were elevated in active AOSD and positively correlated with disease activity.

Identification of novel cytokine to judge the diagnosis and clinical phenotype of adult-onset Still's disease

This study aimed to identify biomarkers to distinguish adult-onset Still's disease (AOSD) and to predict disease phenotypes. In total, 49 patients diagnosed with AOSD and 200 patients with common diseases (controls) were included in the analysis. The levels of 69 cytokines were analyzed using a multi-suspension cytokine array. Cytokine cluster analysis was performed to identify specific molecular networks. Furthermore, random forest analysis and logistic regression analysis were used to rank cytokines based on their importance and to determine specific biomarkers for identification of AOSD patients and phenotypes. Patients with AOSD demonstrated significantly higher macrophage migration inhibitory factor (MIF) and interleukin (IL)-12(p40) serum levels than controls and patients with rheumatoid arthritis. Serum levels of chemokine (C-C motif) ligand (CCL) 8 and CCL22 were significantly lower in AOSD patients with a polycyclic systemic disease phenotype and could be differentiated with high accuracy from the other phenotypes (cutoff value for CCL8 = 122.7 pg/mL, CCL22 = 593.3 pg/mL, sensitivity 66.7%, specificity 87.1%, area under the curve 0.843). Combined MIF and IL-12(p40) levels may represent a biomarker for differentiating patients with AOSD from those with other diseases. The chemokine profiles of AOSD with a polycyclic systemic disease phenotype may differ from other phenotypes.

Advancing personalised precision treatment for Still's disease based on molecular characteristics and disease progression

Still's disease, a systemic autoinflammatory disorder with a classic multigenetic background, is characterised by polyarthritis, high-spiking fever, salmon-like evanescent skin rash, and hyperferritinaemia. Although the exact cause of Still's disease remains unclear, it is believed to be influenced by genetic factors, infections, and immune dysregulation. Current studies indicate that neutrophils and macrophages play crucial roles in the pathogenesis of Still's disease, along with involvement of natural killer cells, T cells, and B cells. Advances in biologic agents have expanded treatment strategies beyond conventional approaches, with cytokine-targeted agents showing promise in the management of Still's disease. Some cytokine-targeting biologic agents can be developed based on clinical manifestations, complications, immune cells, and molecular networks. Emphasis of immunophenotyping for precise clinical subtyping and targeted molecular therapies based on these findings is crucial for optimising treatment outcomes. In this Review, we discuss the latest advancements in the understanding of Still's disease pathogenesis and corresponding therapeutic approaches.

Early identification of macrophage activation syndrome in adult-onset Still's disease: a case report and literature review

Background

Adult-onset Still's disease (AOSD) is a rare systemic inflammatory disorder characterized by high spiking fevers, evanescent rash, and polyarthritis. A serious complication of AOSD is macrophage activation syndrome (MAS), a life-threatening hyperinflammatory condition that can lead to multiorgan failure if not promptly diagnosed and treated.

Objective

This case report and literature review focus on the early identification of MAS in patients with AOSD, highlighting diagnostic challenges, differential diagnoses, and the utility of scoring systems like the HScore and MS score in clinical practice.

Case presentation

We report the case of an 80-year-old woman who presented with a complex diagnostic challenge involving AOSD complicated by MAS and concurrent cytomegalovirus (CMV) infection. Her clinical course was marked by recurrent high fevers, cytopenias, hyperferritinemia, and liver dysfunction. Despite extensive workup, initial diagnoses of infections and autoimmune conditions were considered and ruled out. The HScore and MS score were calculated to be 210 and 1.607, respectively, both indicative of MAS. The patient was treated according to the HLH-94 protocol, with high-dose dexamethasone and etoposide, alongside broad-spectrum antimicrobial and antiviral therapy. She responded well to treatment, with resolution of fever and improvement in clinical symptoms.

Discussion

The overlap between AOSD and MAS symptoms complicates early diagnosis, making scoring systems critical in differentiating MAS from other conditions. The HScore and MS score provided a structured approach to diagnosis, guiding timely intervention and improving the patient's prognosis. Our literature review emphasizes the importance of early recognition and integration of these scoring systems into routine clinical practice to enhance outcomes.

Conclusion

This case underscores the necessity of early identification and intervention in MAS associated with AOSD. The application of diagnostic scoring systems like the HScore and MS score is essential for prompt diagnosis and effective treatment, ultimately improving patient survival rates.

The role of neutrophil extracellular traps in inflammatory rheumatic diseases

PURPOSE OF REVIEW

Dysregulation in neutrophil extracellular trap (NET) formation and degradation has been reported in several inflammatory rheumatic diseases. This review summarizes the recent advances in the understanding the role of NETs in the context of inflammatory rheumatic diseases.

RECENT FINDINGS

NET formation is enhanced in peripheral blood of patients with large vessel vasculitis and polymyalgia rheumatica. NETs are detected in affected organs in autoimmune conditions, and they might play pathological roles in tissues. Several understudied medications and supplements suppress NET formation and ameliorate animal models of inflammatory rheumatic diseases. NETs and anti-NET antibodies have potential utility as disease biomarkers.

SUMMARY

Growing evidence has suggested the contribution of NET dysregulation to the pathogenesis of several inflammatory rheumatic diseases. Further research is warranted in regard to clinical impact of modulating aberrant NET formation and clearance in inflammatory rheumatic diseases.

Efficacy of Photobiomodulation Therapy Utilizing 808 nm and 660 nm Alone and in Combination for Treatment of Paresthesia in Rats

Background/Objectives: This study assessed the efficacy of photobiomodulation therapy (PBM) by 808 nm and 660 nm alone and in combination for the treatment of paresthesia in rats. Methods: This animal study was conducted on 36 adult male Wistar rats. After general anesthesia, the facial nerve of the right side of the face of rats was surgically exposed and pinched, returned in place, and sutured. The rats were randomly assigned to six groups (n = 6) of (I) no-intervention (control), (II) no-laser, (III) 808 nm laser (250 mW, 4 W/cm2, 20 s, 8 J/cm2, (IV) 660 nm laser (150 mW, 0.25 W/cm2, 32 s, 8 J/cm2, (V) 808 nm plus 660 nm laser with the original settings, and (VI) 808 nm plus 660 nm laser with half of the time and energy density. After 16 days, a biopsy sample was taken from the nerve injury site and underwent histological, histometric, and immunohistochemical assessments. Results: Significantly lower edema and congestion were seen in the combined laser group with original settings (p < 0.05); this group had no significant difference with the control group regarding degenerative changes of the nerve fibers and Schwann cells (p > 0.05). The 660 nm, and combined laser groups, had a significantly lower accumulation of inflammatory cells (p < 0.05). The number of blood vessels in combined laser groups was significantly lower than that in the no-laser group (p < 0.05). Conclusions: The results showed the positive efficacy of PBM by 808 nm and 660 nm lasers in resolution of inflammation and reduction of degenerative changes of Schwann cells and nerve fibers.

Comprehensive mapping of immune perturbations associated with secondary hemophagocytic lymphohistiocytosis

Secondary hemophagocytic lymphohistiocytosis (sHLH) is a hyperinflammatory syndrome characterized by immune disorders. It is imperative to elucidate the immunophenotypic panorama and the interactions among these cells in patients. Human peripheral blood mononuclear cells were collected from healthy donors and sHLH patients and tested using multicolor flow cytometry. We used FlowSOM to explore and visualize the immunophenotypic characteristics of sHLH. By demonstrating the phenotypes of immune cells, we discovered that sHLH patients had significantly higher levels of CD56+ monocytes, higher levels of myeloid-derived suppressor cells, low-density neutrophil-to-T cell ratio, and higher heterogeneous T cell activation than healthy donors. However, natural killer cell cytotoxicity and function were impaired. We then assessed the correlations among 30 immune cell types and evaluated metabolic analysis. Our findings demonstrated polymorphonuclear myeloid-derived suppressor cells, CD56+ monocytes, and neutrophil-to-T cell ratio were elevated abnormally in sHLH patients, which may indicate an association with immune overactivation and inflammatory response. We are expected to confirm that they are involved in the occurrence of the disease through further in-depth research.

Deep Immunophenotyping of Circulating T and B Cells in Relapsing Adult-Onset Still's Disease

Adult-onset Still's disease (AOSD) is a complex systemic inflammatory disorder, categorized as an 'IL-1 driven' inflammasomapathy. Despite this, the interaction between T and B cells remains poorly understood. We conducted a study, enrolling 7 patients with relapsing AOSD and 15 healthy control subjects, utilizing deep flow cytometry analysis to examine peripheral blood T- and B-cell subsets. T-cell and B-cell subsets were significantly altered in patients with AOSD. Within CD4+ T cells, Th2 cells were decreased. Additionally, Th17 cell and follicular Th cell subsets were altered within CD45RA-CD62L+ and CD45RA-CD62L- Th cells in patients with AOSD compared to healthy controls. We identified changes in CD8+ T cell maturation and 'polarization' in AOSD patients, with an elevated presence of the TEMRA CD8+ T cell subset. Furthermore, the percentage of Tc1 cells was decreased, while the frequency of CCR6-CXCR3- Tc2 cells was elevated. Finally, we determined that the frequency of CD5+CD27- B cells was dramatically decreased in patients with AOSD compared to healthy controls. Further investigations on a large group of patients with AOSD are required to evaluate these adaptive immunity cells in the disease pathogenesis.