We report a rare long-term case in which systemic polyarteritis nodosa (PAN) was ultimately diagnosed in adulthood after childhood-onset recurrent inflammatory disease with atypical Still-like features. A Japanese man had recurrent febrile episodes from infancy and was diagnosed with juvenile idiopathic arthritis at 9 years of age. In early adulthood, he developed recurrent fever, rash, polyarthralgia, splenomegaly, neutrophilia, and elevated inflammatory markers, and was considered to have Still-spectrum disease. However, ferritin elevation remained modest despite marked systemic inflammation, suggesting that the early phenotype may not have represented typical Still's disease and may instead have reflected a broader autoinflammatory process. At 25 years of age, he developed digital ischaemia with necrosis, palpable nodules, and erectile dysfunction. Angiography demonstrated narrowing of the ulnar and palmar arteries, and skin biopsy showed necrotising vasculitis involving medium-sized vessels, leading to the diagnosis of systemic PAN. He subsequently developed fever, rash, inner-ear involvement, hypertrophic pachymeningitis, and tortuosity/dilatation of a right intercostal artery. A subtle suspected lesion of the right testicular artery later became a definite enlarging aneurysmal lesion on serial imaging. Systemic inflammatory manifestations were subsequently controlled during treatment that included glucocorticoids, azathioprine, and tocilizumab. However, serial imaging demonstrated gradual enlargement of the right testicular artery aneurysmal lesion despite the absence of fever, rash, or C-reactive protein elevation for 5 years. This clinical course suggests that vascular progression may not always be adequately reflected by C-reactive protein levels during interleukin-6 blockade. This case illustrates the diagnostic difficulty of childhood-onset recurrent inflammatory disease with atypical Still-like features that was ultimately recognized as systemic PAN in adulthood. Occult or under-recognized medium-vessel vasculitis may have been present earlier in the disease course. Long-term diagnostic reappraisal, vascular imaging when indicated, and continued follow-up across paediatric and adult rheumatology care may therefore be important in similar patients, particularly in the current biologic era.

Adult-onset Still's disease (AOSD) is a rare systemic autoinflammatory disorder characterized by fever, rash, arthritis, and hyperferritinemia, often presenting as a diagnostic challenge due to its nonspecific manifestations. We report the case of a 35-year-old previously healthy male who presented with a 20-day history of pruritic erythematous skin lesions, high-grade fever, severe odynophagia, and symmetric inflammatory polyarthritis. Laboratory evaluation revealed leukocytosis with neutrophilia, elevated acute-phase reactants, liver enzyme abnormalities, and hyperferritinemia (1,050 ng/mL). Infectious, autoimmune, and neoplastic causes were excluded. During hospitalization, the patient developed chest pain with electrocardiographic changes and elevated troponin levels, consistent with acute pericarditis. Skin biopsy demonstrated nonspecific inflammatory dermatitis. A diagnosis of AOSD was established based on clinical findings and Yamaguchi criteria. Initial treatment with systemic corticosteroids resulted in partial improvement; however, early relapse required escalation to tocilizumab, achieving complete clinical remission at two months. This case highlights the importance of considering AOSD in patients with fever of unknown origin and elevated inflammatory markers, as well as the role of early targeted therapy in improving outcomes.

Chronic obstructive pulmonary disease (COPD) is driven primarily by cigarette smoke exposure, yet modelling its immunopathogenesis in mice is complicated by systemic stress and welfare concerns associated with conventional exposure models. Here, we employ a refined intranasal cigarette smoke extract (CSE) model to examine pulmonary pathology and peripheral immune responses in male and female C57BL/6J mice. Repeated intranasal CSE exposure over 12 weeks was well tolerated and induced dose-dependent pulmonary neutrophilia, airway remodelling, and collagen deposition, with more pronounced pathology observed in female mice at higher exposure levels. In contrast, longitudinal multiparametric flow cytometric analysis revealed no consistent dose-dependent alterations in peripheral immune cell composition or activation, as confirmed by both conventional gating and unbiased clustering approaches. These findings demonstrate that COPD-like lung pathology can arise in the absence of overt systemic immune disruption and highlight the importance of lung inflammatory processes in disease development. This refined intranasal model provides a welfare-conscious platform for studying pulmonary immunopathology in COPD.

Renal complications in diabetes impose substantial morbidity globally, yet early risk stratification remains challenging. The neutrophil-to-HDL cholesterol ratio (NHR) represents an integrated biomarker reflecting both immune activation and dyslipidemia, with neutrophilia promoting renal inflammation and low HDL-C impairing renoprotective mechanisms. We evaluated whether NHR is associated with diabetic nephropathy (DN) in a population-based cross-sectional study. We analyzed 2005 diabetic adults from six NHANES cycles (2007-2018). DN was defined as microalbuminuria (UACR ≥ 30 mg/g) or reduced eGFR (<60 mL/min/1.73m2) calculated via CKD-EPI 2021. NHR was computed as the ratio of neutrophil count to HDL-C concentration. Multivariable logistic regression with sequential covariate adjustment (demographics, socioeconomic factors, and comorbidities) was used to examine NHR-DN associations. Quartile-based dose-response analysis and restricted cubic spline modeling were additionally performed to characterize the association shape. DN prevalence reached 37.31% (n = 748). Individuals with nephropathy exhibited 15% higher median NHR (3.691 vs. 3.211, P < .001). Fully adjusted models revealed that per-unit NHR elevation increased DN odds by 22.48% (OR 1.2248, 95%CI 1.1533-1.3017, P < .001). Quartile analysis demonstrated dose-response relationships: top quartile participants showed 2.70-fold higher nephropathy risk versus bottom quartile (OR 2.6967, 95%CI 1.9965-3.6556, p-trend < 0.001). Higher NHR independently correlates with diabetic nephropathy presence in US adults. This readily calculated index combining inflammatory and metabolic dimensions may enhance clinical risk assessment. These observational findings suggest that NHR may serve as a complementary marker to support kidney disease risk stratification in diabetic patients, pending confirmation by prospective studies.

Cardiopulmonary bypass (CPB) during heart surgery provokes an inflammatory response that can cause post-operative organ injury, yet how CPB shapes key neutrophil effector programs is unclear. We investigated whether CPB differentially regulates neutrophil degranulation versus neutrophil extracellular trap (NET) formation and whether pre-operative neutrophil phenotypes associate with organ dysfunction. In a prospective cohort (n = 39) of children (1 day-4 years) undergoing CPB, blood samples were obtained before CPB and 24 h post-operatively. Purified neutrophils were analyzed for elastase activity and NET formation, alongside phenotypic markers of activation and neutrophil-platelet aggregation. Findings were correlated with acute kidney injury, respiratory failure, and cardiovascular dysfunction. CPB induced marked neutrophilia (4.5-fold rise; p < 0.0001). Elastase release was robustly enhanced after CPB and showed limited augmentation with secondary stimulation but did not predict organ dysfunction. In contrast, NET formation was significantly reduced after CPB. Importantly, diminished pre-operative responsiveness to low-dose NET priming was observed in patients who developed organ injury. Pediatric CPB uncouples neutrophil effector programs, priming degranulation while suppressing NETosis. Pre-operative NET "reserve" may define a clinically relevant innate immune endotype at risk for post-operative organ dysfunction and supports development of biomarker-driven treatment strategies in patients undergoing CPB.

Background: Pericardial effusion has a broad differential diagnosis, whereas bacterial pericarditis is rare. Despite this, routine culturing of pericardial fluid is frequently performed, and its diagnostic yield remains uncertain. Methods: We conducted a retrospective study of all pericardial fluid cultures obtained at a tertiary medical center between January 2016 and May 2024. Cultures were classified as true positive if a recognized bacterial pathogen was isolated or if it was deemed clinically pathogenic by an infectious disease's specialist at the medical record. Contaminants were defined according to CDC criteria. Clinical, laboratory, and imaging variables were analyzed using univariate testing and multivariable logistic regression. Results: Among 198 eligible pericardial fluid cultures, 8 (4%) yielded true bacterial pathogens, whereas 43 (23%) grew contaminants and 147 (73%) remained sterile. Thus, contaminant growth occurred more than five times as frequently as that of true pathogens. The most frequent pathogens were Staphylococcus aureus and Streptococcus species. No demographic features, presenting symptoms, or imaging findings were associated with culture positivity. In multivariable analysis, concurrent bacteremia (odds ratio [OR] 17.49; p = 0.002) and higher peripheral neutrophil percentage (OR 1.20; p = 0.012) independently predicted bacterial pericarditis. In models incorporating pericardial fluid cell counts, a lower mononuclear cell percentage was also independently associated with infection (OR 0.91; p = 0.03). Conclusions: Bacterial pericarditis is uncommon, and routine pericardial fluid cultures, of all pericardial fluid specimens, have a low diagnostic yield with substantial contamination. Laboratory markers, particularly bacteremia and neutrophilia, may help identify patients most likely to benefit from culture. A selective, laboratory-guided approach may improve diagnostic efficiency and reduce unnecessary testing.

Sweet syndrome is a relatively rare disease characterized by neutrophilia, tender and erythematous skin lesions with sudden onset of fever. Oral involvement is usually rare. We report a case of a 5-year-old boy who presented with fever, spontaneous erythematous swelling over the right periorbital and suprasternal region, upper left lip swelling, generalized gingival hyperplasia over the upper gingiva, and a single ulcer on the right soft palate region. Blood results was consistent with bicytopenia and leukocytosis, while biopsy of the skin and gingival lesions revealed dense infiltration of mixed inflammatory cells composed predominantly of neutrophils. Sweet syndrome was suggested based on the clinical presentations and histological features. Steroid treatment was initiated according to the suggested protocol; unfortunately, the child's condition started to deteriorate 3 weeks after his initial presentation, and he passed away 2 weeks later due to massive intracranial bleeding. Proper investigation and screening are crucial when any oral lesions with unknown causes are encountered.

We report a 39-year-old male with MDS/MPN with neutrophilia harboring a germline DDX41mutation. Next sequencing revealed mutational redundancy, wherein high-risk somatic lesions (ASXL1, SRSF2) may contribute to disease evolution in lieu of a detectable DDX41second hit. Despite a favorable karyotype, the patient relapsed early after the first allogeneic hematopoietic stem cell transplantation (allo-HSCT). He achieved remission via venetoclax/azacitidine(VA) bridging followed by a second allo-HSCT. This case expands the phenotypic spectrum of DDX41and underscores that allo-HSCT remains the definitive curative strategy, irrespective of non-transplant response rates or conventional risk models.