Background: Different classification criteria for systemic lupus erythematosus (SLE) have been launched over the years. Our aim was to evaluate the performance of the EULAR/ACR-2019, SLICC-2012 and ACR-1997 classification criteria in a cohort of SLE patients with longstanding disease. Methods: Descriptive observational study in 79 patients with established and longstanding SLE. The three classification criteria sets were applied to those patients. Results: Of the 79 patients, 70 were women (88.6%), with a mean age of 51.8 ± 14 years and a mean disease duration of 15.2 ± 11.5 years. The sensitivity of the different criteria were: 51.9%, 87.3% and 86.1% for ACR-1997, SLICC-2012 and EULAR/ACR-2019, respectively. In total, 68 out of 79 patients (53.7%) met all three classification criteria; 11.4% did not meet any classification criteria and were characterized by low SLEDAI (0.6 ± 0.9), low SLICC/ACR Damage Index (0.88 ± 0.56) and fulfilling only skin domains, antiphospholipid antibodies or hypocomplementemia. To fulfill EULAR/ACR-2019 criteria was associated with low complement levels (p < 0.04), high anti-dsDNA levels (p < 0.001), presence of lupus nephritis III-IV (p < 0.05) and arthritis (p < 0.001). Conclusion: The EULAR/ACR-2019 classification criteria showed high sensitivity, similar to SLICC-2012, in SLE patients with longstanding disease. Patients with serological, articular or renal involvement are more likely to fulfill SLICC-2012 or EULAR/ACR-2019 criteria.

Objectives: Cryoglobulinemia (CG) is marked by abnormal immunoglobulins (Ig) in serum, precipitating at temperatures below 37 °C. Current classification categorizes CG into three subtypes (types I, II, and III) based on Ig clonality. The features distinguishing patients with CG based on their etiology remain unidentified. Aiming to characterize clinical and serological profiles of CG individuals, we conducted an observational analysis of a large cohort of patients and compared their characteristics based on underlying causes: hepatovirus (HV) infections, rheumatic diseases (RD), hematological disorders, and unidentified etiology (essential CG). Methods: We analyzed 252 cryoglobulin-positive serum samples from 182 patients and classified these into the four etiological groups. A separate sub-analysis was carried out for 10 patients meeting criteria for multiple diseases. We collected demographic, clinical, and laboratory data: CG characterization, complement (C3 and C4) levels, antinuclear antibodies (ANA), and rheumatoid factor (RF). Kruskal–Wallis and Wilcoxon–Mann–Whitney U-tests were used for comparisons. Results: Most patients (93.3%) had mixed cryoglobulinemia (types II + III), with 6.7% having type I. HV infection, predominantly hepatitis C, was the main (52.9%) associated condition within the cohort, followed by rheumatic (27.3%) and hematological (9.8%) disorders. In our cohort, ANA were frequent (45.3%) and often associated with RF positivity (43.6%) and decreased complement levels (C3: 42.4%, C4: 32.5%). Essential CG and CG associated with RD had a higher prevalence of cutaneous manifestations (p < 0.01) and renal involvement (p = 0.017). Hematological disorder-related CG showed higher cryoglobulin and RF concentrations (p < 0.01), despite milder symptoms. Conclusions: Our study underscores a mixed prevalence of CG across disease subgroups, with hepatitis-C virus as the primary factor, followed by rheumatic and hematological disorders. Four clinical and serological profiles of CG were identified based on their etiologies.

Platelets (PLTs) can modulate the immune system through the release of soluble mediators or through interaction with immune cells. Monocytes are the main immune cells that bind with PLTs, and this interaction is increased in several inflammatory and autoimmune conditions, including systemic lupus erythematosus (SLE). Our aim was to characterize the phenotypic and functional consequences of PLT binding to monocytes in healthy donors (HD) and in SLE and to relate it to the pathogenesis of SLE. We analyzed the phenotypic and functional features of monocytes with non-activated and activated bound PLTs by flow cytometry. We observed that monocytes with bound PLTs and especially those with activated PLTs have an up-regulated HLA-DR, CD86, CD54, CD16 and CD64 expression. Monocytes with bound PLTs also have an increased capacity for phagocytosis, though not for efferocytosis. In addition, monocytes with bound PLTs have increased IL-10, but not TNF-α, secretion. The altered phenotypic and functional features are comparable in SLE and HD monocytes and in bound PLTs. However, the percentages of monocytes with bound PLTs are significantly higher in SLE patients and are associated with undetectable levels of anti-dsDNA antibodies and hematuria, and with normal C3 and albumin/creatinine levels. Our results suggest that PLTs have a modulatory influence on monocytes and that this effect may be highlighted by an increased binding of PLTs to monocytes in autoimmune conditions.

Background and Objectives: IgG4-related disease is a chronic fibro-inflammatory condition. Despite the development of classification and responder indexes, reliable biomarkers for disease activity and therapeutic monitoring remain limited. We evaluate the performance of a panel of biomarkers, including cytokine profiles, plasmablasts and conventional markers. Materials and Methods: We conducted a cross-sectional, single-center study, involving 35 patients diagnosed with IgG4-RD. Disease activity was evaluated using the IgG4-RD Responder Index (RI), Damage Index (DI) and clinical assessment. Laboratory evaluation included serum IgG4, total IgG, CRP, ESR, eosinophils, IgE, complement levels, and cytokine profiling via multiplex immunoassay. B cell subpopulations were analyzed by flow cytometry. Statistical analyses were performed using STATA/BE 17.0. Results: Patients with active disease (RI > 4 or clinical judgment) exhibited significantly higher levels of total IgG (p = 0.02), IgG4 (p = 0.01), and IL-5 (p = 0.03). PET-positive patients showed a Th1-skewed immune profile, with elevated IFN-γ/IL-4 (p < 0.001), reduced IL-21/IFN-γ (p = 0.03), and increased eosinophils (p = 0.03). Clinician-assessed active disease was associated with higher total IgG levels (p = 0.01). Treatment-specific effects were observed: prednisone was associated with lower IgG4 and C3 levels. Notably, plasmablasts did not consistently correlate with clinical or imaging activity scores, possibly reflecting treatment status or B cell dynamics. Conclusions: This study demonstrates that cytokine ratios, particularly those involving IL-5, IL-13, IL-21, and IFN-γ, offer complementary information to traditional serological markers for IgG4-RD activity. While PET/CT-defined activity was best reflected by biomarkers of an IFN-γ-mediated pathway, the IgG4-RD RI demonstrated a stronger association with conventional humoral markers like serum IgG4 and total IgG. None of these biomarkers correlated with organ damage.

Background: Early identification of risk factors for low bone mass for chronological age (LBMca) and childhood osteoporosis (cOP) in patients undergoing skeletal growth is essential to mitigate long-term skeletal complications. cOP is diagnosed when LBMca (BMD Z-score ≤2) is accompanied by a clinically significant fracture history, or when vertebral fragility fractures are present.Methods: Patients under 21 years of age with at least one risk factor for LBMca (malabsorption syndrome, chronic inflammatory diseases, hematological diseases, endocrinopathies, drugs that affect bone metabolism, or insufficient calcium intake) were included. Data on fractures history and physical activity levels were collected. Spine and whole-body dual-energy x-ray absorptiometry (DXA) and vertebral morphometry were performed. Age-adjusted linear regression analysis evaluated associations between bone mineral density (BMD) and risk factors.Results: A total of 103 patients were included (mean age 9.8 years; 52.4% female), and 96.1% had more than two risk factors. The prevalence of LBMca was 10.5% and the prevalence of cOP was 4.8%. Vertebral BMD was positively associated with male sex. Whole body BMD was negatively associated with sedentary lifestyle and fracture history. Total body less head BMD showed negative associations with current steroid treatment, sedentary lifestyle, and history of fractures.Conclusions: Pediatric populations at risk of LBMca or cOP often have multiple risk factors, notably modifying ones such as physical inactivity. Up to 10.5% of children with risk factors present LBMca and 4.8% have an undiagnosed or unknown cOP. Longitudinal studies are warranted to understand the long-term impact of the identified risk factors, including age, sex, sedentary lifestyle, ethnicity and vitamin D status, on bone health.

Purpose: To describe clinical and biological characteristics of pediatric patients with at least one risk factor (RF) for low bone mass for chronological age (LBMca)/childhood osteoporosis (cOP) and to assess its influence on bone mineral density (BMD).Methods: Patients between 2 and 20 years of age with at least 1 RF were recruited. Daily calcium intake, number of previous fractures and other RFs and their distribution among different groups were assessed. Spine and whole body DXA and vertebral morphometry were performed.Results: 103 patients were included. Mean age was 9.8 years old. 52.4% were female. Of the RFs, 84.5% presented insufficient calcium intake, 38.8% were receiving or had received corticosteroids, 31.1% were receiving other treatments with osteotoxic potential, 13.6% led a sedentary lifestyle, 12.6% presented history of fractures, and up to 8.1% had hypovitaminosis D. 38% of the cohort had 2 RFs, 31% had 3 RFs, 15% had 4 RFs, and 12% associated 5 or more RFs. 10.5% met LBMca criteria and 4.8% met cOP criteria. 73% of vertebral BMD was justified by age and hypovitaminosis D (positive effect), and male sex and Hispanic ethnicity (negative effect). 82% of total body less head BMD was justified by age (positive effect), and Hispanic ethnicity and sedentary lifestyle (negative effect).Conclusions: Pediatric populations with risk of LBM/cOP have 2 or more risk factors. Up to 10.5% of children with RFs present LBM and 4.8% have an unknown cOP. RFs related to changes in BMD are age, sex, sedentary lifestyle, ethnicity, and hypovitaminosis D.