IntroductionMicrovesicles (MVs), earlier referred to as microparticles, represent a major type of extracellular vesicles currently considered as novel biomarkers in various clinical settings such as autoimmune disorders. However, the analysis of MVs in body fluids has not been fully standardized yet, and there are numerous pitfalls that hinder the correct assessment of these structures.MethodsIn this study, we analyzed synovial fluid (SF) samples of patients with osteoarthritis (OA), rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA). To assess factors that may confound MV detection in joint diseases, we used electron microscopy (EM), Nanoparticle Tracking Analysis (NTA) and mass spectrometry (MS). For flow cytometry, a method commonly used for phenotyping and enumeration of MVs, we combined recent advances in the field, and used a novel approach of differential detergent lysis for the exclusion of MV-mimicking non-vesicular signals.ResultsEM and NTA showed that substantial amounts of particles other than MVs were present in SF samples. Beyond known MV-associated proteins, MS analysis also revealed abundant plasma- and immune complex-related proteins in MV preparations. Applying improved flow cytometric analysis, we demonstrate for the first time that CD3+ and CD8+ T-cell derived SF MVs are highly elevated in patients with RA compared to OA patients (p = 0.027 and p = 0.009, respectively, after Bonferroni corrections). In JIA, we identified reduced numbers of B cell-derived MVs (p = 0.009, after Bonferroni correction).ConclusionsOur results suggest that improved flow cytometric assessment of MVs facilitates the detection of previously unrecognized disease-associated vesicular signatures.

SummaryA highly concentrated (20%) immunoglobulin (Ig)G preparation for subcutaneous administration (IGSC 20%), would offer a new option for antibody replacement therapy in patients with primary immunodeficiency diseases (PIDD). The efficacy, safety, tolerability and pharmacokinetics of IGSC 20% were evaluated in a prospective trial in Europe in 49 patients with PIDD aged 2–67 years. Over a median of 358 days, patients received 2349 IGSC 20% infusions at monthly doses equivalent to those administered for previous intravenous or subcutaneous IgG treatment. The rate of validated acute bacterial infections (VASBIs) was significantly lower than 1 per year (0·022/patient‐year, P < 0·0001); the rate of all infections was 4·38/patient‐year. Median trough IgG concentrations were ≥ 8 g/l. There was no serious adverse event (AE) deemed related to IGSC 20% treatment; related non‐serious AEs occurred at a rate of 0·101 event/infusion. The incidence of local related AEs was 0·069 event/infusion (0·036 event/infusion, when excluding a 13‐year‐old patient who reported 79 of 162 total related local AEs). The incidence of related systemic AEs was 0·032 event/infusion. Most related AEs were mild, none were severe. For 64·6% of patients and in 94·8% of IGSC 20% infusions, no local related AE occurred. The median infusion duration was 0·95 (range = 0·3‐4·1) h using mainly one to two administration sites [median = 2 sites (range = 1–5)]. Almost all infusions (99·8%) were administered without interruption/stopping or rate reduction. These results demonstrate that IGSC 20% provides an effective and well‐tolerated therapy for patients previously on intravenous or subcutaneous treatment, without the need for dose adjustment.

Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease with highest prevalence among women of childbearing age. However, children younger than 16 years also can develop SLE (childhood-onset lupus/juvenile-type SLE). The aim of our study was to compare the clinical course of adult and pediatric-onset SLE. Data from 342 adult patients followed at the University of Debrecen, Hungary, and 79 children documented in the Hungarian National Pediatric SLE registry were analyzed using hospital medical records. Organ manifestations, laboratory parameters, and immunoserological characteristics were reviewed and the results were evaluated using SPSS for Windows software.Gender distribution was not significantly different between groups with disease starting in childhood vs adulthood. The prevalence of the following manifestations was significantly higher for pediatric than for adult-onset disease including: lupus nephritis (43% pediatric vs 26.4% for adult-onset), hematological disorders (57% vs 36.4%), photosensitivity (20% vs 9%), butterfly rash (61% vs 35.5%) and mucosal ulceration (11.4% vs 4%). For adult-onset SLE, neurological symptoms (30% vs 6%) and polyarthritis (86% vs 68%) occurred significantly more frequently than in children. Anti-SSA, anti-SSB and antiphospholipid antibodies were detected at significantly higher levels in adult-onset patients compared to those in pediatrics. Children were more commonly given high-dose intravenous immunoglobulin treatment (6.3% vs 0.6%) and mycophenolate mofetil (15.2% vs 5.3%) than adults.These results suggest that pediatric and adult-onset SLE differ in multiple aspects, and it is important to recognize these differences for optimal treatment and prognosis of these patients.