Background: Ultra‐large von Willebrand factor and deficiency of its cleaving protease are important factors in the events leading to thrombotic microangiopathy; however, the mechanisms involved are ...only partly understood. Whereas pathological activation of the alternative complement pathway is linked to atypical hemolytic uremic syndrome, the role of complement activation in thrombotic thrombocytopenic purpura (TTP) is unknown. The aim of this study was to investigate whether signs of complement activation are characteristic of TTP.
Patients and methods: Twenty‐three patients with TTP (18 women, median age 38 years) and 17 healthy controls (13 women, median age 38 years) were included. Complement parameters (C3, Factors H, I, B and total alternative pathway activity) together with complement activation fragments (C3a) or complexes (C1rs‐INH, C3bBbP, sC5b9) were measured by ELISA or RID. ADAMTS13 activity and anti‐ADAMTS13 inhibitory antibodies were measured by the VWF‐FRET73 assay.
Results: Increased levels of C3a, and SC5b9 were observed in TTP during acute episodes, as compared with healthy controls. Decreased complement C3 levels indicative of complement consumption occurred in 15% of acute TTP patients. Significant decrease of complement activation products C3a and SC5b9 was observed during plasma exchange (PEX). The sustained presence of anti‐ADAMTS13 inhibitory antibodies in complete remission was associated with increased complement activation.
Conclusion: These data document in an observational study the presence of complement activation in TTP. Further investigation is needed to determine its potential pathogenetic significance.
Background
Hereditary angioedema is a potentially life‐threatening disorder, because edema occurring in the mucosa of the upper airways can lead to suffocation. The management of HAE consists of ...avoiding the triggering factors, prophylaxis, and the acute treatment of edematous episodes. Medical procedures can also provoke edematous attacks, and therefore, short‐term prophylaxis (STP) is recommended before such interventions. Our aim was to evaluate the efficacy and safety of STP administered before medical procedures.
Methods
We conducted a retrospective analysis before and a prospective survey after establishing the diagnosis in a group of 137 (60 males, 77 females; 20 pediatric and 117 adult) patients with HAE. Both were implemented using questionnaires, patient diaries and hospital charts focusing on medical interventions provoking edematous attack, and the medicinal products (C1‐INH concentrate, tranexamic acid, and danazol) administered for STP.
Results
Comparing surgical interventions performed without pre‐event STP (in 39/89 patients before HAE was diagnosed), or after STP (in 3/55 cases after diagnosis), we found a significant (P < 0.0001, Fisher's exact test) reduction in the number of edematous episodes. Evaluating the efficacy of the drugs administered for STP revealed that C1‐INH concentrate (Berinert®, CSL Behring, Marburg, Germany) was significantly (P = 0.0096, Fisher's exact test) superior to orally administered drugs in reducing the instances of postprocedural edema. None of the medicinal products caused adverse events potentially related to STP.
Conclusions
STP reduces the number of postprocedural edematous episodes. C1‐INH concentrate is safe and effective for prophylaxis. When this agent is not available, danazol is a potential alternative for prophylaxis before elective medical interventions.
The factors influencing the heterogeneous clinical manifestation of hereditary angioedema due to C1‐INH deficiency (C1‐INH‐HAE) represent one of the oldest unsolved problems of the disease. ...Considering that factor XII (FXII) levels may affect bradykinin production, we investigated the contribution of the functional promoter polymorphism F12‐46C/T in disease phenotype. We studied 258 C1‐INH‐HAE patients from 113 European families, and we explored possible associations of F12‐46C/T with clinical features and the SERPING1 mutational status. Given that our cohort consisted of related subjects, we implemented generalized estimating equations (GEEs), an extension of the generalized linear model accounting for the within‐subject correlation. F12‐46C/T carriers exhibited a significantly delayed disease onset (P < 0.001) and did not need long‐term treatment (P = 0.02). In a GEE linear regression model, the presence of F12‐46C/T was significantly associated with a 7‐year delay in disease onset (P < 0.0001) regardless of SERPING1 mutational status. It is concluded that F12‐46C/T carriage acts as an independent modifier of C1‐INH‐HAE severity.
Background: Myasthenia gravis (MG) is an autoimmune disorder mediated by antibodies against the acethylcholine receptor (AchR) of the neuromuscular junction in the majority of patients.
Methods: ...Here, we examined IgG antibodies against the type 1 nuclear antigen of Epstein‐Barr virus (EBNA‐1) in the sera of 158 patients with MG compared to 184 healthy controls.
Results: Although serum concentration in the sera was not different, high anti‐EBNA‐1 IgG titers (above 90th percentile of the normal values) were more common in the patients (26.6 vs. 16.3%, P = 0.024). In addition, high EBNA‐1 IgG levels occurred more frequently amongst the 94 patients with early‐onset myasthenia gravis (EOMG, 30.8%) as compared to the 64 patients with late‐onset disease (LOMG, 14.1%) (P = 0.021). Using multiple logistic regression, high serum concentration of the anti‐EBNA‐1 IgG antibodies was significantly associated with EOMG (OR: 3.17, P = 0.027), even after adjustment for sex, presence/absence of anti‐AchR antibodies and presence/absence of anti‐Titin antibodies. Out of 39 patients with EOMG, who underwent thymectomy, 18 patients (46%) had thymoma, 6 had thymic hyperplasia (15%), and 15 patients had thymic atrophy (39%); there was no difference comparing EBNA‐1 antibody titers in the sera. As no correlation was found between the titers of anti‐AchR, anti‐Titin, and EBNA‐1 antibodies, a dysregulated heterogeneous B‐cell response was unlikely to be responsible for the elevated levels of EBV‐associated antibody in patients.
Conclusions: In summary, our data suggest that high levels of EBNA‐1 antibodies are more common in MG compared to healthy controls and are especially associated with EOMG.
Dense deposit disease (DDD), a subtype of complement factor 3 glomerulopathy (C3G), is a rare entity associated with dysregulation of the alternative complement pathway. It usually affects children, ...with a 50% likelihood of progression to end-stage renal disease within ten years of diagnosis. Description of the case: We report the case of an adolescent male with acute nephritic syndrome and nephrotic range proteinuria, initially diagnosed as acute post-streptococcal glomerulonephritis (APSGN). Despite his spontaneous improvement, renal biopsy, performed due to a persistently low C3 level for over 18 weeks, confirmed the diagnosis of DDD. Complement and genetic studies showed high levels of C3-nephritic factor and risk polymorphisms for developing the disease. He was treated with prednisolone and mycophenolate mofetil (MMF). At the last follow-up, 15 months from onset, the serum creatinine level and 24h-hour total protein excretion were normal.
C3G (including the DDD subtype) should be suspected in apparent APSGN with atypical clinical features at presentation/follow-up, even in the case of spontaneous improvement. Timely and accurate diagnosis, based on histopathological, complement, and genetic studies, is important to initiate the appropriate treatment aimed at preventing or slowing the disease progression. HIPPOKRATIA 2020, 24(4): 191-193.
In patients with typical angina pectoris, inducible myocardial ischaemia and macroscopically normal coronaries (cardiac syndrome X (CSX)), a significantly elevated plasma level of terminal complement ...complex (TCC), the common end product of complement activation, has been observed without accompanying activation of the classical or the alternative pathways. Therefore, our aim was to clarify the role of the ficolin–lectin pathway in CSX. Eighteen patients with CSX, 37 stable angina patients with significant coronary stenosis (CHD) and 54 healthy volunteers (HC) were enrolled. Serum levels of ficolin‐2 and ficolin‐3, ficolin‐3/MASP‐2 complex and ficolin‐3‐mediated TCC deposition (FCN3‐TCC) were determined. Plasma level of TCC was significantly higher in the CSX than in the HC or CHD group (5.45 versus 1.30 versus 2.04 AU/ml, P < 0.001). Serum levels of ficolin‐2 and ficolin‐3 were significantly lower in the CSX compared to the HC or CHD group (3.60 versus 5.80 or 5.20 μg/ml, P < 0.05; 17.80 versus 24.10 or 26.80 μg/ml, P < 0.05). The ficolin‐3/MASP‐2 complex was significantly lower in the CSX group compared to the HC group (92.90 versus 144.90 AU/ml, P = 0.006). FCN3‐TCC deposition was significantly lower in the CSX group compared to the HC and CHD groups (67.8% versus 143.3% or 159.7%, P < 0.05). In the CSX group, a significant correlation was found between TCC and FCN3‐TCC level (r = 0.507, P = 0.032) and between ficolin‐3/MASP‐2 complex level and FCN3‐TCC deposition (r = 0.651, P = 0.003). In conclusion, in patients with typical angina and myocardial ischaemia despite macroscopically normal coronary arteries, low levels of several lectin pathway parameters were observed, indicating complement activation and consumption. Complement activation through the ficolin–lectin pathway might play a role in the complex pathomechanism of CSX.
Cardiac arrest causes generalized ischaemia/hypoxia, and subsequent resuscitation inflicts reperfusion injury, the pathology of which is not fully understood. Moreover, predicting the prognosis of ...comatose, post‐cardiac arrest patients is a complex clinical challenge. We hypothesized that the extent of complement activation might be a reliable predictor of mortality in this population. Forty‐six comatose cardiac arrest patients were enrolled into our prospective cohort study, conducted in a tertiary care university clinic. All subjects were cooled to 32–34 °C body temperature for 24 h and then allowed to rewarm to normothermia. All patients underwent diagnostic coronary angiography. On admission, at 6 and 24 h, blood samples were taken from the arterial catheter. In these, complement products (C3a, C3, C4d, C4, SC5b9 and Bb) were measured by ELISA in blood samples. Patients were followed up for 30 days; 22 patients (47.8%) died by the end of this period. We observed that complement activation (determined as the C3a to C3 ratio) was higher in non‐survivors than in survivors at each time point. In the multivariate Cox regression analysis, the C3a/C3 ratio determined 24 h after the initiation of therapeutic hypothermia predicted 30‐day mortality regardless of age, sex and the APACHE II score. Complement activation occurs in post‐cardiac arrest patients, and its extent correlates with 30‐day survival. The C3a/C3 ratio might prove useful for estimating the prognosis of comatose post‐cardiac arrest patients.
Summary
Several studies suggest that infection by Epstein–Barr virus (EBV) might be one of the environmental factors which facilitates the development of autoimmune disorders in genetically ...susceptible individuals. Recent data indicate that high anti‐Epstein–Barr nuclear antigen 1 (EBNA)‐1 immunoglobulin (Ig)G titre is a strong risk factor for multiple sclerosis (MS) in patients both with and without the main genetic predisposing trait, human leucocyte antigen (HLA)‐DRB1*15:01. Because no similar studies have been published in systemic lupus erythematosus (SLE) patients, we determined the HLA‐DRB1*15:01 carrier state and the serum titres against the whole EBNA‐1 and its small fragments aa35–58 and aa398–404 in 301 SLE patients, 135 MS patients and in 345 healthy controls. The carrier state of the HLA‐DRB1*15:01 allele was deduced from genotyping of a tagSNP (rs3135388) by applying a Taqman‐based assay. The serum concentrations of antibodies to EBNA‐1 and its aa35–58 or aa398–404 fragments were determined using a commercial assay (ETI‐EBNA‐G) and home‐made enzyme‐linked immunosorbent assays, respectively. The serum concentration of anti‐EBNA‐1 antibodies was significantly (P < 0·001) higher both in MS and SLE patients than in controls. Similar significant differences were found both in HLA‐DRB1*15:01 carriers and non‐carriers. Furthermore, titres of antibodies against the aa35–58 EBNA‐1 fragment were elevated both in MS and SLE patients. By contrast, the levels of aa398–404 EBNA‐1 antibodies were elevated significantly only in the SLE patients. These findings indicate that high anti‐EBNA‐1 IgG titres are HLA‐DRB1*15:01‐independent risk factors not only for MS, but also for SLE, while high antibody titres against the aa398–404 fragment are characteristic for SLE.
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