Application of a dried blood spot based proteomic and genetic assay for diagnosing hereditary angioedema

BACKGROUND

Hereditary angioedema (HAE) with C1-inhibitor deficiency (C1-INH-HAE) is a rare disease caused by low level (type I) or dysfunction (type II) of the C1-inhibitor protein with subsequent reduction of certain complement protein levels.

METHODS

To develop and test the reliability of a two-tier method based on C1-INH and C4 quantitation followed by genetic analysis from dried blood spot (DBS) for establishing the diagnosis of C1-INH-HAE. C1-INH and C4 proteins have been quantified in human plasma using a classical immuno-assay and in DBS using a newly developed proteolytic liquid chromatography-mass spectrometry method. Genetic analysis was carried out as reported previously (PMID: 35386643) and by a targeted next-generation sequencing panel, multiplex ligation-dependent probe amplification and in some cases whole genome sequencing.

RESULTS

DBS quantification of C1-INH and C4 showed the same pattern as plasma, offering the possibility of screening patients with AE symptoms either locally or remotely. Genetic analysis from DBS verified each of the previously identified SERPING1 mutations of the tested C1-INH-HAE patients and revealed the presence of other rare variations in genes that may be involved in the pathogenesis of AE episodes.

CONCLUSIONS

C1-INH/C4 quantification in DBS can be used for screening of hereditary AE and DNA extracted from dried blood spots is suitable for identifying various types of mutations of the SERPING1 gene.

C1-inhibitor/C1-inhibitor antibody complexes in acquired angioedema due to C1-inhibitor deficiency

BACKGROUND

Autoantibodies against C1-inhibitor (C1-INH-Ab) have a diagnostic value in acquired angioedema due to C1-inhibitor deficiency (C1-INH-AAE), even though antibodies can circulate in complexes, which can be undetectable by proven methods. Our aim was to measure C1-INH/C1-INH-Ab complexes (CAC) and investigate their connection to C1-INH-Ab and the changes in their titer over time.

RESULTS

19 patients were diagnosed with C1-INH-AAE in the Hungarian Angioedema Center of Reference and Excellence; 79% of them had an underlying disease. Samples were examined with a newly developed in-house complex ELISA method. Patients with high C1-INH-Ab titer had a CAC titer which did not exceed the normal level and the ones with high CAC titer had a C1-INH-Ab titer which did not exceed the normal level. In case of those patients who had C1-INH-Ab and CAC of the same type of immunoglobulin, the increasing titer of C1-INH-Ab went together with the decreasing level of CAC and vice versa. CAC titer was already increased before the diagnosis of the underlying disease.

CONCLUSIONS

Free circulating and complex antibodies are in a dynamically changing equilibrium. CAC measurements can help to predict the development of an underlying disease. The efficiency of the treatment for underlying disease can be monitored by the decreasing CAC titers. Our results show that the CAC can be of important additional information besides the complement panel examination in case of C1-INH-AAE. Measurement of CAC is recommended to be done parallelly with C1-INH-Ab, so as to detect both free and bound antibodies.

Pattern formation and flocking for particles near the jamming transition on resource gradient substrates

We numerically examine a bidisperse system of active and passive particles coupled to a resource substrate. The active particles deplete the resource at a fixed rate and move toward regions with higher resources, while all of the particles interact sterically with each other. We show that at high densities, this system exhibits a rich variety of pattern-forming phases along with directed motion or flocking as a function of the relative rates of resource absorption and consumption as well as the active to passive particle ratio. These include partial phase separation into rivers of active particles flowing through passive clusters, strongly phase separated states where the active particles induce crystallization of the passive particles, mixed jammed states, and fluctuating mixed fluid phases. For higher resource recovery rates, we demonstrate that the active particles can undergo motility-induced phase separation, while at high densities, there can be a coherent flock containing only active particles or a solid mixture of active and passive particles. The directed flocking motion typically shows a transient in which the flow switches among different directions before settling into one direction, and there is a critical density below which flocking does not occur. We map out the different phases as function of system density, resource absorption and recovery rates, and the ratio of active to passive particles.

Diagnosing Pediatric Patients With Hereditary C1-Inhibitor Deficiency—Experience From the Hungarian Angioedema Center of Reference and Excellence

Background

Hereditary Angioedema with C1-inhibitor deficiency (C1-INH-HAE) is a rare disease characterized by recurrent subcutaneous and/or submucosal edematous (HAE) episodes, which may occur at any age. The mean age of the symptom onset is 10–12 years. Diagnostic protocols differ by age group and family history.

Methods

We retrospectively analyzed clinical and laboratory data (C4-, C1-INH concentration and function) from 49 pediatric patients diagnosed with C1-INH deficiency at our Angioedema Center between 2001 and 2020. Moreover, we analyzed the connection between complement parameters and symptom onset.

Results

From the 49 pediatric patients [boy/girl: 23/26, the average age of diagnosis: 6.7 years (min: 0-max: 18.84)], the majority (36/49, 73%) was diagnosed as the result of family screening. Of all the enrolled patients, 34% (17/49) experienced symptoms before the diagnosis. During the observational period, 33% (16/49) of the patients remained asymptomatic, while 33% (16/49) became symptomatic. The average age at symptom onset was 7.8 years (min: 0.5–max: 18). Only 27% (13/49) of pediatric patients were diagnosed after referrals to our center because of typical symptoms. From those patients diagnosed with family screening, 4/36 experienced symptoms at or before the time of the diagnosis. In the case of five newborns from the family screening group, umbilical cord blood samples were used for complement testing. In the case of 3/36 patients, the first complement parameters did not clearly support the disease, but the presence of the mutation identified in the family verified the diagnosis. Complement results were available from 11 patients who became symptomatic during the observational period. Complement parameters 1 year prior to and after the onset of symptoms were compared, and significantly lower concentrations of C1-INH (p = 0.0078) were detected after the onset of symptoms compared to the preceding (symptom-free) period.

Discussion

The majority of pediatric patients were diagnosed as a result of family screening before the onset of symptoms. Early diagnosis allows supplying the patients with special acute treatment for HAE attacks, which may occur at any time. Our results highlight the importance of DNA analysis in pediatric patients in case of a known mutation in the family, and an ambiguous result of complement testing.

Overview of SERPING1 Variations Identified in Hungarian Patients With Hereditary Angioedema

Background

Hereditary angioedema (HAE) due to C1-inhibitor (C1-INH) deficiency (C1-INH-HAE) is a rare autosomal dominant disorder, characterized by recurrent, unpredictable edematous symptoms involving subcutaneous, and/or submucosal tissue. C1-INH-HAE may be caused by more than 700 different mutations in the gene encoding C1-INH (SERPING1) that may lead to decreased protein synthesis or to functional deficiency.

Methods

Concentrations of C1-INH, C4, C1q, and anti-C1-INH antibodies, as well as functional C1-INH activity were determined in subjects suffering from edematous symptoms and admitted to the Hungarian Angioedema Center of Reference and Excellence. In those patients, who were diagnosed with C1-INH-HAE based on the complement measurements, SERPING1 was screened by bidirectional sequencing following PCR amplification and multiplex ligation-dependent probe amplification. For detecting large deletions, long-range PCRs covering the entire SERPING1 gene by targeting 2–7 kb long regions were applied.

Results

Altogether 197 individuals with C1-INH deficiency belonging to 68 families were identified. By applying Sanger sequencing or copy number determination of SERPING1 exons, 48 different mutations were detected in 66/68 families: 5 large and 15 small insertions/deletions/delins, 16 missense, 6 nonsense, and 6 intronic splice site mutations. Two novel variations (p.Tyr199Ser [c.596A>C] and the duplication of exon 7) were shown to cosegregate with deficient C1-inhibitor level and activity, while two other variations were detected in single patients (c.797_800delinsCTTGGAGCTCAAGAACTTGGAGCT and c.812dup). A series of long PCRs was applied in the remaining 2 families without an identified mutation and a new, 2606 bp long deletion including the last 91 bp of exon 6 (c.939_1029+2515del) was identified in all affected members of one pedigree. In the remaining one family, a deep intronic SERPING1 variation (c.1029+384A>G) was detected by a targeted next-generation sequencing panel as reported previously.

Conclusions

Sequencing and copy number determination of SERPING1 exons uncover most pathogenic variants in C1-INH-HAE patients, and further methods are worth to be applied in cases with unrevealed genetic background. Since knowledge of the genetic background may support the establishment of the correct and early diagnosis of C1-INH-HAE, identification of causative mutations and reporting data supporting the interpretation on the pathogenicity of these variants is of utmost importance.

The characteristics of upper airway edema in hereditary and acquired angioedema with C1-inhibitor deficiency

Background

Angioedemas localized in the upper airway are potentially life threatening, and without proper treatment, they may lead to death by suffocation. Upper airway edemas (UAE) in bradykinin‐mediated angioedemas can even be the first symptoms of the disease.

Methods

Our survey was performed with a retrospective long‐term follow‐up method from the medical history of 197 hereditary (C1‐INH‐HAE) and 20 acquired C1‐inhibitor deficiency (C1‐INH‐AAE), 3 factor XII and 3 plasminogen gene mutation (FXII‐HAE, PLG‐HAE) patients treated at our center between 1990 and 2020. The UAE group included edemas localized to the mesopharynx, hypopharynx, and larynx, as narrowing of these anatomical regions can lead to suffocation.

Results

98/197 C1‐INH‐HAE (47 families) and 13/20 C1‐INH‐AAE, 1/3 PLG‐HAE, 1/3 FXII‐HAE patients had experienced UAE at least once according to their medical history. In case of C1‐INH‐HAE patients, in 6/47 families who had undiagnosed ancestors had 13 members who died of suffocation. After the diagnosis, 1‐1 member of two families died of UAE. 44/64 C1‐INH‐HAE patients did not smoke, 20/64 did. The occurrence of UAE was significantly higher in smoker patients. We analyzed 7607 HAE attacks of 56/98 patients. Out of all attacks, the incidence of UAE in the C1‐INH‐HAE group was 4%, and 9.5% in the C1‐INH‐AAE group, respectively.

Conclusion

Early diagnosis is key in bradykinin‐mediated angioedemas cases, since the patient must be provided with adequate treatment; and also it is essential to inform patients about the importance of avoiding the trigger factors and the early symptoms of UAE, as these measures could significantly decrease the incidence of lethal UAEs.

The Global Registry for Hereditary Angioedema due to C1-Inhibitor Deficiency

Hereditary angioedema (HAE) is a rare condition, mostly due to genetic deficiency of complement C1 inhibitor (C1-INH). The rarity of HAE impedes extensive data collection and assessment of the impact of certain factors known to affect the course of this disabling and life-threatening disease. Establishing a global registry could assist to overcome such issues and provides valuable patient data from different countries. The HAE Global Registry is a disease-specific registry, with web-based electronic support, where data are provided by physicians and patients through a dedicated application. We collected data between January 1, 2018, and August 31, 2020. Data on 1297 patients from 29 centers in 5 European countries were collected. At least one attack was recorded for 497 patients during the study period. Overall, 1182 patients were diagnosed with HAE type 1 and 115 with type 2. At the time of database lock, 389 patients were taking long-term prophylactic medication, 217 of which were on danazol. Most recorded attacks affected the abdomen, were generally moderate in severity, and occurred in patients who were not on prophylactic treatment (70.6%, 6244/8848). The median duration of attacks was 780 min (IQR 290-1740) in patients on prophylactic medication and 780 min (IQR 300-1920) in patients not on continuous prophylactic medication. In conclusion, the establishment of a registry for C1-INH-HAE allowed collection of a large amount of data that may help to better understand the clinical characteristics of this disease. This information may enhance patient care and guide future therapeutic decisions.

Triggering receptor expressed on myeloid cells 1 and 2 in patients with chronic maxillary sinusitis

PURPOSE

Chronic sinusitis can result from variable types of immune-mediated process, whose pathogenesis is not fully understood. Triggering receptors expressed on myeloid cells 1 and 2 (TREM-1, TREM-2) are involved in myeloid cell activation enabling these cells to fine-tune the inflammatory response, which may have an impact on subsequent adaptive immunity and may be the key factor in pathogenesis. The aim of the study was to analyse soluble TREM-1 and TREM-2 molecules in maxillary sinus lavage fluid and compare the defined subgroups selected from patients with chronic sinusitis with/without nasal polyps and allergy (asthma and allergic rhinitis).

METHODS

The levels of soluble TREM-1 and TREM-2 were measured by Elisa test in a cohort of patients with chronic maxillary sinusitis (n=45). We compared subgroups of patients with nasal polyps (n=33) and allergy (n=25: inclusive of asthma (n=11) and allergic rhinitis (n=14)) with the control group of patients without nasal polyps (n=13), and without allergy (n=21).

RESULTS

The study did not prove the difference between subgroups with and without nasal polyps. The levels of soluble TREM-1 did not differ significantly between patients with allergy (asthma and allergic rhinitis) and the control group without allergy (p=0.4804). The levels of soluble TREM-2 were significantly higher in patients with allergy (p=0.0028), asthma (p=0.0103) and allergic rhinitis (p=0.0137) as compared with the control group.

CONCLUSION

Our results suggest the role of TREM-2‑mediated activation of myeloid cells in chronic sinusitis accompanied by allergy, asthma, and allergic rhinitis (Tab. 6, Ref. 25).

A follow-up survey of patients with acquired angioedema due to C1-inhibitor deficiency

BACKGROUND

Acquired angioedema due to C1-inhibitor deficiency (C1-INH-AAE) is a rare form of bradykinin-mediated angioedema. It is diagnosed by complement testing; its treatment consists of the management of angioedema (AE) attacks and of underlying disease.

OBJECTIVE

Evaluate the results of the clinical follow-up of patients with C1-INH-AAE.

METHODS

Between 1999 and 2020, 3938 patients with angioedema were evaluated, and 17 diagnosed with acquired C1-INH deficiency were followed-up.

RESULTS

Mean age of the 17 patients was 61 years at diagnosis. In 33%, ACE inhibitors provoked AE attacks. Autoantibodies against C1-INH were detected in 10 patients at diagnosis and in a further patient during follow-up. The AE attacks involved the skin in 70.6%, the upper airways in 41.2% and the tongue/lip in 52.9% of patients. Twelve of the 17 patients had an underlying condition, mainly (n = 11) lymphoproliferative disease. In 10 patients diagnosed with a haematological disorder, AAE symptoms preceded the onset of the latter. One patient has not experienced an AE attack since diagnosis. Twelve patients were treated for angioedema attacks, and 32% of the attacks required acute treatment. PdC1-INH was used to relieve AE attacks, and rituximab for the treatment of underlying disease (in six patients). Six patients had multiple AE attacks before any treatment. The symptom-free period increased in five patients after the on-demand administration of pdC1-INH concentrate and following treatment of the underlying disease in two patients.

CONCLUSION

Early diagnosis of C1-INH-AAE and underlying disease is indispensable to reduce disease burden by introducing appropriate, individualized treatment and regular follow-up.

Identification of ovine-associated staphylococci by MALDI-TOF mass spectrometry

The objective of this study was to use matrix-assisted laser desorption ionisation–time of flight mass spectrometry (MALDI-TOF MS) for the identification of ovine-associated staphylococci. Presumptive Staphylococcus isolates were recovered from ovine udder surface (US), individual raw milk, bulk tank milk, and cheese samples and were characterised by conventional phenotypic methods. A total of 69 bacterial isolates were further confirmed by MALDI-TOF MS. Forty-two (60.9%) of 69 isolates were successfully identified on genus and species level. Two thirds (n = 28) of the 42 identified isolates were shown to be Staphylococcus spp. These 28 staphylococcal isolates formed two clusters, one consisting of 22 Staphylococcus aureus strains and the other composed of 6 non-aureus staphylococci, including S. simulans (n = 3), S. auricularis, S. equorum, and S. haemolyticus. MALDI-TOF MS has proven to be a reliable tool for the identification of staphylococci from raw sheep's milk, especially bulk tank milk; however, currently it appears to be less useful for the identification of bacterial isolates originating from ovine US samples. This is the first study to evaluate the applicability of MALDI-TOF MS for identification of Staphylococcus spp. in ovine raw milk, cheese, and US samples in Hungary.

How Angioedema Quality of Life Questionnaire Can Help Physicians in Treating C1-Inhibitor Deficiency Patients?

The Angioedema Quality of Life Questionnaire (AE-QoL) is an angioedema (AE)-specific validated questionnaire, which surveys the quality of life of diagnosed patients. The questionnaire has been used in multiple clinical trials. Our aim was to investigate how the questionnaire can assist physicians in the everyday practice of following up and managing C1-inhibitor deficiency patients. In a prospective trial conducted in our center between 2016 and 2018, 125 hereditary angioedema and 10 diagnosed with acquired angioedema completed an AE-QoL during their annual follow-up visit. Laboratory indices (i.e., complement levels) were obtained for each patient. Statistical analysis comparing clinical data with QoL parameters was performed. Results of the analysis show that AE-QoL total score and number of AE attacks per year correlated well (r = 0.47; p < 0.0001). Women reached higher AE-QoL total score values than men, over a 3-year period (p = 0.0014). The highest AE-QoL total scores were reached by the 41–60-year age group; we obtained a similar result, when analyzing the four domains. No correlation was found between the AE-QoL total score and complement parameters. Patients with a negative correlation between AE-QoL total score and number of AE attacks had a positive correlation with psychologic attributes like fatigue/mood and fears/shame domains. Patients that acquired HAE showed a significant correlation between the annual number of AE attacks and the AE-QoL total scores (r = 0.46; p < 0.0001). The study establishes the use of AE-QoL as a clinical tool for follow-up which can help in the complex assessment of both hereditary and acquired HAE patients, and help to develop better therapeutic strategies.

Pathways of Neutrophil Granulocyte Activation in Hereditary Angioedema with C1 Inhibitor Deficiency

Hereditary angioedema (HAE) with C1-inhibitor deficiency belongs to bradykinin-mediated angioedemas. It is characterized by recurrent subcutaneous and/or submucosal swelling episodes (HAE attacks) and erythema marginatum skin rash as a pre-attack (prodromal) phase. HAE attacks were shown to be accompanied by peripheral blood neutrophilia. We aimed to find molecular mechanisms that may explain the distinct role of neutrophil granulocytes in HAE. Plasma levels of blood cells and factors related to neutrophil activation (cytokines, chemokines, chemotactic factors, enzymes, and neutrophil extracellular trap) were measured in plasma samples obtained from patients during symptom-free periods (n = 77), during prodromal phase (n = 8) and attacks (n = 14), during a spontaneously resolved attack (n = 1), and in healthy controls (n = 79). Higher counts of white blood cells, lymphocytes, and neutrophil granulocytes were found in symptom-free patients compared with controls; these cell counts were elevated further during HAE attacks. The level of chemokine (C–C motif) ligand 5, monocyte chemoattractant protein-1, and myeloperoxidase were also higher in the symptom-free patients than in the controls. Levels of monocyte chemoattractant protein-1, leukotriene B4, neutrophil elastase, and myeloperoxidase were elevated during attacks. During erythema marginatum, white blood cells and monocyte count and levels of interleukin 8 were elevated compared with symptom-free period. Similar changes were detected during the attack follow-up. We conclude that the activation of NGs in symptom-free periods and a further increase observed during attacks suggests that NGs may be involved in the pathomechanism of HAE with C1-INH deficiency.

Patterns of C1-Inhibitor/Plasma Serine Protease Complexes in Healthy Humans and in Hereditary Angioedema Patients

C1-inhibitor (C1-INH) is an important regulator of the complement, coagulation, fibrinolytic and contact systems. The quantity of protease/C1-INH complexes in the blood is proportional to the level of the in vivo activation of these four cascade-like plasma enzyme systems. Parallel determination of C1-INH-containing activation complexes could be important to understand the regulatory role of C1-INH in diseases such as hereditary angioedema (HAE) due to C1-INH deficiency (C1-INH-HAE). We developed in-house ELISAs to measure the concentration of complexes of C1-INH formed with active proteases: C1r, C1s, MASP-1, MASP-2, plasma kallikrein, factor XIIa, factor XIa, and thrombin, as well as to determine total and functionally active C1-INH. We measured the concentration of the complexes in EDTA plasma from 6 healthy controls, from 5 with type I and 5 with type II C1-INH-HAE patients during symptom-free periods and from five patients during HAE attacks. We also assessed the concentration of these complexes in blood samples taken from one C1-INH-HAE patient during the kinetic follow-up of a HAE attack. The overall pattern of complexed C1-INH was similar in controls and C1-INH-HAE patients. C1-INH formed the highest concentration complexes with C1r and C1s. We observed higher plasma kallikrein/C1-INH complex concentration in both type I and type II C1-INH-HAE, and higher concentration of MASP-1/C1-INH, and MASP-2/C1-INH complexes in type II C1-INH-HAE patients compared to healthy controls and type I patients. Interestingly, none of the C1-INH complex concentrations changed significantly during HAE attacks. During the kinetic follow-up of an HAE attack, the concentration of plasma kallikrein/C1-INH complex was elevated at the onset of the attack. In parallel, C1r, FXIIa and FXIa complexes of C1-INH also tended to be elevated, and the changes in the concentrations of the complexes followed rather rapid kinetics. Our results suggest that the complement classical pathway plays a critical role in the metabolism of C1-INH, however, in C1-INH-HAE, contact system activation is the most significant in this respect. Due to the fast changes in the concentration of complexes, high resolution kinetic follow-up studies are needed to clarify the precise molecular background of C1-INH-HAE pathogenesis.

Changes of coagulation parameters during erythema marginatum in patients with hereditary angioedema

BACKGROUND

Hereditary angioedema (HAE) with C1-inhibitor deficiency (C1-INH-HAE) is characterized by recurrent episodes of subcutaneous/submucosal edema, which may be preceded by erythema marginatum (EM) as a prodromal symptom. Our aim was to analyze the changes occurring in the parameters of the coagulation system during the development of EM and HAE attacks.

MATERIALS AND METHODS

Eight C1-INH-HAE patients (1 male, 7 females, median age: 41.7 years) were studied. Blood samples were obtained from all patients (during symptom-free periods, EM, and HAE attacks), as well as from 20 sex- and age-matched healthy controls. Prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, D-dimer, Factor V, Factor VII, Factor X, Factor XI, and Factor XII levels were measured.

RESULTS

D-dimer levels were significantly lower, whereas aPTT was significantly prolonged in healthy controls vs. the values measured during the symptom-free period (p = 0.0497; p = 0.0043), in the presence of EM (p = 0.002; p = 0.0002), or during HAE attacks (p < 0.0001; p = 0.0002). We observed the following differences between samples taken during HAE attacks vs. in symptom-free periods: D-dimer levels were significantly elevated (p = 0.0391), while aPTT was significantly shorter during HAE attacks (p = 0.0159). D-dimer levels were significantly higher during EM than in symptom-free periods (p = 0.0078). Comparing the samples drawn during EM or during HAE attacks, there were no significant differences in the study parameters.

CONCLUSIONS

D-dimer levels were elevated during EM and this suggests that EM may be part of the HAE attack. Nevertheless, further research into the complement and kinin-kallikrein systems is needed in more patients for a better understanding of the pathomechanism of EM.

Hereditary bilateral sudden sensorineural hearing loss

OBJECTIVES

The aim of our study is to demonstrate a causal link between two distinct diagnoses, the hereditary hearing loss, and the sudden sensorineural hearing loss.

BACKGROUND

Sudden sensorineural hearing loss is an emergency condition in otolaryngology and a rare diagnosis in childhood. Most often it only affects one ear and its cause remains unknown.

METHODS

We present a clinical study of a 10-year-old female patient presenting with bilateral sudden sensorineural hearing loss analyzed by Sanger sequencing of the GJB2 gene.

RESULTS

The subject was referred to the hospital for bilateral sudden hearing loss which developed 3 days before the admission. Audiometric testing confirmed bilateral asymmetric sensorineural hearing loss. All routine diagnostic procedures including MRI and CT imaging showed normal results. She was treated with intravenous and intratympanic corticosteroids followed by hyperbaric oxygen therapy with partial hearing recovery in one ear. DNA analysis of the GJB2 gene identified biallelic c.35delG deletion. The subject had no other affected family members and her auditory development to that time was normal.

CONCLUSION

Our finding extends the knowledge on phenotype variability in GJB2 variants. We suggest considering genetic testing in pediatric cases of bilateral sudden sensorineural hearing loss (Tab. 1, Fig. 4, Ref. 24).

[Analysis of the relationship between vitamin D3 level and disease severity in hereditary angioedema]

Introduction: In recent years, many papers analyzed the relationship between serum vitamin D₃ level and the frequency and activity of various diseases at least partially attributed to immune mechanisms. Aim: We looked for correlations among the number and location of edematous episodes occurring in patients with hereditary angioedema due to C1-inhibitor deficiency (C1-INH-HAE) and the quantity of the C1-inhibitor used for supplementation as well as the vitamin D₃ levels of patients. Method: We measured vitamin D₃ levels in 118 of the 175 C1-INH-HAE patients of the National Angioedema Reference Center during the winter-spring (n = 111) and the summer-autumn periods (n = 105) in 2013-2014. Complement levels and clinical data were extracted from the National Angioedema Registry and from patient diaries. Results: The proportion of vitamin D₃ deficient patients (serum level <20 ng/ml) was approximately 59.5% during winter-spring, 27.6% in summer-autumn, and 23.5% during both periods. There was a significant difference between vitamin D₃ serum levels measured in the winter-spring or in the summer-autumn months (p<0.0001). The same applies to the number of the vials of C1-inhibitor concentrate administered as acute treatment for angioedema attacks (p = 0.01). In any season, vitamin D₃ level did not correlate with the number of attacks experienced by the patients during the given period or of the vials of C1-inhibitor concentrate administered. Conclusions: We could not demonstrate a relationship between vitamin D₃ level and the frequency or location of edematous episodes in HAE patients. The need for treatment (as reflected by the number of the vials administered) was higher in the winter-spring period. As vitamin D₃ deficiency was more severe than expected in our patients, supplementation is clearly necessary. Orv Hetil. 2019; 160(25): 987-993.

Approaching the Gamow Window with Stored Ions: Direct Measurement of ^{124}Xe(p,γ) in the ESR Storage Ring

We report the first measurement of low-energy proton-capture cross sections of ^{124}Xe in a heavy-ion storage ring. ^{124}Xe^{54+} ions of five different beam energies between 5.5 and 8 AMeV were stored to collide with a windowless hydrogen target. The ^{125}Cs reaction products were directly detected. The interaction energies are located on the high energy tail of the Gamow window for hot, explosive scenarios such as supernovae and x-ray binaries. The results serve as an important test of predicted astrophysical reaction rates in this mass range. Good agreement in the prediction of the astrophysically important proton width at low energy is found, with only a 30% difference between measurement and theory. Larger deviations are found above the neutron emission threshold, where also neutron and γ widths significantly impact the cross sections. The newly established experimental method is a very powerful tool to investigate nuclear reactions on rare ion beams at low center-of-mass energies.

Dietary fibers, prebiotics, and exopolysaccharides produced by lactic acid bacteria: potential health benefits with special regard to cholesterol-lowering effects

The gastrointestinal (GIT) microbiota, which plays a crucial role in human health, is influenced by a number of factors including diet. Consumption of specific dietary ingredients, such as dietary fibers and prebiotics, is an avenue by which the microbiota can be positively modulated. These substances may also reduce serum cholesterol levels through various mechanisms. Interest has increased in methods of reducing blood cholesterol level, because dyslipidemia is recognized as a contributory risk factor for the development of cardiovascular diseases. Several drugs have been developed for the treatment of hypercholesterolemia; however, undesirable side effects were observed, which have caused concerns about their long-term therapeutic use. Alternatively, many nonpharmacological approaches were tested to reduce elevated serum cholesterol levels. Dietary fibers and prebiotics have particularly beneficial effects on the GIT microbiome, and can also reduce serum cholesterol level through various mechanisms. Lactic acid bacteria (LAB) are potentially capable of synthesizing different polysaccharides, e.g. exopolysaccharides (EPS), which may play a role as prebiotics. LAB-based EPS have the potential to affect the gastrointestinal microbiome and reduce cholesterol. However, as dietary fibers comprise a complex group of substances with remarkably diverse structures, properties, and impacts, EPS also differ greatly and show a multitude of beneficial health effects. This review discusses the current knowledge related to the effects of dietary fibers and prebiotics on the human GIT microbiome, the prebiotic properties of EPS produced by LAB, and the health-promoting benefits of these polymers with special emphasis being given to cholesterol lowering.

Engaging stakeholders in research to address water-energy-food (WEF) nexus challenges

The water-energy-food (WEF) nexus has become a popular, and potentially powerful, frame through which to analyse interactions and interdependencies between these three systems. Though the case for transdisciplinary research in this space has been made, the extent of stakeholder engagement in research remains limited with stakeholders most commonly incorporated in research as end-users. Yet, stakeholders interact with nexus issues in a variety of ways, consequently there is much that collaboration might offer to develop nexus research and enhance its application. This paper outlines four aspects of nexus research and considers the value and potential challenges for transdisciplinary research in each. We focus on assessing and visualising nexus systems; understanding governance and capacity building; the importance of scale; and the implications of future change. The paper then proceeds to describe a novel mixed-method study that deeply integrates stakeholder knowledge with insights from multiple disciplines. We argue that mixed-method research designs-in this case orientated around a number of cases studies-are best suited to understanding and addressing real-world nexus challenges, with their inevitable complex, non-linear system characteristics. Moreover, integrating multiple forms of knowledge in the manner described in this paper enables research to assess the potential for, and processes of, scaling-up innovations in the nexus space, to contribute insights to policy and decision making.

Complete kinetic follow-up of symptoms and complement parameters during a hereditary angioedema attack

We studied the kinetics of C1-inhibitor (C1-INH) and other complement parameters in a self-limited edematous attack (EA) in a patient with hereditary angioedema due to C1-INH deficiency to better understand the pathomechanism of the evolution, course, and complete resolution of EAs. C1-INH concentration and functional activity (C1-INH_c+f ), C1(q,r,s), C3, C4, C3a, C4a, C5a, and SC5b-9 levels were measured in blood samples obtained during the 96-hour observation period. The highest C1-INH_c+f , C4, and C1(q,r,s) levels were measured at baseline, and their continuous decrease was observed during the entire observation period. C4 depletion started at prodromal phase, and C4 was lowest after the maximum severity peak. Compared to baseline, C4a level was four times higher 7 hours before the onset of the attack. C1-INH did not increase after resolution of the attack suggesting that factors other than C1-INH may be important in this process. C4a may be a useful biomarker for the prediction of EAs.

Elevated complement C3 is associated with early restenosis after eversion carotid endarterectomy

Early restenosis following carotid endarterectomy (CEA) is an inflammatory process leading to myointimal hyperplasia of smooth muscle cells. The risk for restenosis is increased in homozygous carriers of the normal (A) allele of mannose-binding lectin (MBL2) gene. Our objective was to study the associ-ations of C3 and as control three non-complement acute-phase reactants (APRs) (C-reactive protein, haptoglobin and α2HS-glycoprotein) with early restenosis following CEA.We also considered, whether MBL2 genotype relates to C3 levels and to the risk of restenosis. Concentrations of the APRs were determined by radial immunodiffusion or immunoturbidimetric methods in 64 patients who underwent eversion CEA and were followed up with carotid duplex scan (CDS) examinations for at least one year. MBL2 genotypes were determined by a PCR-SSP method. C3 levels increased during the follow-up and correlated with the percentage of restenosis detected by CDS at 14 months postsurgery, in MBL2 A/A allele carriers. Patients with high C3 levels had nearly five-fold higher odds for the presence of significant restenosis (>50% reduction in diameter) even after adjusting for MBL2 genotype, age and gender. By contrast, no such associations were detected between the non-complement APRs and early restenosis. C3 is associated with and might have a direct role in the development of an early restenosis following CEA, which is partially related to an intact MBL lectin pathway, thus determining C3 levels might have clinical importance. On the other hand, our results indicate that the regulation of C3 differs from non-complement APRs.

Effect of genetic and nongenetic factors on chemical composition of individual milk samples from dromedary camels (Camelus dromedarius) under intensive management

The aims of the present study were to monitor the changes in gross chemical composition of individual dromedary camel milk over a 5-yr period, to provide reference values, and to determine the effect of genetic and nongenetic factors influencing camel milk composition under intensive management. A total of 1,528 lactating dromedary camels were included in the study. Animals were fed a constant diet and were milked twice a day in a herringbone parlor. Milk samples were collected at monthly intervals using a sampling device and then fat, protein, lactose, total solids (TS), and solids-nonfat (SNF) concentrations of raw camel milk were determined with an automatic milk analyzer. For each milk sample, production parameters were recorded and quantities (grams) of milk constituents were calculated. The overall mean quantity and fat, protein, lactose, SNF, and TS concentrations of the morning milk were 4.0 kg, 2.58%, 2.95%, 4.19%, 8.08%, and 10.46%, respectively. Milk quantity showed a positive correlation with lactose and a negative correlation with all other components. Parity exerted a strong effect on all milk parameters. Primiparous dromedaries (n = 60) produced less milk with higher concentrations of components than did multiparous animals (n = 1,468). Milk composition varied among the 7 breeds tested, but none of the genotypes was found to be superior to the others in this respect. We detected a significant, yet small calf sex-biased difference in milk yield and composition. Stage of lactation and season strongly influenced milk yield and all milk components. We also found a significant interaction between month postpartum (mPP) and month of the year. The concentration of all milk components decreased from 1 to 5 mPP. Later, lactose concentration and quantity continued to decrease parallel with decreasing milk production. The concentration of other components showed a temporary increase in mid lactation, from 6 to 11 mPP, and in late lactation, from 18 to 23 mPP. Mean fat, protein, SNF, and TS concentrations showed a high seasonal variation (9.5 to 28.7%), with the lowest and highest values being measured during summer and winter, respectively. This seasonal variation was independent of nutrition and may reflect an endogenous circannual rhythm. We observed a noticeable variation among years. Dromedary camels could provide a useful in vivo model to study the homeorhetic regulation of mammary cell function by endogenous and environmental factors.

A danazolkezelés hatása C1-inhibitor-hiány okozta hereditaer angiooedemás gyermekek növekedésére

Abstract:

Introduction: Attenuated androgens are used for the prevention of angioedema attacks of hereditary angioedema with C1-inhibitor deficiency. After prepuberty, their use can lead to growth retardation. Aim: We assessed the effect of danazol on the growth of pediatric patients with hereditary angioedema. Method: In the retrospective study on 42 patients diagnosed with hereditary angioedema, we calculated the deviation from the mid-parental target height, and analyzed it against the gender, the dose and duration of danazol treatment administered before the age of 21 years and before the age of 16 years. Results: Regarding the deviation from the mid-parental target height, we did not find any significant difference between patients taking vs. not taking danazol, males vs. females taking danazol. The dose and the duration of danazol treatment did not influence that value neither before 21, nor before 16 years of age. Conclusions: Our findings suggest that treatment with the lowest effective doses of danazol does not influence growth. Orv Hetil. 2017; 158(32): 1269–1276.

The role of the complement system in hereditary angioedema

Hereditary angioedema (HAE) is a rare, but potentially life-threatening disorder, characterized by acute, recurring, and self-limiting edematous episodes of the face, extremities, trunk, genitals, upper airways, or the gastrointestinal tract. HAE may be caused by the deficiency of C1-inhibitor (C1-INH-HAE) but another type of the disease, hereditary angioedema with normal C1-INH function (nC1-INH-HAE) was also described. The patient population is quite heterogeneous as regards the location, frequency, and severity of edematous attacks, presenting large intra- and inter-individual variation. Here, we review the role of the complement system in the pathomechanism of HAE and also present an overview on the complement parameters having an importance in the diagnosis or in predicting the severity of HAE.

International consensus on the diagnosis and management of pediatric patients with hereditary angioedema with C1 inhibitor deficiency

Background

The consensus documents published to date on hereditary angioedema with C1 inhibitor deficiency (C1‐INH‐HAE) have focused on adult patients. Many of the previous recommendations have not been adapted to pediatric patients. We intended to produce consensus recommendations for the diagnosis and management of pediatric patients with C1‐INH‐HAE.

Methods

During an expert panel meeting that took place during the 9th C1 Inhibitor Deficiency Workshop in Budapest, 2015 (www.haenet.hu), pediatric data were presented and discussed and a consensus was developed by voting.

Results

The symptoms of C1‐INH‐HAE often present in childhood. Differential diagnosis can be difficult as abdominal pain is common in pediatric C1‐INH‐HAE, but also commonly occurs in the general pediatric population. The early onset of symptoms may predict a more severe subsequent course of the disease. Before the age of 1 year, C1‐INH levels may be lower than in adults; therefore, it is advisable to confirm the diagnosis after the age of one year. All neonates/infants with an affected C1‐INH‐HAE family member should be screened for C1‐INH deficiency. Pediatric patients should always carry a C1‐INH‐HAE information card and medicine for emergency use. The regulatory approval status of the drugs for prophylaxis and for acute treatment is different in each country. Plasma‐derived C1‐INH, recombinant C1‐INH, and ecallantide are the only agents licensed for the acute treatment of pediatric patients. Clinical trials are underway with additional drugs. It is recommended to follow up patients in an HAE comprehensive care center.

Conclusions

The pediatric‐focused international consensus for the diagnosis and management of C1‐INH‐HAE patients was created.

Bacteriuria increases the risk of edematous attacks in hereditary angioedema with C1-inhibitor deficiency

Urinary tract infections are considered among the most common infectious disorders in humans. Various infections may have a role in inducing HAE attacks. Our study intended to evaluate bacteriuria in the urinalysis of patients with C1-INH-HAE. Urine specimens contributed by 139 patients with C1-INH-HAE at the annual control visits were studied retrospectively for microorganisms. We analyzed the presence of bacteriuria in relation to the clinical symptoms. Taking into account three randomly selected urine specimens, we found that the cumulative number of edematous attacks was higher in patients with bacteriuria than in those without (P = 0.019, P = 0.022, P = 0.014). Considering the same patients, attack number was significantly higher (14.51 vs 8.63) in patients with bacteriuria than in those without (P < 0.0001). In patients with bacteriuria, we found a higher incidence of edema formation during the year before evaluation, which may suggest the triggering role of bacteriuria in the occurrence of edematous episodes.

Assessment of inhibitory antibodies in patients with hereditary angioedema treated with plasma-derived C1 inhibitor

BACKGROUND

Limited data are available regarding C1 inhibitor (C1-INH) administration and anti-C1-INH antibodies.

OBJECTIVE

To assess the incidence of antibody formation during treatment with pasteurized, nanofiltered plasma-derived C1-INH (pnfC1-INH) in patients with hereditary angioedema with C1-INH deficiency (C1-INH-HAE) and the comparative efficacy of pnfC1-INH in patients with and without antibodies.

METHODS

In this multicenter, open-label study, patients with C1-INH-HAE (≥12 years of age) were given 20 IU/kg of pnfC1-INH per HAE attack that required treatment and followed up for 9 months. Blood samples were taken at baseline (day of first attack) and months 3, 6, and 9 and analyzed for inhibitory anti-C1-INH antibody (iC1-INH-Ab) and noninhibitory anti-C1-INH antibodies (niC1-INH-Abs).

RESULTS

The study included 46 patients (69.6% female; mean age, 38.9 years; all white) who received 221 on-site pnfC1-INH infusions; most patients received 6 or fewer infusions. No patient tested positive (titer ≥1:50) for iC1-INH-Ab at any time during the study. Thirteen patients (28.2%) had detectable niC1-INH-Abs in 1 or more samples. Nine patients (19.6%) had detectable niC1-INH-Abs at baseline; 3 of these had no detectable antibodies after baseline. Of 10 patients (21.7%) with 1 or more detectable result for niC1-INH-Abs after baseline, 6 had detectable niC1-INH-Abs at baseline. Mean times to symptom relief onset and complete symptom resolution per patient were similar for those with or without anti-niC1-INH-Abs.

CONCLUSION

Administration of pnfC1-INH was not associated with iC1-INH-Ab formation in this population. Noninhibitory antibodies were detected in some patients but fluctuated during the study independently of pnfC1-INH administration and appeared to have no effect on pnfC1-INH efficacy.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01467947.

Association of Low Ficolin-Lectin Pathway Parameters with Cardiac Syndrome X

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.

Risk of thromboembolism in patients with hereditary angioedema treated with plasma-derived C1-inhibitor

BACKGROUND

Plasma-derived C1-inhibitor (C1-INH) concentrates (pdC1-INH) have been used as safe and effective treatments for hereditary angioedema with C1-INH deficiency (C1-INH-HAE) for >30 years. Notwithstanding this, sporadic reports and a study into the high-dose therapy of neonates with C1-INH concentrate administered in an off-label indication raised concerns that this drug might increase the risk of thromboembolism.

OBJECTIVE

To investigate the incidence of thromboembolism and the background of the risk factors related to treatment with pdC1-INH.

METHODS

Our retrospective cohort study of 144 patients with C1-INH-HAE compared the incidence of thromboembolism and its risk factors in patients who received pdC1-INH with those who did not receive pdC1-INH as well as with those treated with danazol or with tranexamic acid.

RESULTS

During the observation period (29 years), 104 of the 144 subjects received pdC1-INH. The average dose per treatment was 573.59 IU. None of the patients used an indwelling central venous catheter. Multiple risk factors for thromboembolism were identified in 93 of the 104 patients treated with pdC1-INH. The incidence rate of thromboembolism was 0.0019/100 person-years in patients treated with pdC1-INH, whereas it was 0.0211/100 person-years in the not-treated group.

CONCLUSION

Our cohort study did not find any evidence for an increased risk of thromboembolism during treatment with pdC1-INH, despite the presence of multiple predisposing factors.

The effect of long-term danazol treatment on haematological parameters in hereditary angioedema

BACKGROUND

The 17-alpha-alkylated derivatives of testosterone are often used for the prevention of oedematous episodes in hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE). However, these agents can have many adverse effects, including erythrocytosis and polyglobulia. Our aim was to investigate occurrence of erythrocytosis and polyglobulia after long-term danazol prophylaxis in C1-INH-HAE.

METHODS

During the initial stage of our retrospective study, we explored whether C1-INH-HAE is associated with susceptibility to erythrocytosis and/or polyglobulia. In the second stage, we analyzed the haematological parameters of 39 C1-INH-HAE patients before, as well as after treatment with danazol for 1, 3, or 5 years. In the third stage, we studied the incidence of erythrocytosis and of polyglobulia after dosing with danazol for more than 5 years.

RESULTS

We did not find any significant difference between C1-INH-HAE patients not receiving danazol and healthy controls as regards the occurrence of erythrocytosis or polyglobulia. The haematological parameters did not change after treatment with danazol for 1, 3, or 5 years. Platelet count was an exception-it decreased significantly (p = 0.0115) versus baseline, but within the reference range. Treatment-related polyglobulia did not occur. We observed erythrocytosis in a single female patient after 1-year-and in three female patients after more than 5-year long-treatment with danazol. Erythrocytosis did not require intervention or the discontinuation of danazol therapy.

CONCLUSIONS

We conclude that neither erythrocytosis, nor polyglobulia occurs more often in C1-INH-HAE patients than in healthy individuals; it can be observed only sporadically even after treatment with danazol.

Neutrophil activation during attacks in patients with hereditary angioedema due to C1-inhibitor deficiency

BACKGROUND

Earlier studies have shown that the absolute number of neutrophil granulocytes (NGs) may increase during attack of hereditary angioedema due to C1-inhibitor deficiency (C1-INH-HAE). Whether NGs undergo activation during attack has not yet been investigated. However, as neutrophil elastase (NE) can cleave and inactivate C1-INH which may contribute to the dysregulation of the kallikrein-kinin system and hence, to edema formation. Our aim was to investigate the possible activation of NGs during attacks.

METHODS

We studied blood samples obtained from 26 patients with C1-INH-HAE during symptom-free periods and during attacks, along with samples from 26 healthy volunteers. NG count (NGC), NE, myeloperoxidase (MPO), pentraxin 3 (PTX3), CRP, C5a, factor H, IL-8, and TNF-α levels were measured.

RESULTS

NGC was higher during attacks than during symptom-free periods (p = 0.0132), and the same was observed for NE (p = 0.0026), MPO (p = 0.0008), and PTX3 levels (p = 0.0409). There was a strong positive correlation between NE and MPO levels during attacks (p < 0.0001, R = 0.709). Furthermore, IL-8 (p = 0.0061) and TNF-α (p = 0.0186) levels were also elevated during attacks, compared with symptom-free periods. By contrast, C5a and factor H levels were similar in samples obtained during attacks or in symptom-free periods.

CONCLUSION

Increased NGC was associated with elevated NE and MPO levels - this suggests neutrophil activation during attacks. The strong positive correlation between NE and MPO levels, together with the elevated PTX3 concentration, may indicate the expression of neutrophil extracellular traps. All these processes may contribute to the activation of kallikrein-kinin system, which leads to the onset of an edematous episode.

F12-46C/T polymorphism as modifier of the clinical phenotype of hereditary angioedema

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.

Comprehensive study into the activation of the plasma enzyme systems during attacks of hereditary angioedema due to C1-inhibitor deficiency

Background

The activation of plasma enzyme systems contributes to hereditary angioedema attacks. We aimed to study the activation markers of the fibrinolytic, coagulation, and contact systems in a larger number of paired samples obtained from the same C1-INH-HAE patients in symptom-free periods and during attacks.

Methods

Eleven parameters (Factors XI, XII, and C1-inhibitor activity; the concentrations of the D-dimer, prothrombin fragments 1 + 2, plasminogen, plasminogen activator inhibitor-1 [PAI-1], thrombin-anti-thrombin III [TAT] complex, fibrinogen) were measured along with prothrombin time and activated partial thromboplastin time (aPTT), using commercial kits. We compared these markers in samples obtained from the same 39 patients during attack-free periods and during 62 edematous episodes. Forty healthy subjects of matching sex and age served as controls.

Results

Compared with the healthy controls, significantly higher FXI and FXII activity (p = 0.0007, p = 0.005), as well as D-dimer (p < 0.0001), prothrombin fragments 1 + 2 (p < 0.0001), and TAT (p = 0.0303) levels were ascertained in the patients during symptom-free periods. The evaluation of samples from symptom-free periods or obtained during attacks revealed the increase of FXII activity, as well as of the concentration of D-dimer, prothrombin fragments 1 + 2, and TAT during edematous episodes. PAI-1 level, prothrombin time, and aPTT decreased significantly during attacks, compared with symptom-free periods. D-dimer level was significantly higher during multiple- vs. single-site attacks.

Conclusions

Comparing a large number of paired samples from symptom-free periods or from edematous episodes allowed accurate appraisal of the changes occurring during attacks. Moreover, our study pointed out that individual episodes may be characterized by different marker patterns.