Hereditary angio-oedema with C1 inhibitor deficiency: Characteristics and diagnostic delay of Czech patients from one centre

BACKGROUND

Hereditary angio-oedema (HAE) is manifested by repeated episodes of localised subcutaneous or sub-mucosal oedema. Symptoms are extremely variable in frequency, localisation, and severity. Atypical or mild clinical symptoms of the disease may lead to erroneous diagnosis, causing diagnostic delay. The goal of this study was to assess how diagnostic delay has changed over 33 years at a single referral centre.

METHODS

We analysed diagnostic delay and first symptoms of HAE in patients who were diagnosed at an immunology department between 1980 and 2013. Patient's records were analysed.

RESULTS

The median diagnostic delay in 77 HAE type 1 and 2 patients was seven (range, 0-42) years. The difference observed in diagnostic delay between probands (18 [0-42] years) and others (1 [0-37] year) was significant (p<0.001). Our data show a significant negative correlation between the length of diagnostic delay and the year of diagnosis in our group of patients (p=0.024). The median age of first symptoms among all HAE patients (N=64) was 17 (1-40) years. The first symptoms of HAE in 64 patients were analysed. Twenty-six patients had abdominal, seventeen peripheral, five facial, two urogenital, and three had laryngeal oedema as the first manifestation of the disease. The last death that was attributed to HAE was in 1977.

CONCLUSIONS

Our observations demonstrate improved awareness of HAE among physicians, as documented by the significant decrease in diagnostic delay. It is believed that earlier treatment will improve patient quality of life and life expectancy.

[One case of hereditary angioneurotic laryngeal edema]

Hereditary angioneurotic laryngeal edema (HALE) is an autosomal dominant hereditary disease in which there is a decrease or defect in the C1 inhibitor (C1-INH). The pathophysiology of HALE is characterized by recurrent spontaneous episodes of transient edema of the laryngeal mucose and submucosal tissue with remission at irregular. Patients may die because of a life-threatening acute upper airway obstruction caused by laryngeal edema. HALE was diagnosed on the clinical symptoms, family history, and markedly decreased serum C1-INH activity and C1-INH protein.

Target levels of functional C1-inhibitor in hereditary angioedema

BACKGROUND

  Hereditary angioedema (HAE) is a heterozygous deficiency of first component of complement-inhibitor (C1INH). Insufficient C1INH activity leads to uncontrolled activation of plasma cascade systems, which results in acute angioedema attacks in patients with HAE. Plasma-derived or recombinant C1INH products are approved for the treatment of such angioedema attacks. The target level of C1INH activity needed to achieve optimal efficacy, however, remains unknown. We determined the plasma level of C1INH associated with optimal clinical efficacy in the treatment of angioedema attacks.

METHODS

  Efficacy and pharmacokinetic data were reviewed from recently published placebo-controlled randomized trials in the treatment of HAE with either plasma-derived or recombinant C1INH products, tested at various doses.

RESULTS

  A dose-dependent effect was observed on time to the beginning of relief of symptoms, on time to resolution of symptoms, and on the response rate within 4 h. Optimal efficacy of C1INH therapy is achieved at doses ≥50 U/kg. This dose increases plasma C1INH activity in almost all patients to values ≥0.7 U/ml (70% of normal), the lower limit of the normal range. The differences in half-lives of the various C1INH products do not have an obvious effect on clinical efficacy.

CONCLUSION

  A review of the efficacy and pharmacokinetic data from recently published controlled studies in the treatment of HAE attacks suggests that efficacy of C1INH therapy is optimal when C1INH activity levels are restored to the normal range.

Type III hereditary angio-oedema: clinical and biological features in a French cohort

BACKGROUND

Hereditary angio-oedema (HAE) has been associated with C1inhibitor deficiency. The first cases of type III HAE were described in patients with normal C1Inh antigenic protein level and function and normal C4 levels in 2000. This finding has been reported mostly in women with a family history and may be influenced by exogenous oestrogen exposure.

OBJECTIVES

The purpose of this article is to describe the clinical, biological and genetic characteristics of a French population suffering from type III HAE.

PATIENTS AND METHODS

We conducted a retrospective analysis of angio-oedema (AE) cases seen in the National Reference Centre of AE between 2000 and 2009.

RESULTS

We found 26 patients (from 15 unrelated families) with type III HAE. All but four were women and presented with typical AE attacks, exacerbated by pregnancy or oral contraceptives containing oestrogens (OC). We also found that 54.5% of women were worsened with oestrogen and 23% were oestrogen dependent. All patients improved on long-term prophylactic tranexamic acid treatment; some acute attacks improved with C1Inh concentrate infusion. All of the patients had normal C1Inh and C4 levels. C1Inh function was also normal, except in women receiving OC or during a pregnancy: transient, moderately low levels (32-74% of the normal range) were found in 18 patients tested (67%). No SERPING1 gene mutation was found. Six patients from three unrelated families were heterozygous for an F12 gene variant.

CONCLUSION

Diagnosis of type III HAE should be based on clinical (typical attacks, often hormonally influenced), laboratory (normal C1Inh antigenic protein) and genetic (F12 gene mutation) evidence.

[Clinical features of hereditary angioedema: analysis of 133 cases]

OBJECTIVE

To investigate the clinical characteristics of hereditary angioedema (HAE).

METHODS

The clinical data of 133 cases with HAE from 40 unrelated families were analyzed retrospectively.

RESULTS

Recurrent extremity swelling and/or facial and genital edema were reported in all patients (100%); 76.7% of the patients recalled abdominal symptoms; ascites was found in all 6 ultrasound examined patients in acute episodes. The ages of the patients ranged from 1.5 to 70. with the mean age of the first episode of 18 +/- 7. The time between onset and diagnosis was 16 years. Eight of the 133 patients were recognized as sporadic cases, without definite family history. The serum C1-INH levels of 130 patients were low, only the C1-INH levels of 3 cases in 1 family were a little bit higher than the normal level. Only one of the 40 families was diagnosed as with type II HAE (HAE-II). 43.6% of the patients received prophylaxis with danazol. Danazol had a good efficacy in all patients and were well tolerated by most of them.

CONCLUSIONS

A rare autosomal dominant disease, and characterized by recurrent episodes of cutaneous swelling, abdominal pain, and laryngeal edema, HAE can be fatal. Abdominal symptoms are often underestimated. HAE-II is very rare in China. Prophylaxis with danazol is effective and can be well tolerated.

Beneficial effects of C1 esterase inhibitor in ST-elevation myocardial infarction in patients who underwent surgical reperfusion: a randomised double-blind study

BACKGROUND

The inflammatory cascade has been hypothesized to be an important mechanism of post-ischaemic myocardial reperfusion injury and several studies demonstrated that C1 esterase inhibitor (C1-INH) is effective in post-ischaemia myocardial protection. Therefore, we aimed to investigate prospectively in a randomised double-blind study the cardioprotective effects of C1-INH in ST segment elevation myocardial infarction (STEMI) in patients who underwent emergent reperfusion with coronary artery bypass grafting (CABG).

METHODS

In this study, we enrolled 80 patients affected with STEMI who underwent emergent CABG. Patients were assigned in two groups (C1-INH group: receive 1000 UI of C1-INH; and placebo group: receive a saline solution). The effects of C1-INH on complement inhibition, myocardial cell injury extension and clinical outcome were studied. Haemodynamic data and myocardial function were monitored. C1-INH, C3a, C4a complement activation fragments and cardiac troponin I (cTnI) serum levels were measured before, during and after surgery.

RESULTS

Patient characteristics were not different between the two groups. The overall in-hospital mortality rate was 6.2%. No statistical significant difference was observed between the two groups with regard to early mortality (p=0.36). Statistical significant difference between the two groups was showed for cardiopulmonary bypass support (p=0.04), administration of high dose of inotropes drugs (p=0.001), time of intubation (p=0.03), intensive care unit (ICU) stay (p=0.04) and in-hospital stay (p=0.03). A significant improvement in mean arterial pressure (p=0.03), cardiac index (p=0.02) and stroke volume (p=0.03) was showed in C1-INH group versus placebo group. The serum cTnI levels were significantly low in the C1-INH group versus placebo group after reperfusion, during the observation period. Plasma levels of C3a and C4a complement fragments were reduced significantly in C1-INH group. No drugs-related adverse effects were observed.

CONCLUSIONS

The inhibition of the classic complement pathway by C1-INH appears to be an effective mean of preserving ischaemic myocardium from reperfusion injury as demonstrated by low serum cTnI levels in C1-INH group. Therefore, the use of C1-INH during CABG as a rescue therapy in STEMI patients is probably an effective treatment to inhibit complement activity and to improve cardiac function and haemodynamic performance without impacting early mortality. Large randomised study should be performed to support our results.

Angioedema and systemic lupus erythematosus--a complementary association?

INTRODUCTION

We report angioedema as a rare presentation leading to a diagnosis of systemic lupus erythematosus (SLE).

CLINICAL PICTURE

A diagnosis of angioedema was delayed in a patient presenting with limb and facial swelling until she developed acute upper airway compromise. After excluding allergic and hereditary angioedema, acquired angioedema (AAE) was suspected, possibly precipitated by respiratory tract infection. Associated clinical and laboratory features led to a diagnosis of SLE.

TREATMENT

Management proved challenging and included high dose steroids and immunosuppressants.

OUTCOME

The patient responded to treatment and remains in remission without recurrence of the angioedema.

CONCLUSION

AAE occurs due to the acquired deficiency of inhibitor of C1 component of complement (C1 INH). Lymphoproliferative disorders and anti-C1 INH antibodies are well-described associations. However, one should also consider the possibility of SLE.

Studying multiple protein profiles over time to assess biomarker validity

Protein profile analysis is increasingly used for identification of disease biomarkers. The approaches vary from surface-enhanced laser desorption/ionization to protein arrays. Newer platforms are constantly being developed. Almost all are based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and are often coupled with sophisticated software tools. Protein profiling has been applied to a variety of samples including plasma, urine, cerebrospinal fluid, saliva and solid tissue. This article focuses on those instances where it is possible to obtain sequential samples from the same individual. In the authors use of a profile method, many protein changes with highly significant correlations to disease have been found. The main challenge lies in the validation of the marker to demonstrate its adequacy for use in the clinical setting. The latter requires a methodology that is robust and amenable to high-throughput. One problem is that interindividual variability among the healthy population can mask major changes that occur on an intraindividual basis. Often, a large change for an individual may remain within the range of healthy individuals. Thus, one strategy to optimize biomarker discovery is to examine serial samples from a given individual, where a disease biomarker is established by comparison with the individual's own baseline sample. The focus of this review is to illustrate the principle and value of serial protein profiling using a rapid protein extraction method.

C1 inhibitor deficiency: diagnosis

This is the first of two articles on C1 inhibitor deficiency based on a recent UK consensus document covering diagnosis and management of the disorder in both adults and children. This paper focuses on diagnosis of this disorder.

DDI-microFIA--A readily configurable microarray-fluorescence immunoassay based on DNA-directed immobilization of proteins

We describe a chip-based immunoassay for multiplex antigen detection, based on the self-assembly of semi-synthetic DNA-protein conjugates to generate an easily configurable protein microarray. The general principle of this microarray-fluorescence immunoassay (microFIA) is similar to that of a two-sided (sandwich) immunoassay. However, covalent single-stranded DNA-streptavidin conjugates are employed for the efficient immobilization of biotinylated capture antibodies through hybridization to complementary surface-bound DNA oligomers. In a model system, we use the DNA-directed immobilization (DDI) of antibodies to generate an antibody microarray for the parallel detection of the tumor marker human carcinoembryonic antigen (CEA), recombinant mistletoe lectin rViscumin (rVis), ceruloplasmin (CEP), and complement-1-inactivator (C1A) in human blood serum samples. Detection limits down to 400 pg mL(-1) are reached. In addition, we describe a method for the internal standardization of protein microarray analyses, based on the simultaneous measurement of constant amounts of the blood proteins CEP and C1 A, intrinsically present in human serum, to compensate for interexperimental variations usually occurring in microarray analyses. The standardization leads to a significantly higher data reliability and reproducibility in intra- and interassay measurements. We further demonstrate that the DDI-microFIA can also be carried out in a single step by tagging of the analyte simultaneously with both capture and detection antibody and subsequent immobilization of the immunocomplex formed, on the DNA microarray capture matrix. This protocol significantly reduces handling time and costs of analysis.

Acquired C1 esterase inhibitor deficiency or serendipity? The chance finding of a paraprotein after an apparently low C1 esterase inhibitor concentration

Acquired C1 esterase inhibitor deficiency is a rare condition, usually presenting after the 2nd decade of life, and is often related to underlying conditions such as autoimmune and lymphoproliferative disorders. This case report describes a man whose initial clinical presentation with acute angioedema and whose initial estimation of a low C1 esterase inhibitor concentration indicated that he had an acquired angioedema, possibly secondary to a B cell neoplasm. A paraprotein was detected, and although its detection was serendipitous because it hinged on a spurious C1 esterase inhibitor result, this case confirms the role of C4 concentrations in the investigation of C1 esterase inhibitor deficiency. It also confirms the need to obtain repeat confirmatory samples before arriving at a diagnosis, however convincing the clinical signs may be.

High normal serum levels of C3 and C1 inhibitor, two acute-phase proteins belonging to the complement system, occur more frequently in patients with Crohn's disease than ulcerative colitis

Few data are available on measurements of serum concentrations of complement proteins in inflammatory bowel disease (IBD). Therefore we measured serum levels of C3, C4, and C1-esterase inhibitor (C1-INH) as well as C-reactive protein (CRP) in 167 patients with Crohn's disease (CD) and 111 patients with ulcerative colitis (UC). Median serum concentrations of C3 and C1-INH were significantly higher in CD than in UC. According to multiple logistic regression analysis adjusted to age, sex, activity of disease, and presence of extraintestinal manifestations, IBD patients with high-normal (> or = 128%, > or = 75th percentile ) C1-INH concentrations had significantly (0.0275) higher odds ratio to have a diagnosis of CD than UC. Patients with high-normal C3 (> or = 1.40 g/liter) and high (> or =20 mg/liter) CRP concentrations had an even higher odds ratio of a CD diagnosis (P = 0.0132). Our findings indicate that measurement of C3, C1-INH, and CRP can be used as an additional marker to pANCA/ASCA for distinguishing patients with CD and UC.

Exogenous oestrogen as an alternative to food allergy in the aetiology of angioneurotic oedema

Although frequently reported as an aetiology for chronic angioneurotic oedema or urticaria, food allergy is often a diagnosis proposed in the absence of more convincing evidence, as illustrated by the disappointing results of eviction regimens. We report a series of women with an initial diagnosis of food allergy, but in whom the role of oral contraceptives was subsequently demonstrated. Detailed medical history was obtained from 26 young women presenting with chronic angioneurotic oedema or urticaria initially attributed to food allergy, but in whom C1-esterase inhibitor (C1 INH) deficiency was demonstrated. We investigated the effects of oral contraception on C1 INH levels, C1 INH activity and clinical symptoms of these patients. Discontinuation of oral contraception induced an increase in C1 INH levels and C1 INH activity, associated with recovery or marked improvement of the clinical symptoms formerly attributed to food allergy. The relatively high frequency of women taking cyproterone acetate in this population appeared to be a remarkable finding. Replacement of the initial contraception containing ethinylestradiol by a progestogen maintained or even accentuated these good therapeutic results. Exogenous oestrogens, such as those contained in most oral contraceptives, may play an iatrogenic role in the aetiology of chronic angioneurotic oedema or urticaria.

[Evaluation of C3c, C4 and C1-esterase inhibitor (C1-INH) during unstable angina]

BACKGROUND

The complement system plays an important role in the physiopathology of acute myocardial infarction (AMI) taking part in myocardial damage and reperfusion injury. The aim of this study is to investigate the plasmatic levels of some complement components (C3c, C4 and C1-INH) during unstable angina (C1-INH) and their different concentrations in relation to the different myocardial areas affected by ischemia.

METHODS

The plasmatic levels of C1-INH, C3c and c4 in 30 patients affected by unstable angina, and those of 22 clinically healthy subjects (control group) were evaluated (Nefelometer Behering). The patients were divided into four groups according to the different myocardial area affected by ischemia (anterior, antero-lateral, lateral or inferior ischemia),

RESULTS

No statistically significant differences were found in plasmatic levels of C3c, C4 and C1-INH between the group of patients and the control group. There is a statistically significant difference between the C1-INH levels of the patients with inferior ischemia and the plasmatic concentrations of the whole patients' group (p<0,01), the control group (p<0,01) and the group of patients with lateral ischemia (p<0,02).

CONCLUSIONS

There seems to be a different activation of the complement system during unstable angina, in relation to the different myocardial area affected by ischemia.

Prevalence of monoclonal gammopathy in patients presenting with acquired angioedema type 2

PURPOSE

Acquired angioedema type 1 is characterized by a C1 inhibitor deficiency in patients with lymphoproliferative disorders, whereas acquired angioedema type 2 is characterized by anti-C1 inhibitor antibodies, and has not been thought to be associated with lymphoproliferative disease. We studied the clinical features, complement profiles, and associated diseases in 19 new patients with diagnosed acquired angioedema type 2.

SUBJECTS AND METHODS

Plasma concentrations and functional activity of complement components were measured by conventional techniques. Functional C1 inhibitor activity was assessed by a chromogenic assay. Autoantibodies to C1 inhibitor were detected using an enzyme-linked immunosorbent assay.

RESULTS

The 11 men and 8 women (median age, 60 years) presented with recurrent attacks of angioedema. All patients had detectable anti-C1 inhibitor antibodies in serum. A monoclonal gammopathy was detected in 12 patients (63%) at the time of diagnosis, 11 of whom had an immunoglobulin peak of the same heavy- and light-chain isotypes as the acquired anti-C1 inhibitor antibody. Three of these 12 patients developed a malignant lymphoproliferative disease.

CONCLUSION

As with type 1 disease, a large proportion of patients with acquired angioedema type 2 have a lymphoproliferative disorder.

A multicentre evaluation of the diagnostic efficiency of serological investigations for C1 inhibitor deficiency

AIM

To determine the diagnostic efficiency of assays routinely used in the investigation of hereditary angio-oedema.

METHODS

Over a four year period, 1144 samples were received for analysis from 907 patients suspected of C1 inhibitor deficiency. Analyses were performed for C4 and C1 inhibitor (functional and immunochemical). Notes were reviewed retrospectively on patients with low serological indicators to determine diagnosis.

RESULTS

These are the first data to indicate the sensitivity, specificity, and predictive values of the assays most frequently used to screen for C1 inhibitor deficiency. A combination of low C4 and low C1 inhibitor function has 98% specificity for C1 inhibitor deficiency in this population and a 96% negative predictive value, and is thus a very effective screen. All patients with untreated C1 inhibitor deficiency had a low C4 value.

CONCLUSIONS

All patients considered for a diagnosis of C1 inhibitor deficiency should have serum examined to measure both C4 and functional C1 inhibitor. If either is normal at presentation this essentially excludes a diagnosis of C1 inhibitor deficiency. These tests can be performed sequentially. If C4 is normal it is not necessary to proceed to C1 inhibitor analysis. If C1 inhibitor function and C4 are both low then a repeat sample should be obtained to confirm the findings.

Microheterogeneous changes of the C1-esterase inhibitor in plasma cannot predict operability, postoperative complications, or recurrence in cancer surgery

OBJECTIVE

To find out if microheterogeneous changes--such as in molecular weight, isoelectric point, electrophoretic mobility, lectin binding or complexation of the C1-esterase inhibitor--exist in plasma samples from various subgroups of patients. If so, whether these differences could be used diagnostically in single plasma samples from patients with cancer for prognostic assessment of operability or risk of recurrence, and whether any change indicated an increased risk for development of postoperative complications.

DESIGN

Retrospective study.

SETTING

University hospital, Sweden.

SUBJECTS

16 patients operated on as emergencies for acute peritonitis, 118 patients electively operated on for benign diseases, 274 patients electively operated on for cancer, and 212 patients admitted with acute abdominal pain.

MAIN OUTCOME MEASURES

Curative operation, diagnoses, postoperative complications, recurrence of cancer within 2 years.

RESULTS

There were no biochemical differences in the C1-esterase inhibitor between single or sequential plasma samples from four large groups of patients with benign disease, cancer, or inflammatory disease, with operable or inoperable cancer, with postoperative complications or not, or with or without early recurrence of cancer.

CONCLUSIONS

Specialised biochemical analyses of C1-esterase inhibitor, the most important plasma protease inhibitor of the complement and kinin systems and of contact activation in plasma, cannot be used for prognostic assessment of operability, risk of postoperative complications, or risk of recurrence in patients with cancer.

Coagulopathy following major liver resection: the effect of rBPI21 and the role of decreased synthesis of regulating proteins by the liver

This prospective study investigated the role of reduced hepatic synthesis of regulating proteins in coagulopathy after partial hepatectomy (PH) compared with major abdominal surgery (MAS) without involvement of the liver. Furthermore, we studied the effect of rBPI21, an endotoxin-neutralizing agent, on coagulopathy after PH was studied. Compared with MAS, PH resulted in significantly elevated levels of thrombin-antithrombin-III and plasmin-alpha2-antiplasmin complexes. Levels of antithrombin-3, alpha2-antiplasmin, fibrinogen, plasminogen, alpha2-macroglobulin (alpha2-M), and C1-inhibitor remained lower following PH. Treatment with rBPI21 led to significantly lower levels of tissue-type plasminogen activator (t-PA). Post-operative disseminated intravascular coagulation (DIC) was associated with significantly higher bilirubin and t-PA plasma levels and significantly lower levels of alpha2-M. This study indicates that PH induced hepatic failure results in decreased synthesis of hepatic regulating plasma proteins and subsequent activation of coagulation and fibrinolysis. Prevention of t-PA release by rBPI21 may have important clinical implications. Decreased availability of alpha2-M may be a factor in post-operative DIC.

Regulation of in situ complement activation via the lectin pathway in patients with IgA nephropathy

The lectin pathway, which is initiated by mannose-binding lectin (MBL) and MBL-associated serine protease (MASP), is one of the possible routes to activate the complement cascade in immunoglobulin A (IgA) nephropathy. The purpose of this study was to elucidate the regulatory mechanism of the pathway. Levels of complement activation products and regulatory proteins were measured in sera from 27 patients with IgA nephropathy, and generation of fluid-phase complement activation products in the presence of pooled normal human serum was quantified to evaluate activation in vitro. Although there were no significant differences in the serum levels and in vitro activation between the MBL-MASP positive (n = 14) and negative (n = 13) groups, there were positive correlations between complement activation products (Bb fragment and C4d fragment) and regulatory proteins (factor H, C4-binding protein, and C1 inhibitor) in the MBL-MASP-positive group. Furthermore, immunohistochemical studies demonstrated glomerular deposition of the regulatory protein (C4-binding protein, alpha2-macroglobulin, and factor H) in all patients in the MBL-MASP-positive group. These findings suggest that the regulatory proteins control in situ complement activation via the lectin pathway immediately, and continuous activation due to inadequate control will lead to the advanced glomerular injury.

Complement-mediated host defense in the lung

Complement is a system of plasma proteins that aids in the elimination of pathogens from the body. We hypothesized that there is a functional complement system present in the lung that aids in the removal of pathogens. Western blot analysis revealed complement proteins of the alternative and classical pathways of complement in bronchoalveolar lavage fluids (BALF) from healthy volunteers. Functional classical pathway activity was detected in human BALF, but there was no significant alternative pathway activity in lavage fluid, a finding that correlates with the low level of the alternative pathway protein, factor B, in these samples. Although the classical pathway of complement was functional in lavage fluid, the level of the classical pathway activator C1q was very low. We tested the ability of the lung- specific surfactant proteins, surfactant protein A (SP-A) and surfactant protein D (SP-D), to substitute for C1q in classical pathway activation, since they have structural homology to C1q. However, neither SP-A nor SP-D restored classical pathway activity to C1q-depleted serum. These data suggest that the classical pathway of complement is functionally active in the lung where it may play a role in the recognition and clearance of bacteria.

Hereditary angioedema with normal C1-inhibitor activity in women

BACKGROUND

Hereditary angioedema (HAE) is a well defined autosomal dominant disease (Mendelian Inheritance in Man #106100) that results from an inherited deficiency of C1 (the activated first component of complement) inhibitor function. We report an unusual variant of HAE with normal biochemical C1-inhibitor function, occurring only in women.

METHODS

We screened 574 patients with recurrent angioedema of the skin for presence of HAE. 283 patients were selected, in whom angioedema was associated with abdominal pain attacks or recurrent life-threatening episodes of upper-airway obstruction, or both, rather than with urticaria. We measured C1-inhibitor concentration and functional activity as well as complement C4 concentration and took pedigrees to characterise patients.

FINDINGS

94 HAE cases with C1-inhibitor deficiency, positive family history, or both were identified. Biochemical testing showed that 84 patients from 49 families had a functional C1-inhibitor deficiency. 11 of these patients had no affected family members (probably representing de-novo mutations). Ten women with HAE, from ten families, had normal C1-inhibitor protein concentrations and function, and normal C4 concentration. A more detailed study of these families identified another 26 affected members, who were also all women. Of those women, 14 could be studied and also had normal C1-inhibitor concentration and function. The disease was seen in successive generations, and in offspring of affected mothers, the sex ratio (M/F) was shifted to 1/1.5.

INTERPRETATION

HAE with normal C1-inhibitor concentration and function represents a unique genetic disease arising only in women. The formal genetics of this entity are suggestive of an X-linked dominant mode of inheritance. For this disorder we propose the term hereditary angioedema type 3 (HAE III).

Usefulness of detection of complement activation products in evaluating SLE activity

Complement activation products, such as C1rs-C1inh, specific for the activation of the classical pathway, C3b(Bb)P, specific for the activation of the alternative pathway and SC5b-9, specific for common terminal pathway of the complement cascade, were measured in healthy donors and in patients with clinically active and inactive systemic lupus erythematosus (SLE). Plasma levels of C3b(Bb)P and SC5b-9 were moderately, those of C1rs-C1inhibitor (C1rs-C1inh) were markedly elevated in patients with clinically inactive SLE, compared with healthy controls. The difference between active and inactive stages of the disease was best reflected by C3b(Bb)P plasma concentration (P<0.001), which also showed the highest correlation with the SLEDAI (Rs=0.41 P<0.001) and which was the most useful in distinguishing active and inactive sample pairs as well. The difference between SC5b-9 levels in the active and inactive stages was also significant (P=0.007), while that of C1rs-C1inh did not differ significantly (P=0.136). The correlation of the SLEDAI with SC5b-9 was 0.3 (P=0.015), while with C1rs-C1inh it was 0.21 (P=0. 089). These findings suggest that the measurement of complement activation products, especially that of the alternative pathway, are sensitive markers of the activity of SLE and can be used for clinical purposes.

Complement component 1 inhibitor (C1-INH) like protein on murine spermatozoa: anti-C1-INH inhibits in vitro fertilization

We investigated if complement component 1 inhibitor-like (C1-INH-L) protein found on human spermatozoa exists on mouse spermatozoa and is relevant to reproduction. We used Western blot analysis and immunofluorescence assays to detect C1-INH on murine sperm and tested the effects of the antibodies to C1-INH and albumin (negative control) on in vitro mouse sperm motility and fertilization. C1-INH-L, with molecular weight similar to human C1-INH (100 kDa), was present on the surface of spermatozoan head and midpiece. Treating mouse sperm with anti-C1-INH reduced the mouse sperm motility (P < 0.01), in vitro fertilization (P < 0.01) and embryo development rates (P < 0.01). Anti-albumin failed to do so. We conclude that C1-inhibitor-like protein is present on mouse sperm surface and appears to be relevant to reproduction.

Complement activation in patients with systemic lupus erythematosus without nephritis

OBJECTIVE

To study the association between disease activity and complement activation prospectively in patients with systemic lupus erythematosus (SLE).

PATIENTS AND METHODS

Twenty-one SLE patients were examined monthly for 1 yr. Disease activity, autoantibodies, conventional complement tests and the following complement activation products were investigated: C1rs-C1inh complexes, C4bc, Bb, C3a, C3bc, C5a and the terminal SC5b-9 complement complex (TCC).

RESULTS

Modest variation in disease activity was noted. None of the patients had nephritis. Flare was observed at 27 visits. Four patients had anti-C1q antibodies in conjunction with modestly low C1q concentrations. The complement parameters were rather constant during the observation period. Slightly to moderately decreased C4 (0.05-0.10 g/l) was found in 10 patients and severely decreased C4 (<0.05 g/l) in seven patients. Decreased C4 was not associated with increased complement activation. Complement activation products were either normal or slightly elevated. TCC was the only activation product correlating significantly with score for disease activity at flare. None of the variables tested predicted flares.

CONCLUSION

Complement tests are of limited importance in routine examination of SLE without nephritis, although TCC is suggested to be one of the most sensitive markers for disease activity.

Hereditary angioedema with gastrointestinal involvement: endoscopic appearance

We present the first reported case of hereditary angioedema (HAE) with gastric involvement to be successfully evaluated by endoscopy both during and after an attack. A 31-year-old man who had a family history of angioedema was admitted to our hospital with complaints of abdominal pain and swelling of extremities. Computed tomography scan and endoscopy carried out during this attack revealed transient gastrointestinal wall edema which, along with decreased levels of serum C4 and C1 inhibitor, confirmed the diagnosis of HAE with gastrointestinal involvement. During the attack, the gastric mucosa was erythematous and edematous, and parts of its surface bulged into the gastric lumen, resembling a submucosal tumor, as a result of massive submucosal edema. During the healing process, a number of small nodules and raised erosions developed over the entire gastric mucosal surface after healing of prominent gastric edema. Within 55 days, the gastric mucosa had returned to normal. The endoscopic findings for the stomach in HAE have not, to our knowledge, been previously described.

Human homozygous type I plasminogen deficiency and ligneous conjunctivitis

On the basis of a questionnaire sent to the ophthalmology departments of hospitals throughout Germany, 10 patients with ligneous conjunctivitis or pseudomembranous disease, ranging in age from 1 to 71 years were identified. All 10 patients had severely reduced plasminogen levels. Genetic analysis revealed homozygous type I plasminogen deficiency (which had not previously been described in humans) in 7 patients and compound heterozygous plasminogen deficiency in 1 patient. Clear differentiation was not possible in 2 patients. Most of the parents had heterozygous plasminogen deficiency. None of the patients had experienced any episodes of thrombosis. Additionally, the following observations were made: 1) Levels of polymorphonuclear (PMN)-elastase protein were markedly elevated in 6 of 6 patients and 10 of 11 parents tested, and levels were higher in homozygotes than in heterozygotes. 2) Hereditary factor XII deficiency was found in 3 of 6 patients tested. 3) C1-inhibitor was elevated in 2 of 4 patients, prekallikrein was elevated in 1 of 4 patients, and plasminogen activator inhibitor type 1 was elevated in 1 of 4 patients. Infusions of lys-plasminogen concentrate induced pronounced fibrinolytic activity as indicated by high levels of D-dimer, increases in plasmin-antiplasmin complex and decreases in polymorphonuclear elastase. C1-inhibitor, prekallikrein and PAI-1 normalized after repeated infusions of lys-plasminogen. In contrast to dysplasminogenemia, severe type I plasminogen deficiency might be seen as a problem of extravascular space, in particular of the mucous membranes, possibly triggered by mechanically induced or inflammatory lesions of the vessels supplying the tissue.

Activation of clotting factor XI without detectable contact activation in experimental human endotoxemia

Evidence of factor XI (FXI) activation in vivo is scarce. In addition, it remains uncertain whether thrombin, factor XIIa (FXIIa), or perhaps another protease is responsible for FXI conversion. We investigated the activation of FXI in eight healthy volunteers after infusion of a low dose of endotoxin (4 ng/kg of body weight). Activation of prekallikrein FXII, FXI, and prothrombin was measured with sensitive enzyme-linked immunosorbent assays (ELISAs), and FXI activation was measured with a novel enzyme capture assay that detects noncomplexed FXIa. Activation of FXI was apparent with a significant plasma peak level of noncomplexed FXIa of 10 to 11 pmol/L at 1 and 2 hours after endotoxin infusion, followed by a gradual increase in FXIa-FXIa inhibitor complexes, measured in the ELISAs, with a summit of 11 to 15 pmol/L at 6 and 24 hours, respectively. In accordance with previous studies, thrombin generation was detected 1 hour after endotoxin infusion to become maximal after 3 to 4 hours. In contrast, we did not find any evidence of contact activation, because markers of activation of prekallikrein and FXII remained undetectable. From the FXIa data a theoretical model was constructed which suggested that inhibition of FXIa does not take place in the plasma compartment, but is localized on a surface. These data provide the first evidence for FXI activation in low-grade endotoxemia and suggest that FXI is activated independently of FXII.

The role of complement and gp120-specific antibodies in virus lysis and CD4+ T cell depletion in HIV-1-infected patients

The substantial virus lysis was induced by HIV-1-infected patient serum and normal human complement serum in the presence of purified patient IgG. Non-infected CD4+ T cells coated with the whole virus or with a recombinant HIV-1 envelope gp120 and sensitised with patient IgG were also shown to be susceptible to complement-dependent lysis. The serum level of complement regulatory protein in a fluid phase, the C1-esterase inhibitor, was significantly correlated with serum concentration of C1q-circulating immune complexes (P=0.0062), but inversely with CD4+ T cell count (P < 0.0001). Accordingly, the disease progression in HIV-1-infected patients was significantly correlated with the level of complement activation as determined by serum level of C1-esterase inhibitor (P=0.0001), and inversely correlated with CD4+ cell count (P < 0. 0001) and gp120-specific antibody titre (P=0.0086). These results strongly suggest that the complement activation by gp120-specific antibodies play a very important role in virus clearance, but also in depletion of infected as well as gp120-coated non-infected CD4+ bystander T cells during the course of HIV-1 infection.

High-dose intravenous immunoglobulin treatment activates complement in vivo

Several complement modulating effects of high-dose intravenous immunoglobulins (IVIG) have been proposed from in vitro studies and experimental animal models. However, the in vivo effects of IVIG on plasma complement in humans are yet not known. We have investigated the in vivo effects of IVIG on complement in seven women with unexplained recurrent spontaneous abortion who were without evidence of autoimmune disease. Samples were obtained before and after the very first infusion of IVIG. There was a marked increase in immunoglobulin G (IgG) from (median and range) 12.4 (9.4-15.9) to 26.8 (22.4-30.0) g/l but no change in immunoglobulin A (IgA) or immunoglobulin M (IgM). A significantly increased complement activation was demonstrated using neoepitope-specific enzyme immunoassays to the activation products C3bc (median increased from 9.8 to 31.2 AU/ml), Bb (0.66-1.66 g/ml), C5a (10.5-12.7 ng/ml), and TCC (0.81-2.19 AU/ml) (P = 0.015 for all). There were no changes in antigenic concentrations of individual complement components or regulators (C1q, C4, C3, C1-inhibitor, C4b-binding protein) and no decrease in complement haemolytic activity (classical and alternative CH50), which were all within the normal range. The classical pathway activation products C1rs/C1-inhibitor complexes, C4bc and C4d were elevated in all patients before IVIG treatment and did not change significantly during treatment. In conclusion, IVIG induced a significant activation of complement in vivo.

Complement C1-inhibitor expression in Alzheimer's disease

In situ and in vitro studies suggest that activation of locally produced complement factors may act as a mediator between amyloid deposits and neurodegenerative changes seen in Alzheimer's disease (AD). C1-esterase inhibitor (C1-Inh), which regulates activation of C1 of the complement classical pathway, can be detected immunohistochemically in its inactivated form in activated astrocytes and dystrophic neurites in AD plaque areas. In this study, designed to investigate the cellular source of C1-Inh, C1-Inh was found to be secreted in a functionally active form by astrocytes cultured from postmortem human brain specimens as well as by neuroblastoma cell lines. Recombinant human interferon-gamma (IFN-gamma), which stimulates C1-Inh synthesis in various cell types, several-fold stimulated C1-Inh protein secretion by cultured human astrocytes derived from different regions of the central nervous system and by one (SK-N-SH) of two neuroblastoma cell lines (SK-N-SH and IMR-32) included in this study. In contrast to IFN-gamma, other cytokines [interleukin (IL)-1beta, IL-6 and tumor necrosis factor (TNF)-alpha] that can be found in brain areas affected by AD, did not stimulate C1-Inh secretion by astrocytes or neuroblastomas in vitro. This inability to secrete C1-Inh is probably due to unresponsiveness at the transcriptional level, since C1-Inh secretion paralleled the expression of the 2.1-kb C1-Inh mRNA. In situ hybridization with a C1-Inh RNA antisense probe labeled neurons rather than astrocytes, suggesting a role for neurons as producers of complement regulatory proteins in vivo. Since IFN-gamma is apparently lacking in the brain parenchyma, and amyloid plaque-associated cytokines (IL-1beta, IL-6, TNF-alpha) do not stimulate C1-Inh expression in vitro, the nature of the stimulus responsible for neuronal C1-Inh expression in AD brains remains to be investigated.

SC5b-9 is the most sensitive marker in assessing disease activity in Brazilian SLE patients

This study investigated whether increased plasma levels of terminal complement complex (SC5b-9) or split products correlate with disease activity and clinical manifestations in Brazilian systemic lupus erythematosus (SLE) patients. Comparisons with conventional measurements of complement and other inflammatory markers were also performed. Plasma levels of SC5b-9, C3a desArg, C1rs-C1Inhibitor, C3b(Bb)P, C3, C4, erythrocyte sedimentation rate (ESR) and mucoproteins (MP) were measured in 41 patients with SLE of different disease activity: 10 patients with none, 15 patients with mild, and 16 patients with moderate or severe activity. All parameters, with the exception of C3 and C3b(Bb)P, showed a statistically significant correlation with disease activity. Plasma levels of SC5b-9, C3a desArg, C4, CH50, ESR and MP revealed significant differences between the groups of patients without activity and those with moderate or severe disease. Although none of the variables were able to discriminate between patients without and those with mild activity, SC5b-9, C3a desArg, C4, ESR and mucoproteins showed significant differences between the patients with mild and those with moderate or severe disease. Among all the variables, SC5b-9 levels showed the most significant results and correlated well with the severity of the disease (p < 0.0005). Our data suggest that elevated levels of complement activation products, particularly of SC5b-9 are more sensitive markers in assessing disease activity than conventional laboratory diagnosis. Modern complement diagnosis is therefore recommended for monitoring disease progress in SLE patients.

Chromogenic assays for equine coagulation factors VII, VIII:C, IX, and X, and C1-esterase inhibitor

OBJECTIVES

To adapt manual human chromogenic assays for coagulation factors VII (F.VII), VIII:coagulant (F.VIII:C), IX (F.IX), and X (F.X), and C1-esterase inhibitor (C1-INH) for use with an automated analyzer, and to measure the activity of these proteins in horses.

ANIMALS

10 healthy horses were used to determine ranges for the assays. Pooled plasma for standards was collected from an additional 20 healthy horses.

PROCEDURE

A computer-assisted analyzer was programmed from the manual method for commercially available human F.VII, F.VIII:C, F.IX, F.X, and C1-INH chromogenic assay kits. Standards were prepared from pooled citrated equine plasma for the F.VII, F.VIII:C, and F.X assays, and from commercial pooled citrated human plasma for F.IX and C1-INH assays.

RESULTS

Mean +/- SD activities in citrated equine plasma from 10 horses were 226 +/- 19% for F.VII; 209 +/- 31% for F.VIII:C; 149 +/- 38% for F.IX; 88 +/- 12% for F.X; and 18.4 +/- 8.4% for C1-INH. Intra-assay coefficients of variation (CV) were 5.3% for F.VII; 2.1% for F.VIII:C; and 3.0% for C1-INH. Interassay CV were 5.7% for F.VII; 7.4% for F.VIII:C; 3.8% for F.IX; 14.4% for F.X; and 22.0% for C1-INH.

CONCLUSIONS

Human chromogenic assay kits can be automated and used to measure F.VII, F.VIII:C, F.IX, F.X, and C1-INH activities in citrated equine plasma.

CLINICAL RELEVANCE

Human chromogenic assays can be routinely used to measure F.VII, F.VIII:C, F.IX, F.X, and C1-INH in horses, and may be useful in evaluation of horses with disorders of hemostasis.

Analysis of coagulation proteins as acute-phase reactants in horses with colic

OBJECTIVES

To measure coagulation factor VIII:coagulant (F.VIII:C) and C1-esterase inhibitor (C1-INH), hemostasis-associated acute-phase reactant proteins and coagulation factors VII (F.VII), IX (F.IX), and X (F.X), hemostasis proteins not associated with an acute-phase response, in a select population of horses with colic and hemostasis abnormalities, and presumed to have acute-phase changes. To compare these values and other routine hemostasis test results in the horses with colic with values for a population of healthy horses. To correlate the values of known equine acute-phase reactants, F.VIII:C and fibrinogen, to those of other tests of hemostasis. To identify hemostasis-associated acute-phase reactant proteins and gain insights into the effects the acute-phase response has on hemostatic abnormalities in horses with colic syndrome.

SAMPLE POPULATION

54 plasma samples from horses with colic attributable to inflammatory (n = 39) or strangulating (n = 15) intestinal disorders.

PROCEDURE

Plasma samples were evaluated for activities of F.VII, F.VIII:C, F.IX, F.X, C1-INH, antithrombin III, protein C, plasminogen, and alpha 2-antiplasmin (alpha 2AP); fibrinogen concentration; and prothrombin (PT) and activated partial thromboplastin (APTT) times.

RESULTS

Horses with colic had significantly higher fibrinogen concentration, greater alpha 2AP and protein C activities, and longer PT and APTT than did healthy horses. Horses with colic also had significantly lower mean F.VII activity than did healthy horses. Significant positive correlations between fibrinogen concentration and F.VIII:C, C1-INH, and alpha 2AP values, and between F.VIII:C activity and fibrinogen, C1-INH, alpha 2AP, and plasminogen values were identified.

CONCLUSIONS

An acute-phase response contributes to changes observed in coagulation proteins in horses with colic attributable to inflammatory and strangulating intestinal disorders. The data suggest that plasminogen, alpha 2AP, and C1-INH, should be considered equine acute-phase proteins.

Complement and contact activation in term neonates after fetal acidosis

AIMS

To evaluate complement and contact activation after fetal acidosis.

METHODS

Fifteen term neonates with hypoxic-ischaemic encephalopathy after umbilical arterial pH < 7.10 were compared with 15 healthy neonates with umbilical arterial pH > 7.20. Determinations of the complement function and C1-inhibitor activity were performed as kinetic tests 22-28 hours after birth. C1q, C1-inhibitor, and factor B concentrations were determined by radial immunodiffusion and those of C3a, C5a, and factor XIIa by enzyme immunoabsorbent assay.

RESULTS

Median complement function (46 vs 73%), C1q (4.3 vs 9.1 mg/dl), and factor B (5.2 vs 7.7 mg/dl) decreased after fetal acidosis. The activated split products C3a (260 vs 185 micrograms/l), C5a (5.0 vs 0.6 micrograms/l), and factor XIIa (3.2 vs 1.3 micrograms/l) increased in the neonates after fetal acidosis. No differences were found in the concentration and activity of C1-inhibitor.

CONCLUSIONS

Complement and contact activation occurred in the newborns with hypoxic-ischaemic encephalopathy. Activation of these systems generates mediators which can trigger inflammation and tissue injury.

Screening of concentrations of C-reactive protein and various plasma protease inhibitors preoperatively for the prediction of postoperative complications

OBJECTIVE

To find out whether concentrations of albumin (reflecting nutritional state), C-reactive protein (reflecting an acute phase reaction) or plasma protease inhibitors (reflecting ongoing proteolysis) are good predictors of postoperative complications, and whether other biochemical tests may improve diagnostic accuracy.

DESIGN

Retrospective study.

SETTING

University hospital, Sweden.

SUBJECTS

260 patients undergoing elective surgery for malignant (n = 149) or benign (n = 111) disease.

MAIN OUTCOME MEASURES

Preoperative biochemical plasma measurements and postoperative complications.

RESULTS

192 patients recovered uneventfully and 35 had minor and 33 major postoperative complications. An increased plasma C-reactive protein concentration preoperatively, as well as a reduced albumin concentration, predicted the risk of developing major postoperative complications. Measurement of plasma protease inhibitors (C1-esterase inhibitor, alpha-2-macroglobulin and antithrombin III), specific biochemical studies of microheterogeneity, or comparison of quantitative and functional concentrations of the inhibitors gave no additional information.

CONCLUSION

One measurement of the C-reactive protein and albumin concentrations preoperatively will identify patients at risk of developing severe postoperative complications.

[Hereditary angioedema: clinical and laboratory aspects of 7 cases]

Hereditary angioedema is caused by a defect in C1 inhibitor activity (C1INH). Its occurrence is rare and it is associated with an autosomal dominant mode of inheritance. We describe seven patients (4M:3F), age from 12 to 50 years old, who are affected by hereditary angioedema; four of them belong to the same family. The main clinical manifestations were: angioedema of face, hands and feet (6/7) and abdominal pain (2/7). No triggering factors were associated with symptoms in 4/7 patients and trauma (2/7) and menses (1/7) were reported in the other three ones. One patient was submitted to laparotomy for partial intestinal resection, before diagnosis. Laboratory complement analysis revealed the absence of hemolytic function of complement, reduced C4 (6/7) and low C1INH levels. All patients received Danazol (100 mg/day) with clinical control. Hereditary angioedema has to be considered in the differential diagnosis of angioedema, since an early diagnosis of this immunodeficiency, leading to specific treatment in order to decrease the complications.