A Breast Cancer Candidate Locus at 6q Narrowed to 6q15-q21.

Although a number of high-risk breast cancer genes have been identified, including BRCA1 and BRCA2, the risk profile of many high-risk families cannot be explained using known breast cancer genes. Previously, we have shown strong indications of new breast cancer risk loci at chromosomes 2p, 6q, and 14q in a family of six generations including 10 breast cancer cases. In this study, we identified and traced four new family branches descending from siblings of the parents in the top generation of the studied family. One distantly related branch included four breast cancer cases, two of whom were diagnosed at age < 45 years. DNA samples from the cases were typed at selected polymorphic markers from all three chromosome loci, to test identical origin of the haplotypes. All four cases were shown to segregate a common 6q haplotype with a region identical to the previously identified 6q haplotype. The data strongly support a new breast cancer locus at 6q, and narrow it down to a 17 MB interval at 6q15-q21.

Atypical hemolytic uremic syndrome triggered by mRNA vaccination against SARS-CoV-2: Case report.

Atypical hemolytic uremic syndrome (aHUS), also called complement-mediated hemolytic uremic syndrome (CM-HUS), is a rare disease caused by dysregulation in the alternative complement activation pathway. It is a life-threatening condition causing ischemia of a number of organs, and it typically causes acute kidney injury. This disorder may be triggered by various factors including viral or bacterial infections, pregnancy, surgery, and injuries. In about 60% of cases, the genetic origin of the disease can be identified-commonly mutations affecting complementary factor H and MCP protein. Eculizumab, a monoclonal antibody to the C5 component of the complement, represents the current effective treatment.We describe a case of a young woman with a previous history of polyvalent allergies, who developed atypical hemolytic uremic syndrome after vaccination with mRNA vaccine against SARS-CoV-2. The disease manifested by scleral bleeding, acute renal insufficiency, anemia, and thrombocytopenia. The patient was treated with plasma exchanges without sufficient effect; remission occurred only after starting treatment with eculizumab. Genetic examination showed that the patient is a carrier of multiple inherited risk factors (a rare pathogenic variant in CFH, MCPggaac haplotype of the CD46 gene, and the risk haplotype CFH H3). The patient is currently in hematological remission with persistent mild renal insufficiency, continuing treatment with eculizumab/ravulizumab. By this case report, we meant to point out the need for careful monitoring of people after vaccination, as it may trigger immune-mediated diseases, especially in those with predisposing factors.

Eculizumab use in a tertiary care nephrology center: data from the Vienna TMA cohort.

BACKGROUND: Practice patterns of eculizumab use are not well described. We examined indications for, and outcomes of, eculizumab therapy in a tertiary care nephrology center. METHODS: We used the "Vienna TMA cohort" and the hospital pharmacy database at the Medical University of Vienna to identify patients that received eculizumab treatment between 2012 and 2019. We describe clinical characteristics, details of eculizumab use, and outcomes of patients with complement gene-variant mediated TMA (cTMA), secondary TMA (sTMA) and C3 glomerulopathy (C3G). RESULTS: As of December 2019, 23 patients received complement blockade at the Division of Nephrology and Dialysis: 15 patients were diagnosed with cTMA, 6 patients with sTMA and 2 patients with C3G. Causes of sTMA were bone marrow transplantation (n = 2), malignant hypertension, malignant tumor, systemic lupus erythematosus, antiphospholipid syndrome and lung transplantation (each n = 1). Across all indications, patients had a median age of 31 and were predominantly female (78%) and the median duration of treatment was 227 days. Hematological recovery was seen in most patients, while renal response was best in patients with cTMA. Adverse events were recorded in 26%. CONCLUSIONS: In summary, eculizumab is the treatment of choice for cTMA patients that do not respond to plasma therapy. In patients with sTMA and C3G, the response rates to therapy are much lower and therefore, the decision to start therapy needs to be considered carefully.

Variant Transthyretin Amyloidosis (ATTRv) in Hungary: First Data on Epidemiology and Clinical Features.

BACKGROUND: Variant transthyretin amyloidosis (ATTRv) is an autosomal dominant inherited disease, where the mutation of the transthyretin gene (TTR) results in the deposition of pathogenic protein fibrils in various tissues. The mutation type influences the clinical course. Until now, no data were available on the genotype, phenotype, and prevalence of Hungarian ATTRv patients. The aim of our study was to assess the prevalence, regional distribution, genotypes, and phenotypes of Hungarian patients with ATTRv. METHODS: With the collaboration of Hungarian regional and university centers, we identified patients diagnosed with ATTRv. We also searched prior publications for case studies of Hungarian ATTRv patients. RESULTS: 40 individuals in 23 families with ATTRv were identified within the borders of Hungary. At the time of the diagnosis, 24 of them were symptomatic. The two most common mutations were ATTRHis88Arg (nine families) and ATTRIle107Val (8 families). ATTRVal30Met was demonstrated in 2 families, and ATTRVal122del, ATTRPhe33Leu, ATTRIle84Ser, and ATTRAsp18Gly in one family each. The median age of the symptomatic patients at the time of clinical diagnosis was 65 years. The most common clinically significant organ involvement was restrictive cardiomyopathy, found in 24 patients. Polyneuropathy was diagnosed in 20 patients. A total of 19 patients showed a mixed phenotype. The leading symptom was heart failure in 8 cases (3 of them had only cardiac symptoms), polyneuropathy in 11 cases (all of them also had cardiac symptoms), and equally severe cardiac and neuropathy symptoms were present in 3 cases. Out of 24 symptomatic patients, 10 received targeted pharmacological therapy. The follow-up period ranged from 1 to 195 months. At the time of the retrospective analysis, 12 patients had already died, and 1 patient underwent heart transplantation. CONCLUSIONS: As TTR genotype influences the phenotype and clinical course of ATTRv, it is important to know the regional data. In Hungary, ATTRHis88Arg and ATTRIle107Val are the most common mutations in ATTRv, both presenting with mixed phenotype, but the median age at the time of the diagnosis is 9 years lower in patients with ATTRHis88Arg than in patients with ATTRIle107Val.

Screening for Plasminogen Mutations in Hereditary Angioedema Patients.

Hereditary angioedema (HAE) is a rare disease belonging to the group of bradykinin-mediated angioedemas, characterized by recurring edematous episodes involving the subcutaneous and/or submucosal tissues. Most cases of HAE are caused by mutations in the SERPING1 gene encoding C1-inhibitor (C1-INH-HAE); however, mutation analysis identified seven further types of HAE: HAE with Factor XII mutation (FXII-HAE), with plasminogen gene mutation (PLG-HAE), with angiopoietin-1 gene mutation (ANGPT1-HAE), with kininogen-1 gene mutation (KNG1-HAE), with a myoferlin gene mutation (MYOF-HAE), with a heparan sulfate-glucosamine 3-sulfotransferase 6 (HS3ST6) mutation, and hereditary angioedema of unknown origin (U-HAE). We sequenced DNA samples stored from 124 U-HAE patients in the biorepository for exon 9 of the PLG gene. One of the 124 subjects carried the mutation causing a lysine to glutamic acid amino acid exchange at position 330 (K330E). Later, the same PLG mutation was identified in the patient's son. The introduction of new techniques into genetic testing has increased the number of genes identified. As shown by this study, a biorepository creates the means for the ex-post analysis of recently identified genes in stored DNA samples of the patients. This makes the diagnosis more accurate with the possibility of subsequent family screening and the introduction of appropriate therapy.

The Role of Mannose-binding Lectin in Infectious Complications of Pediatric Hemato-Oncologic Diseases.

The complement system is essential for protection against infections in oncologic patients because of the chemotherapy-induced immunosuppression. One of the key elements in the activation of the complement system via the lectin pathway is the appropriate functioning of mannose-binding lectin (MBL) and mannose-binding lectin-associated serine protease 2 (MASP2) complex. The objective of our study was to find an association between polymorphisms resulting in low MBL level and activation of the MBL-MASP2 complex. Also, we aimed at finding a connection between these abnormalities and the frequency and severity of febrile neutropenic episodes in children suffering from hemato-oncologic diseases. Ninety-seven patients had been enrolled and followed from the beginning of the therapy for 8 months, and several characteristics of febrile neutropenic episodes were recorded. Genotypes of 4 MBL2 polymorphisms (-221C/G, R52C, G54D, G57E) were determined by real-time polymerase chain reaction. Activation of the MBL-MASP2 complex was evaluated by enzyme-linked immunosorbent assay at the time of diagnosis and during an infection. The number of febrile neutropenic episodes was lower, and the time until the first episode was longer in patients with normal MBL level than in patients with low MBL level coding genotypes. The MBL-MASP2 complex activation level correlated with the MBL genotype and decreased significantly during infections in patients with low MBL level. Our results suggest that infections after immunosuppression therapy in children suffering from hemato-oncologic diseases are associated with the MBL2 genotype. Our results may contribute to the estimation of risk for infections in the future, which may modify therapeutic options for individuals.

Early Increase in Complement Terminal Pathway Activation Marker sC5b-9 Is Predictive for the Development of Thrombotic Microangiopathy after Stem Cell Transplantation.

Hematopoietic stem cell transplantation (HSCT)-associated thrombotic microangiopathy (TA-TMA) is a multifactorial complication, and its prediction is largely unresolved. Our aim was to analyze changes of complement profile after HSCT to identify potential markers of TA-TMA development. Thirty-three consecutive pediatric patients (9.6 ± 4.4 years old) who underwent allogeneic HSCT due to malignant (n = 17) or nonmalignant (n = 16) indications were included in this study. Graft-versus-host disease (GVHD) was diagnosed using Glucksberg criteria, viral reactivation was monitored, 5 different TA-TMA diagnostic criteria were applied, and all important clinical and laboratory parameters of TA-TMA activity were registered. Complement pathway activities, components and terminal pathway activation marker (sC5b-9) levels were systematically measured before transplantation and on days 28, 56, and 100 after HSCT. During the first 100 days after HSCT, 1 of 33 patients died (day 50, multiple organ failure), whereas 10 subjects met the criteria for TA-TMA, typically on day 61 (range, 16 to 98 days). TA-TMA was preceded by acute GVHD in 3 of 10 patients, by viral reactivation in 2 of 10, or by both in 4 of 10 cases. Baseline sC5b-9 levels did not differ in patients without (200 [interquartile range, 144 to 266] ng/mL), or with (208 [interquartile range, 166 to 271] ng/mL) subsequent TA-TMA; however, on day 28 significant differences were observed (201 [interquartile range, 185 to 290] ng/mL versus 411 [interquartile range, 337 to 471] ng/mL; P = .004). Importantly, all 10 patients with TMA showed increase in sC5b-9 level from baseline level to day 28, whereas in patients without TMA the same tendency was observed for only 9 of 23 patients (P = .031). No additional complement parameters were closely associated with the development of TA-TMA. Development of TA-TMA occurred in 30% of our patients, typically after GVHD and/or viral reactivation. However, early raise of sC5b-9 activation marker was predictive for later development of TA-TMA, and should therefore be considered as an alarming sign necessitating a careful monitoring of all TA-TMA activity markers. Further studies enrolling a higher number of patients are necessary to determine if terminal pathway activation is an independent predictor of TA-TMA.

Complement activation, inflammation and relative ADAMTS13 deficiency in secondary thrombotic microangiopathies.

BACKGROUND: The secondary forms of hemolytic uremic syndrome/thrombotic thrombocytopenic purpura (secondary TMA) emerge as complications of coexisting diseases. OBJECTIVES: We hypothesized that secondary TMA could be characterized by the presence of relative ADAMTS13 deficiency and complement activation, and this relationship may have a prognostic value for outcome. PATIENTS AND METHODS: Fifty-three patients with thrombotic microangiopathy (TMA) and coexisting disease (such as malignancies, sepsis, heart surgery with extracorporeal circulation, solid organ transplantation, systemic autoimmune disorders), 41 patient controls, and 34 healthy controls were enrolled in our case-control study with 30days follow-up. Complement profile (from serum) and activation products, von Willebrand factor (VWF, from EDTA plasma), and ADAMTS13 activity were determined. RESULTS: ADAMTS13 activity was reduced, while VWF level was elevated in secondary TMA patients. The activity of the classical, lectin and alternative pathways, as well as the levels of C3, C4, and Factor H were significantly lower in secondary TMA patients, and were accompanied by high activation product levels (C3a and sC5b-9). Factor H concentration correlated to relative ADAMTS13 deficiency (i.e. VWF/ADAMTS13 ratio (r=-0.368, p=0.019)). 28/53 patients (53%) died during the follow-up period. Increased sC5b-9, C3a, and C reactive protein levels were all associated with a poor patient outcome. CONCLUSIONS: Our results indicate that the secondary TMA syndrome and its poor outcome is characterized by relative ADAMTS13 deficiency, inflammation, and complement activation with consumption via the classical and alternative pathways. It is yet to be determined whether complement inhibition could be a possible therapeutic option for patients with secondary TMA.

Frequency of the virilising effects of attenuated androgens reported by women with hereditary angioedema.

BACKGROUND: Danazol, a drug extensively used in the management of hereditary angioedema due to C1 inhibitor deficiency (C1-INH-HAE), has various side effects. This study investigated the virilizing actions of this drug in 31 danazol-treated female patients with HAE-C1-INH. We compared our findings with those of healthy controls and with literature data. METHODS: The patients were interviewed individually about the type and severity of the virilizing effects, as well as about their satisfaction with danazol therapy. RESULTS: The average duration of danazol treatment was 10.31 years [2 to 23] and its mean daily dose was 131.7 mg [33 to 200]. The most common adverse effects were hirsutism (n=14), weight gain (n=13), and menstrual disturbances (n=8). The severity of danazol adverse effects did not differ by duration of treatment or by daily drug dose. The mean level of patient satisfaction with the treatment was high. The comparison of age-matched healthy controls and of HAE-C1-INH patients receiving danazol did not demonstrate a statistically higher incidence of any of the monitored symptoms in the danazol group. CONCLUSIONS: Our findings indicate that long-term danazol treatment - using the lowest effective dose - has only a mild virilizing effect.

The role of complement activation in the pathogenesis of Fuchs' dystrophy.

PURPOSE: Inflammation can be an etiologic factor of Fuchs' dystrophy according to previous studies. Our aim was to analyse the activation of the complement system in the aqueous humor in this pathological condition. METHODS: 100 µl aqueous humor sample was taken during keratoplasty of 11 Fuchs' dystrophic patients and during phacoemulsification surgery of 18 control patients. The samples were mixed with EDTA and stored at -80 °C. Concentrations of C1rC1sC1Inh and C3bBbP complexes as markers of the activation of the classical and alternative complement pathways, respectively, were measured with ELISA method. The results of the patient group and the control group were compared with statistical analysis (non-parametric Mann Whitney test). RESULTS: Both the concentrations of C1rC1sC1Inh [4.3 (3.2-20.2)AU/ml] and of C3bBbP [15.3 (7.8-22.6)AU/ml] were significantly higher in the Fuchs' dystrophic group than in the control group [C1rC1sC1Inh: 0.0 (0.0-5.6)AU/ml, C3bBbP: 1.4 (0.0-7.8)AU/ml]. The median value is shown along with the (25% and 75% percentiles). CONCLUSIONS: Based on our results, the complement system may be activated both through the classical and alternative pathways in the aqueous humor of the patients with Fuchs' dystrophy.

Effective humoral immunity against diphtheria and tetanus in patients with systemic lupus erythematosus or myasthenia gravis.

INTRODUCTION: Controversy exists about the effectiveness of vaccine-induced immune response in patients with immunoregulatory disorders. Our aim was to determine the antibody titers to diphtheria and tetanus in patients with either of two autoimmune diseases. METHODS: 279 patients with SLE (205 females, aged 45.0 ± 13.8 years), 158 patients with myasthenia gravis (MG) (101 females, aged 55 ± 18.7 years) and 208 healthy subjects (122 females, aged 48 ± 14.6 years) were enrolled. Serum concentrations of diphtheria-antitoxin-IgG (A-DIPHTH) and tetanus-antitoxoid-IgG (A-TET) were determined with ELISA. RESULTS: Equal proportions of healthy subjects, as well as patients with SLE or MG exhibited proper antibody responses and immune protection against diphtheria and tetanus. In all three test groups, serum concentration of A-DIPHTH decreased significantly (p<0.001) with age throughout the study population, while titers of A-TET dropped only in the elderly (>60-years-old) subjects. There were no significant differences among the groups in the age-related changes of A-TET and A-DIPHTH except that in <40-years-old subjects, A-DIPHTH level was significantly (p=0.029) lower in SLE patients than in controls. CONCLUSIONS: Our findings suggest that the level of vaccine-induced immunity against diphtheria and tetanus infections in patients with SLE or MG is comparable to the healthy population.

Elevated C1rC1sC1inh levels independently predict atherosclerotic coronary heart disease.

UNLABELLED: Clinical studies as well as animal models emphasized the importance of the complement system in the pathogenesis of coronary atherosclerosis and cardiovascular diseases. Our aim was to examine the extent and clinical implication of complement system activation in patients with stable atherosclerotic coronary heart disease (ACHD). Seventy-six patients with stable angina pectoris (SAP) scheduled for elective coronary angiography were enrolled into the study. Percutaneous coronary intervention (PCI) was performed in 24 patients, in 27 patients (NOPCI group) the coronary angiography showed significant stenosis and bypass surgery (CABG) or optimal medical therapy (OMT) were advised, whereas in 25 patients the coronary angiography was negative (NC group). 115 volunteers served as healthy controls (HC). In all individuals, the plasma level of several complement activation products - C1rC1sC1inh, C3bBbP and SC5b-9 - were determined on admission, strictly before the coronary angiography. In patients with angiographically proven ACHD (PCI and NOPCI groups), the baseline C1rC1sC1inh levels were significantly higher compared to NC group and HC (p<0.0001, for both comparisons). According to the multiple logistic regression analysis, high C1rC1sC1inh level proved to be an independent biomarker of coronary heart disease (p<0.026, OR: 65.3, CI: 1.628-2616.284). CONCLUSION: Activation of the classical complement pathway can be observed in angiographically proven coronary atherosclerosis. Elevated C1rC1sC1inh levels might represent an useful biomarker for coronary artery disease.

Complement activation in the aqueous humor of pseudophakic bullous keratopathy patients.

BACKGROUND/AIMS: According to some studies, inflammation is a potential etiological factor in pseudophakic bullous keratopathy (PBK). Our aim was to obtain information on the activation of the complement system in the aqueous humor in this disorder. METHODS: Aqueous humor samples were collected during keratoplasty of 12 PBK patients, as well as during phacoemulsification surgery of 18 control patients. The concentrations of the protein-protein complexes generated during complement activation (C1rC1sC1inh and C3bBbP) through the classical and alternative pathways, respectively, as well as of the C3 cleavage product C3a, were measured with ELISA methods. The correlation among the complement factors and between the duration of the edema, the stage of the disease, and the level of the complement activation products was examined. RESULTS: The concentration of C1rC1sC1inh, C3bBbP complex and C3a was significantly higher in the PBK group (p < 0.001) compared to the control group. In PBK patients, a correlation was found between the levels of the C1rC1sC1inh complex and C3a only. CONCLUSION: Our new findings indicate that in PBK the complement system is activated - via the classical pathway - in the aqueous humor. The activated complement may play a role in increased endothelial cell loss.

Strong correlation of high EBNA-1-IgG levels with edematous attacks involving upper airway mucosa in hereditary angioedema due to C1-inhibitor deficiency.

Elevated level of IgG-type antibodies against Type 1 nuclear antigen (anti-EBNA-1-IgG) of the Epstein-Barr virus is a strong risk factor for certain autoimmune diseases. We measured anti-EBNA-1 IgG titers in 107 patients with hereditary angioedema due to C1-inhibitor deficiency (HAE-C1-INH). In the sera from 33 longitudinally tested patients, we found a very strong correlation (R>0.75, p=0.0005) between anti-EBNA-1-IgG titers measured in 2004 and 2010, respectively. High (>200 U/ml) anti-EBNA-1 levels were strongly correlated with the frequency of upper airway attacks (p=0.003) and the dose requirement of C1-inhibitor concentrate (p=0.008), while no significant association with the frequency of subcutaneous and abdominal attacks was found. These novel findings indicate that the underlying/triggering mechanisms of upper airway attacks in HAE-C1-INH may differ from that of other types of attacks and measurement of the anti-EBNA-1 IgG levels may be suitable for the prediction of upper airway attacks and C1-inhibitor concentrate requirement in HAE-C1-INH patients.

Endothelial cell function in patients with hereditary angioedema: elevated soluble E-selectin level during inter-attack periods.

BACKGROUND: The bradykinin pathway in the pathomechanism of hereditary angioedema due to C1-inhibitor deficiency (henceforward "hereditary angioedema") has been thoroughly studied; however, much less is known about endothelial cell function. Enhanced endothelial cell permeability is obvious during edematous attacks, but not during inter-attack periods. Our knowledge about other endothelial characteristics is even more incomplete. OBJECTIVE: Therefore the aim of this study was to characterize endothelial cell function in hereditary angioedema patients during symptom-free, inter-attack periods. METHODS: We measured the serum levels of soluble E-selectin, endothelin-1, and von Willebrand factor along with collagen-binding activity in 49 hereditary angioedema patients and in 50 healthy controls. RESULTS: Endothelin-1 and von Willebrand factor level, as well as its collagen-binding activity, were similar in hereditary angioedema patients and in controls; however, we found elevated soluble E-selectin levels in the patients. Interestingly, soluble E-selectin concentration did not correlate with any of the inflammatory markers or smoking, and it is not the consequence of the known E-selectin/C1-inhibitor interaction (an analytical phenomenon). In a multiple logistic regression model, the difference in soluble E-selectin between hereditary angioedema patients and controls remained highly significant when adjusted for age, gender, smoking, C-reactive protein, and AB0 blood groups. CONCLUSION: These results demonstrate that in hereditary angioedema, the majority of endothelial functions are normal during inter-attack periods; however, soluble E-selectin levels are elevated. The higher soluble E-selectin plasma concentration is unlikely to result from inflammation; rather, it reflects enhanced shedding mechanisms.

Association of celiac disease and hereditary angioedema due to C1-inhibitor deficiency. Screening patients with hereditary angioedema for celiac disease: is it worth the effort?

OBJECTIVE: Hereditary angioedema due to C1-inhibitor deficiency is a life-threatening condition, which manifests as edematous attacks involving subcutaneous tissues and/or the upper airway/gastrointestinal mucosa. Celiac disease is a gluten-sensitive small intestinal disorder that can lead to severe villous atrophy, malabsorption, and malignancy. Both hereditary angioedema and celiac disease may present with abdominal symptoms. Our aim was to study the occurrence of celiac disease in the hereditary angioedema population, as well as to analyze the clinical course of cases with both diseases. METHODS: One hundred and twenty-eight patients with hereditary angioedema were screened for celiac disease, using serological methods [antiendomysial antibodies-immunoglobulin A (IgA), antiendomysial antibodies-IgG and tissue transglutaminase-IgA, tissue transglutaminase-IgG]. Clinical data of a child with hereditary angioedema and celiac disease diagnosed earlier were added to the dataset to be analyzed. Thus, the total number of patients was 129, comprising 107 adults and 22 pediatric patients. In patients with celiac disease, molecular genetics analysis (human leukocyte antigen-DQA1, human leukocyte antigen-DQB1) was carried out along with the introduction of a gluten-free diet and regular follow-up. RESULTS: Four out of the 22 children were diagnosed with celiac disease in our hereditary angioedema population. The prevalence of celiac disease among our pediatric patients with hereditary angioedema (22 children) was higher than in the general population (18.1 vs. 1.2%). Switching from the wheat starch-containing tranexamic acid product to danazol and introducing a gluten-free diet mitigated abdominal symptoms of hereditary angioedema. CONCLUSION: Similarities between the symptoms of hereditary angioedema and celiac disease may cause difficulties in differential diagnosis, as well as in choosing the appropriate therapy. In our opinion, screening hereditary angioedema patients for celiac disease is warranted if abdominal attacks or neurological symptoms persist despite adequate management. Complement testing is recommended whenever abdominal symptoms persist despite the histological and serological remission of gluten-sensitive enteropathy after the introduction of a gluten-free diet.

The effect of long-term danazol prophylaxis on liver function in hereditary angioedema-a longitudinal study.

BACKGROUND: Danazol is a drug most widely used for the prophylaxis of hereditary angioedema resulting from the deficiency of the C1-inhibitor. Potential hepatotoxic or liver tumor-inducing side effects of long-term danazol prophylaxis have been investigated during the follow-up of hereditary angioedema patients. METHODS: Characteristic parameters of liver function (including bilirubin, GOT, GPT, gammaGT, total protein, ALP, LDH), as well as findings of viral serology screens and abdominal ultrasonography-determined during years 0 and 5 of follow-up of patient groups taking/not taking danazol-have been reviewed and analyzed comparatively. RESULTS: From a population of 126 hereditary angioedema patients, 46 subjects taking danazol and another 46 not taking danazol fulfilled the inclusion criteria. Longitudinal follow-up did not reveal any clinically relevant difference between the liver function parameters determined in years 0 and 5 in the two groups. Abdominal ultrasound did not detect neoplastic or other potentially treatment-related alterations of the liver parenchyma. There were no discontinuations of treatment during the study. CONCLUSIONS: Our results clearly suggest that, administered at the lowest effective dose, danazol does not induce liver injury in hereditary angioedema patients.

Grb2 associated binder 2 couples B-cell receptor to cell survival.

B-cell fate during maturation and the germinal center reaction is regulated through the strength and the duration of the B-cell receptor signal. Signaling pathways discriminating between apoptosis and survival in B cells are keys in understanding adaptive immunity. Gab2 is a member of the Gab/Dos adaptor protein family. It has been shown in several model systems that Gab/Dos family members may regulate both the anti-apoptotic PI3-K/Akt and the mitogenic Ras/MAPK pathways, still their role in B-cells have not been investigated in detail. Here we studied the role of Gab2 in B-cell receptor mediated signaling. We have shown that BCR crosslinking induces the marked phosphorylation of Gab2 through both Lyn and Syk kinases. Subsequently Gab2 recruits p85 regulatory subunit of PI3-K, and SHP-2. Our results revealed that Ig-alpha/Ig-beta, signal transducing unit of the B-cell receptor, may function as scaffold recruiting Gab2 to the signalosome. Overexpression of Gab2 in A20 cells demonstrated that Gab2 is a regulator of the PI3-K/Akt but not that of the Ras/MAPK pathway in B cells. Accordingly to the elevated Akt phosphorylation, overexpression of wild-type Gab2 in A20 cells suppressed Fas-mediated apoptosis, and enhanced BCR-mediated rescue from Fas-induced cell death. Although PH-domain has only a stabilizing effect on membrane recruitment of Gab2, it is indispensable in mediating its anti-apoptotic effect.