Neutrophil elastase and endogenous inhibitors in Behçet’s disease saliva

Behçet’s disease (BD) is a vasculitis of unknown aetiology typified by chronic recurrent oral ulcers and systemic inflammatory manifestations. Neutrophils, and specifically their protease neutrophil elastase (NE), have been implicated in its pathology. Although NE is an effective anti-microbial, excessive NE can damage host tissue. Recurrent oral ulceration is a primary BD symptom, therefore we hypothesized that excessive neutrophil infiltration evidenced by increased NE and a reduction in specific endogenous inhibitors, secretory leucocyte protease inhibitor (SLPI) and alpha1-anti-trypsin (α1AT) contributes to BD mucosal instability. NE, SLPI and α1AT were quantified in saliva from BD patients with active oral ulcers (BDa) and quiet without ulcers (BDq), recurrent aphthous stomatitis (RASa; RASq) and healthy controls (HC). Although BDq saliva had marginally higher median NE levels (1112 ng/ml) compared to both RASq (1043 ng/ml) and HC (999 ng/ml), SLPI was significantly reduced in BDq (P < 0·01). Despite decreased SLPI protein, mRNA expression was significantly increased in BDq buccal epithelial swabs compared to RASq and HC (P < 0·05, P < 0·001). NE remained enzymatically active, although α1AT levels were at least eight times higher than SLPI in all groups, suggesting that α1AT does not have a primary role in counteracting NE in saliva. Furthermore, NE levels in BDa patients medicated with both azathioprine (AZA) and colchicine (COLC) were significantly lower than those on COLC (P = 0·0008) or neither (P = 0·02), indicating that combining AZA + COLC may help to regulate excessive NE during ulceration. This study showed that enzymatically active NE coupled with reduced SLPI in BD saliva may contribute to recurrent oral ulcerations.     

Necrotizing villitis and decidual vasculitis in the placentas of mothers with Behçet disease

Beh?et disease is an inflammatory disorder characterized by recurrent aphthous stomatitis, genital ulcers, uveitis, and skin lesions. There are occasional reports of neonatal Beh?et disease suggesting a possible prenatal transmission. However, no placental Beh?et disease lesion has been reported. Here, we report characteristic necrotizing inflammation in placentas and decidua from 2 patients with Beh?et disease. The first patient had full-term delivery after uneventful medical therapy. The second patient underwent therapeutic abortion in the first trimester because of the fetal exposure to a potentially harmful medication for Beh?et disease. Both placentas showed focal necrotizing villitis with neutrophil-dominant infiltration, similar to the characteristic Beh?et disease lesions in other organs. Intervillous fibrinous exudates with neutrophilic infiltrates and granuloma-like histiocytic aggregates were present. The decidua also showed neutrophilic vasculitis. No evidence of infection was present. Our observation suggests that Beh?et disease may involve placentas from the early stage of pregnancy. It may be implicated in potential fetal compromise and/or intrauterine transmission of the disease.     

Anti-endothelial cell antibodies and central nervous system involvement in Behçet's disease

INTRODUCTION: Previous studies have detected the presence of anti-endothelial cell antibodies (AECA) in patients with Beh?et's disease (BD). However, no real evidence exists whether these antibodies exert any influence on clinical presentation and/or activity of this disease. OBJECTIVES: To determine the frequency of AECA in patients with BD and analyze possible clinical associations. METHODS: 50 patients with BD who fulfilled diagnostic criteria were selected. Thirty-seven patients were females, and 13 were males; the mean age was 44 +/- 9 years with a mean follow-up time of 10 +/- 7.5 years. AECA were assayed by ELISA using ECV-304 cells as the antigenic substrate. The prevalence of AECA was determined, and their possible relationships with present and past clinical features were investigated. RESULTS: AECA were detected in the sera of 38% of the patients (IgG in 13, IgM in four, and IgG plus IgM in two). An association was observed between AECA and a previous history of central nervous system involvement (OR= 5.4, p= 0.03). This association was more evident for IgG-AECA (OR= 6.0, p= 0.02). A trend of an increased risk of aneurysms was also observed in patients with IgG-AECA (OR= 2.58, p= 0.77). None of the other clinical characteristics showed a relevant association with these antibodies. CONCLUSION: Our data suggest that IgG-AECA may be a marker of more severe lesions in patients with BD based on the higher frequency of previous central nervous system manifestations in patients who presently display circulating AECA.     

Microvascular assessment in Behçet disease: videocapillaroscopic study

The aim of this study was to evaluate microvascular assessment in patients with Behcet disease (BD) by means of an intravital videocapillaroscopic study. Sixteen BD patients were compared with an equivalent group of healthy subjects matched for age and sex. Videocapillaroscopy (VCP) was performed in peripheral areas and in conjunctiva, and morphological and quantitative parameters were assessed. In both areas VCP showed several morphological alterations (microaneurysms, megacapillaries, desertification areas) detectable in a high percentage of patients; quantitatively we found significant changes of incisuring and sludging score, of capillary loop intermediate branch length (in peripheral areas) and of arteriole/venule diameter (in conjunctiva). Therefore, vessel involvement included both the number and the whole vessel structure and was seen both in peripheral and conjunctival areas when the two different vascular beds of micro- and paramicrocirculation were examined. We conclude that an important rearrangement of microcirculation is detectable in BD and that VCP may have diagnostic and prognostic value, providing qualitative and quantitative information able to define the systemic extension of vascular damage and the degree of vessel wall alteration.     

Angiotensin-converting enzyme gene and endothelial nitric oxide synthase gene polymorphisms in Behçet’s disease with or without ocular involvement

Purpose

The association of known ACE gene and eNOS gene polymorphisms with BD in a group of Turkish patients with or without ocular involvement has been investigated.

Methods

The ACE and eNOS gene polymorphisms were investigated in 73 BD patients and 90 controls.

Results

The distrubition of “DD”, “ID” and “II” genotypes of the ACE gene were 32 (43.8%), 29 (39.8%) and 12 (16.4%) for BD patients and 32 (35.5%), 35 (38.9%) and 23 (25.6%) for healthy controls. There was no significant difference between the groups (p = 0.140, OR 1.44, CI 0.90–2.30). When Behçet patients with ocular involvement were compared to the control group, statistical significance was found (p = 0.049, OR 2.18, CI 1.00–4.81). The “bb”, “ba”, and “aa” genotype frequencies of the eNOS gene were 48 (65.8%), 23 (31.5%), and 2 (2.7%) for patients with BD and 75 (83.3%), 15 (16.7%), and 0 (0%) for healthy controls, respectively. The significant difference found in allelic frequencies between the two groups (p = 0.011, OR 2.32, CI 1.11–4.87). When Behçet patients with ocular involvement were compared, sharper statistical significance was found (p = 0.001,OR 4.61,CI 1.85–11.52).

Discussion

The ACE gene polymorphism does not play a role in the pathogenesis of BD. The findings of the eNOS gene polymorphisms confirmed the significant association with BD and even more in patients with ocular involvement.     

Macrophage activation syndrome in rheumatic disease: what is the role of the antigen presenting cell?

Macrophage Activation Syndrome (MAS), alternatively referred to as secondary hemophagocytic lymphohistiocytosis (HLH), is a complication of many rheumatic diseases, most commonly Systemic Juvenile Idiopathic Arthritis (SJIA). MAS consists of a fulminant picture of pan-cytopenia, hectic high fevers, hepatosplenomegaly, lymphadenopathy, rash, and central nervous systemic inflammation. It can arise from genetic defects in the cytotoxic effector response of CD8+ T-cells, resulting in an inability to terminate antigen presentation, which in turn leads to uncontrolled immune activation. However, in the case of most rheumatic diseases, no such defect in cytotoxic killing is present. Little is known about what the contributions from the antigen presenting cells are in the pathogenesis of MAS. In fact, macrophages may be playing a regulatory, anti-inflammatory in MAS. We review the proposed pathogenesis of MAS/HLH, what role macrophages may play in the disease, and the relationship of MAS to its most common associated rheumatic disease, SJIA.     

Red blood cell alloimmunization and antigen matching in sickle cell disease – the African perspective

In sickle cell disease (SCD), blood transfusion facilitates improved blood and tissue oxygenation, reduces the propensity to sickling by diluting host cells, and suppresses the production of red blood cells (RBCs) containing sickle haemoglobin (HbS). Delivery of RBC transfusions to patients with SCD varies by method (simple vs. exchange) and frequency (episodic vs. chronic). However, due to the genetic differences between blood donors and recipients, repeated transfusions increase the risk of developing alloantibodies to RBC antigens. The antigens most frequently involved belong to the Rh, Kell, Kidd, Duffy, Lewis, and MNS blood group systems. Consequences of RBC alloimmunization include delays and difficulties in obtaining compatible blood for future transfusions, the occurrence of delayed haemolytic transfusion reactions (DHTRs), the hyperhaemolysis syndrome and autoimmunization. In Europe and USA, RBC alloimmunization rates ranging from 18% to 76% have been reported in SCD while other multiply transfused (OMT) patients had alloimmunization rates of 5% to 20% indicating that SCD patients are at a higher risk of developing RBC alloantibodies. To prevent alloimmunization in SCD patients, the standard practice in Europe and USA is to determine their extended RBC phenotype (ABO, Rh, Kell, Kidd, Duffy, Lewis, MNS) before commencing transfusion therapy and perform antigen matching for C, E and K antigens for patients without prior alloantibody formation. However in Africa, lower RBC alloimmunization prevalence rates of 6–10% have been reported in SCD patients and no differences were observed between SCD and OMT patients. This may be explained by the presumed high phenotypic compatibility between donors and SCD patients who were all Black Africans. Also, a low transfusion load (a median 3 U of blood were transfused) in SCD patients might have led to the poor response to alloantigenic challenge. Anti-K alloimmunization was notably rare among African SCD patients compared to anti-S. In many African countries, pre-transfusion immunohaematologic testing includes neither the detection of RBC alloimmunization nor preventive antigen matching. Most transfusion laboratories are understaffed and underequipped; they perform ABO/D typing plus room temperature saline cross-matches and do not screen for RBC alloantibodies. Hence, immunized SCD patients are not diagnosed and do not have the opportunity of receiving antigen-negative blood. Furthermore, data on the occurrence of DHTRs are lacking. Introducing pre-transfusion RBC alloantibody screening in all African countries will significantly improve the transfusion management of SCD patients. A program of limited phenotype matching for C, E and S antigens is recommended to prevent additional alloantibody formation in immunized SCD patients in Africa.     

Neutrophil activation in Alzheimer’s disease and mild cognitive impairment: A systematic review and meta-analysis of protein markers in blood and cerebrospinal fluid

Inflammation is involved in the pathophysiology of Alzheimer’s disease (AD), with multiple inflammatory processes implicated in its risk and progression. This review included original peer-reviewed studies measuring the cerebrospinal fluid or peripheral blood concentrations of protein markers specifically related to neutrophil activity in healthy controls (HC) and in patients with AD or mild cognitive impairment (MCI). A total of 35 studies (N_HC = 3095, N_AD = 2596, N_MCI = 1203) were included. Random-effects meta-analyses were used to estimate between-groups standardized mean differences (SMD) and 95 % confidence intervals. In blood, concentrations of myeloperoxidase (MPO; N_AD/N_HC = 271/209, SMD = 0.41 [0.20, 0.62]; I² = 15.7 %) and neutrophil gelatinase associated lipocalin (NGAL; N_AD/N_HC = 273/185, SMD = 0.30 [0.11, 0.49]; I² < 0.005 %) were significantly higher in AD relative to HC. Peripheral blood concentrations of NGAL were also higher in MCI compared to HC (N_MCI/N_HC = 489/145, SMD = 0.39 [0.11, 0.67]; I² = 38.6 %). None of the protein markers exhibited a significant difference between HC, MCI, or AD groups in the cerebrospinal fluid. The evidence suggests that peripheral neutrophil activation, as indicated by blood concentrations of NGAL and MPO, may be a pathological feature of cognitive impairment due to AD, evident at stages of MCI and AD dementia.     

Microvesiculation and cell interactions at the brain–endothelial interface in cerebral malaria pathogenesis

Cerebral malaria (CM) is still a major world health problem whose pathogenic mechanisms remain incompletely understood. After reviewing some particularities of anti-malarial immunity, we focus here on the neurovascular aspects of CM. We specifically address the central role of endothelial activation and alteration in disease pathogenesis. We discuss the respective roles of “mediator-induced” versus “host cell-induced” mechanisms of endothelial alteration. The former include cytokines, chemokines and their receptors, while the latter encompass cells located inside and outside the vessel, notably glial cells. We also present evidence for a pathogenic role for membrane microparticles (MP) in CM, based on studies in African patients and in a recognised mouse model. Intervention studies on MP production, via either gene knockout or pharmacological inhibition, can prevent the neurological syndrome and its associated mortality, suggesting potential new therapeutic avenues.     

Genetics and immunodysfunction underlying Behçet’s disease and immunomodulant treatment approaches

Behçet’s disease (BD) is a chronic autoimmune condition primarily prevalent in populations along the Mediterranean Sea. The exact etiology of BD has not been fully explained yet, but the disease occurrence is associated with a genetic factor, human leukocyte antigen (HLA)-B51 antigen. Among the various immunodysfunctions that are found in BD, patients are increased neutrophil motility and superoxide production, as well as elevated production of tumor necrosis factor (TNF)-α and decreased production of interleukin (IL)-10. Elevated levels of inflammatory cytokines like IL-1 and IL-17 in BD have been found associated with aberrant expression of microRNA. Gene polymorphisms in BD patients have been observed in molecules involved in responses to pathogens that can ultimately modulate the host antimicrobial response. Moreover, several single nucleotide polymorphisms (SNPs) have been reported in genes encoding chemokines and adhesion molecules; many of these changes manifest as increases in vascular inflammation and vascular damage. Lastly, genetic and epigenetic changes have been suggested as involved in the pathogenesis of BD. Modifications in DNA methylation have been found in BD patient monocytes and lymphocytes, leading to adverse function of these cells. This review presents a comprehensive compilation of the literature with regard to the immunodysfunction underlying BD, as well as of the genetics, newly described clinical specifications and novel treatment strategies using immunomodulants based on the current understanding of BD.     

Biotherapies in Behçet's disease

Behçet's disease (BD) is a systemic large-vessel vasculitis characterized by a wide clinical spectrum including recurrent oral and genital ulcerations, uveitis, vascular, neurological, articular, renal and gastrointestinal manifestations. Therapeutic management of BD depends on the clinical presentation and organ involved. Although colchicine, nonsteroidal antiinflammatory agents and topical treatments with corticosteroids are often sufficient for mucocutaneous and joint involvements, more aggressive approach with immunosuppressive agents is warranted for severe manifestations such as posterior uveitis, retinal vasculitis, vascular, and neurological and gastrointestinal involvements. However, some patients still have refractory disease, relapse, sight threatening eye disease, or irreversible organ damage. Recent improvements in the understanding of the pathogenic mechanisms have led to the identification of potential targets and future biological therapies for BD. In contrast to current non-specific immunosuppressive agents, the emergence of biotherapies provides the possibility of interfering with specific pathogenic pathways. Novel targeted biotherapies might be used in the future for BD.     

T cell receptor binding kinetics and special role of Vα in T cell development and activation

The kinetics of the interaction between T cell receptor (TCR) and major histocompatibility complex (MHC) has an important role in determining thymocyte-positive and-negative selection in the thymus, as well as in T cell activation. The α chain of the TCR is the major player in determining how the TCR fits onto the MHC ligand, and thus has a major role in determining whether a T cell develops as class I or class II restricted. In this article, we summarize recent data from our laboratory and otherson the role of poly-morphism in the Vα combining site in determining MHC class restriction, and on kinetic parameters in thymocyte selection.     

New insights in the clinical understanding of Behçet's disease

Behçet''s disease is a chronic relapsing multisystemic inflammatory disorder characterized by four major symptoms (oral aphthous ulcers, genital ulcers, skin lesions, and ocular lesions) and occasionally by five minor symptoms (arthritis, gastrointestinal ulcers, epididymitis, vascular lesions, and central nervous system symptoms). Although the etiology of Behçet''s disease is still unknown, there have been recent advances in immunopathogenic studies, genome-wide association studies, animal models, diagnostic markers, and new biological agents. These advances have improved the clinical understanding of Behçet''s disease and have enabled us to develop new treatment strategies for this intractable disease, which remains one of the leading causes of blindness.     

Platelet activation and red blood cell phosphatidylserine exposure evaluated by flow cytometry in patients with Behçet's disease: are they related to thrombotic events?

Beh?et's disease (BD) is associated with an increased risk of venous and arterial thromboses that are associated with morbidity and mortality increase, although the mechanisms are not well established. In the present study, we used whole blood cytometry to determine the exposure of CD62 on the surface of platelets and the expression of phosphatidylserine (PS) on the surface of circulating red blood cells. Microparticle and microaggregate formation from platelets were also determined in a well-classified group of 72 patients (39 males, 33 females, aged 46.5 +/- 12.5 years) with BD, in comparison with a well-matched control group of 72 healthy volunteers. Results showed no differences in the above-mentioned parameters when BD patients and controls were compared. However, when we compared BD patients with/without thrombosis using these parameters, there were significant differences between both groups. BD patients with previous thrombosis had a higher percentage of circulating CD62-positive platelets and a higher number of circulating microaggregates than those without thrombosis, suggesting that platelet activation may be involved in the development of thrombotic events in these patients.