CD72-semaphorin3A axis: A new regulatory pathway in systemic lupus erythematosus.

CD72 is a regulatory co-receptor on B cells, with a role in the pathogenesis of systemic lupus erythematosus (SLE) in both human and animal models. Semaphorin3A (sema3A) is a secreted member of the semaphorin family that can reconstruct B cells' regulatory functions by upregulating IL-10 expression and inhibiting the pro-inflammatory activity of B and T cells in autoimmune diseases. The aim of our present study was to identify a new ligand for CD72, namely sema3A, and exploring the signal transduction pathways following its ligation in B cells. We established that CD72 functions as sema3A binding and signal-transducing receptor. These functions of CD72 are independent of neuropilin-1 (NRP-1) (the known sema3A receptor). We discovered that sema3A induces the phosphorylation of CD72 on tyrosine residues and the association of CD72 with SHP-1 and SHP-2. In addition, the binding of sema3A to CD72 on B cells inhibits the phosphorylation of STAT-4 and HDAC-1 and induces the phosphorylation of p38-MAPK and PKC-theta in B-cells derived B-lymphoblastoid (BLCL) cells, and in primary B-cells isolated from either healthy donors or SLE patients. We concluded that sema3A is a functional regulatory ligand for CD72 on B cells. The sema3A-CD72 axis is a crucial regulatory pathway in the pathogenesis of autoimmune and inflammatory diseases namely SLE, and modulation of this pathway may have a potential therapeutic value for autoimmune diseases.

The Involvement of LAG-3positive Plasma Cells in the Development of Multiple Myeloma.

The Lymphocyte-Activation Protein 3 (LAG-3) inhibitory receptor is expressed on regulatory plasma cells (PCs). Micro-environmental cells that express LAG-3 were found to be increased during the progression of smoldering multiple myeloma (SMM). To assess the possible role of LAG-3 expression on regulatory PCs in patients with plasma cell dyscrasia. Purified Cluster of Differentiation 138 (CD138+) PCs from patients with premalignant conditions, active multiple myeloma (MM), and controls were analyzed for the expression of LAG-3 by flow cytometry. Autologous CD8+T cells were incubated with sorted LAG-3pos or LAG-3neg PCs for 24 h. The expression of granzyme (Grz) in CD8+T cells was assessed by flow cytometry. LAG-3 expression on PCs in active MM (newly diagnosed and relapse refractory MM) was significantly increased compared to monoclonal gammopathy of undetermined significance (MGUS)/ SMM. Grz expression was significantly decreased in CD8+T cells incubated with CD138+LAG-3pos PCs, compared to CD138+LAG-3neg PCs in patients with plasma cell dyscrasia, n = 31, p = 0.0041. LAG-3 expression on malignant PCs can be involved in the development of MM from MGUS by decreasing the expression of Grz in CD8+T cells.

Lysyl oxidase-a possible role in systemic sclerosis-associated pulmonary hypertension: a multicentre study.

OBJECTIVE: Lysyl oxidase (LOX) is an extracellular enzyme that cross-links collagen fibrils. LOX was found to be increased in serum of SSc patients and was suggested to be related to skin fibrosis, yet a vascular source of LOX has been demonstrated in idiopathic pulmonary arterial hypertension (iPAH). We aimed to validate elevated LOX serum levels in SSc and to study its correlation with clinical characteristics and investigate its main source at the tissue level. METHODS: A total of 86 established SSc patients were compared with 86 patients with very early diagnosis of systemic sclerosis (VEDOSS), 110 patients with primary RP (PRP) and 80 healthy controls. LOX serum levels were determined by ELISA. Five lung and 12 skin biopsies from SSc patients were stained for LOX and compared with controls. RESULTS: Serum levels of LOX in SSc were significantly higher than in VEDOSS, PRP and healthy controls (P < 0.001). LOX inversely correlated with the diffusing capacity of the lung for carbon monoxide diffusing capacity (DLCO) in diffuse SSc (r = -0.376, P = 0.02). Patients with moderate to severe estimated systolic PAH had higher LOX levels (P < 0.01). Lung biopsies demonstrated intense LOX staining in SSc patients with PAH that was predominantly located in the endothelium of the remodelled pulmonary vessels. CONCLUSION: Serum LOX levels are increased in established SSc and inversely correlate with the DLCO. LOX is elevated in patients with moderate to severe PAH and is located in the proliferating endothelium in lung arterioles, suggesting a possible role for LOX in SSc-associated PAH.

Semaphorin-3A inhibits multiple myeloma progression in a mouse model.

Previous studies revealed that progression of multiple myeloma (MM) is associated with downregulation of semaphorin-3A (sema3A) expression in bone marrow endothelial cells. We therefore determined if serum sema3A concentrations are correlated with MM progression and if sema3A can affect MM progression. We find that the concentration of sema3A in sera of MM patients is strongly reduced and that the decrease is correlated with disease progression. A similar depletion is found in patients having acute myeloid leukemia and acute lymphoblastic leukemia but not in cancer forms that do not involve the bone marrow such as in colon cancer. Expression of a modified sema3A [furin-resistant sema3A (FR-sema3A)] stabilized against cleavage by furin-like proprotein convertases in CAG MM cells did not affect their behavior in-vitro. CAG cells injected into the tail vein of severe combined immunodeficient (SCID) mice home to the bone marrow and proliferate, mimicking MM disease progression. Disease progression in mice injected with CAG cells expressing FR-sema3A was inhibited, resulting in prolonged survival and a lower incidence of bone lesions. Histological examination and fluorescence-activated cell sorting analysis revealed that FR-sema3A expression reduced the infiltration of the CAG cells into the bone marrow, reduced bone marrow necrosis and reduced angiogenesis induced by the MM cells in the bone marrow. Our results suggest that measurement of sema3A serum concentrations may be of use for the diagnosis and for the monitoring of malignancies of the bone marrow such as MM. Furthermore, our results suggest that FR-sema3A may perhaps find use as an inhibitor of MM disease progression.

Hemostasis in Allergy.

The involvement of the hemostatic system in immune-mediated inflammation is widely reported. Many coagulation factors play a role in the pathogenesis of autoimmune diseases, such as systemic vasculitis and systemic lupus erythematosus. Hemostatic disorders are also involved in asthma and chronic spontaneous urticaria (CSU). Factor XIIa (FXIIa) was one of the first coagulation factors implicated in inducing both humoral and cellular responses and is therefore considered a prime new therapeutic target in immune-mediated inflammation. The involvement of coagulation factors, such as tissue factor and fibrinogen, in the pathogenesis of asthma has been reported. The finding of platelet activation in asthma also indicates a link between bronchial inflammation and hemostasis. The pathogenesis of mast cell degranulation and CSU was also shown to be associated with the activation of hemostatic factors such as fibrinogen and FXIIa. Increased plasma levels of D-dimer have been widely reported as a biological marker for the duration and severity of CSU. In addition, endothelial-induced cell activation by the kallikrein-high molecular weight complex and the release of heat shock protein 90 was shown to be involved in mast cell degranulation disorders. In this narrative review, the authors aim to summarize the role of hemostasis in inflammation, asthma, and CSU by focusing on the increasing information linking hemostatic factors and immune-mediated disorders.

Semaphorin 3A: Is a key player in the pathogenesis of asthma.

Immune semaphorins are key players in regulating immune mediated inflammation. Semaphorin3A (sema3A) a secreted and membrane bound member of this family, is well reported for its properties in maintaining self-tolerance. Semaphorin3A was recognized to be a marker for T-regulatory cells (Tregs), and as such is a useful tool for assessing the status of these cells in preventing immune mediated diseases. This study was designed aiming to evaluate how sema3A is possibly involved in bronchial asthma. Here, we found sema3A serum levels and the expression of sema3A on Tregs significantly lower in patients with moderate to severe asthma when compared to healthy individuals. Co-culture of condition medium with 2mcg/ml of recombinant human sema3A with CD4+ T cells, increased the expression of FoxP3 in Tregs, suggesting sema3A a potent immune-regulator of inflammation including that of asthma. Further in-vivo studies will better establish the beneficial effect of sema3A in regulating inflammation in asthma.

The association between semaphorin 3A levels and gluten-free diet in patients with celiac disease.

Celiac disease (CD) is an inflammatory disease affecting the small intestine. We aim to assess serum level and expression of semaphorin 3A (Sema3A) on T regulatory (Treg) cells in CD patients. Twenty-six newly diagnosed celiac patients, 13 celiac patients on a gluten-free diet and 16 healthy controls included in the study. Sema3A protein level in the serum of celiac patients was significantly higher compared to healthy group (7.17±1.8ng/ml vs. 5.67±1.5ng/ml, p=0.012). Sema3A expression on Treg cells was statistically lower in celiac patients compared to healthy subjects (p=0.009) and significantly lower in celiac patients compared to celiac patients on gluten free diet (p=0.04). Negative correlation was found between Sema3A on Teg cells and the level of IgA anti-tTG antibodies (r=-0.346, p<0.01) and anti-DGP (r=-0.448, p<0.01). This study suggests involvement of the Sema3A in the pathogenesis of CD.

Semaphorins 4A and 4D in chronic inflammatory diseases.

Long-term inflammatory processes directed at a particular endogenous or exogenous antigen, or sometimes of unknown etiology, form the pathogenetic basis for many debilitating conditions, such as cardiovascular, pulmonary, autoimmune, neurologic diseases, and cancer. Recent discoveries of neuroimmune semaphorins 4A and 4D (Sema4A and Sema4D, respectively) expression and function in the immune system and their key regulatory roles in fine tuning of inflammatory processes made them the molecules of interest for a potential immunotherapy. In this short review, we discuss the current knowledge in the Sema4A and Sema4D actions in chronic inflammation underlying the outlined above diseases.

The Expression of Neuropilin-1 in Human Placentas From Normal and Preeclamptic Pregnancies.

Preeclampsia (PET) is a hypertensive disorder that affects 2% to 8% of pregnant women. Recent observations support the hypothesis that upregulation of placental anti-angiogenic factors are responsible for the clinical manifestations of the disease. Neuropilin-1 (NP-1) is a transmembrane protein that acts as a coreceptor for vascular endothelial growth factor and as a regulatory protein in the immune system. The aim of the study was to evaluate the expression of NP-1 in PET and normal placentas. Nineteen placental specimens from severe PET pregnancies were compared with 20 placental specimens of women with low-risk pregnancy. All the specimens underwent immunohistochemical staining with anti-human NP-1 antibody. The degree of NP-1 staining was measured both for intensity and extent. Our study demonstrated NP-1 immunoreactivity mainly in the decidual cells, the intermediate trophoblast, and the syncytiotrophoblast, particularly in the areas in the syncytial knots and shed particles. The particles were strongly NP-1 immunoreactive. The expression of NP-1 in the syncytiotrophoblast was lower in placentas of PET compared with control (P=0.017). Shedding of syncytiotrophoblast particles from placenta to maternal blood occurs in normal pregnancies and is enhanced during PET and contributes to the maternal vascular injury that characterizes PET. Our new observation that shows strong NP-1 immunoreactivity of these particles, and decreased NP1 expression in syncytiotrophoblast of PET placentas in comparison to the control group, may imply a role of NP-1 in PET.

[THE ROLE OF SEMAPHORIN 7A IN SYSTEMIC SCLEROSIS].

INTRODUCTION: Semaphorins are a large group of membrane bound and secreted proteins. The semaphorins were first recognized for their important role in neurodevelopment and specifically their repulsive axonal growth guidance during embryonic development. Recently, semaphorins have also been found to have an important role in the regulation of the immune system, thus denoted as "immune semaphorins". Semaphorin 7A is a membrane bound protein which mediated its effect by two receptors: the ß1 integrin subunit and plexin C1. Interactions between semaphorin 7A and its receptors contribute to inflammation and immunity by the stimulation of macrophage chemotaxis and cytokine production, regulation of dendritic cell migration and modulation of T cell function. Recently, semaphorin 7A has been found to have a role in the induction of fibrosis by tumor growth factor ß1 (TGF ß1). TGFß1 activates semaphorin 7A and its receptors plexin C1 and ß1 integrin subunit and induces proliferation of fibroblasts, lung fibrosis and remodeling in mice. A small study of 4 patients with systemic sclerosis (SSc) has recently demonstrated increased expression of semaphorin 7A mRNA on fibroblasts and B lymphocytes in peripheral blood. AIMS: To evaluate the expression of semaphorin 7A on regulatory T cells and B cells from peripheral blood of patients with SSc compared to healthy controls and to try and correlate the expression of semaphorin 7A with pulmonary fibrosis, skin fibrosis and other clinical characteristics of SSc patients. METHODS: Twenty six SSc patients were compared to 10 healthy controls. The expression of semaphorin 7A was evaluated by flow cytometry analysis of B cells using monoclonal antibodies to CD 108 and CD 19 and on peripheral regulatory T cells using monoclonal antibodies to CD 3 and CD 108. The analysis was conducted using flow-cytometry. Demographic, clinical and laboratory data were prospectively collected. Further data collection included: Systolic pulmonary artery pressure as assessed by echocardiography, lung function tests including diffusing capacity, nailfold video capillaroscopy pattern, modified Rodnan skin score (MRSS), Valentini activity index and Medsger severity score. Pulmonary involvement was determined by high resolution CT scan if it was suspected, according to impaired lung functions or auscultatory findings. RESULTS: Ten patients with diffused SSC (8 of whom suffered from pulmonary fibrosis) and 16 patients with limited disease were compared with 10 healthy controls. There was no difference between the groups with regard to age, gender, BMI or smoking habits. Semaphorin 7A expression on regulatory T cells was not different between SSc patients and healthy controls 4.2±6.5 % vs. 2.3±1.1 % (p< 0.35) nor was a difference found between SSC patients with diffuse disease compared to limited disease 2.5±8 % vs. 5.1±14 % (p< 0.3). Comparing the expression of semaphorin 7A on B cells did not reveal a difference between SSc patients and healthy controls as well 9.7±9.4 % vs. 4.9±1.7% (p< 0.12). No correlation was found between skin score, activity score or severity score and levels of expression of sempahorin 7A on B cells or regulatory T cells. CONCLUSIONS: In this small scale study we were not able to validate the role of semaphorin 7A as a mediator of fibrosis in SSc, as was suggested by a previous pilot study. Larger scale studies and investigation of semaphorin 7A on other peripheral cells and in tissues are needed in order to delineate the exact role of semaphorin as a mediator of fibrosis in SSc.

Increased soluble CD72 in systemic lupus erythematosus is in association with disease activity and lupus nephritis.

INTRODUCTION: B cell receptor (BCR) -mediated signals are enhanced when CD72 expression is deficient on B cells in autoimmune diseases. The significance of soluble CD72 (sCD72) has not been elucidated. METHODS: Soluble CD72 was analyzed in the serum of 159 SLE patients, 40 rheumatoid arthritis (RA) patients, and 100 healthy individuals. Correlations between sCD72 and SLE disease activity (SLEDAI) were assessed. RESULTS: Soluble CD72 was found increased in SLE patients, when compared to both RA patients and healthy individuals (20.2 ± 1.2 ng/ml; 10.6 ± 4.6 ng/ml and 7.2 ± 3.3 ng/ml; p < 0.001). Soluble CD72 level was significantly higher in SLE patients with renal involvement than in patients without (31.8 ± 2.3 ng/ml vs 13.9 ± 0.9 ng/ml; p < 0.001) and also with the presence of auto-antibodies. CONCLUSION: Soluble CD72 is significantly increased in SLE patients mainly in those with renal involvement. Increased sCD72 may become a potential biomarker for renal involvement in SLE.

Seasonal Exacerbation of Asthma Is Frequently Associated with Recurrent Episodes of Acute Urticaria.

BACKGROUND: Asthma and urticaria are both partially mediated by an increased release of histamine from highly activated mast cells. They are pathophysiologically different, as mast cell degranulation in these 2 disorders results from different mechanisms. OBJECTIVE: To assess the incidence of urticaria in patients with asthma, and of asthma in patients with chronic spontaneous urticaria (CSU). PATIENTS AND METHODS: Over 1 year of follow-up, asthma patients (n = 110) were assessed for the incidence and characteristics of urticaria, and a link, if it existed, to seasonal exacerbations and the severity of asthma was traced. We also prospectively assessed CSU patients (n = 95) during the same period of time for the incidence of asthma. Healthy individuals (n = 100), serving as a control group, were also assessed. RESULTS: Episodes of urticaria occurred in 26/110 asthma patients (23.6%), but in only 2/100 healthy control subjects (2%) (p < 0.0001). During the 1-year observation period, episodes of urticaria were significantly more frequent in asthma patients with positive skin-prick test reactions (mainly seasonal pollens), and consequently occurred mostly during seasonal asthma exacerbation, i.e. during acute episodes of urticaria. The incidence of asthma in CSU patients was recorded in 10.5% of the group, similar to that in the healthy control population. DISCUSSION: Our study demonstrates, for the first time, that asthma patients frequently develop acute urticaria, mainly during seasonal exacerbations. In contrast, CSU patients do not show an increased incidence of asthma.

Semaphorin 3A, a potential immune regulator in familial Mediterranean fever.

OBJECTIVES: Semaphorin 3A (sema3A) plays a regulatory role in immune responses with effects on both T and B regulatory cells. Familial Mediterranean fever (FMF) is an autoinflammatory disease, yet a possible role for regulatory T and B cells has been described. METHODS: 17 FMF patients during attack and then in remission, 8 FMF patients with smoldering disease and 12 healthy controls were enrolled. Sema3A in serum and its expression on regulatory T and B cells was evaluated. Clinical parameters of FMF patients were assessed. RESULTS: Semaphorin 3A serum level was lower in FMF patients during attack, smoldering disease or remission than healthy controls, (242.3±9.8 ng/ ml vs. 258.9±11.5 ng/ml vs. 232.5±22.7 ng/ml vs. 323.3±160.2 ng/ml, respectively p<0.05). This decrease was specifically noted on regulatory B and T cells in FMF patients during attack and in smoldering disease and normalized in remission. CONCLUSIONS: Sema3A expression on T and B regulatory lymphocytes is low in FMF patients during attack and in smoldering disease compared to the expression in remission and healthy controls. These results are in line with previous descriptions suggesting a possible role of regulatory T cells in termination of FMF attacks. Further studies are needed to verify these preliminary findings.

Adaptation and Validation of the Israeli Version of the Chronic Urticaria Quality of Life Questionnaire (CU-Q2oL).

BACKGROUND: Chronic urticaria (CU) is a common disabling disorder. The CU-Q2oL (Chronic Urticaria Quality of Life Questionnaire) is a specific questionnaire for evaluating quality of life in CU patients. It consists of 23 items divided into six quality-of-life dimensions. It was initially developed in Italy and later validated in other countries. OBJECTIVES: To validate and adapt the CU-Q2oL to the Hebrew language in order to make it suitable for use in Israel. METHODS: The CU-Q2oL questionnaire was translated to Hebrew. A group of 119 CU patients were asked to complete this version, in addition to the Dermatology Life Quality Index (DLQI) and Urticaria Activity Score (UAS) questionnaires. A factorial analysis was performed to identify CU-Q2oL subscales, internal consistency and convergent validity assessment, as well as factors determining quality-of-life scores. RESULTS: The factor analysis identified six scales of the Israeli CU-Q2oL: (i) sleep and concentration, (ii) function and mental status, (iii) embarrassment and clothing limitations, (iv) itching, (v) eating behavior and medication side effects, and (vi) swelling, which accounted for 77% of the data variance. Five scales showed good internal consistency over 0.81. The mean ± SD score of CU-Q2oL in our patients with CIU was 41 ± 21.7. We found a strong positive correlation between the overall scores of CU-Q2oL and DLQI questionnaires (r = 0.8, P < 0.01). Additionally, we found a positive correlation between UAS and both CU-Q2oL and DLQI (r = 0.62, P < 0.01, and r = 0.53, P < 0.01, respectively). CONCLUSIONS: This study demonstrates that the Israeli CU-Q2oL questionnaire is suitable for both clinical use and research in Israel.

[REGULATORY B CELLS].

B lymphocytes represent a major component of the immune system. In addition to their best understood functions, B cells have also been demonstrated to downregulate inflammatory reactions and induce tolerance. The general concept that B cells might have the ability to induce tolerance was already introduced in the 1970s. In mice subpopulations, regulatory B cells and their precursors seem to be able to arise from different subpopulations of Br1 and Br2 cells. In contrast to the murine studies, there is a paucity of data regarding regulatory B cells in healthy people or in patients with autoimmune disease, but such data exists. The composition of regulatory B cells is similar to that of regulatory T cells. In analogy to regulatory T cells, which can be subdivided into Treg, Tr1 and Th3 according to their expression of FoxP3, IL-10 and transforming growth factor TGF-ß, respectively, it is proposed to classify human regulatory B cells into Breg, Br1(10) and Br3. Regulatory T and B cells function at different time points. Br1 may be involved in the initiation of pathological responses and Tregs in their maintenance and progression. The main functions of regulatory B cells are mediated by releasing immunosuppressive cytokines and inducing target cell apoptosis. IL-10 is the hallmark cytokine of regulatory B cells. Impaired regulatory capacity of these cells might play a role in the development of inflammatory diseases. Their released cytokines have a broad range of target cells. Therefore, they downregulate the proinflammatory functions of both innate and adaptive immune cells. Targeting B regulatory cells for therapeutic applications holds great promise for the future treatment of autoimmune and allergic inflammatory conditions.

Semaphorin 3A: an immunoregulator in systemic sclerosis.

ABSTARCT: Semaphorin 3A (sema3A) plays a regulatory role in immune responses, mainly affecting the activation of regulatory T cells. It has been found to correlate with disease activity in rheumatoid arthritis and systemic lupus erythematosus (SLE). To investigate the expression of sema3A in patients with systemic sclerosis (SSc) compared to healthy controls and SLE disease controls and to correlate it with clinical characteristics, 27 SSc patients, 42 SLE patients and 28 healthy controls were enrolled. Serum level of sema3A was measured by ELISA, and expression of sema3A on regulatory T cells was evaluated by FACS analysis. SSc patients were evaluated for demographics, clinical manifestations, routine laboratory results, nailfold videocapillaroscopy, pulmonary function tests, echocardiograms, modified Rodnan skin score, and disease activity and severity scores. Serum levels of semaphorin 3A were lower in SSc compared to healthy controls 14.38 ± 5.7 versus 27.14 ± 8.4 ng/ml, p < 0.0001 and similar to SLE 15.7 ± 4.3 ng/ml. The expression of semaphorin 3A on regulatory T cells was also lower in SSc compared to healthy controls 61.7 ± 15.7 versus 88.7 ± 3. 7 % (p < 0.0001). Semaphorin 3A serum level inversely correlated with the duration of disease: r = -0.4, p = 0.036 and with low C4 level r = 0.66, p = 0.026. SCL-70 antibody positivity was associated with a lower semaphorin 3A level (difference in mean of 3.44, p = 0.06). Sema3A expression is low in SSc serum and more specifically on regulatory T cells. This may help explain the reduced activation of regulatory T cells in SSc.

Interferon-gamma-release assay prevents unnecessary tuberculosis therapy.

BACKGROUND: The mass influx of immigrants from tuberculosis-endemic countries into Israel was followed by a considerable increase in the incidence of tuberculosis (TB). All contacts of active TB patients are obliged to be screened by tuberculin skin tests (TST) and, if found positive, prophylactic treatment is considered. OBJECTIVES: To assess the utility of interferon-gamma (IFNγ)-release assay with a prolonged follow-up in preventing unnecessary anti-TB therapy in individuals with suspected false positive results. METHODS: Between 2008 and 2012 the QuantiFERON TB gold-in-tube test (QFT-G) was performed in 278 sequential individuals who were mostly TST-positive and/or were in contact with an active TB patient. In all, whole blood was examined by the IFNγ-release assay. We correlated the TST diameter with the QFT-G assay and followed those patients with a negative assay. RESULTS: The QFT-G test was positive in only 72 (42%) of all 171 TST-positive individuals. There was no correlation between the diameter of TST and QFT-G positivity. Follow-up over 5 years was available in 128 (62%) of all QFT-G-negative individuals. All remained well and none developed active TB. CONCLUSIONS: A negative QFT-G test may obviate the need for anti-TB therapy in more than half of those with a positive TST.

The role of B regulatory cells and Semaphorin3A in atopic diseases.

When the pathogenesis of allergic inflammatory diseases such as asthma, allergic rhinitis and atopic dermatitis is discussed, one should take into consideration the involvement of regulatory cells/molecules whose role is to prevent the induction and/or deterioration of such diseases. The involvement of T regulatory cells and FoxPp3 is well established in asthma, but only little is known about the involvement of B regulatory cells (Bregs) and the soluble regulatory molecule semaphorin3A (sema3A) in atopic diseases. During the last decade, research has sought to better define the various subtypes of Breg cells and how similar they are to their parallel subtypes of Tregs. In this review, we focus on the newly reported role of Bregs in both experimental and human models of asthma. Bregs are also involved in the pathophysiology of food allergy. We also show how sema3A plays a role in the pathogenesis of allergic rhinitis and atopic dermatitis. Determining the above processes could facilitate the use of regulatory molecules as therapeutic tools in treating these diseases.