Basophils and autoreactive IgE in the pathogenesis of systemic lupus erythematosus

Is Atopic Dermatitis Only a Skin Disease?

Atopic dermatitis (AD) is a chronic, pruritic, inflammatory dermatosis that imposes significant patient and population burdens. In addition to the cutaneous signs and symptoms, growing evidence suggests that AD is systemic in nature. Certain diseases can possibly co-occur with AD as a result of coincidental exposure to similar environmental factors. However, it is also suspected that they are linked to the pathogenesis of AD through more complex genetic and immunological mechanisms, but these correlations remain less understood. It is of great need to seek explanations for the higher frequency of the number of cardiovascular, autoimmune, neurological, psychiatric, and metabolic disorders that have been observed in epidemiologic investigations among AD patients. Moreover, analysing the immunology of chronic inflammation and its correction, activation, or suppression may prevent the development of a variety of comorbidities. As comorbid diseases in patients diagnosed with AD may potentially go undetected, physicians should be aware of them.

Lupus Nephritis in an Adolescent Girl With Hyper-Immunoglobulin E

We report the case of an adolescent girl with frequent hospital admissions for severe eczematous skin rashes with recurrent epistaxis and chest infections. Investigations revealed persistent severely elevated serum total immunoglobulin E (IgE) levels but normal levels of other immunoglobulins, suggesting hyper-IgE syndrome. The first skin biopsy revealed superficial dermatophytic dermatitis (tinea corpora). Another biopsy performed after six months revealed a prominent basement membrane with dermal mucin, suggesting an underlying autoimmune disease. Her condition was complicated by proteinuria, hematuria, hypertension, and edema. A kidney biopsy revealed class IV lupus nephritis, according to the International Society of Nephrology/Renal Pathology Society (ISN/RPS). Based on the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) criteria, she was diagnosed with systemic lupus erythematosus (SLE). She was first administered with intravenous pulse methylprednisolone (600 mg/m²) for three consecutive days, followed by oral prednisolone (40 mg/m²) daily, mycophenolate mofetil tablets (600 mg/m²/dose) twice daily, hydroxychloroquine (200 mg) once daily, and three classes of antihypertensive medications. She maintained normal renal functions with no lupus morbidity for 24 months, then rapidly progressed to end-stage kidney disease, and was then started on three to four sessions of regular hemodialysis per week. Hyper-IgE is known to be a marker of immune dysregulation as it facilitates the generation of immune complexes (ICs) that mediate lupus nephritis and juvenile SLE. Regardless of the different factors that are impacting the production of IgE, the present case illustrated that juvenile patients with SLE may have increased IgE levels, indicating that higher IgE levels might have a role in lupus pathogenesis and prognosis. The mechanisms regarding the increased levels of IgE in subjects with lupus need further investigation. Further studies are thus required to assess the incidence, prognosis, and possible new specific management for hyper-IgE in juvenile SLE.

Immunoglobulin E response in health and disease beyond allergic disorders

Immunoglobulin E is the latest discovered of immunoglobulin family and has been long associated with anaphylaxis and worm expulsion. Immunoglobulin E, along with mast cells, basophils, and eosinophils, is also a hallmark of type 2 immunity which is dysregulated in numerous diseases such as asthma, rhinitis, atopic dermatitis, and eosinophilic esophagitis in addition to anaphylaxis as aforementioned. However, recent advances have shed light on IgE regulation and memory explaining the low level of free IgE, the scarcity of IgE plasma cells that are mainly short live and the absence of IgE memory B cells in homeostatic conditions. Furthermore, IgE was implicated in inflammatory conditions beyond allergic disorders where IgE-mediated facilitated antigen presentation can enhance cellular and humoral response against autoantigens in systemic lupus or chronic urticaria leading to more severe disease and even against neoantigen facilitating tumor cell lysis. At last, IgE was unexpectedly associated with allograft rejection or atheromatous cardiovascular diseases where precise mechanisms remain to be deciphered. The purpose of this review is to summarize these recent advances in IgE regulation, biology, and physiopathology beyond allergic diseases opening whole new fields of IgE biology to explore.

Time-dependent blood eosinophilia count increases the risk of kidney allograft rejection

Background

Growing evidence suggest that type 2 immune effectors play a role in solid organ transplantation. The aim of this study was to evaluate the impact of blood count eosinophils (BCEo) on immunological outcomes in kidney transplant recipients with stable graft function after 3 months post-transplant.

Method

We performed cause-specific Cox model considering BCEo, the use of calcineurin inhibitors and systemic corticoids as time-dependent explicative variables on a prospective cohort of 1013 kidney transplant patients who experienced kidney allograft rejection and/or the appearance of de novo donor specific antibodies after excluding common causes of increased BCEo..

Findings

BCEo ≥ 0.3 G/L was associated with a 3-fold increased risk of rejection independent of immunosuppressive regimen after 3 months post-transplant in patients without pre-transplant DSAs and with CNI-based immunosuppression. No association between BCEo either with donor specific antibodies or graft survival was noticed.

Interpretation

These observations in this large cohort support the hypothesis of eosinophils in allo-immunity in human and claim for further mechanistic research.

Funding

This study was supported by the French National Research Agency, The “Institut de Recherche en Santé Respiratoire des Pays de la Loire” and the University hospital of Nantes.

The roles of basophils in mediating the immune responses

Basophils are the rarest blood cell population and have not been extensively studied. Our understanding of the functions of basophils is limited to their roles as the main effector cells in hypersensitivity reactions. Similar to mast cells, basophils express high-affinity IgE receptor (FcεRI), contain granules, and release hypersensitivity-associated mediators (such as histamine). The roles of basophils have not been fully elucidated; however, with the rapid development of monoclonal techniques, high-purity cell sorting techniques, and basophil-deficient mouse models, understanding of the functions and phenotypes of basophils has increased. This facilitates further investigations on the relationships between basophils and host immunity. Basophils are not only involved in mediating the generation of allergic reactions but also play important roles in immunomodulation and are responsible for the onset of infectious, allergic, and autoimmune diseases. In this review, we summarize the progress in understanding the roles of basophils in mediating immune responses with an emphasis on autoimmune diseases, particularly systemic lupus erythematosus and rheumatoid arthritis.

IgE Autoreactivity in Atopic Dermatitis: Paving the Road for Autoimmune Diseases?

Atopic dermatitis (AD) is a common skin disease affecting 20% of the population beginning usually before one year of age. It is associated with the emergence of allergen-specific IgE, but also with autoreactive IgE, whose function remain elusive. This review discusses current knowledge relevant to the mechanisms, which leads to the secretion of autoreactive IgE and to the potential function of these antibodies in AD. Multiple autoantigens have been described to elicit an IgE-dependent response in this context. This IgE autoimmunity starts in infancy and is associated with disease severity. Furthermore, the overall prevalence of autoreactive IgE to multiple auto-antigens is high in AD patients. IgE-antigen complexes can promote a facilitated antigen presentation, a skewing of the adaptive response toward type 2 immunity, and a chronic skin barrier dysfunction and inflammation in patients or AD models. In AD, skin barrier defects and the atopic immune environment facilitate allergen sensitization and the development of other IgE-mediated allergic diseases in a process called the atopic march. AD is also associated epidemiologically with several autoimmune diseases showing autoreactive IgE secretion. Thus, a potential outcome of IgE autoreactivity in AD could be the development of further autoimmune diseases.

Allergic rhinitis and risk of systemic lupus erythematosus: A systematic review and meta-analysis

OBJECTIVE

The current study was conducted to comprehensively investigate whether patients with allergic rhinitis (AR) are at a higher risk of incident systemic lupus erythematosus (SLE) compared with individuals without AR by using systematic review and meta-analysis techniques to combine data from all available studies.

METHODOLOGY

Systemic literature review was performed using EMBASE and MEDLINE databases up to March 2020. Eligible studies could be either case-control or cohort studies. Cohort studies had to evaluate whether patients with AR have a higher risk of incident SLE than comparators. Relative risk (RR) with associated 95% confidence intervals (CI) comparing the incidence of SLE between participants with and without AR had to be provided. Eligible case-control studies had to provide odds ratio (OR) with 95% CI comparing the prevalence of AR between cases with SLE and controls without SLE. Point estimates and standard errors from each eligible study were combined together using the generic inverse variance method of DerSimonian and Laird.

RESULTS

A total of 21 486 articles were retrieved. After 2 rounds of review, 1 cohort study and 7 case-control studies with 3 326 171 participants were included into the meta-analysis. The pooled analysis found that patients with AR had a significantly higher risk of SLE than individuals without AR with the pooled OR of 1.36 (95% CI 1.08-1.72; I² of 80%).

CONCLUSIONS

A significantly increased 1.4 fold risk of SLE among patients with AR was observed in this systematic review and meta-analysis.

Patients with asthma have a higher risk of systemic lupus erythematosus: a systematic review and meta-analysis

OBJECTIVE

This study aimed to investigate the association between asthma and risk of systemic lupus erythematosus (SLE) using systematic review and meta-analysis technique.

METHODS

Potentially eligible studies were identified from Medline and EMBASE databases from inception to March 2020 using search strategy that comprised of terms for "asthma" and "systemic lupus erythematosus." Qualified cohort study must consist of one cohort of patients with asthma and another cohort of individuals without asthma. Then, the study must report relative risk (RR) with 95% confidence intervals (95% CIs) of incident SLE between the two groups. Qualified case-control studies must consist of cases with SLE and controls without SLE. Then, the study must explore their history of asthma. Odds ratio (OR) with 95% CIs of the association between asthma status and SLE must be reported. Point estimates and standard errors were extracted from each study and were combined using the generic inverse variance method.

RESULTS

A total of 21,486 articles were identified. After two rounds of independent review by three investigators, three cohort studies and seven case-control studies met the eligibility criteria and were included into the meta-analysis. Patients with asthma had a significantly higher risk of SLE compared with individuals without asthma with the pooled odds ratio of 1.37 (95% CI 1.14-1.65; I² 67%). Funnel plot was symmetric and did not suggest the presence of publication bias.

CONCLUSIONS

The current study found a significant association between asthma and increased risk of SLE. Key Points • Studies have suggested an elevated risk of systemic lupus erythematosus among patients with asthma; however, the results from existing studies are inconsistent. • This meta-analysis included data from three cohort studies and seven case--control studies. • A significant association between asthma and elevated risk of systemic lupus erythematosus was observed, with the pooled odds ratio of 1.37 (95% CI 1.14-1.65; I² 67%).

Paradigm Shifts in Mast Cell and Basophil Biology and Function: An Emerging View of Immune Regulation in Health and Disease

The physiological role of the mast cell and basophil has for many years remained enigmatic. In this chapter, we briefly summarize some of the more recent studies that shed new light on the role of mast cells and basophils in health and disease. What we gain from these studies is a new appreciation for mast cells and basophils as sentinels in host defense and a further understanding that dysregulation of mast cell and basophil function can be a component of various diseases other than allergies. Perhaps the most important insight reaped from this work is the increasing awareness that mast cells and basophils can function as immunoregulatory cells that modulate the immune response in health and disease. Collectively, the recent knowledge provides new challenges and opportunities toward the development of novel therapeutic strategies to augment host protection and modify disease through manipulation of mast cell and basophil function.

Elevated interleukin-25 and its association to Th2 cytokines in systemic lupus erythematosus with lupus nephritis

Systemic lupus erythematosus (SLE) is an autoimmune disorder that is associated with lupus nephritis, initiated by the deposition of immune complexes in the kidney; subsequently, this induces the overexpression of cytokines. Lupus nephritis is known as one of the major clinical manifestations that affect the disease severity in SLE patients. An increased number of resident periglomerular and immune cells in the kidney has the potential to affect the equilibrium of different immune cell subsets, such as Th1, Th2, Th17, and Tregs, which may be central to the induction of tissue damage in kidney by exerting either proinflammatory or anti-inflammatory effects, or both. This equilibrium has yet to be confirmed, as new players such as IL-25 remain undiscovered. IL-25 is a cytokine of the IL-17 family, which stimulates Th2-mediated immune response when overly expressed. Thus, the aim of this research is to determine the plasma levels of IL-25 and Th2-associated cytokines (IL-4, IL-5, IL-6, IL-9, IL-10, IL-13) in SLE patients with (SLE-LN) and without lupus nephritis. Sixty-four (n = 64) SLE patients and fifteen (n = 15) healthy individuals were recruited. This study demonstrated that the IL-9, IL-10 and IL-25 had significantly increased expressions in SLE-LN, followed by SLE without LN, compared to healthy controls. Meanwhile, IL-5 and IL-6 had significantly reduced. No significant difference was observed with IL-13, while the level of IL-4 was undetectable. Furthermore, IL-9 and IL-10 were significantly correlated with the IL-25, and IL-25, IL-9 and IL-10 were positively correlated with the disease severity score, SLEDAI. In conclusion, IL-25 and its associated Th2 cytokines (IL-9 and IL-10) may be involved in SLE pathogenesis. These cytokines could be potential biomarkers in monitoring and predicting the disease severity during SLE pathogenesis.

Efficacy and Pharmacodynamic Modeling of the BTK Inhibitor Evobrutinib in Autoimmune Disease Models

Because of its role in mediating both B cell and Fc receptor signaling, Bruton's tyrosine kinase (BTK) is a promising target for the treatment of autoimmune diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Evobrutinib is a novel, highly selective, irreversible BTK inhibitor that potently inhibits BCR- and Fc receptor-mediated signaling and, thus, subsequent activation and function of human B cells and innate immune cells such as monocytes and basophils. We evaluated evobrutinib in preclinical models of RA and SLE and characterized the relationship between BTK occupancy and inhibition of disease activity. In mouse models of RA and SLE, orally administered evobrutinib displayed robust efficacy, as demonstrated by reduction of disease severity and histological damage. In the SLE model, evobrutinib inhibited B cell activation, reduced autoantibody production and plasma cell numbers, and normalized B and T cell subsets. In the RA model, efficacy was achieved despite failure to reduce autoantibodies. Pharmacokinetic/pharmacodynamic modeling showed that mean BTK occupancy in blood cells of 80% was linked to near-complete disease inhibition in both RA and SLE mouse models. In addition, evobrutinib inhibited mast cell activation in a passive cutaneous anaphylaxis model. Thus, evobrutinib achieves efficacy by acting both on B cells and innate immune cells. Taken together, our data show that evobrutinib is a promising molecule for the chronic treatment of B cell-driven autoimmune disorders.

Sera of patients with systemic lupus erythematosus cross-neutralizes dengue viruses

Dengue is the most prevalent mosquito-borne disease in Southeast Asia, where the incidence of systemic lupus erythematosus (SLE) is approximately 30 to 53 per 100,000. Severe dengue, however, is rarely reported among individuals with SLE. Here, whether sera of patients with SLE cross-neutralize dengue virus (DENV) was investigated. Serum samples were obtained from individuals with SLE who were dengue IgG and IgM serology negative. Neutralization assays were performed against the three major DENV serotypes. Of the dengue serology negative sera of individuals with SLE, 60%, 61% and 52% of the sera at 1/320 dilution showed more than 50% inhibition against dengue type-1 virus (DENV-1), DENV-2 and DENV-3, respectively. The neutralizing capacity of the sera was significantly greater against DENV-1 (P < 0.001) and DENV-3 (P < 0.01) than against DENV-2 (P < 0.05). Neutralization against the DENV correlated with dengue-specific IgG serum titers below the cut-off point for dengue positivity. Depletion of total IgG from the sera of patients with SLE resulted in significant decreases of up to 80% in DENV inhibition, suggesting that IgG plays an important role. However, some of the SLE sera was still able to neutralize DENV, even with IgG titers <0.1 OD absorbance. Our findings suggest that sera of patients with SLE contain IgG, and possibly other type of antibodies, that can cross-neutralize DENV, which may explain the rarity of severe dengue in individuals with SLE. Further studies, are needed to further substantiate this finding and to elucidate the specific neutralizing epitopes recognized by the sera of individuals with SLE.

Reduction in White Blood Cell, Neutrophil, and Red Blood Cell Counts Related to Sex, HLA, and Islet Autoantibodies in Swedish TEDDY Children at Increased Risk for Type 1 Diabetes

Islet autoantibodies (IAs) precede the clinical onset of type 1 diabetes (T1D); however, the knowledge is limited about whether the prodrome affects complete blood counts (CBCs) in 4- to 12-year-old children with increased genetic risk for T1D. This study tested whether CBCs were altered in 4- to 12-year-old children without (n = 376) or with one or several IAs against insulin, GAD65, or IA-2 (n = 72). CBC was analyzed during longitudinal follow-up in 448 Swedish children enrolled in The Environmental Determinants of Diabetes in the Young (TEDDY) study. A linear mixed-effects model was used to assess potential association between IA and CBC measurements over time. The white blood cell and neutrophil counts were reduced in children with IAs, primarily in boys. In contrast, girls had lower levels of hemoglobin and hematocrit. Positivity for multiple IAs showed the lowest counts in white blood cells and neutrophils in boys and red blood cells, hemoglobin, and hematocrit in girls. These associations were primarily observed in children with the HLA-DR3-DQ2/DR4-DQ8 genotype. We conclude that the reduction in neutrophils and red blood cells in children with multiple IAs and HLA-DR3-DQ2/DR4-DQ8 genotype may signal a sex-dependent islet autoimmunity detected in longitudinal CBCs.

IgE in lupus pathogenesis: Friends or foes?

Systemic lupus erythematosus (SLE) is a complex autoimmune disease involving multiple immunological pathways. Recently, several studies have suggested an implication of Immunoglobulin E (IgE) in the pathophysiology of SLE. In the Lyn^-/- and FcγIIB^-/-.Yaa lupus mouse models, autoreactive IgE activate basophils, and promote a Th2 environment with, subsequently, production of autoantibodies by plasma cells. Autoreactive IgE has been also shown to play a role in the activation of human plasmacytoid dendritic cells (pDCs), in synergy with IgG, which results in an increase of interferon-alpha (IFN-α) production. In contrast, a protective effect of total non-autoreactive IgE has also been suggested, through a decreased ability of FcεRI-triggered pDCs to secrete IFN-α. This review summarizes in a comprehensive manner the emerging recent literature in the field, and propose new concepts to reconcile the observations.

Low level of circulating basophil counts in biopsy-proven active lupus nephritis

Basophils have been shown to be important players in promoting lupus nephritis (LN). However, the relationship between circulating basophil counts and renal pathology activity of LN remains unclear. In this retrospective study, 159 clinical and pathology samples from patients with biopsy-proven LN were analyzed. The renal activity and classification were evaluated according to renal pathology. The correlations between circulating basophil counts and renal pathology activity index were assessed. Overall, circulating basophil counts correlated with total systemic lupus erythematosus disease activity index (SLEDAI) score (r = - 0.31), renal SLEDAI score (r = - 0.35), activity index (AI) score(r = - 0.40), and renal histologic activity parameters (p < 0.05, respectively). Compared with systemic lupus erythematosus (SLE) non-LN patients, the LN group had lower basophil counts (0.007 ± 0.007 vs. 0.011 ± 0.010 × 10⁹/L, p = 0.04). Subgroup analyses revealed that the circulating basophil counts in group B (AI > 8) were significantly lower than that in group A (AI ≤ 8) (0.004 ± 0.006 vs. 0.009 ± 0.009 × 10⁹/L, p < 0.001). The difference was still significant when eliminating the influence of SLEDAI. Significant differences were found in circulating basophil counts among LN pathology classification groups (p < 0.01). Groups of classes III, IV, and V were more likely to have lower circulating basophil counts when compared with group of class I/II (p < 0.05). These findings suggest a potential role of circulating basophil counts as a convenient and helpful marker for renal activity of LN.

Comparisons of neutrophil-, monocyte-, eosinophil-, and basophil- lymphocyte ratios among various systemic autoimmune rheumatic diseases

This study was aimed to evaluate levels of neutrophil- (NLR), monocyte- (MLR), eosinophil- (ELR), and basophil-lymphocyte ratio (BLR) and their association with inflammatory markers in systemic autoimmune rheumatic diseases (SARDs). A total of 1139 SARD patients and 170 healthy individuals were enrolled. Clinical and laboratory data were extracted. NLR and MLR were significantly increased, but BLR decreased in most SARD patients (p < 0.05). ELR were significantly decreased in systemic lupus erythematosus (SLE) patients, but increased in those with other SARDs (p < 0.001). In SLE patients, C-reactive protein (CRP) showed positive correlation with NLR, MLR, and BLR. IgG negatively correlated with NLR, and did positively with ELR. IgM negatively correlated with NLR and MLR. In those with rheumatoid arthritis (RA), ankylosing spondylitis (AS), and osteoarthritis (OA), NLR and MLR positively correlated with erythrocyte sedimentation rate (ESR) and CRP. In primary Sjögren's syndrome (pSS) patients, ESR showed positive correlation with NLR and MLR. IgA had positive correlation with BLR. In polymyositis/dermatomyositis (PM/DM) patients, ESR and CRP positively correlated with NLR. Additionally, significant correlations were also found between CRP and BLR, IgG and ELR, IgM and ELR. In systemic sclerosis (SSc) patients, clear correlations were only observed between CRP and NLR or MLR. In mixed connective tissue disease (MCTD) patients, NLR positively correlated with ESR and CRP, while NLR and MLR did negatively with IgM. In polymyalgia rheumatic (PMR) patients, MLR positively correlated with CRP, while ELR did negatively with IgG. This study demonstrated increased NLR and MLR and deceased BLR in most SARDs, decreased ELR in SLE and increased ELR in other SARDs. Furthermore, NLR and MLR may be useful tools to reflect inflammatory status of SARDs.

Balance between IL-3 and type Iinterferons and their interrelationship with FasL dictates lifespan and effector functions of human basophils

BACKGROUND

In contrast to eosinophils and neutrophils, the regulation of the lifespan of human basophils is poorly defined, with the exception of the potent anti-apoptotic effect of IL-3 that also promotes pro-inflammatory effector functions and phenotypic changes. Type I IFNs (IFN-α, IFN-β), which are well known for their anti-viral activities, have the capacity to inhibit allergic inflammation.

OBJECTIVE

To elucidate whether type I IFNs have the potential to abrogate the lifespan and/or effector functions of human basophils.

METHODS

We cultured human basophils, and for comparison, eosinophils and neutrophils, with IL-3, interferons, FasL and TRAIL, alone or in combination, and studied cell survival, effector functions and signalling pathways involved.

RESULTS

Despite an identical pattern of early signalling in basophils, eosinophils and neutrophils in response to different types of interferons, only basophils displayed enhanced apoptosis after type I IFN treatment. IFN-γ prolonged survival of eosinophils but did not affect the lifespan of basophils. IFN-α-mediated apoptosis required STAT1-STAT2 heterodimers and the contribution of constitutive p38 MAPK activity. Whereas the death ligands FasL and TRAIL-induced apoptosis in basophils per se, IFN-α-mediated apoptosis did neither involve autocrine TRAIL signalling nor did it sensitize basophils to FasL-induced apoptosis. However, IFN-α and FasL displayed an additive effect in killing basophils. Interestingly, IL-3, which protected basophils from IFN-α-, TRAIL- or FasL-mediated apoptosis, did not completely block the additive effect of combined IFN-α and FasL treatment. Moreover, we demonstrate that IFN-α suppressed IL-3-induced release of IL-8 and IL-13. In contrast to IFN-α-mediated apoptosis, these inhibitory effects of IFN-α were not dependent on p38 MAPK signalling.

CONCLUSIONS AND CLINICAL RELEVANCE

Our study defines the unique and granulocyte-type-specific inhibitory and pro-apoptotic function of type I IFNs and their cooperation with death ligands in human blood basophils, which may be relevant for the anti-allergic properties of type I IFNs.

Rabex-5 is a lenalidomide target molecule that negatively regulates TLR-induced type 1 IFN production

Immunomodulatory drugs (IMiDs) are a family of compounds derived from thalidomide. Binding of the IMiD molecule to the Lon protease Cereblon initiates the degradation of substrates via the ubiquitin proteasome pathway. Here, we show that Cereblon forms a complex with Rabex-5, a regulator of immune homeostasis. Treatment with lenalidomide prevented the association of Cereblon with Rabex-5. Conversely, mutation of the IMiD binding site increased Cereblon-Rabex-5 coimmunoprecipitation. The thalidomide binding region of Cereblon therefore regulates the formation of this complex. Knockdown of Rabex-5 in the THP-1 macrophage cell line up-regulated Toll-like receptor (TLR)-induced cytokine and type 1 IFN production via a STAT1/IRF activating pathway. Thus, we identify Rabex-5 as a IMiD target molecule that functions to restrain TLR activated auto-immune promoting pathways. We propose that release of Rabex-5 from complex with Cereblon enables the suppression of immune responses, contributing to the antiinflammatory properties of IMiDs.

Autoreactive IgE in Chronic Spontaneous/Idiopathic Urticaria and Basophil/Mastocyte Priming Phenomenon, as a Feature of Autoimmune Nature of the Syndrome

Recent years of research have shed a new light on the role of IgE in immune reactions. It seems to be more than just a contribution to immediate type of allergic response. It appears that monomeric IgE may enhance mast cell activity without cross-linking of FcεRI by IgE specific allergen or autoreactive IgG anti-IgE antibodies. Monomeric IgE molecules are heterogeneous concerning their ability to induce survival and activation of mast cells only by binding the IgE to FcεRI, but not affecting degranulation of cells. It also turned out that IgE may react to autoantigens occurring in the blood not only in chronic spontaneous urticaria (CSU) but also in other autoimmune diseases. The aforementioned phenomena may promote the activity of mast cells/basophils in CSU that easily degranulate when influenced by various inner (autoreactive IgG against IgE and FcεRI, autoreactive IgE for self-antigens) and outer factors (cold, heat, pressure) or allergens. These findings forced the new approach to the role of autoimmunity, self-antigens and IgE autoantibodies in the pathology of CSU. CSU put in the scheme of autoreactive IgG and autoreactive IgE seems to be either a kind of an autoimmune disease or a clinical manifestation of some other defined autoimmune diseases or both.

CTLA4Fcε, a novel soluble fusion protein that binds B7 molecules and the IgE receptors, and reduces human in vitro soluble CD23 production and lymphocyte proliferation

Immunoglobulin E-mediated allergy and certain autoimmune diseases are characterized by the presence of a T helper type 2 (Th2) immune response and allergen-specific or self-reactive IgE. Soluble CD23 (sCD23) is a B-cell factor that fosters IgE class-switching and synthesis, suggesting that sCD23 may be a therapeutic target for these pathologies. We produced a recombinant protein, CTLA4Fcε, by fusing the ectodomain of the immunoregulatory molecule cytotoxic T-lymphocyte antigen 4 (CTLA-4) with a fragment of the IgE H-chain constant region. In SDS-PAGE/inmunoblot analyses, CTLA4Fcε appeared as a 70,000 MW polypeptide that forms homodimers. Flow cytometry showed that CTLA4Fcε binds to IgE receptors FcεRI and FcεRII/CD23, as well as to CTLA-4 counter-receptors CD80 and CD86. Binding of CTLA4Fcε to FcεRII/CD23 appeared stronger than that of IgE. Since the cells used to study CD23 binding express CD80 and CD86, simultaneous binding of CTLA4Fcε to CD23 and CD80/CD86 seems to occur and would explain this difference. As measured by a human CD23-specific ELISA, CTLA4Fcε - but not IgE - induced a concentration-dependent reduction of sCD23 in culture supernatants of RPMI-8866 cells. Our results suggest that the simultaneous binding of CTLA4Fcɛ to CD23-CD80/CD86 may cause the formation of multi-molecular complexes that are either internalized or pose a steric hindrance to enzymatic proteolysis, so blocking sCD23 generation. CTLA4Fcε caused a concentration-dependent reduction of lymphocyte proliferation in human peripheral blood mononuclear cell samples stimulated in vitro with concanavalin A. The ability to bind IgE receptors on effector cells, to regulate the production of sCD23 and to inhibit lymphocyte proliferation suggests that CTLA4Fcɛ has immunomodulatory properties on human Th2 responses.

Association between allergic diseases and risks of HSP and HSP nephritis: a population-based study

BACKGROUND

Some allergic inflammation-associated mediators have been reported in acute stage of Henoch-Schönlein purpura (HSP). However, the association of children with allergic diseases and their subsequent risks of HSP and HSP nephritis remain unknown.

METHODS

In this study, we included 2,240 children with HSP diagnosed between 2000 and 2008 as well as 8,960 non-HSP controls matched for age, sex, and level of urbanization. The odds ratios (ORs) of HSP were calculated with respect to associations with pre-existing allergic diseases.

RESULTS

Children with allergic diseases had an increased subsequent risk of HSP; the lowest adjusted OR (aOR) was 1.33 for allergic conjunctivitis (95% confidence interval (CI): 1.17-1.52) and the highest was 1.68 for asthma (95% CI: 1.48-1.91). The aOR increased to 2.03 (95% CI: 1.80-2.31) in children with at least two allergic diseases. Children who visited medical institutes more often per year for associated allergic diseases had an increased risk of HSP. Of the 2,240 children with HSP, 249 (11%) had HSP nephritis and 45.8% of those with nephritis had history of any allergic disease.

CONCLUSION

Atopic children had an increased subsequent risk of HSP but not an increased risk of HSP nephritis.

A link: Allergic rhinitis, Asthma & Systemic Lupus Erythematosus

This review has discussed a link between allergic rhinitis, asthma and systemic lupus erythematosus (SLE) and a case report in this area. A clear link with symptoms of allergic rhinitis, asthma and SLE exists. Several articles found on pubmed in the literature are listed on allergic rhinitis and allergy, Th1-immune responses, mast cells in autoimmunity, total immunoglobulin E levels in lupus, atopic diseases and SLE are reviewed. In addition, risks and correlations, genetic predisposition, environmental factors, immune regulation, elevated serum IgE levels, regulatory B cells for both allergic and autoimmune diseases are mentioned, Asthma and the vascular endothelial cell growth factor, asthma and autoimmune diseases, allergy and autoimmunity, neutrophils, innate and adaptive immunity in the development of SLE, the (Tim) gene family, complement activation in SLE and immunomodulation, hypersensitivity reactions in autoimmunity are discussed.

Paradigm shifts in mast cell and basophil biology and function: an emerging view of immune regulation in health and disease

The physiological role of the mast cell and basophil has for many years remained enigmatic. In this chapter we briefly summarize some of the more recent studies that shed new light on the role of mast cells and basophils in health and disease. What we gain from these studies is a new appreciation for mast cells and basophils as sentinels in host defense and a further understanding that dysregulation of mast cell and basophil function can be a component of various diseases other than allergies. Perhaps, the most important insight reaped from this work is the increasing awareness that mast cells and basophils can function as immunoregulatory cells that modulate the immune response in health and disease. Collectively, the recent knowledge provides new challenges and opportunities towards the development of novel therapeutic strategies to augment host protection and modify disease through manipulation of mast cell and basophil function.

Basophil count, a marker for disease activity in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic multisystem autoimmune disease, with frequent flares amid remissions. Basophils contribute to the immunopathogenesis of SLE. This retrospective clinical study evaluated blood basophil count as a potential marker of SLE activity. This study included 213 patients with SLE, 70 with non-SLE chronic kidney disease (CKD), and 100 healthy volunteers. SLE disease activity was scored using the SLE Disease Activity Index (SLEDAI). Baseline and post-immunosuppressant bioparameters were compared in patients with active SLE, with second samples taken at total SLEDAI ≤4. Blood basophil counts and other conventional biomarkers were compared among the groups. Among the 213 SLE patients (192 women, 21 men; mean age 33.0 ± 12.0 years), 149 had active disease. Basophil counts were significantly lower in patients with SLE than in patients with non-SLE CKD and healthy controls (0.009 ± 0.010 vs. 0.025 ± 0.015 vs. 0.022 ± 0.010 × 10(9)/L, p <0.001), and lower in patients with active than inactive SLE (0.008 ± 0.009 vs. 0.014 ± 0.012 × 10(9)/L, p <0.001). Basophil counts in SLE patients were significantly higher after than before immunosuppressive treatment (0.021 ± 0.017 vs. 0.008 ± 0.008 × 10(9)/L, p <0.001) and correlated with total SLEDAI score (r = -0.30, p <0.001). Receiver operator curve analysis showed that basophil counts were similar to conventional markers (leukocytes, platelets, and double-stranded (ds) DNA IgG) in differentiating active from inactive SLE. These findings indicate that blood basophil counts may be a useful biomarker in evaluating SLE activity.

Immunoglobulin E plays an immunoregulatory role in lupus

The (patho)physiological role of IgE in nonallergic inflammatory diseases is not well understood. Here, we explored the effect of IgE deficiency on the inflammatory response in FcγRIIB-deficient mice as well as in mice carrying both a deletion of FcγRIIB and the chromosomal translocation of Y-linked autoimmune acceleration (Yaa) that hastens and results in a more aggressive lupuslike disease in these mice. The findings show that deficiency of IgE delays disease development and severity as demonstrated by reduced autoantibody production and amelioration of organ pathologies. This was associated with decreased numbers of plasma cells and reduced levels of IgG2b and IgG3. Unexpectedly, the loss of IgE also caused a striking decrease of immune cell infiltration in secondary lymphoid organs with a marked effect on the presence of dendritic cells, monocytes, neutrophils, and eosinophils in these organs and decreased activation of basophils. The presence of autoreactive IgE in human systemic lupus erythematosus subjects was also associated with increased basophil activation and enhanced disease activity. These findings argue that IgE facilitates the amplification of autoimmune inflammation.

Increased Incidence of juvenile onset systemic lupus erythematosus in children with atopic dermatitis

Herein, we investigated the risk of juvenile-onset systemic lupus erythematosus (JSLE) in children with atopic dermatitis (AD). From 2000 to 2007, 192,357 children with newly diagnosed AD and 769,428 matched non-AD controls were identified. By the end of 2008, incidences and hazard ratios (HRs) of JSLE were measured. JSLE incidence in the AD cohort was 2.90-fold greater than that in the non-AD cohort (3.25 vs. 1.12 per 100,000 person-years), with a Cox model-measured adjusted HR of 2.92 (95% CI: 1.85-4.60); the risk of JSLE was greater for older children and girls. The AD-to-non-AD cohort HR was 6.6 (95% CI: 2.88-13.1) for children aged >12 years compared with 1.81 (95% CI: 0.98-3.32) for children aged ≤ 12 years. The HR of JSLE in AD children increased from 1.55 (95% CI: 0.88-2.76) for those with ≤ 3 clinical visits to 66.3 (95% CI: 33.1-132.8) for those with >6 visits (p < 0.0001, by trend test). The risk of developing SLE in the AD cohort was the highest within five years after AD diagnosis (HR: 4.02; 95% CI: 2.83-7.08). Children with AD are at a high risk of developing JSLE during their growth period.

Increased incidence of juvenile-onset systemic lupus erythematosus among children with asthma

BACKGROUND

Children with systemic lupus erythematosus (SLE) have an especially aggressive disease course and poor outcomes. Previous studies demonstrated a possible association between SLE and allergies, but the relationship between these disorders remains unclear. This population-based cohort study aimed to investigate the incidence and risk of juvenile-onset SLE (JSLE) among children with asthma.

METHODS

From 2000 to 2003, 120,939 children with newly diagnosed asthma and 483,756 randomly selected non-asthma controls were enrolled. We used a multivariable Cox proportional hazard regression model to measure and compare the incidence rate and risk of JSLE in the asthma and non-asthma cohorts.

RESULTS

The overall incidence of JSLE was 2.52 times greater in the asthma cohort than that in the non-asthma cohort [3.49 vs. 1.53 per 100,000 person-years; 95% confidence interval (CI): 1.59-3.99]. The risk of JSLE was greatest among boys [hazard ratio (HR) 3.02, 95% CI: 1.21-7.52] and children aged 6-10 yr (HR 3.50, 95% CI: 1.75-7.02). The HR of JSLE increased with greater frequency of asthma-related medical visits from 1.22 (95% CI: 0.67-1.41) for those with ≤2 visits/yr to 5.88 (95% CI: 3.43-10.1) for subjects with >2 visits/yr (trend test p < 0.001). However, the risk of JSLE declined over time.

CONCLUSION

We found an increased incidence of JSLE among children with asthma. The mechanism of asthma on JSLE development should be elucidated to establish innovative disease intervention programs.

Autoreactive IgE is prevalent in systemic lupus erythematosus and is associated with increased disease activity and nephritis

The presence of autoantibodies in systemic lupus erythematosus, particularly those of the IgG subclass, have long been associated with disease onset and activity. Here we explored the prevalence of autoreactive IgE in SLE and its relevance to disease in French (n = 79) and United States (US) (n = 117) cohorts with a mean age of 41.5 ± 12.7 and 43.6 ± 15.3 years and disease duration of 13.5 ± 8.5 and 16.6 ± 11.9 years, respectively. Our findings show that approximately 65% of all SLE subjects studied produced IgE antibodies to the seven autoantigens tested. This positivity was increased to almost 83% when only those subjects with active disease were considered. SLE subjects who were positive for anti-dsDNA, -Sm, and -SSB/La -specific IgE showed a highly significant association in the levels of these antibodies with disease activity similar to that of the corresponding IgG's. A strong association of IgE autoantibodies with active nephritis was also found in the combined cohort analysis. A test of the predictive value of autoreactive IgE's and IgGs for disease activity (SLE Disease Activity Index (SLEDAI) ≥ 4) revealed that the best predictors were dsDNA-specific IgE and IgG, and that the age of an SLE subject influenced this predictive model. The finding argue that the overall levels of IgE autoantibodies, independently or in combination with IgG autoantibodies, may serve as indicators of active disease.

Spleen tyrosine kinase inhibitors: a review of the patent literature 2010 - 2013

INTRODUCTION

The non-receptor tyrosine kinase, spleen tyrosine kinase (Syk), is primarily expressed in haematopoietic cells and appears to be particularly important in B cells. Syk is involved in signal transduction processes and appears to regulate allergic, inflammatory and autoimmune responses. It also appears to play a significant role in the development of haematological malignancies. Inhibitors of Syk are potentially useful in treating asthma, rheumatoid arthritis, lupus, chronic lymphocytic leukaemia and lymphomas.

AREAS COVERED

This article reviews the increasing number of patent filings between 2010 and 2013 claiming Syk inhibitors and focuses on the multiple structural classes of Syk inhibitors disclosed. It also comments on recent developments with Syk inhibitors, both clinical results and licensing deals.

EXPERT OPINION

The increased interest in the identification of Syk inhibitors has seen a sharp increase in patent filings claiming such compounds. However, the number of these is well below that of filings relating to other pro-inflammatory kinases (p38, JAK). These filings have also claimed an increasingly diverse range of chemical classes moving away from the 2,4-diaminopyrimidine motif present in drugs such as fostamatinib and PRT-06207. Many of the claimed compounds are Syk inhibitors with potencies considerably better than fostamatinib. However, good kinase selectivity is also likely to be essential if a Syk inhibitor is to prove useful enough to emulate the JAK inhibitor tofacitinib in gaining marketing authorisation. Recent clinical failures with Syk inhibitors are expected to result in a decrease in the rate of patent filings claiming Syk inhibitors.

The deleterious role of basophils in systemic lupus erythematosus

Systemic lupus erythematosus is a complex autoimmune disease of multifactorial origins. All compartments of the immune system appear to be affected, at least in some way, and to contribute to disease pathogenesis. Because of an escape from negative selection autoreactive T and B cells accumulate in SLE patients leading to the production of autoantibodies mainly raised against nuclear components and their subsequent deposition into target organs. We recently showed that basophils, in an IgE and IL-4 dependent manner, contribute to SLE pathogenesis by amplifying autoantibody production. Here, we summarize what we have learned about the deleterious role of basophils in lupus both in a mouse model and in SLE patients. We discuss which possible pathways could be involved in basophil activation and recruitment to secondary lymphoid organs during SLE, and how basophils may amplify autoantibody production.