Immunoglobulin E and systemic lupus erythematosus

Soybean Agglutinin Alters the Gut Microbiota and Promotes Inflammation in Lupus-Prone MRL/lpr Mice

BACKGROUND

Certain foods can trigger flares in patients with systemic lupus erythematosus. Lectins in edible plants have been reported to increase inflammation.

OBJECTIVE

This study aimed to determine the effects of 1-time intake of soybean agglutinin (SBA) on the gut microbiota and immune response in lupus-prone MRL/MpJ (MRL)/lpr mice.

METHODS

MRL/MpJ-Faslpr/J (MRL/lpr) and MRL mice were randomly assigned into 4 groups (8 mice/group): MRL mice + phosphate-buffered saline (PBS) (CON), MRL mice + SBA (CS), MRL/lpr mice + PBS (LPR), and MRL/lpr + SBA (LS). PBS and SBA were orally administered at 16 wk of age, and all mice were killed 24 h after oral challenge. The disease phenotype, levels of proinflammatory cytokines, and composition of the intestinal microbiota were determined.

RESULTS

Interferon-gamma (IFN-γ) in the serum was significantly higher, whereas the level of serum IL-10 was significantly lower in LS mice than in LPR mice [fold change (FC) = 1.31 and FC = 0.36, respectively]. The expression levels of IL-6 and TNF-α in the spleen of LS mice were significantly higher than those in LPR mice (FC = 1.66 and FC = 1.96, respectively). The expression levels of IL-6, TNF-α, and IL-1β in the kidney were also significantly higher in LS mice than in LPR mice (FC = 2.89, FC = 3.78, and FC = 2.02, respectively). The relative abundances of Erysipelotrichaceae and Turicibacter in LS mice were significantly higher than those in LPR mice (FC = 1.73 and FC = 1.74, respectively). The percentage of Breg cells in the mesenteric lymph nodes was significantly lower in LS mice than in LPR mice (FC = 0.53) (P < 0.05). No change was found between SBA treatment or not in the control (MRL) mice.

CONCLUSIONS

One-time intake of SBA can promote the secretion of proinflammatory cytokines, downregulate Breg cells, and alter the intestinal flora in MRL/lpr mice within 24 h of oral challenge, which may contribute to exacerbation of lupus.

Anti-dsDNA IgE induces IL-4 production from basophils, potentially involved in B-cell differentiation in systemic lupus erythematosus

OBJECTIVES

Recently, the involvement of basophils and IgE-type autoantibodies in the pathogenesis of SLE has been elucidated using mouse models; however, few studies have been conducted in humans. In this study, the role of basophils and anti-double-stranded DNA (dsDNA) IgE in SLE was examined using human samples.

METHODS

The correlation between disease activity and serum levels of anti-dsDNA IgE in SLE was evaluated using enzyme-linked immunosorbent assay. Cytokines produced by IgE-stimulated basophils from healthy subjects were assessed using RNA sequences. The interaction of basophils and B cells to promote B cell differentiation was investigated using a co-culture system. The ability of basophils from patients with SLE with anti-dsDNA IgE to create cytokines that may be involved in B cell differentiation in response to dsDNA was examined using real-time PCR.

RESULTS

Anti-dsDNA IgE levels in the serum of patients with SLE correlated with disease activity. Healthy donor basophils produced IL-3, IL-4 and TGF-β1 after anti-IgE stimulation. Co-culture of B cells with anti-IgE-stimulated basophils increased plasmablasts which were cancelled by neutralizing IL-4. After encountering the antigen, basophils released IL-4 more quickly than follicular helper T cells. Basophils isolated from patients with anti-dsDNA IgE promoted IL-4 expression by adding dsDNA.

CONCLUSIONS

These results suggest that basophils contribute to the pathogenesis of SLE by promoting B cell differentiation via dsDNA-specific IgE in patients similar to the process described in mouse models.

Basophils beyond allergic and parasitic diseases

Basophils bind IgE via FcεRI-αβγ2, which they uniquely share only with mast cells. In doing so, they can rapidly release mediators that are hallmark of allergic disease. This fundamental similarity, along with some morphological features shared by the two cell types, has long brought into question the biological significance that basophils mediate beyond that of mast cells. Unlike mast cells, which mature and reside in tissues, basophils are released into circulation from the bone marrow (constituting 1% of leukocytes), only to infiltrate tissues under specific inflammatory conditions. Evidence is emerging that basophils mediate non-redundant roles in allergic disease and, unsuspectingly, are implicated in a variety of other pathologies [e.g., myocardial infarction, autoimmunity, chronic obstructive pulmonary disease, fibrosis, cancer, etc.]. Recent findings strengthen the notion that these cells mediate protection from parasitic infections, whereas related studies implicate basophils promoting wound healing. Central to these functions is the substantial evidence that human and mouse basophils are increasingly implicated as important sources of IL-4 and IL-13. Nonetheless, much remains unclear regarding the role of basophils in pathology vs. homeostasis. In this review, we discuss the dichotomous (protective and/or harmful) roles of basophils in a wide spectrum of non-allergic disorders.

Correlation between serum immunoglobulin levels and retinal structure in patients with newly diagnosed Vogt‑Koyanagi‑Harada disease

Immunoglobulins serve immunomodulatory roles in numerous autoimmune diseases. The aim of the present study was to investigate the correlations between serum Ig levels and retinal structural parameters in patients with newly diagnosed acute Vogt‑Koyanagi‑Harada (VKH) disease. A total of 138 participants were enrolled and the foveal thickness (FT), serous retinal detachment (SRD), sensory retinal thickness, central FT (CFT), cube volume (V) and cube average thickness (AT) were assessed by optical coherence tomography. The patients were divided, according to the extent of SRD, into a high‑detachment group (>500 µm) and a low‑detachment group (≤500 µm). Rate‑scattering turbidimetry was performed to measure the Ig levels. The high‑detachment group comprised 51 (36.96%) patients. The proportion of males was significantly greater in the high‑detachment group compared with the low‑detachment group (58.82 vs. 40.23%; P<0.05) and best‑corrected visual acuity was significantly worse in the high‑detachment group compared with the low‑detachment group (P<0.001). The IgE levels in the high‑detachment group were significantly greater compared with the low‑detachment group (P<0.05). FT, SRD, CFT, V and AT were significantly greater in the high‑detachment group compared with the low‑detachment group (P<0.001). The IgE levels were positively associated with SRD, CFT and AT (P<0.05). Multivariate binary logistic regression analysis demonstrated that male sex (B=2.447; P<0.05) and serum IgE levels (B=0.997, P<0.05) may be independent risk factors for severe SRD. The results of the present study demonstrated that males are more likely to develop severe SRD and that serum IgE levels were associated with the extent of detachment. These data suggested that IgE may be involved in the progression of VKH disease.

Elevated Serum Immunoglobulin E Levels are Associated with the Severity of Newly Diagnosed, Acute Vogt-Koyanagi-Harada Disease

OBJECTIVE

To investigate the correlation between serum immunoglobulin E (IgE) levels and severity of Vogt-Koyanagi-Harada (VKH) disease.

METHODS

The medical records of patients with VKH disease between 2015 and 2020 were reviewed. Serum immunoglobulins (IgA, IgE, IgG, and IgM), tumor necrosis factor α (TNFα) and C-reactive protein (CRP) were measured. Patients were divided into IgE-positive (IgE ≥ 100 IU/mL) and IgE-negative (IgE < 100 IU/mL) groups. The best-corrected visual acuity (BCVA) and macular morphologic characteristics including foveal thickness (FT), serous retinal detachment (SRD), sensory retinal thickness (SRT), central foveal thickness (CFT), cube volume (V), and cube average thickness (AT) were determined in patients in both groups.

RESULTS

Of 128 patients included in the study, 35 (27.34%) patients were IgE-positive, BCVA (logMAR) was worse in the IgE-positive group. The mean CRP (P= .012) and TNFα (P≤ 0.001) levels were greater in the IgE-positive group than in the IgE-negative group. Regarding macular morphologic characteristics, FT (P= .010), SDR (P= .004), CFT (P= .008), V (P= .013), and AT (P= .006) were significantly greater in the IgE-positive group than in the IgE-negative group.

CONCLUSIONS

Elevated serum IgE levels were associated with more severe macular changes in patients with VKH disease. These findings suggest that IgE may be involved in the progression of VKH disease.

IgE in the Pathogenesis of SLE: From Pathogenic Role to Therapeutic Target

Systemic lupus erythematosus (SLE) is a multifactorial chronic autoimmune disease, marked by the presence of autoantibodies to nuclear antigens belonging to different isotype classes. For several years, IgE antibodies have been incriminated in the development of allergic diseases and parasitic infections and different anti-IgE therapies have been developed to encounter the pathogenic role of IgE in these pathologies. Recently, multiple studies showed the presence of elevated total IgE levels and demonstrated a pathogenic role of autoreactive IgE in SLE. This review aims to summarize the findings incriminating IgE and autoreactive IgE in the pathophysiology of SLE, to describe their functional outcomes on their targeted cells as well as to discuss different IgE-related therapeutic modalities that emerged and that may be beneficial for SLE patient care.

IgE-Mediated Immune Response and Antibody-Mediated Rejection

BACKGROUND AND OBJECTIVES

Active antibody-mediated rejection is the main cause of kidney transplant loss, sharing with SLE the alloimmune response and the systemic activation of the IFN-α pathway. IgE-mediated immune response plays a key role in the development of SLE nephritis and is associated with IFN-α secretion. The aim of our study was to investigate IgE-mediated immune response in antibody-mediated rejection.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a cross-sectional study of 56 biopsy-proven antibody-mediated rejection study participants, 80 recipients with normal graft function/histology (control), 16 study participants with interstitial fibrosis/tubular atrophy, and six participants with SLE. We evaluated graft IgE deposition, tryptase (a mast cell marker), and CD203 (a specific marker of activated basophils) by immunofluorescence/confocal microscopy. In addition, we measured serum concentration of human myxovirus resistance protein 1, an IFN-α-induced protein, and anti-HLA IgE.

RESULTS

We observed a significantly higher IgE deposition in tubules and glomeruli in antibody-mediated rejection (1766±79 pixels) and SLE (1495±43 pixels) compared with interstitial fibrosis/tubular atrophy (582±122 pixels) and control (253±50 pixels). Patients with antibody-mediated rejection, but not control patients and patients with interstitial fibrosis/tubular atrophy, presented circulating anti-HLA IgE antibodies, although with a low mean fluorescence intensity. In addition, immunofluorescence revealed the presence of both mast cells and activated basophils in antibody-mediated rejection but not in control and interstitial fibrosis/tubular atrophy. The concentration of circulating basophils was significantly higher in antibody-mediated rejection compared with control and interstitial fibrosis/tubular atrophy. MxA serum levels were significantly higher in antibody-mediated rejection compared with control and correlated with the extent of IgE deposition.

CONCLUSIONS

Our data suggest that IgE deposition and the subsequent recruitment of basophils and mast cells within the kidney transplant might play a role in antibody-mediated rejection.

Total Serum Immunoglobulin E Levels in Patients with Psoriasis

Introduction

Psoriasis is a common chronic skin disorder characterized by inflammation and abnormal epidermal proliferation. Its severity ranges from a chronic plaque psoriasis (CPP) to generalized psoriatic erythroderma (PE). The cause of psoriasis is unknown although most evidence supports the hypothesis that psoriasis is an immunologically mediated disease. The T-helper (Th) 1 and Th17 cells are responsible for the inflammation of psoriasis. Immunoglobulin E (IgE) is a class of immunoglobulin essential for the allergic response. There is some evidence that IgE may take a part in the pathogenesis of psoriasis.

Aim

The aim of the study was to compare serum levels of total IgE between patients with psoriasis and healthy subjects, and to assess the difference between localized form (CPP) and extensive form of disease (PE).

Methods

Seventy-five patients with psoriasis and 30 healthy subjects were enrolled in this study. Data on age, gender, personal and family history, clinical type and duration of disease were collected and analyzed. Serum levels of IgE were measured using nephelometric method.

Results

Serum levels of total IgE were significantly higher in patients than in controls (46.7% vs.. 10%; p<0.05). Statistical difference of IgE concentration was also observed between CPP and PE. Comparison between patients and controls with regard to the median of the serum level of total IgE levels showed a statistically highly significant elevation in patients (425 IU/ml) compared with controls (54.5 IU/ml) (p<0,05). A higher total IgE concentration was observed in the group of patients with a longer period of skin changes. No relation was found between the serum level of IgE and family history of psoriasis, age or sex (p>0.05).

Conclusions

This study supports the evidence that elevation of total serum IgE is associated with psoriasis. The exact role of serum IgE in psoriasis should be additionally investigated in future studies.

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.

Antinuclear antibodies in autoimmune and allergic diseases

Antinuclear antibodies (ANA) are primarily significant in the diagnosis of systemic connective tissue diseases. The relationship between their occurrence in allergic diseases is poorly documented. However, the mechanism of allergic and autoimmune diseases has a common thread. In both cases, an increased production of IgE antibodies and presence of ANA in selected disease entities is observed. Equally important is the activation of basophils secreting proinflammatory factors and affecting the differentiation of TH17 lymphocytes. Both autoimmune and allergic diseases have complex multi-pathogenesis and often occur in genetically predisposed individuals. The presence of antinuclear antibodies was confirmed in many systemic connective tissue diseases and some allergic diseases. Examples include atopic dermatitis, non-allergic asthma, and pollen allergy. Co-occurring allergic and autoimmune disorders induce further search for mechanisms involved in the aetiopathogenesis of both groups of diseases.

Pathogenic mechanisms of IgE-mediated inflammation in self-destructive autoimmune responses

Autoantibodies of the IgG subclass are pathogenic in a number of autoimmune disorders such as systemic lupus erythomatosus. The presence of circulating IgE autoantibodies in autoimmune patients has also been known for almost 40 years. Despite their role in allergies, IgE autoantibodies are not associated with a higher rate of atopy in these patients. However, recently they have been recognized as active drivers of autoimmunity through mechanisms involving the secretion of Type I interferons by plasmacytoid dendritic cells (pDC), the recruitment of basophils to lymph nodes, and the activation of adaptive immune responses through B and T cells. Here, we will review the formation, prevalence, affinity, and roles of the IgE autoantibodies that have been described in autoimmunity. We also present novel evidence supporting that triggering of IgE receptors in pDC induces LC3-associated phagocytosis, a cellular process also known as LAP that is associated with interferon responses. The activation of pDC with immune complexes formed by DNA-specific IgE antibodies also induce potent B-cell differentiation and plasma cell formation, which further define IgE's role in autoimmune humoral responses.

Atopy in children with juvenile systemic lupus erythematosus is associated with severe disease

The influence of co-existing atopy on the prognosis of juvenile systemic lupus erythematosus (JSLE) was assessed in this study. Patients diagnosed with JSLE between October 2005 and April 2016 were enrolled in a prospective study and followed up for 2 years. Management of patients was evaluated using the systemic lupus erythematosus disease activity index 2000 (SLEDAI-2K) score and laboratory variables. Eighty JSLE patients were enrolled at diagnosis and divided into those with (n = 35) and without (n = 45) atopy. When compared with the non-atopic group, atopic patients showed higher SLEDAI-2K score at disease onset (16.09 vs. 11.18), higher erythrocyte sedimentation rate (52.89 vs. 38.27 mm/h), higher percentage of total B-cells (25.85 vs. 19.51%), lower percentage (7.26 vs. 9.03%) and cytotoxicity (9.92 vs. 11.32%) of natural killer cells, and lower complement C3 (0.51 vs. 0.69 g/L) (all p<0.05). At 1, 3, 6, 12, 18, and 24 months, JSLE patients with atopy reached higher SLEDAI-2K score and lower ΔSLEDAI-2K improvement rate (at 1 month, 8.34 vs. 4.71 and 43.63 vs. 57.95%, respectively; at 3 months, 8.57 vs. 2.62 and 48.39 vs. 75.10%, respectively; at 6 months, 6.91 vs. 2.38 and 53.59 vs. 77.26%, respectively; at 12 months, 4.71 vs. 1.80 and 69.54 vs. 84.10%, respectively; at 18 months, 4.66 vs. 2.02 and 68.14 vs. 82.93%, respectively; at 24 months, 8.57 vs. 2.62 and 70.00 vs. 81.88%, respectively; all p<0.05). During the 24 months of follow-up, the total number of disease flares was higher in JSLE patients with co-existing atopy (3.77 vs. 1.51, p<0.05), and the atopic group needed much more time to reach the stable condition of the disease (6.88 vs. 4.65 months, p<0.05). JSLE patients combined with co-existing atopy had more severe disease at diagnosis and poorer outcomes than JSLE patients without atopy.

IL-1β and IL-6 Are Highly Expressed in RF+IgE+ Systemic Lupus Erythematous Subtype

Background. Systemic lupus erythematosus (SLE) is an autoimmune disease with great heterogeneity in pathogenesis and clinical symptoms. Rheumatoid factor (RF) is one key indicator for rheumatoid arthritis (RA) while immunoglobulin E (IgE) is associated with type I hypersensitivity. To better categorize SLE subtypes, we determined the dominant cytokines based on familial SLE patients. Methods. RF, IgE, and multiple cytokines (i.e., IL-1β, IL-6, IL-8, IL-10, IL-17, IFN-γ, IP-10, MCP-1, and MIP-1β) were measured in sera of familial SLE patients (n = 3), noninherited SLE patients (n = 108), and healthy controls (n = 80). Results. Three familial SLE patients and 5 noninherited SLE cases are with features of RF+IgE+. These RF+IgE+ SLE patients expressed significantly higher levels of IL-1β and IL-6 than the other SLE patients (P < 0.05). IL-6 correlated with both IgE and IL-1β levels in RF+IgE+ SLE patients (r² = 0.583, P = 0.027; r² = 0.847, P = 0.001), and IgE also correlated with IL-1β (r² = 0.567, P = 0.031). Conclusion. Both IL-1β and IL-6 are highly expressed cytokines in RF+IgE+ SLE subtype which may be related to the pathogenesis of this special SLE subtype and provide accurate treatment strategy by neutralizing IL-1β and IL-6.

Comorbidity and pathogenic links of chronic spontaneous urticaria and systemic lupus erythematosus--a systematic review

Chronic spontaneous urticaria (CSU) is a common mast cell-driven disease characterized by the development of wheals (hives), angioedema (AE), or both for > 6 weeks. It is thought that autoimmunity is a common cause of CSU, which is often associated with autoimmune thyroiditis, whereas the link to other autoimmune disorders such as systemic lupus erythematosus (SLE) has not been carefully explored. Here, we systematically reviewed the existing literature for information on the prevalence of CSU in SLE (and vice versa) and we examined the possible clinical and pathogenetic relationship between CSU and SLE. The prevalence of CSU and CSU-like rash in SLE was investigated by 42 independent studies and comorbidity in adult patients reportedly ranged from 0% to 21.9% and 0.4% to 27.5%, respectively (urticarial vasculitis: 0-20%). In children with SLE, CSU was reported in 0-1.2% and CSU-like rash in 4.5-12% (urticarial vasculitis: 0-2.2%). In contrast, little information is available on the prevalence of SLE in patients with CSU, and more studies are needed to determine the rate of comorbidity. Recent insights on IgG- and IgE-mediated autoreactivity suggest similarities in the pathogenesis of CSU and SLE linking inflammation and autoimmunity with the activation of the complement and coagulation system. Future studies of patients with either or both conditions could help to better define common pathomechanisms in CSU and SLE and to develop novel targeted treatment options for patients with CSU and SLE.

Role of IgE in autoimmunity

There is accumulating evidence to suggest that IgE plays a significant role in autoimmunity. The presence of circulating self-reactive IgE in patients with autoimmune disorders has been long known but, at the same time, largely understudied. However, studies have shown that the increased IgE concentration is not associated with higher prevalence for atopy and allergy in patients with autoimmune diseases, such as systemic lupus erythematosus. IgE-mediated mechanisms are conventionally known to facilitate degranulation of mast cells and basophils and promote TH2 immunity, mechanisms that are not only central to mounting an appropriate defense against parasitic worms, noxious substances, toxins, venoms, and environmental irritants but that also trigger exuberant allergic reactions in patients with allergies. More recently, IgE autoantibodies have been recognized to participate in the self-inflicted damaging immune responses that characterize autoimmunity. Such autoimmune responses include direct damage on tissue-containing autoantigens, activation and migration of basophils to lymph nodes, and, as observed most recently, induction of type 1 interferon responses from plasmacytoid dendritic cells. The importance of IgE as a central pathogenic mechanism in autoimmunity has now been clinically validated by the approval of omalizumab, an anti-IgE mAb, for patients with chronic spontaneous urticaria and for the clinical benefit of patients with bullous pemphigoid. In this review we summarize recent reports describing the prevalence of self-reactive IgE and discuss novel findings that incriminate IgE as central in the pathogenesis of inflammatory autoimmune disorders.

Rethinking the role of immunoglobulin E and its high-affinity receptor: new insights into allergy and beyond

Immunoglobulin E (IgE) and its high-affinity receptor (FcεRI) are well-known participants in the allergic response. The interaction of allergens with FcεRI-bound IgE antibodies is an essential step in mast cell/basophil activation and the subsequent release of allergic mediators. It is known that the affinity of the interaction between an IgE antibody and an allergen may differ, raising the question of whether FcεRI can decipher these differences. If so, do the cellular and physiological outcomes vary? Are the molecular mechanisms initiated by FcεRI similarly under low- or high-affinity interactions? Could the resulting inflammatory response differ? Recent discoveries summarized herein are beginning to shed new light on these important questions. What we have learned from them is that IgE and FcεRI form a complex regulatory network influencing the inflammatory response in allergy and beyond.

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.

Comparative proteomics of inhaled silver nanoparticles in healthy and allergen provoked mice

Background

Silver nanoparticles (AgNPs) have been associated with the exacerbation of asthma; however, the immunological basis for the adjuvant effects of AgNPs is not well understood.

Objective

The aim of the study reported here was to investigate the allergic effects of AgNP inhalation using proteomic approaches.

Methods

Allergen provoked mice were exposed to 33 nm AgNPs at 3.3 mg/m³. Following this, bronchoalveolar lavage fluid (BALF) and plasma were collected to determine protein profiles.

Results

In total, 106 and 79 AgNP-unique proteins were identified in the BALF of control and allergic mice, respectively. Additionally, 40 and 26 AgNP-unique proteins were found in the plasma of control and allergic mice, respectively. The BALF and plasma protein profiles suggested that metabolic, cellular, and immune system processes were associated with pulmonary exposure to AgNPs. In addition, we observed 18 proteins associated with systemic lupus erythematosus that were commonly expressed in both control and allergic mice after AgNP exposure. Significant allergy responses were observed after AgNP exposure in control and allergic mice, as determined by ovalbumin-specific immunoglobulin E.

Conclusion

Inhaled AgNPs may regulate immune responses in the lungs of both control and allergic mice. Our results suggest that immunology is a vital response to AgNPs.

Increased IgE serum levels are unrelated to allergic and parasitic diseases in patients with juvenile systemic lupus erythematosus

OBJECTIVE

The aim of this study was to assess the IgE serum levels in juvenile systemic lupus erythematosus patients and to evaluate possible associations with clinical and laboratory features, disease activity and tissue damage.

METHODS

The IgE serum concentrations in 69 consecutive juvenile systemic lupus erythematosus patients were determined by nephelometry. IgG, IgM and IgA concentrations were measured by immunoturbidimetry. All patients were negative for intestinal parasites. Statistical analysis methods included the Mann-Whitney, chi-square and Fisher's exact tests, as well as the Spearman rank correlation coefficient.

RESULTS

Increased IgE concentrations above 100 IU/mL were observed in 31/69 (45%) juvenile systemic lupus erythematosus patients. The mean IgE concentration was 442.0 ± 163.4 IU/ml (range 3.5-9936.0 IU/ml). Fifteen of the 69 patients had atopic disease, nine patients had severe sepsis and 56 patients presented with nephritis. The mean IgE level in 54 juvenile systemic lupus erythematosus patients without atopic manifestations was 271.6 ± 699.5 IU/ml, and only nine of the 31 (29%) patients with high IgE levels had atopic disease. The IgE levels did not statistically differ with respect to the presence of atopic disease, severe sepsis, nephritis, disease activity, or tissue damage. Interestingly, IgE concentrations were inversely correlated with C4 levels (r = -0.25, p = 0.03) and with the SLICC/ACR-DI score (r = -0.34, p = 0.005). The IgE concentration was also found to be directly correlated with IgA levels (r = 0.52, p = 0.03).

CONCLUSIONS

The present study demonstrated for the first time that juvenile systemic lupus erythematosus patients have increased IgE serum levels. This increase in IgE levels was not related to allergic or parasitic diseases. Our results are in line with the hypothesis that high IgE levels can be considered a marker of immune dysregulation.

Basophils and autoreactive IgE in the pathogenesis of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a heterogeneous disease that can affect multiple organs. A hallmark of this disease, as is the case for other autoimmune diseases, is the presence of large numbers of autoantibodies. As such, SLE is considered to be a B-cell disease perpetuated by the expansion of autoreactive T and B cells. The T cells involved have long been considered to be T-helper type 1 (Th1) and Th17 cells, as these potent proinflammatory cells can be found in the tissues of SLE patients. Recent advances point to a role for the Th2 environment in contributing to SLE through promotion of autoantibody production. Here we describe the recent work focusing on autoreactive IgE and the activation of basophils as promoting the production of autoantibodies in SLE. The findings, both in a murine model of SLE and in humans with SLE, support the concept that the activation of the basophil by autoreactive IgE-containing immune complexes serves to amplify the production of autoantibodies and contributes to the pathogenesis of disease. We propose that therapeutic targeting of this amplification loop by reducing the levels of circulating autoreactive IgE may have benefit in SLE.

Basophils, IgE, and autoantibody-mediated kidney disease

Basophils are of interest in immunology due to their ability to produce a Th2-signature cytokine, IL-4, following activation. A new understanding of the role of basophils in immunity shows novel functions at a cellular level through which basophils influence adaptive immunity. This review summarizes new advances in basophil biology and discusses new roles for basophils in human disease, especially in the mediation of the pathogenesis of lupus nephritis. Recently, basophils have been shown to contribute to self-reactive Ab production in systemic lupus erythematosus and may enhance pre-existing loss of B cell tolerance, suggesting that basophils, IL-4, and IgE mediate the pathogenesis of lupus nephritis by promoting the Th2 environment and activating autoreactive B cells. In addition to envisaging exciting therapeutic prospects, these novel findings open the way for the study of basophils in other autoimmune and renal diseases.

Glutamate signaling through the kainate receptor enhances human immunoglobulin production

CD23 is implicated as a regulator of IgE synthesis. A soluble form of CD23 (sCD23) is released following cleavage by ADAM10 and enhanced sCD23 is correlated with increased IgE. In the CNS, signaling through the kainate receptor (KAR) increases ADAM10. In B cells, activation of KARs produced a significant increase in ADAM10 and sCD23 release as well as an increase in B cell proliferation and immunoglobulin production. In addition, ADAM10 inhibitors reduce IgE synthesis from in vitro cultures of human B cells. Thus, we report for the first time the unique presence of the kainate receptor in B cells and that activation of KARs could serve as a novel mechanism for enhancing B cell activation.

Total serum IgE levels in systemic lupus erythematosus and associations with childhood onset allergies

Elevated serum IgE has been described in systemic lupus erythematosus (SLE), but associations with disease risk and characteristics remain unresolved. We assessed total serum IgE levels and atopy (IgE > 100 IU/ml) in recently diagnosed SLE patients (n = 228) compared with population controls (n = 293) and in relation to disease activity, autoantibodies, clinical features, total immunoglobulins, C-reactive protein, and allergy history. Multivariate models estimated determinants of IgE and atopy in patients and controls, and associations of SLE with allergy and atopy. Total IgE levels were higher in patients than controls (median = 42 vs. 29 IU/ml); 32% of patients and 25% of controls were atopic (p = 0.06). IgE levels were significantly higher in non-Whites and patients reporting childhood onset (<18 years) asthma and hives, and in controls reporting childhood asthma, hay fever, eczema, and adult onset hives. After accounting for racial differences, atopy was not associated with SLE, nephritis, or other clinical and laboratory parameters. In sum, our findings provide limited evidence of a direct association between total serum IgE and SLE overall or with other disease characteristics after adjusting for demographic characteristics and allergy history. Future studies may want to explore potentially shared risk factors for development of allergy, atopy, and SLE.

Basophils and the T helper 2 environment can promote the development of lupus nephritis

In systemic lupus erythematosus (SLE), self-reactive antibodies can target the kidney (lupus nephritis), leading to functional failure and possible mortality. We report that activation of basophils by autoreactive IgE causes their homing to lymph nodes, promoting T helper type 2 (T(H)2) cell differentiation and enhancing the production of self-reactive antibodies that cause lupus-like nephritis in mice lacking the Src family protein tyrosine kinase Lyn (Lyn(-/-) mice). Individuals with SLE also have elevated serum IgE, self-reactive IgEs and activated basophils that express CD62 ligand (CD62L) and the major histocompatibility complex (MHC) class II molecule human leukocyte antigen-DR (HLA-DR), parameters that are associated with increased disease activity and active lupus nephritis. Basophils were also present in the lymph nodes and spleen of subjects with SLE. Thus, in Lyn(-/-) mice, basophils and IgE autoantibodies amplify autoantibody production that leads to lupus nephritis, and in individuals with SLE IgE autoantibodies and activated basophils are factors associated with disease activity and nephritis.

Anti-dsDNA antibodies in Brazilian patients of mainly African descent with systemic lupus erythematosus: lack of association with lupus nephritis

Renal disease is associated with morbidity and mortality in systemic lupus erythematosus (SLE) and anti-dsDNA antibodies with SLE immunopathogenesis. We investigated the dsDNA antibody profile of 84 Brazilian SLE patients, 27 with lupus nephritis. Thirty-six (39.1%) patients had dsDNA IgG antibodies shown in enzyme-linked immunosorbent assay (454.7 +/- 281.1 WHO units/mL), nine presenting renal disease. The following profile of dsDNA antibodies was demonstrated in Crithidia luciliae test: IgA (seven out of 36; 19.4%), IgG (22 out of 36, 66.1%); IgM (nine out of 36, 25.0%), and IgE (four out of 36, 11.1%). Two or three isotypes of dsDNA antibodies were observed in nine (25.0%) patients, while 11 (30.5%) were seronegative in the C. luciliae test. Patients with dsDNA antibodies had lower serum C3 and C4 when compared with SLE individuals without these immunoglobulins (P < 0.01 and P < 0.001, respectively). There was no association between any dsDNA antibody isotype and lupus kidney disease nor was anti-dsDNA IgM antibody associated with absence of nephritis.

Allergy and autoimmunity: parallels and dissimilarity: the yin and yang of immunopathology

The etiopathogenesis of allergy and autoimmune diseases is caused by genetic and acquired (environmental) factors, which might be common to both immunopathologies. Genetic factors play an important role in the development and process of immunopathological diseases. Several studies suggest a close relation between gene polymorphism of HLA and cytokines and development of autoimmunity and allergy. Certain gene polymorphisms act as risk or as protective factors. The infection also plays an important role in the induction of allergy and autoimmunity--as a trigger or as a protective factor. Moreover, similar clinical manifestations of both immunopathologies could result in diagnostic problems. This review summarizes the linkage of mechanisms of etiopathogenesis, clinical manifestations and therapeutic strategy between allergic and autoimmune diseases.

Treatment with rituximab affects both the cellular and the humoral arm of the immune system in patients with SLE

Herein we investigated how rituximab-induced B cell depletion affected leukocyte subpopulations and antibody titers in SLE patients. We focused our analysis on time points related to absence and return of B cells after depletion. A correlation was found between the baseline frequency and time to repopulation; the fewer B cells initially, the longer to their return. While the few B cells remaining after treatment were of memory, double-negative (IgD-CD27-), and CD5+ phenotype, the returning B cells were mainly naïve, indicating de novo production of B cells. Serum levels of IgG and antibodies against Ro52, Ro60, La44, measles and tetanus remained unchanged, while decreases in IgM, IgE, anti-dsDNA and anti-C1q antibodies were observed. Additionally, a significant increase in activated CD4+ and CD8+ T cells, as well as CD25bright FOXP3+ regulatory T cells was observed. In conclusion, both the humoral and the cellular immune systems were affected by treatment with rituximab.

The Th2 lymphoproliferation developing in LatY136F mutant mice triggers polyclonal B cell activation and systemic autoimmunity

Lat(Y136F) knock-in mice harbor a point mutation in Tyr(136) of the linker for activation of T cells and show accumulation of Th2 effector cells and IgG1 and IgE hypergammaglobulinemia. B cell activation is not a direct effect of the mutation on B cells since in the absence of T cells, mutant B cells do not show an activated phenotype. After adoptive transfer of linker for activation of T cell mutant T cells into wild-type, T cell-deficient recipients, recipient B cells become activated. We show in vivo and in vitro that the Lat(Y136F) mutation promotes T cell-dependent B cell activation leading to germinal center, memory, and plasma cell formation even in an MHC class II-independent manner. All the plasma and memory B cell populations found in physiological T cell-dependent B cell responses are found. Characterization of the abundant plasmablasts found in secondary lymphoid organs of Lat(Y136F) mice revealed the presence of a previously uncharacterized CD93-expressing subpopulation, whose presence was confirmed in wild-type mice after immunization. In Lat(Y136F) mice, B cell activation was polyclonal and not Ag-driven because the increase in serum IgG1 and IgE concentrations involved Abs and autoantibodies with different specificities equally. Although the noncomplement-fixing IgG1 and IgE are the only isotypes significantly increased in Lat(Y136F) serum, we observed early-onset systemic autoimmunity with nephritis showing IgE autoantibody deposits and severe proteinuria. These results show that Th2 cells developing in Lat(Y136F) mice can trigger polyclonal B cell activation and thereby lead to systemic autoimmune disease.

Sympathetic nervous system plays an important role in the relationship between immune mediated diseases

T helper (Th) lymphocytes have been classified into distinct subsets, Th1 and Th2 on the basis of the cytokines they produce. According to the cross-regulatory properties of Th1 and Th2 cells, one would assume that to be affected by a Th1 type disease increases susceptibility to a Th1 type disease and inhibits a Th2 type disease and vice versa about being affected by a Th2 type disease. However, the pattern of related diseases does not necessarily follow the conventional pattern of inhibitory effects of Th1 and Th2 immune responses on each other. For example, Mycobacteria including BCG, that induce Th1 immune responses; can modulate some Th1 type autoimmune diseases including MS, experimental autoimmune encephalomyelitis (EAE; an animal model for Multiple Sclerosis) and insulin-dependent diabetes mellitus (IDDM) thereby leading to an alleviation of their symptoms. Also BCG precipitates a syndrome similar to systemic lupus erythematosus (SLE), a Th2 type disease; in NOD mice. The coexistence of the major Th2-mediated atopic diseases such as asthma, eczema and allergic rhinitis with the Th1-mediated autoimmune conditions including; coeliac disease (CD), IDDM, rheumatoid arthritis (RA) and psoriasis is another example that is in apparent disagreement with counter-regulatory effects of Th1/Th2 phenotypes.

HYPOTHESIS

SNS can be stimulated by pro-inflammatory cytokines, production of which is induced by mycobacteria including BCG. Although these cytokines can inhibit SNS activity in the site of inflammation and secondary lymphoid organs, they increase sympathetic tone in other places. Increased sympathetic tone can induce an anti-inflammatory and Th2 type milieu. This milieu can inhibit MS and IDDM and provide a susceptible environment for starting of SLE. Atopic diseases are Th2 type immune mediated diseases; therefore, they increase the production of Th2 type cytokine and decrease production of pro-inflammatory cytokines in the site of allergic reaction and also in secondary lymphoid organs. Therefore, atopic diseases decrease sympathetic tone in all tissues except in the sites of allergic reaction and secondary lymphoid organs. Decreased sympathetic tone results in a pro-inflammatory milieu and in such an environment, Th1 type autoimmune diseases can affect tissues.