Anti-IgE autoantibodies in systemic lupus erythematosus. Prevalence and biologic activity

Autoantibodies to IgE can induce the release of proinflammatory and vasoactive mediators from human cardiac mast cells

Mast cells are multifunctional immune cells with complex roles in tissue homeostasis and disease. Cardiac mast cells (HCMCs) are strategically located within the human myocardium, in atherosclerotic plaques, in proximity to nerves, and in the aortic valve. HCMCs express the high-affinity receptor (FcεRI) for IgE and can be activated by anti-IgE and anti-FcεRI. Autoantibodies to IgE and/or FcεRI have been found in the serum of patients with a variety of immune disorders. We have compared the effects of different preparations of IgG anti-IgE obtained from patients with atopic dermatitis (AD) with rabbit IgG anti-IgE on the release of preformed (histamine and tryptase) and lipid mediators [prostaglandin D₂ (PGD₂) and cysteinyl leukotriene C₄ (LTC₄)] from HCMCs. Functional human IgG anti-IgE from one out of six AD donors and rabbit IgG anti-IgE induced the release of preformed (histamine, tryptase) and de novo synthesized mediators (PGD₂ and LTC₄) from HCMCs. Human IgG anti-IgE was more potent than rabbit IgG anti-IgE in inducing proinflammatory mediators from HCMCs. Human monoclonal IgE was a competitive antagonist of both human and rabbit IgG anti-IgE. Although functional anti-IgE autoantibodies rarely occur in patients with AD, when present, they can powerfully activate the release of proinflammatory and vasoactive mediators from HCMCs.

IgG Autoantibodies Against IgE from Atopic Dermatitis Can Induce the Release of Cytokines and Proinflammatory Mediators from Basophils and Mast Cells

IgE-mediated release of proinflammatory mediators and cytokines from basophils and mast cells is a central event in allergic disorders. Several groups of investigators have demonstrated the presence of autoantibodies against IgE and/or FcεRI in patients with chronic spontaneous urticaria. By contrast, the prevalence and functional activity of anti-IgE autoantibodies in atopic dermatitis (AD) are largely unknown. We evaluated the ability of IgG anti-IgE from patients with AD to induce the in vitro IgE-dependent activation of human basophils and skin and lung mast cells. Different preparations of IgG anti-IgE purified from patients with AD and rabbit IgG anti-IgE were compared for their triggering effects on the in vitro release of histamine and type 2 cytokines (IL-4, IL-13) from basophils and of histamine and lipid mediators (prostaglandin D₂ and cysteinyl leukotriene C₄) from human skin and lung mast cells. One preparation of human IgG anti-IgE out of six patients with AD induced histamine release from basophils, skin and lung mast cells. This preparation of human IgG anti-IgE induced the secretion of cytokines and eicosanoids from basophils and mast cells, respectively. Human monoclonal IgE was a competitive antagonist of both human and rabbit IgG anti-IgE. Human anti-IgE was more potent than rabbit anti-IgE for IL-4 and IL-13 production by basophils and histamine, prostaglandin D₂ and leukotriene C₄ release from mast cells. Functional anti-IgE autoantibodies rarely occur in patients with AD. When present, they induce the release of proinflammatory mediators and cytokines from basophils and mast cells, thereby possibly contributing to sustained IgE-dependent inflammation in at least a subset of patients with this disorder.

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.

Autoimmunity, IgE and FcεRI-bearing cells

Antibody-mediated autoimmune diseases (AAID) involve several isotypes of autoreactive antibodies. In a growing number of AAID, autoreactive IgE are present with a significant prevalence and are often associated with the presence of IgG anti-IgE and/or anti-FcεRIα (high affinity IgE receptor α chain). FcεRI-bearing cells, such as basophils or mast cells, are key players in some of these AAID. Recent advances in the pathophysiology of these diseases led to the passed or current development of anti-IgE strategies that showed very potent effects in some of them. The present review centralizes the information on the relevance of autoreactive IgE and FcεRI-bearing cells in the pathophysiology of different AAID and the ones where the anti-IgE therapeutic strategy shows or may show some benefits for the patients.

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.

Acid Stripping of Surface IgE Antibodies Bound to FcεRI is Unsuitable for the Functional Assays that Require Long-Term Culture of Basophils and Entire Removal of Surface IgE

Basophils are rare granulocytes and dysregulated functions of these cells are associated with several atopic and non-atopic allergic diseases of skin, respiratory system and gastrointestinal tract. Both cytokines and immunoglobulin E (IgE) are implicated in mediating the basophil activation and pathogenesis of these disorders. Several reports have shown that healthy individuals, and patients with allergic disorders display IgG autoantibodies to IgE and hence functional characterization of these anti-IgE IgG autoantibodies is critical. In general, anti-IgE IgG autoantibodies modulate basophil activation irrespective of allergen specificity by interacting with constant domains of IgE. Therefore, an ideal solution to prove the functions of such anti-IgE IgG autoantibodies would be to completely eliminate type I high affinity immunoglobulin E receptor (FcɛRI)-bound IgE from the surface of basophils and to demonstrate in an unequivocal manner the role of anti-IgE IgG autoantibodies. In line with previous reports, our data show that FcɛRI on peripheral blood basophils are almost saturated with IgE. Further, acetic acid buffer (pH 4) efficiently removes these FcɛRI-bound IgE. Although immediately following acetic acid-elution of IgE had no repercussion on the viability of basophils, following 24 h culture with interleukin-3 (IL-3), the viability and yield of basophils were drastically reduced in acid-treated cells and had repercussion on the induction of activation markers. Lactic acid treatment on the other hand though had no adverse effects on the viability of basophils and IL-3-induced activation, it removed only a small fraction of the cell surface bound IgE. Thus, our results show that acid buffers could be used for the elution of FcɛRI-bound IgE on the basophil surface for the biochemical characterization of IgE antibodies or for the immediate use of basophils to determine their sensitivity to undergo degranulation by specific allergens. However, these methods are not utile for the functional assays of basophils that require longer duration of culture and entire removal of surface IgE to validate the role of anti-IgE IgG autoantibodies that interact with FcɛRI-bound IgE irrespective of allergen specificity.

Immunoglobulin (Ig)G antibodies against IgE identified by basophil activation test as the putative causative agent of a serious allergic transfusion reaction: potential utility of the test as a new safety measure for allergic transfusion reactions

BACKGROUND

In most cases of allergic transfusion reactions (ATRs), the causative agents have not been identified and the mechanisms are largely unknown, with a few exceptions. The basophil activation test (BAT) was recently introduced in the field of transfusion to investigate the causal relationships between ATRs and transfusion, as well as the mechanisms behind them.

STUDY DESIGN AND METHODS

The BAT was used to screen the residual supernatants (SNs) of 43 blood components associated with serious ATRs for those that can activate basophils of many healthy volunteers. The SNs were then fractionated by centrifugal ultrafiltration and protein G column chromatography and each separated fraction was reexamined by the BAT.

RESULTS

Of the 43 such blood components, one activated basophils from 19 of 21 healthy volunteers. In the blood component, the IgG antibody against IgE was identified as a putative causative agent.

CONCLUSION

Blood donors who possessed the IgG antibody against IgE may be dangerous to transfusion recipients. The BAT would be useful in identifying such high-risk blood donors, when it is used to screen the blood components associated with serious ATRs for residual SNs that can activate the basophils of many healthy volunteers.

Associations of chronic urticaria with atopic and autoimmune comorbidities: a nationwide population-based study

BACKGROUND

Most cases of chronic urticaria (CU) are idiopathic. Circumstantial evidence suggests that some CU cases have an autoimmune pathogenesis. Previous research indicates that a substantial percentage of patients with CU have an atopic background.

OBJECTIVES

This study aims to examine the association between CU, and atopic and autoimmune diseases.

METHODS

This population-based retrospective cohort study identified 9,332 patients with CU and 37,328 controls matched for age, sex, and number of dermatological clinic visits from the Taiwan National Health Insurance Research Database for 2004-2009. Using multiple logistic regression, we estimated odds ratios (OR) and 95% confidence intervals (CI) for associations of CU with atopic and autoimmune diseases.

RESULTS

CU was most strongly associated with Kawasaki disease (modified OR, 2.76; 95% CI 1.15-6.63), followed by Henoch-Schönlein purpura (HSP), atopic dermatitis (AD), systemic lupus erythematosus (SLE), allergic rhinitis (AR), autoimmune thyroid diseases, Sjögren syndrome, inflammatory bowel disease (IBD), and asthma, which had the lowest adjusted OR (1.11; 95% CI 1.01-1.22) among comorbidities significantly associated with CU. The associations varied in relation to age, group, and sex. Among women, CU was significantly associated with AD, AR, autoimmune thyroid diseases, SLE, vitiligo, and HSP. Among men, CU was significantly associated with AD, AR, autoimmune thyroid diseases, Kawasaki disease, and IBD.

CONCLUSION

CU is associated with atopic/autoimmune diseases. Increased awareness of atopic and autoimmune comorbidities may be warranted for patients with CU.

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.

Lpr-induced systemic autoimmunity is unaffected by mast cell deficiency

The function of mast cells in allergic and organ-specific autoimmune responses is highly controversial. In the current study, we aimed to dissect the role of mast cells in systemic autoimmunity in the B6(lpr/lpr) mouse, a spontaneous model of systemic lupus erythematosus. B6(lpr/lpr) mice were interbred with C57Bl/6-Kit(W-sh/W-sh) (Wsh) mice, resulting in mast cell deficiency. The offspring from this cross (Lpr/Wsh mice) developed symptoms of lupus of the same severity as B6(lpr/lpr) mice. Loss of mast cells on the Lpr background did not alter autoantibody production, proteinuria, the composition of T and B cell populations or autoimmune pathology. Reduced c-Kit expression did drive expanded splenomegaly and impeded interleukin-4 production by CD4(+) cells, suggesting minor functions for mast cells. In general, we conclude that mast cell deficiency and c-Kit deficiency do not play a role in the pathogenesis of lupus in B6(lpr/lpr) mice.

"Auto-anti-IgE": naturally occurring IgG anti-IgE antibodies may inhibit allergen-induced basophil activation

Background

Naturally occurring IgE-specific IgG autoantibodies have been identified in patients with asthma and other diseases, but their spectrum of functions is poorly understood.

Objective

Address the hypothesis that: (i) IgG anti-IgE autoantibodies are detectable in the serum of all subjects but elevated in asthmatic patients regardless of atopic status as compared with controls; (ii) some activate IgE-sensitized basophils; and (iii) some inhibit allergen-induced basophil activation.

Methods

IgE-specific IgG autoantibodies were detected and quantified in sera using ELISA. Sera were examined for their ability to activate IgE-sensitized human blood basophils in the presence and absence of allergen using a basophil activation test, and to inhibit allergen binding to specific IgE on a rat basophilic cell line stably expressing human FcεRI.

Results

IgG autoantibodies binding to both free and FcεRI-bound IgE were detected in patients with atopic and non-atopic asthma, as well as controls. While some were able to activate IgE-sensitised basophils, others inhibited allergen-induced basophil activation, at least partly by inhibiting binding of IgE to specific allergen.

Conclusion

Naturally occurring IgG anti-IgE autoantibodies may inhibit, as well as induce, basophil activation. They act in a manner distinct from therapeutic IgG anti-IgE antibodies such as omalizumab. They may at least partly explain why atopic subjects who make allergen-specific IgE never develop clinical symptoms, and why omalizumab therapy is of variable clinical benefit in severe atopic asthma.

Polarization toward Th1-type response in active, but not in inactive, lupus inhibits late allergic rhinitis in lupus-prone female NZB×NZWF(1) mice

The association of allergic diseases and disease activity in systemic lupus erythematosus (SLE, lupus) is controversial. The study investigates lupus activity-related differences in the induction of late allergic rhinitis (LAR) in the female NZB×NZW(B/W)F(1) mouse model for lupus. The LAR, which is induced by ovalbumin, was examined during the preactive (before clinical onset) and active (after clinical onset) phases in mice. Induction of LAR was less severe in mice with active lupus in contrast to clinically healthy lupus mice that developed a more severe allergic rhinitis. Inhibition of the development of LAR may be due to reduced eosinophilia and local interleukin-4 secretion during active autoimmune disease. In addition, systemic interferon-γ, but not IL-4, production increased during the active phase, but not the preactive phase. This suggests that the predominating Th1 lineage commitment in mice with active lupus may be responsible for the inhibition of the allergic Th2 response. The present study may shed some light on the controversy of the prevalence of allergic diseases in SLE patients.

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.

PTPN22 polymorphism presumably plays a role in the genetic background of chronic spontaneous autoreactive urticaria

BACKGROUND

The association of chronic urticaria (CU) with autoimmune disorders is relatively well proved. Protein tyrosine phosphatase-22 (PTPN22) is considered to be one of the strongest genetic factors for human autoimmunity. We decided to evaluate whether additional, non 1858C>T, PTPN22 variants are independent contributors to the risk of CU occurrence in the Polish population.

METHODS

A total of 91 CU patients with a positive result of autologous serum skin test and 100 healthy volunteers were enrolled in the study. The Urticaria Activity Score was used in disease intensity assessment. In all subjects rs3811021, rs1310182 and rs2488457 polymorphisms were genotyped.

RESULTS

We found a higher prevalence of -1123 C allele among CU patients. No differences in the allele and genotype distribution were found in the other analyzed polymorphisms. Haplotype construction of the three SNPs revealed statistically significant CU association of rs2488457C, rs1310182T and rs3811021T.

CONCLUSIONS

Contrary to previous findings, the contribution of PTPN22 to disease susceptibility is suggested. We can speculate that CU is a genetically complex disease and that its occurrence needs multiple genetic and environmental risk factors.

Current and novel therapeutics in the treatment of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease with significant clinical heterogeneity. Recent advances in our understanding of the genetic, molecular, and cellular bases of autoimmune diseases and especially SLE have led to the application of novel and targeted treatments. Although many treatment modalities are effective in lupus-prone mice, the situation is more complex in human subjects. This article reviews the general approach to the therapy of SLE, focusing on current approved therapies and novel approaches that might be used in the future.

Mast cells in the pathogenesis of rheumatic diseases and as potential targets for anti-rheumatic therapy

Increasing evidence suggests that mast cells (MCs), in addition to acute allergic reactions, are involved in the pathogenesis of chronic inflammatory diseases and in particular in rheumatoid arthritis (RA). MCs reside in connective tissues and in synovial tissue of joints. They produce an array of proinflammatory mediators, tissue destructive proteases, and cytokines, most prominently tumor necrosis factor-alpha, which is one of the key cytokines in the pathogenesis of RA. MCs may also participate in the development of secondary or amyloid A amyloidosis, as the partial degradation of the serum amyloid A (SAA) protein by MCs leads to the generation of a highly amyloidogenic N-terminal fragment of SAA. MCs may contribute to the pathogenesis of connective tissue diseases, scleroderma, vasculitic syndromes, and systemic lupus erythematosus, although the data available are limited. Inhibition of the most important growth factor receptor of human MCs, c-Kit, by the selective tyrosine kinase inhibitor imatinib mesylate, induces apoptosis of synovial tissue MCs. As MCs are long-lived cells, induction of their apoptosis could be a feasible approach to inhibit their functions. Preliminary findings suggest that a drug that inhibits c-Kit could have anti-rheumatic activity in the treatment of patients with RA and spondyloarthropathies.

Immunoglobulin E and systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by intense polyclonal production of autoantibodies and circulating immune complexes. Some reports have associated SLE with a Th2 immune response and allergy. In the present study 21 female patients with SLE were investigated for total IgE and IgE antibodies to dust house aeroallergens by an automated enzyme-linked fluorescent assay, and were also evaluated for antinuclear IgE autoantibodies by a modified indirect immunofluorescence test using HEp-2 cells as antigen substrate. Additionally, immunocapture ELISA was used to investigate serum anti-IgE IgG autoantibodies. Serum IgE above 150 IU/ml, ranging from 152 to 609 IU/ml (median = 394 IU IgE/ml), was observed in 7 of 21 SLE patients (33%), 5 of them presenting proteinuria, urinary cellular casts and augmented production of anti-dsDNA antibodies. While only 2 of 21 SLE patients (9.5%) were positive for IgE antibodies to aeroallergens, all 10 patients with respiratory allergy (100%) from the atopic control group (3 males and 7 females), had these immunoglobulins. SLE patients and healthy controls presented similar anti-IgE IgG autoantibody titers (X = 0.37 +/- 0.20 and 0.34 +/- 0.18, respectively), differing from atopic controls (0.94 +/- 0.26). Antinuclear IgE autoantibodies were detected in 17 of 21 (81%) sera from SLE patients, predominating the fine speckled pattern of fluorescence, that was also observed in IgG-ANA. Concluding, SLE patients can present increased IgE levels and antinuclear IgE autoantibodies without specific clinical signs of allergy or production of antiallergen IgE antibodies, excluding a possible association between SLE and allergy.

Allergic diseases, drug adverse reactions and total immunoglobulin E levels in lupus erythematosus patients

BACKGROUND

The association of allergic diseases, drug adverse reactions and elevated total immunoglobulin E (IgE) concentration in systemic lupus erythematosus patients remains controversial. The aim of the study was to investigate the prevalence of those features in active and inactive systemic lupus erythematosus patients, and in the control group as well.

METHODS

Total IgE concentration was evaluated by enzyme-linked immunosorbent assay.

RESULTS AND CONCLUSIONS

The results of our study revealed that concomitant allergic diseases were not more frequent in systemic lupus erythematosus patients than in the general population. Total IgE concentration was significantly higher during the active stage of the disease. Drug reactions were very frequent but not connected with IgE elevation. Our results indicate that IgE may play a role in lupus pathogenesis, especially in the active phase of the disease.

Molecular aspects of allergy

Atopic diseases such as asthma, rhinitis, eczema and food allergies have increased in most industrialised countries of the world during the last 20 years. The reasons for this increase are not known and different hypotheses have been assessed including increased exposure to sensitising allergens or decreased stimulation of the immune system during critical periods of development. In allergic diseases there is a polarisation of the Th2 response and an increase in the production of type 2 cytokines which are involved in the production of immunoglobulin E and the development of mast cells, basophils and eosinophils leading to inflammation and disease. The effector phase of atopy is initiated by interaction with Fc epsilon RI expressed on effector cells such as mast cells and basophils but also found on an ever increasing list of cells. Binding of a polyvalent allergen to the variable part of IgE leads to a cross-link of the receptor that triggers the cell to release histamine and pharmacological mediators of the symptomatic allergic response. Cross-linking of Fc epsilon RI by autoantibodies against the alpha-chain of the Fc epsilon RI, causing subsequent histamine release is thought to be involved in the pathogenesis of other diseases such as chronic idiopathic urticaria (CIU). To date, most therapeutic strategies are aimed at inhibiting and controlling components of the inflammatory response. Recently, new treatment strategies have emerged that focus on the development of preventive and even curative treatments. The most promising therapeutic approaches are aimed at inhibiting the IgE-Fc epsilon RI interaction with the use of non-anaphylactogenic anti-IgE or anti-Fc epsilon RIalpha autoantibodies. Clinical trials in humans using an humanised anti-IgE antibody showed that this antibody was well tolerated and reduced both symptoms and use of medication in asthma and allergic rhinitis. Thus interruption of the atopic cascade at the level of the IgE-Fc epsilon RI interaction with the use of non-anaphylactogenic antibodies is effective and represents an attractive therapy for the treatment of atopic disease.

Celecoxib for systemic lupus erythematosus: case series and literature review of the use of NSAIDs in SLE

The primary objectives of this study were to evaluate the safety and efficacy of the cyclooxygenase-2 inhibitor celecoxib in systemic lupus erythematosus (SLE) patients both with and without a self-reported sulfa drug allergy and to review the literature on the use of nonsteroidal agents in SLE subjects. A retrospective review of medical records was performed for 50 SLE patients seen by a community-based rheumatologist and treated with open label celecoxib in doses of 200-400 mg/day for a period of 1-9 months. A MEDLINE search of all articles pertaining to the use of NSAIDs in patients with SLE since 1966 was undertaken. We noted that, in this cohort of celecoxib-treated SLE patients from an office rheumatology practice, the majority demonstrated some improvement, and little toxicity was observed. SLE patients with self-reported sulfa allergies were not more likely to have adverse reactions to celecoxib than non-sulfa allergic patients. The literature review performed herein reveals that, although NSAID toxicity should be a continuing concern in an SLE population, structural dissimilarities between celecoxib and the sulfonamide antimicrobials may make true cross-allergenicity less likely to be a clinical problem. These results suggest that patients with SLE can be safely and effectively treated with celecoxib; however, further studies are needed to assess the effectiveness and safety of all NSAIDs in SLE.

IgG anti-IgE autoantibodies in visceral leishmaniasis

Procedures for IgG depletion in visceral leishmaniasis (VL) and schistosomiasis sera using Sepharose-protein G beads also deplete IgE. In this study, the presence of IgG anti-IgE autoantibodies in sera from patients with VL (n = 10), and hepatic-intestinal schistosomiasis (n = 10) and from healthy individuals (n = 10) was investigated. A sandwich ELISA using goat IgG anti-human IgE to capture serum IgE and goat anti-human IgG peroxidase conjugate to demonstrate the binding of IgG to the IgE captured was performed. VL sera had higher titers (p < 0.05) of IgG anti-IgE autoantibodies (OD = 2.01 +/- 0.43) than sera from healthy individuals (OD = 1.35 +/- 0.16) or persons infected with Schistosoma mansoni (OD = 1.34 +/- 0.18). The immunoblotting carried out with eluates from Sepharose-protein G beads used to deplete IgG from these sera and goat anti-human IgE peroxidase conjugate, showed a similar pattern of bands, predominating the 75 kDa epsilon-heavy chain and also polypeptides resulting from physiological enzymatic digestion of IgE. A frequent additional band immediately above 75 kDa was observed only in VL sera.

The anti-IgE/anti-FcepsilonRIalpha autoantibody network in allergic and autoimmune diseases

Basophil granulocytes and tissue mast cells and their mediators play a role in the pathogenesis of several immune and inflammatory disorders. Human basophils and mast cells (FcepsilonRI+ cells) can be activated through immunological interaction with the IgE-FcepsilonRI network. FcepsilonRI+ cells can be triggered by cross-linking between the Fab portions of IgE and multivalent antigens (direct anaphylaxis). 'Reverse type' anaphylaxis can occur through three distinct mechanisms: antibodies against the Fcepsilon portion of IgE (anti-IgE), antibodies against epitopes of the alpha chain of FcepsilonRI (anti-FcepsilonRIalpha) and anti-IgG acting on IgG-IgE complexes bound to FcepsilonRI. Anti-IgE autoantibodies are occasionally present even in normal donors and more frequently in a variety of allergic (chronic urticaria, atopic dermatitis and bronchial asthma) and autoimmune disorders (rheumatoid arthritis, lupus erythematosus and systemic sclerosis). IgG anti-IgE from a small percentage of patients induces the release of mediators from human FcepsilonRI+ cells. Some of the anti-IgE autoantibodies present in allergic patients are non-anaphylactogenic, thus representing a possible protective mechanism preventing the association of IgE with FcepsilonRI. Anti-FcepsilonRIalpha autoantibodies also occur in a significant percentage of patients of chronic urticaria and probably non-allergic asthma and some autoimmune diseases. Although anti-IgE and anti-FcepsilonRIalpha autoantibodies, present in a percentage of patients with immune disorders, are relevant to the pathogenesis of these conditions, much remains to be learnt about their immunochemistry, their prevalence and precise role in various inflammatory diseases.

IgE and non-IgE mediated allergic disorders in systemic lupus erythematosus

OBJECTIVE

To ascertain the prevalence of IgE and non-IgE mediated allergic disorders in patients with systemic lupus erythematosus (SLE).

METHODS

49 SLE cases (all satisfying at least four "Revised ARA Criteria") and 98 healthy, age, and sex matched controls (randomly selected through two urban general practices and one rural general practice) were interviewed by telephone to screen for a history of allergy. Subjects with a history of allergic rhinitis, asthma or atopic eczema then underwent skin prick testing to confirm underlying IgE mediated disease.

RESULTS

Analysis of the data by conditional logistic regression revealed no significant difference in frequency of allergic disorders in SLE cases and controls (odds ratio (OR) 0.92, 95% confidence intervals (CI) 0.45, 1.86). In addition a subgroup analysis of subjects with IgE mediated/associated atopic disorders, showed that cases and controls were at a similar risk of having these conditions (OR 0.90, 95% CI 0.41, 1.96).

CONCLUSIONS

This study suggests that people with SLE are not at an increased risk of IgE mediated/associated allergic disorders, in contrast with previous reports.

Human auto-anti-idiotypic antibodies to mite-specific IgE can degranulate human basophils in vitro

BACKGROUND

Anti-idiotypic antibodies (anti-Ids) to specific IgE antibodies are formed spontaneously during an anti-allergen immune response and can be induced by immunotherapy. Although anti-Ids can down-regulate the production of IgE antibodies, at least in experimental models, their possible role in the modulation of target cell reactivity remains ill-defined.

OBJECTIVE

The capacity of human anti-Ids to modulate the release of histamine was examined in an in vitro system of human basophil degranulation. Anti-Ids were prepared from the serum of six Dermatophagoides pteronyssinus (Dp)-hypersensitive patients suffering from atopic dermatitis and who had never been desensitized. Basophils were obtained from the blood of atopic donors. The extent of histamine release was determined using a fluorometric assay.

RESULTS

We show that: anti-Ids trigger the release of histamine in an allergen-specific, dose- and IgE-dependent manner; the release is not due to the presence of allergen and/or anti-IgE antibodies; and that the degranulating activity can be removed by absorption with affinity-purified anti-Dp antibodies of the corresponding patient.

CONCLUSION

These results indicate that spontaneously produced human anti-Ids can modulate the reactivity of human basophils.

Naturally occurring human IgA autoantibodies against IgE-DES myeloma protein. Prevalence and specificity

The prevalence and specificity of naturally occurring human IgA anti-IgE autoantibodies (a-E Ab) were studied by ELISA with anti-IgA monoclonal antibodies (mAb) and a purified myeloma IgE as solid-phase protein, i.e., IgE-DES(kappa). Such detected IgA a-E Ab were common among adults, and significantly increased geometric means (GM) were found in patients with atopy (P = 0.006; n = 41; GM = 79.3 arbitrary units (AU)/ml) and filariasis (P = 0.02; n = 41; GM = 75.9 AU/ml), as compared with nonatopic controls (n = 42; GM = 48.8 AU/ml). No such difference was observed between age-matched nonatopic (n = 22; GM = 36.7 AU/ml) and atopic (n = 22; GM = 38.6 AU/ml) children. Children had significantly (P < 0.001) lower IgA a-E Ab concentrations than adults, probably as a result of age, because IgA a-E Ab concentrations and age of children were significantly correlated (n = 44; P < 0.05; r = 0.30). IgA a-E Ab concentrations were very low in cord serum (n = 32; median < 0.1 AU/ml). Sex did not influence IgA a-E Ab concentrations in any study group. The specificity of IgA a-E Ab in nine sera was studied by ELISA inhibition assay using IgE-DES myeloma as solid-phase protein and inhibitory proteins of the IgG, IgM, IgD, and IgE classes, including five different IgE myeloma proteins, as well as three enzymatic fragments of IgE-DES. The inhibitions indicated that all IgA a-E Ab tested reacted in a low-affinity reaction with determinants restricted to IgE-DES, i.e., the solid-phase protein.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro basophil histamine-releasing activity of circulating IgG1 and IgG4 autoanti-IgE antibodies from asthma patients and the demonstration that anti-IgE modulates allergen-induced basophil activation

In this study we have examined the relationship between the in vitro basophil histamine-releasing activity of human IgG anti-IgE, isolated as euglobulin fractions from sera of asthmatic patients, and its IgG1/IgG4 subclass distribution. In particular, we have investigated whether IgG anti-IgE modulates allergen-induced basophil activation. The study has revealed that only a small proportion of IgG anti-IgE samples triggered histamine release from basophils of an asthmatic individual (4/21; 19%), a hay fever sufferer (4/10; 40%) and a healthy person (7/21; 33%). The basophil histamine-releasing activity of IgG anti-IgE did not seem to be determined by the IgG1/IgG4 subclass composition of the IgG anti-IgE preparation used. Furthermore, we have demonstrated that autoanti-IgE antibodies modulate allergen-induced basophil histamine release. The three modulatory effects exerted by IgG anti-IgE antibodies on allergen-triggered basophil activation (i.e. additive, synergistic and blocking) were not dependent on the subclass nature of IgG anti-IgE or the use of histamine-releasing anti-IgE preparations. Our data suggest that IgG anti-IgE antibodies in asthma patients may consist of two functionally distinct subpopulations: those which up-regulate (pro-allergic) and those which down-regulate (anti-allergic) the allergic release of mediators from mast cells and basophils.

Human basophil releasability. VIII. Increased basophil releasability in patients with scleroderma

We evaluated basophil releasability in 16 female patients with scleroderma (systemic sclerosis) and in 16 normal age- and sex-matched donors. Basophils from patients with scleroderma released significantly more histamine "spontaneously" than did those from normal donors (12.9 +/- 2.1% versus 4.5 +/- 0.7%; P less than 0.0005). Basophil reactivity (maximal percentage histamine release) to anti-IgE was higher in patients with scleroderma than in controls (57.0 +/- 7.5% versus 35.4 +/- 7.8%; P less than 0.05). Basophil sensitivity (the concentration of anti-IgE that causes 40% of maximal percentage histamine release) to anti-IgE in scleroderma patients was similar to that found in controls (4.6 +/- 2.8 x 10(-2) micrograms/ml versus 2.3 +/- 1.0 x 10(-1) micrograms/ml; P not significant). Scleroderma patients also showed enhanced releasability compared with that of the controls when challenged in vitro with interleukin-3 (8.3 +/- 1.7% versus 3.2 +/- 0.6%; P less than 0.01). Releasability induced by the formyl-containing tripeptide, f-met peptide, was significantly higher in the scleroderma patients than in the controls at the 2 lower concentrations used. No differences in basophil reactivity and sensitivity to f-met peptide and calcium ionophore A23187 were found between patients and normal donors. These results show that spontaneous basophil releasability and releasability in response to IgE cross-linking and activation of interleukin-3 receptors are increased in patients with scleroderma.

Leflunomide (HWA 486), a novel immunomodulating compound for the treatment of autoimmune disorders and reactions leading to transplantation rejection

Leflunomide has been shown to be very effective in preventing and curing several autoimmune animal diseases. Further, this agent is as effective as cyclosporin A in preventing the rejection of skin and kidney transplants in rats. Preliminary results from patients suffering from severe cases of rheumatoid arthritis demonstrated that clinical and immunological parameters could be improved with leflunomide therapy. Mode of action studies revealed that this substance antagonizes the proliferation inducing activity of several cytokines and is cytostatic for certain cell types. In this light, we could show that tyrosine phosphorylation of the RR-SRC peptide substrate and the autophosphorylation of the epidermal growth factor (EGF) receptor were, dose dependently, inhibited by leflunomide. EGF activates the intrinsic tyrosine kinase of its receptor, which stimulates the phosphorylation of a variety of peptides, the amino acid residue in all cases is tyrosine. These results indicate that much of leflunomide's activity could be due to the inhibition of tyrosine-kinase(s), which is an important general mechanism for the proliferation of various cell types. Thus, leflunomide, which is effective against autoimmune diseases and reactions leading to graft rejection, would seem to have a mode of action separating it from known immunosuppressive drugs.

IgE-containing immune complexes in synovial fluid of patients with rheumatoid arthritis

The prevalence and composition of IgE-containing immune complexes in paired synovial fluid and serum of 42 patients with classical or definite rheumatoid arthritis were studied. IgE-containing immune complexes were found in 15/42 synovial fluids; 15 sera were also positive. The correlation between serum and synovial fluid complexed IgE levels was high (r = 0.77). The mean ratio of synovial fluid/serum levels was 1.96, i.e. significantly higher than 0.33, the synovial fluid/serum ratio for alpha-2-macroglobulin (molecular weight 820 kD), which was taken as high molecular weight control protein (p less than 0.0001). Apart from IgE in immune complex form, monomeric IgE was also significantly higher in synovial fluid compared to serum (ratio = 2.94). Other constituents which could be found in the immune complexes, i.e. anti-IgE antibodies, rheumatoid factors and anticollagen antibodies, were also higher in synovial fluid than predicted. Our results suggest intra-articular production of IgE-containing complexes in the synovial fluid, in addition to possible exudation of the complexes from the serum. These findings provide further evidence for the role of IgE-containing immune complexes in rheumatoid synovitis.

Anti-IgE autoantibodies in systemic sclerosis (scleroderma)

An enzyme immunoassay was used to determine the prevalence of anti-IgE auto-antibodies in 66 patients with systemic sclerosis (scleroderma) stratified according to extent and duration of disease. Serum IgG anti-IgE antibodies were detected in 14 (21%) patients and IgM anti-IgE antibodies in nine (14%) patients. The overall prevalence of IgG or IgM isotypes was 21/66, (32%). Anti-IgE autoantibodies were not found in six patients with undifferentiated connective tissue disease or two patients with eosinophilic fasciitis. Attempts to demonstrate histamine release from basophils in vitro by using serum samples containing high titre anti-IgE antibody were unsuccessful. By multivariate analysis the presence of anti-IgE antibody was not associated with duration of systemic sclerosis; extent of scleroderma; specific visceral features, including heart, lung, renal, and gastrointestinal involvement; or mortality.