Lowering anti-dsDNA antibodies--what's new?

Paranasal sinus occupancy assessed from magnetic resonance images-associations with clinical indicators in patients with systemic lupus erythematosus

OBJECTIVES

Nasal, paranasal sinus and mucosal disorders are common symptoms in autoimmune rheumatic diseases. Soft tissue changes and fluid accumulation in the osteomeatal complexes and paranasal sinuses manifest as opaqueness on radiological images which can be assessed using visual scoring and computational methods on CT scans, but their results do not always correlate. Using MRI, we investigate the applicability of different image analysis methods in SLE.

METHODS

We assessed paranasal sinus opaqueness on MRI from 51 SLE patients, using three visual scoring systems and expert-delineated computational volumes, and examined their association with markers of disease activity, inflammation, endothelial dysfunction and common small vessel disease (SVD) indicators, adjusting for age and sex-at-birth.

RESULTS

The average paranasal sinus volume occupation was 4.55 (6.47%) [median (interquartile range) = 0.67 (0.25-2.65) ml], mainly in the maxillary and ethmoid sinuses. It was highly correlated with Lund-Mackay (LM) scores modified at 50% opaqueness cut-off (Spearman's ρ: 0.71 maxillary and 0.618 ethmoids, P < 0.001 in all), and with more granular variations of the LM system. The modified LM scores were associated with SVD scores (0: B = 5.078, s.e. = 1.69, P = 0.0026; 2: B = -0.066, s.e. = 0.023, P = 0.0045) and disease activity (anti-dsDNA: B = 4.59, s.e. = 2.22, P = 0.045; SLEDAI 3-7: 2.86 < B < 4.30; 1.38 < s.e. < 1.63; 0.0083 ≤ P ≤ 0.0375). Computationally derived percent opaqueness yielded similar results.

CONCLUSION

In patients with SLE, MRI computational assessment of sinuses opaqueness and LM scores modified at a 50% cut-off may be useful tools in understanding the relationships among paranasal sinus occupancy, disease activity and SVD markers.

Anti-dsDNA titre in female systemic lupus erythematosus patients: relation to disease manifestations, damage and antiphospholipid antibodies

Background Attempts are ongoing to unveil unresolved queries about anti-double-stranded deoxyribonucleic acid (anti-dsDNA), their precise pathogenic effects and to what extent blocking them would be a useful therapeutic goal. Objectives The aim of the present study was to determine the anti-dsDNA antibodies titre in systemic lupus erythematosus (SLE) patients and investigate their relation to the disease characteristics, activity, damage and antiphospholipid autoantibodies (aPL). Methods Seventy female SLE patients and 35 age- and sex-matched controls were included. The anti-dsDNA level and aPL were measured. Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) and Systemic Lupus International Collaborative Clinics/American College of Rheumatology Damage Index (SLICC/ACR-DI) were assessed. Results The mean age of the patients was 27.5 ± 5.1 years, disease duration 7.7 ± 5.4 years, and SLEDAI and SLICC/ACR-DI scores were 6.8 ± 8.04 and 1.2 ± 1.3, respectively. Anti-dsDNA was positive in 61.4% of the patients and the titre (133.2 ± 100.5 IU/ml) was significantly higher compared to controls (22.03 ± 17.2 IU/ml) ( p < 0.0001). The anti-dsDNA level was significantly increased in those with musculoskeletal manifestations ( p = 0.007) and positive anti-β2 glycoprotein (anti-β2GP) ( p = 0.037) and decreased in those with neuropsychiatric manifestations ( p = 0.004) and those receiving cyclophosphamide (CYC) ( p = 0.013). The anti-dsDNA level tended to be higher in active patients. The anti-dsDNA titre significantly correlated with the erythrocyte sedimentation rate ( p = 0.001), anticardiolipin IgG and IgA antibodies ( p = 0.008) and anti-β2GP IgG ( p = 0.03) and IgA ( p = 0.002) and inversely with the total leucocytic count ( p < 0.0001) and SLICC/ACR-DI ( p = 0.001). Conclusion Anti-dsDNA is remarkably increased in SLE patients especially those with musculoskeletal manifestations and aPL. A protective role seems likely in those with neuropsychiatric manifestations and those receiving CYC and may form a shield against disease tissue damage.

The diagnosis and clinical management of the neuropsychiatric manifestations of lupus

Neuropsychiatric (NP) involvement in Systemic Lupus Erythematosus (SLE), can be a severe and troubling manifestation of the disease that heavily impacts patient's health, quality of life and disease outcome. It is one of the most complex expressions of SLE which can affect central, peripheral and autonomous nervous system. Complex interrelated pathogenetic mechanisms, including genetic factors, vasculopathy, vascular occlusion, neuroendocrine-immune imbalance, tissue and neuronal damage mediated by autoantibodies, inflammatory mediators, blood brain barrier dysfunction and direct neuronal cell death can be all involved. About NPSLE a number of issues are still matter of debate: from classification and burden of NPSLE to attribution and diagnosis. The role of neuroimaging and new methods of investigation still remain pivotal and rapidly evolving as well as is the increasing knowledge in the pathogenesis. Overall, two main pathogenetic pathways have been recognized yielding different clinical phenotypes: a predominant ischemic-vascular one involving large and small blood vessels, mediated by aPL, immune complexes and leuko-agglutination which it is manifested with more frequent focal NP clinical pictures and a predominantly inflammatory-neurotoxic one mediated by complement activation, increased permeability of the BBB, intrathecal migration of autoantibodies, local production of immune complexes and pro-inflammatory cytokines and other inflammatory mediators usually appearing as diffuse NP manifestations. In the attempt to depict a journey throughout NPSLE from diagnosis to a reasoned therapeutic approach, classification, epidemiology, attribution, risk factors, diagnostic challenges, neuroimaging techniques and pathogenesis will be considered in this narrative review based on the most relevant and recent published data.

Epitope spreading induced by immunization with synthetic SSB peptides

Sjogren's syndrome type B (SSB)/La antibody is an autoantibody generally observed in connective tissue diseases whereas double-stranded deoxyribonucleic acid (dsDNA) antibodies are the most characteristic autoantibodies found in systemic lupus erythematosus (SLE) patients. The relationship of these autoantibodies remains unclear. The aim of the study was to determine the profile of antibody production in rabbits immunized with synthetic SSB peptides alone or with dsDNA. For this purpose, 214–225aa peptide of SSB antigen was synthesized based on the organic chemistry solid-phase peptide synthesis. Rabbits were immunized with the following antigens: i) synthetic SSB peptides linked with keyhole limpet hemocyanin (KLH); ii) dsDNA; iii) SSB plus dsDNA; iv) KLH; and v) phosphate-buffered saline. SSB peptide antibody was measured using the enzyme-linked immunosorbent assay while extractable nuclear antigens (ENA) antibody and dsDNA antibody were measured by immunoblotting and immunofluorescence, respectively. The results showed that a specific anti-SSB peptide antibody was produced following immunization with SSB epitope alone or with dsDNA. The SSB peptide antibody titer in the coimmunization group was higher than that of the SSB alone group. In addition, antibodies against ribonucleoprotein (RNP), Smith and/or dsDNA were detected in rabbits of the coimmunization group. The presence of anti-dsDNA antibodies in the rabbits immunized with SSB peptide suggested the induction of epitope spreading. In conclusions, SSB antibodies were produced in rabbits immunized with SSB peptide or SSB+dsDNA, whereas SSB antibody titers were higher in the coimmunization group. Furthermore, coimmunization was associated with epitope spreading.

Recent advances and current state of immunotherapy in systemic lupus erythematosus

INTRODUCTION

Systemic lupus erythematosus (SLE) is an autoimmune syndrome that poses significant challenges in diagnosis and treatment. Dysregulated innate and adaptive immune systems are involved in its pathogenesis. A plethora of novel immunotherapies have been developed for the treatment of SLE but many have failed early clinical trials.

AREAS COVERED

This review summarizes immunotherapies under recent development with relevance to the targeted cellular or soluble factors involved in the pathogenesis of SLE.

EXPERT OPINION

SLE is a complicated disease with much heterogeneity. Novel immunotherapies with different mechanisms of action that are currently under development include biologic agents targeting co-stimulatory molecules, cytokines or their receptors and signaling molecules and B cells, cell-based therapy and peptide therapy. Together with good scientific rationale and advanced biological engineering techniques, optimization of clinical trial design, patient selection and disease outcome measures are essential to demonstrate the clinical efficacy and safety of these agents.

The role of positive feedback loops involving anti-dsDNA and anti-anti-dsDNA antibodies in autoimmune glomerulonephritis

Autoimmune glomerulonephritis (GN) is a potentially life-threatening renal inflammation occurring in a significant percentage of systemic lupus erythematosus (SLE) patients. It has been suggested that GN develops and persists due to a positive feedback loop, in which inflammation is promoted by the deposition in the kidney of immune complexes (IC) containing double-stranded DNA (dsDNA) and autoantibodies specific to it, leading to cellular death, additional release to circulation of dsDNA, continuous activation of dsDNA-specific autoreactive B cells and further formation of IC. We have recently presented a generic model exploring the dynamics of IC-mediated autoimmune inflammatory diseases, applicable also to GN. Here we extend this model by incorporating into it a specific B cell response targeting anti-dsDNA antibodies-a phenomenon whose occurrence in SLE patients is well-supported empirically. We show that this model retains the main results found for the original model studied, particularly with regard to the sensitivity of the steady state properties to changes in parameter values, while capturing some disease-specific observations found in GN patients which are unaccountable using our previous model. In particular, the extended model explains the findings that this inflammation can be ameliorated by treatment without lowering the level of anti-dsDNA antibodies. Moreover, it can account for the inverse oscillations of anti-dsDNA and anti-anti-dsDNA antibodies, previously reported in lupus patients. Finally, it can be used to suggest a possible explanation to the so-called regulatory role of TLR9, found in murine models of lupus; i.e., the fact that the knockdown of this DNA-sensing receptor leads, as expected, to a decrease in the level of anti-dsDNA antibodies, but at the same time results in a counter-intuitive amplification of the autoreactive immune response and an exacerbated inflammation. Several predictions can be derived from the analysis of the presented model, allowing its experimental verification.

Monocyte chemoattractant-1 as a urinary biomarker for the diagnosis of activity of lupus nephritis in Brazilian patients

OBJECTIVE

Monocyte chemotactic protein (MCP-1), involved in the pathogenesis of lupus nephritis (LN), has recently been indicated as a new biomarker of kidney activity in systemic lupus erythematosus (SLE). Our aim was to assess urinary MCP-1 (uMCP-1) as a biomarker of renal activity in patients with SLE and to compare it to other disease activity markers, using the ELISA.

METHODS

Seventy-five female Brazilian patients with SLE and a control group participated in our study. Patients with SLE were distributed among 3 groups according to kidney involvement and classified according to disease activity based on clinical and laboratory measures such as urinary sediment, proteinuria, kidney function, C3, C4, anti-dsDNA, disease activity index, and renal SLE disease activity index. The serum and uMCP-1 concentrations were measured by sandwich ELISA.

RESULTS

In the A-LN group (active lupus nephritis: SLE with kidney involvement), the concentration of uMCP-1 was significantly higher than in other groups. A cutoff point was established using the results of the control group to apply this test in the detection of LN. A-LN had a higher frequency of positive results for uMCP-1 in comparison to the other groups (p < 0.001). To detect disease activity in patients with LN, a new cutoff was determined based on the results of patients with SLE with kidney involvement. Setting specificity at 90%, the sensitivity of the test was 50%.

CONCLUSION

The high specificity makes uMCP-1 a useful test as a predictor of kidney activity in SLE, especially when associated to other measures used in clinical practice.

Modeling immune complex-mediated autoimmune inflammation

A number of autoimmune diseases are thought to feature a particular type of self-sustaining inflammation, caused by the deposition of immune complexes (IC) in the inflamed tissue and a consequent activation of local effector cells. The persistence of this inflammation is due to a positive feedback loop, where autoantigen particles released as part of the tissue damage caused by the inflammation stimulate autoreactive B cells, leading to the formation of further immune complexes and their subsequent deposition. We present a mathematical model for the exploration of IC-mediated autoimmune inflammation and its clinical implications. We characterize the possible differences between normal individuals and those susceptible to such inflammation, and show that both random perturbations and bifurcations can lead to disease onset. Our model explains how defects in the mechanisms responsible for cellular debris clearance contribute to the development of disease, in agreement with empirical evidence. Moreover, we show that parameters governing the dynamics of immune complexes, such as their clearance rate, have an even stronger effect in determining the behavior of the system. We demonstrate the existence of hysteresis, implying that once IC-mediated autoimmune inflammation is triggered, its long-term suppression may be difficult to achieve. Our results can serve to guide the development of novel therapies to autoimmune diseases involving this type of inflammation.

Gene expression profiles in a rabbit model of systemic lupus erythematosus autoantibody production

We previously reported the establishment of a rabbit (Oryctolagus cuniculus) model in which peptide immunization led to production of lupus-like autoantibodies including anti-Sm, -RNP, -SS-A, -SS-B, and -dsDNA characteristic of those produced in systemic lupus erythematosus (SLE) patients. Some neurologic symptoms in the form of seizures and nystagmus were observed. The animals used in the previous and in the current study were from a National Institute of Allergy and Infectious Diseases colony of rabbits that were pedigreed, Ig-allotype defined, but not inbred. Their genetic heterogeneity may correspond to that found among patients of a given ethnicity. We extended the information about this rabbit model by microarray-based expression profiling. We first demonstrated that human expression arrays could be used with rabbit RNA to yield information on molecular pathways. We then designed a study evaluating gene expression profiles in eight groups of control and treated rabbits (47 rabbits in total). Genes significantly upregulated in treated rabbits were associated with NK cytotoxicity, Ag presentation, leukocyte migration, cytokine activity, protein kinases, RNA spliceosomal ribonucleoproteins, intracellular signaling cascades, and glutamate receptor activity. These results link increased immune activation with upregulation of components associated with neurologic and anti-RNP responses, demonstrating the utility of the rabbit model to uncover biological pathways related to SLE-induced clinical symptoms, including neuropsychiatric lupus. Our finding of distinct gene expression patterns in rabbits that made anti-dsDNA compared with those that only made other anti-nuclear Abs should be further investigated in subsets of SLE patients with different autoantibody profiles.

Review: Lupus nephritis: pathologic features, epidemiology and a guide to therapeutic decisions

Systemic lupus erythematosus may present with renal manifestations that frequently are difficult to categorize and lupus nephritis is an important predictor of poor outcome. The type and spectrum of renal injury may remain undiagnosed until full-blown nephritic and/or nephrotic syndrome appear with increased risk of end-stage renal disease. These abnormalities occur within the first few years after the diagnosis of lupus is made on clinical grounds and with the support of laboratory tests in high risk patients. An early renal biopsy is helpful in patients with an abnormal urinalysis and/or reduced glomerular filtration rate and the results form the basis for therapeutic decisions. The biopsy also provides vital prognostic information based on histological categorization of different types of lupus nephritis, the degree of activity, chronicity and the immunopathogenesis. In the current armamentarium, the use of cyclophosphamide and azathioprine and recently mycophenolate mofetil, reduce morbidity and maintenance therapies reduce the risk of end-stage renal disease. Clinical trials underway promise new, effective and safe immunosuppressive regimens for the treatment of proliferative lupus nephritis.

The role of B cells in lupus pathogenesis

Autoantibodies clearly contribute to tissue inflammation in systemic lupus erythematosus. In order to therapeutically target B cells making pathogenic autoantibodies, it is necessary to identify their phenotype. It is also important to understand the defects in B cell repertoire selection that permit pathogenic autoreactive B cells to enter the immunocompetent B cell repertoire. We present the data that both marginal zone and follicular B cells can produce pathogenic autoantibodies. Moreover, we discuss how B cell survival and maturation are regulated centrally prior to antigen activation and in the periphery after antigen activation to form the repertoire that generates the spectrum of circulating antibodies.

Anti-dsDNA antibody subtypes and anti-C1q antibodies: toward a more reliable diagnosis and monitoring of systemic lupus erythematosus and lupus nephritis

The putative distinct diagnostic and pathogenic potential of aDNA-Ab subtypes, differing in their affinity or epitope specificity, was subject of several studies with controversial results. Comparing five assays, characterized by different reaction conditions and nature/source of dsDNA, we investigated the abovementioned problem in a retrospective study on 100 systemic lupus erythematosus (SLE) patients and 100 controls (other CTD, autoimmune hepatopathies). As demonstrated, only assay 3 (Farrzyme, TBS, UK) and 5 (Farr-RIA, Trinity Biotech, Ireland) are really suitable to detect primarily high avidity aDNA-Ab. Both were significantly linked to lupus nephritis (specificity 84%) and highly specific for SLE (95 and 96%). Thereby, assay 3 was found to be the first solid phase ELISA probably suitable to replace the Farr-RIA. Classical ELISAs (assay 1, Orgentec, Germany, and 2, Bindazyme, TBS, UK), detecting aDNA-Ab more or less independent from their avidity, or tests with only intermediate specificity for high avidity Ab (assay 4, ELIAdn, Sweden Diagnostics, Germany), were less specific for SLE (83, 79, 91%, respectively) and not associated with renal involvement (specificity 54-57%). At least in the patients studied here, obvious antigen-related differences could not be observed. With slight differences, all assays were suitable to monitor disease activity and therapy in SLE, agreeing with the ECLAM score in about 70-80% of cases. For lupus nephritis, aC1q-Ab are as specific as high avidity aDNA-Ab and capable to close a diagnostic gap in some cases. Thus, to enhance the specificity (up to 98%) and to consider the distinct diagnostic/pathogenic potential of aDNA-Ab subtypes in SLE, under routine clinical laboratory conditions it should be recommended to combine a sensitive screening test with a more specific second assay.

Suppressive oligodeoxynucleotides delay the onset of glomerulonephritis and prolong survival in lupus-prone NZB x NZW mice

OBJECTIVE

Synthetic oligodeoxynucleotides (ODN) expressing TTAGGG motifs suppress the production of proinflammatory cytokines and have been proven effective at blocking the development of certain organ-specific autoimmune diseases. We undertook this study to determine whether suppressive ODN alter the development of systemic autoimmunity, by evaluating their effect on the progression of lupus-like disease in NZB x NZW (NZB/NZW) mice.

METHODS

We repeatedly treated mice with suppressive ODN before or after the onset of proteinuria. We monitored the effect of treatment on the onset, severity, and immunologic correlates of disease.

RESULTS

Treatment with suppressive ODN significantly prolonged lifespan while delaying the onset and progression of glomerulonephritis in NZB/NZW mice. Clinical improvement was accompanied by a significant reduction in anti-double-stranded DNA autoantibody production and by significantly reduced secretion of interferon-gamma and interleukin-12 in vivo.

CONCLUSION

Suppressive ODN may be of benefit in the treatment of chronic systemic autoimmune diseases such as systemic lupus erythematosus.

The role of pathogenic B-cell clones in antibody mediated autoimmune disorders

Our understanding of the role of B-cells in the immunopathogenesis of certain antibody mediated diseases has developed remarkably in the past few years. In this review, autoantibody mediated immune disorders associated with pathogenic B-cell clones are discussed. We have focused on the roles and pathogenic mechanisms of B-cell clones in autoantibodyimmune diseases. The roles of pathogenic B-cells in Castleman's disease in PNP patients is used as one example. The developments in the treatment of B-cell mediated autoimmune diseases, such as intravenous immunoglobulin (IVIg), targets the regulatory pathway of B-cells, using anti-CD20, CD19, CD22 and, CD95 monoclonal antibody therapy, etc. are also discussed. Immunotherapy, targeting specific pathogenic B-cells, is believed to be one approach in the management of autoimmune diseases.

Predictors of neuropsychiatric damage in systemic lupus erythematosus: data from the Maryland lupus cohort

OBJECTIVE

To identify factors predictive of significant neuropsychiatric (NP) damage in systemic lupus erythematosus (SLE).

METHODS

One hundred and thirty patients with SLE were followed at the University of Maryland Lupus Clinic from 1992 until 2003. NP manifestations were defined according to the revised American College of Rheumatology (ACR) nomenclature and case definitions for NP-SLE syndromes. Disease activity was measured using the SLE Disease Activity Index (SLEDAI), organ damage using the Systemic Lupus International Collaborating Clinics Damage Index SLICC/ACR (SDI); NP damage (NPDI) was measured with the corresponding domain of the SDI. At end of study period, 64 patients exhibited no NP damage (NPDI = 0) and 66 patients developed significant NP damage (defined as NPDI > or =1). The baseline features for these two patient groups were compared, and variables found to be significantly different were examined by multivariable analyses to determine their contribution to NP damage.

RESULTS

Significant NP damage is common in SLE; mortality is infrequent and the cause of death is unrelated to NP damage. Independent predictors of significant NP damage were disease activity, Caucasian ethnicity and the presence of antiphospholipid antibodies and anti-Ro/SSA antibody. Certain clinical features at baseline predicted specific NP damage. For example, higher disease activity at baseline was predictive of psychosis and cognitive impairment, anti-dsDNA was predictive of polyneuropathy, and antiphospholipid antibodies were predictive of seizures and cerebrovascular accidents.

CONCLUSIONS

In this longitudinal SLE cohort, significant cumulative NP damage occurred. Early aggressive therapy targeted towards NP manifestations may prevent the occurrence of NP damage.

Expression of the Cytoplasmic Tail of LMP1 in Mice Induces Hyperactivation of B Lymphocytes and Disordered Lymphoid Architecture

The oncogenic EBV protein LMP1 mimics a dysregulated CD40 receptor in vitro. To compare CD40 and LMP1-mediated events in vivo, transgenic mice were engineered to express mouse CD40 (mCD40tg) or a protein with extracellular mCD40 and cytoplasmic LMP1 (mCD40-LMP1tg). Transgenic and CD40(-/-) mice were bred so that only the transgenic CD40 molecule is expressed in B cells, macrophages, and dendritic cells. mCD40-LMP1tg mice had normal lymphocyte subsets, and immunization elicited an antibody response featuring normal isotype switching, affinity maturation, and germinal center (GC) formation. However, unimmunized mCD40-LMP1tg mice had expanded immature and germinal center B cells, produced autoantibodies, exhibited marked splenomegaly and lymphadenopathy, and elevated serum IL-6. Thus, signaling through the LMP1 cytoplasmic tail results in amplified and abnormal mimicry of CD40 functions in vivo, indicating possible ways in which LMP1 contributes to the pathogenesis of EBV-associated human disease.