Pattern of cutaneous immunoglobulin G deposition in subacute cutaneous lupus erythematosus is reproduced by infusing purified anti-Ro (SSA) autoantibodies into human skin-grafted mice

HIF-1 regulates pathogenic cytotoxic T cells in lupus skin disease

Cutaneous lupus erythematosus (CLE) is a disfiguring autoimmune skin disease characterized by an inflammatory infiltrate rich in T cells, which are strongly implicated in tissue damage. How these cells adapt to the skin environment and promote tissue inflammation and damage is not known. In lupus nephritis, we previously identified an inflammatory gene program in kidney-infiltrating T cells that is dependent on HIF-1, a transcription factor critical for the cellular and developmental response to hypoxia as well as inflammation-associated signals. In our present studies using a mouse model of lupus skin disease, we find that skin-infiltrating CD4+ and CD8+ T cells also express high levels of HIF-1. Skin-infiltrating T cells demonstrated a strong cytotoxic signature at the transcript and protein levels, and HIF-1 inhibition abrogated skin and systemic diseases in association with decreased T cell cytotoxic activity. We also demonstrate in human CLE tissue that the T cell-rich inflammatory infiltrate exhibited increased amounts of HIF-1 and a cytotoxic signature. Granzyme B-expressing T cells were concentrated at sites of skin tissue damage in CLE, suggesting relevance of this pathway to human disease.

Current Knowledge of the Molecular Pathogenesis of Cutaneous Lupus Erythematosus

Cutaneous lupus erythematosus (CLE) is an autoimmune disease, which can be limited to the skin or associated with systemic lupus erythematosus (SLE). Gene expression analysis has revealed that both the innate and adaptive immune pathways are activated in CLE. Ultraviolet (UV) light, the predominant environmental factor associated with CLE, induces apoptosis in keratinocytes, and the endogenous nucleic acids released from the apoptotic cells are recognized via pattern recognition receptors, including Toll-like receptors. This leads to the production of type I interferon, a major contributor to the pathogenesis of CLE, by plasmacytoid dendritic cells. UV irradiation can also induce the externalization of autoantigens, such as SS-A/Ro, exposing them to circulating autoantibodies. T-helper 1 cells have been reported to play important roles in the adaptive immune response to CLE. Other environmental factors associated with CLE include drugs and cigarette smoke. Genetic factors also confer a predisposition to the development of CLE, and many susceptibility genes have been identified. Monogenetic forms of CLE also exist. This article aims to review current knowledge about the pathogenesis of CLE. A better understanding of the environmental, genetic, and immunoregulatory factors that drive CLE may provide important insights for the treatment of CLE.

The role of organ-deposited IgG in the pathogenesis of multi-organ and tissue damage in systemic lupus erythematosus

Systemic lupus erythematosus (SLE), often known simply as lupus, is a severe chronic autoimmune disease that is characterized by multi-organ and tissue damage and high levels of autoantibodies in serum. We have recently investigated, using animal models, the role of organ-deposited IgG autoantibodies in the pathogenesis of organ and tissue damage in SLE. We found that intra-organ injection of serum from mice with lupus (i.e., lupus mice) into healthy mice triggered inflammation in tissue and organs but that serum from other healthy mice did not, and that the severity of inflammation was related to the dose of serum injected. Immunohistochemistry showed that a large number of IgG molecules are deposited at the site of organ and tissue damage in lupus mice, and that IgG is a major contributor to the development of tissue inflammation triggered by serum from lupus mice or patients. The development of tissue inflammation induced by IgG in serum from lupus mice requires the presence of monocytes/macrophages, but not of lymphocytes or neutrophils; tumor necrosis factor (TNF)/tumor necrosis factor receptor 1 (TNFR1) and interleukin 1 (IL-1) also play essential roles in the development of tissue inflammation triggered by IgG. In addition, it has been found that TNFR1 inhibitors can suppress skin injury in lupus mice and that spleen tyrosine kinase (Syk) inhibitors, which can block the signaling transduction of IgG/Fc gamma receptors (FcγRs), can prevent and treat skin injury and kidney damage in lupus mice. We have also observed that lupus IgG might protect against bone erosion. Based on these results, we conclude that IgG plays a crucial role in the development of organ and tissue damage in SLE and in protecting bone erosion and arthritis, and we suggest that the IgG/FcγR signaling pathway is an important therapeutic target in SLE.

Cutaneous Manifestations of "Lupus": Systemic Lupus Erythematosus and Beyond

Lupus, Latin for "wolf," is a term used to describe many dermatologic conditions, some of which are related to underlying systemic lupus erythematosus, while others are distinct disease processes. Cutaneous lupus erythematosus includes a wide array of visible skin manifestations and can progress to systemic lupus erythematosus in some cases. Cutaneous lupus can be subdivided into three main categories: acute cutaneous lupus erythematosus, subacute cutaneous lupus erythematosus, and chronic cutaneous lupus erythematosus. Physical exam, laboratory studies, and histopathology enable differentiation of cutaneous lupus subtypes. This differentiation is paramount as the subtype of cutaneous lupus informs upon treatment, disease monitoring, and prognostication. This review outlines the different cutaneous manifestations of lupus erythematosus and provides an update on both topical and systemic treatment options for these patients. Other conditions that utilize the term "lupus" but are not cutaneous lupus erythematosus are also discussed.

Current Insights in Cutaneous Lupus Erythematosus Immunopathogenesis

Cutaneous Lupus Erythematosus (CLE) is a clinically diverse group of autoimmune skin diseases with shared histological features of interface dermatitis and autoantibodies deposited at the dermal-epidermal junction. Various genetic and environmental triggers of CLE promote infiltration of T cells, B cells, neutrophils, antigen presenting cells, and NK cells into lesional skin. In this mini-review, we will discuss the clinical features of CLE, insights into CLE immunopathogenesis, and novel treatment approaches.

Neonatal lupus erythematosus in identical twins, showing transient bullous lesions

One of identical twin girls was born with ulcers on her leg, and shortly after birth developed a flaccid blister on the leg. Subepidermal blister with vacuolar degeneration of basal cell layer and the heavy infiltration of mononuclear cells in the upper dermis were observed in the blister lesion. She also had generalized livedo. Her identical twin sister did not exhibit ulcers or blisters, but was born with milia on her limbs. Their mother was found to have lupus erythematosus with positive anti-Ro/SSA antibodies and developed Sjögren syndrome. We emphasize neonatal blistering and congenital milia unique manifestations of neonatal lupus erythematosus.

Cutaneous lupus in infancy and childhood

Cutaneous lupus may occur in infancy as transient lesions associated with and probably caused by maternal autoantibodies, or later in childhood, associated with the endogenous development of autoimmunity. In this review, clinical findings, diagnosis, management, and pathogenesis of neonatal lupus are discussed, and the management of cutaneous lupus in children is detailed.

Preclinical rheumatoid arthritis: identification, evaluation, and future directions for investigation

Rheumatoid arthritis (RA) likely develops in several phases, beginning with genetic risk, followed by asymptomatic autoimmunity, then finally, clinically apparent disease. Investigating the phases of disease that exist prior to the onset of symptoms (ie, the preclinical period of RA) will lead to understanding of the important relationships between genetic and environmental factors that may lead to disease, as well as allow for the development of predictive models for disease, and ultimately preventive strategies for RA.

Anti-ribonucleoproteins autoantibodies in patients with systemic autoimmune diseases. Relation with cutaneous photosensitivity

A common feature between patients with a certain group of systemic autoimmune pathologies (SAPs) with rheumatic component, such as lupus erythematosus (LE) in all its forms, is the presence of cutaneous photosensitivity (CP) as well as the existence of autoantibodies (Aabs). These Aabs have also high incidence in other SAPs that do not present CP, like primary Sjögren's syndrome and rheumatoid arthritis. Cutaneous photosensitivity is a condition that consists of an exacerbated skin reaction to solar radiations; its incidence can reach 90% in systemic LE. The mechanisms involved in the development of CP have been extensively studied focusing on different approaches; however, the exact mechanism has not been fully elucidated yet. There are many theories that relate specifically the presence of circulating anti-Ro/SS-A Aabs with the CP phenomenon, though there are several studies which are in disagreement. In this study, we evaluated the Aabs profile (anti-Ro/SS-A 52 kDa, anti-Ro/SS-A 60 kDa, anti-La/SS-B, anti-Sm and ANAs) as well as their titer or reactivity, in a local cohort of 169 patients with SAPs. We related those Aabs profiles and titers with the presence or absence of CP, and we found that there was no significant association between the presence of anti-Ro/SS-A Aabs and the occurrence of CP. On the other hand, a statistically significant positive association was found between CP and high reactivity anti-Sm Aabs, though this fact could be biased by the incidence of both events in SLE patients. To sum up, in the particular population studied, there is no direct relationship between anti-Ro/SS-A Aabs and CP, which is in agreement with some authors and in disagreement with many others, contributing to the endless discussion of this issue.

Lupus serum IgG induces skin inflammation through the TNFR1 signaling pathway

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by high autoantibody levels and multiorgan tissue damage, including kidney and skin. Cutaneous manifestations are frequent in patients with SLE, yet the etiology and pathogenesis of skin injury in SLE remains unclear. We reasoned that lupus serum containing high levels of autoreactive Ig contributes to skin injury. In this article, we report that serum from SLE patients and lupus-prone mice induces skin inflammation following intradermal injection into normal mice. Lupus serum depleted of IgG failed to cause skin inflammation. Monocytes, but not lymphocytes, were found to be crucial in the development of lupus serum-induced skin inflammation, and lupus serum IgG induced monocyte differentiation into dendritic cells (DCs). TNF-alpha and TNFR1, but not TNFR2, were required for the development of lupus serum-induced skin inflammation. TNFR1, not TNFR2, represented the main molecule expressed in the skin lesions caused by injected lupus serum. Our studies demonstrated that lupus serum IgG causes skin injury by involving the TNFR1 signaling pathway and monocyte differentiation to DCs. Accordingly, disruption of the TNFR1-mediated signaling pathway and blockade of DC generation may prove to be of therapeutic value in patients with cutaneous lupus erythematosus.

Autoantibodies from Sjögren's syndrome induce activation of both the intrinsic and extrinsic apoptotic pathways in human salivary gland cell line A-253

Sjögren's syndrome (SS) is an autoimmune rheumatic disease that targets salivary and lachrymal glands, characterized by a high concentration of serum autoantibodies directed against nuclear and cytoplasmic antigens. It is known that autoantibodies can enter viable cells and this phenomenon has functional consequences including activation of apoptotic process. The objective of this work was to explore whether autoantibodies contained in IgG purified from Sjögren sera trigger apoptotic process in an experimental model represented by the human salivary gland cell line A-253. To define if the intrinsic or extrinsic pathways are activated, we examined which caspases are critical for inducing cell death. The results have demonstrated that morphological changes and DNA laddering, consistent with apoptotic cell death, occurred in A-253 cells treated with IgG from Sjögren sera. Sjögren IgG induced cleavage and activation of the effector caspase-3 and degradation of the caspase-3 substrate poly(ADP-ribose)polymerase. Both the intrinsic and extrinsic apoptotic pathways were activated, since both caspase-8 and caspase-9 cleavages occurred. In conclusion, autoantibodies contained in IgG purified from Sjögren sera mediate apoptosis of the A-253 cell line in a caspase-dependent manner.

Lúpus eritematoso cutâneo: aspectos clínicos e laboratoriais

O lúpus eritematoso é doença auto-imune do tecido conjuntivo que reúne manifestações exclusivamente cutâneas ou multissistêmicas, podendo apresentar exuberância de auto-anticorpos. As lesões cutâneas do lúpus eritematoso são polimorfas e podem ser específicas ou inespecíficas. A diversidade de manifestações clínicas da doença reflete-se no amplo espectro de achados laboratoriais. Este artigo descreve as variadas formas clínicas do lúpus eritematoso cutâneo correlacionando-os com achados histopatológicos, de imunofluorescência direta e sorológicos.

Transient autoimmunity related to maternal autoantibodies: neonatal lupus

Neonatal lupus (NLE) is an autoimmune disease associated with maternal antibodies to Ro/La and characterized by cutaneous lesions, heart block, cardiomyopathy, hepatobiliary disease, and hematologic cytopenias. In most cases, only one organ is affected, although multiple organ involvement is not unusual. Since NLE is presumably caused by maternal autoantibodies, the disease process is transient. However, cardiac NLE, in particular, may be fatal or persistently disabling. Optimal therapy has not yet been determined. Mothers of babies with NLE are often initially asymptomatic, but eventually most develop symptoms of autoimmune disease, particularly diseases associated with anti-Ro/La autoantibodies, such as Sjogren's syndrome and systemic lupus erythematosus. Children who have had NLE are probably at increased risk for autoimmunity later in life, sometimes as early as pre-adolescence, but the magnitude of the risk for the children is not known. Only a small percentage of babies exposed to maternal autoantibodies to Ro and/or La develop NLE. The factors governing which babies develop disease and, if disease develops, which organs will be affected have yet to be fully elucidated. In this review the clinical features, diagnosis, therapy, and prognosis of NLE are discussed, and a summary of experimental data relating to pathogenesis is presented.

The intracellular 52-kd Ro/SSA autoantigen in keratinocytes is up-regulated by tumor necrosis factor ? via tumor necrosis factor receptor I

OBJECTIVE

Previous studies have shown that the nuclear Ro/SSA autoantigens involved in photosensitive cutaneous lupus manifestations are regulated by ultraviolet B (UVB) irradiation. UVB exposure triggers the release of tumor necrosis factor alpha (TNFalpha) from keratinocytes in the epidermis and from mast cells in the dermis. The present study aimed to characterize the effect of TNFalpha on messenger RNA (mRNA) and protein expression of the intracellular 52-kd Ro/SSA autoantigen in primary human keratinocytes and to elucidate the TNFalpha receptor (TNFR) signaling pathways mediating this effect.

METHODS

Expression of 52-kd Ro/SSA mRNA in primary human keratinocytes was investigated by quantitative real-time polymerase chain reaction (LightCycler system) using GAPDH as the housekeeping gene. Expression of 52-kd Ro/SSA protein was studied by flow cytometry after staining intracellular protein with IgG purified from an anti-52-kd Ro/SSA-positive serum. TNFR function was assessed by culturing cells in the presence and absence of neutralizing antibodies directed against the TNFR subunits TNFRI and TNFRII.

RESULTS

TNFalpha-induced up-regulation of 52-kd Ro/SSA mRNA expression peaked at 4 hours, followed by up-regulation of intracellular 52-kd Ro/SSA protein expression at 24 hours, independently of apoptosis. Between different donors, a high variability of both constitutive expression levels and TNFalpha-induced changes in 52-kd Ro/SSA mRNA and protein expression was observed. The up-regulatory effect of TNFalpha on 52-kd Ro/SSA mRNA and protein expression was inhibited by anti-TNFRI antibodies but enhanced by anti-TNFRII antibodies.

CONCLUSION

The finding that TNFalpha up-regulates 52-kd Ro/SSA expression in keratinocytes via TNFRI suggests that it may play a role in the pathogenesis of anti-Ro/SSA-associated cutaneous lupus erythematosus.

Differential expression of a human endogenous retrovirus E transmembrane envelope glycoprotein in normal, psoriatic and atopic dermatitis human skin

BACKGROUND

Psoriasis is a common inflammatory skin disease characterized by uncontrolled proliferation of keratinocytes and recruitment of T lymphocytes into the skin. The possible role of human endogenous retroviruses (HERVs) in the induction of psoriasis has been suggested, based upon the previous observations of retrovirus-like particles in psoriasis from skin lesional plaques, urine and stimulated lymphocytes.

OBJECTIVES

To investigate the expression of HERV-E transmembrane envelope glycoprotein (HERV-E env) in normal, psoriatic and atopic human skin, and to examine the influence of ultraviolet (UV) B irradiation on HERV-E env expression in normal human epidermal keratinocytes.

METHODS

The analysis was performed on both skin biopsies and organotypic skin cultures using immunofluorescence and Western immunoblotting. UVB irradiation (312 nm) of cultured normal human keratinocytes was performed using a dose of 30 mJ cm(-2).

RESULTS

Positive staining was observed in most of the psoriatic and atopic skin samples, whereas only 15% of the normal skin samples were faintly positive. In addition, the pattern of expression of HERV-E env differed markedly in psoriasis vs. atopy. By Western blotting analysis, two main proteins of 54 and 57 kDa were detected in extracts of normal skin, normal keratinocyte cultures and reconstructed epidermis from psoriatic and normal punch biopsies. An increased level of expression of these proteins was noted in extracts from psoriatic vs. normal reconstructed epidermis. The overexpression of the 57-kDa protein in normal human cultured keratinocytes was dramatically reduced by UVB irradiation.

CONCLUSIONS

These data suggest for the first time that HERV-E env is expressed in normal and pathological human skin. Further studies are now required to elucidate the role of such viral proteins in the pathogenesis of psoriasis.

Neonatal lupus erythematosus

Neonatal lupus Erythematosus (NLE) is a disorder characterized by maternal autoantibodies against RNA protein complex, Ro/SSA or SSB/La. These maternal IgG antibodies cross the placenta and potentially lead to fetal tissue damage and the clinical manifestations NLE. NLE is uncommon, affects females more than males, has no race predilection, and involves multiple organs. It has cutaneous manifestations similar to subacute cutaneous lupus erythematosus (SCLE). In addition to skin findings, patients with NLE have a significant risk of congenital heart block (CHB), a potentially fatal complication. Less frequently, hematologic and hepatic abnormalities occur. Approximately half of the reported cases have skin disease and half have CHB. Approximately 10% have both CHB and skin findings. The cutaneous, hematologic, and hepatic abnormalities are transient, clearing by 6 months of age. However, CHB is permanent and requires a pacemaker in many cases. The disorder results from the passive transfer of maternal autoantibodies, anti-RoSSA and anti-La/SSB. Sontheimer and McCauliffe reviewed the pathogenic role of anti-Ro antibody in NLE lesions and summarize evidence supporting its pathogenic role. Additional evidence suggests the possibility that Ro-antigen-specific T-cells may be present in SCLE patients and have the capacity to cause direct injury to the skin. McCuistion and Schoch first suggested this hypothesis in 1954 when they described an infant with LE skin findings born to a mother with systemic lupus erythematosus (SLE). Since this initial observation, a number of researchers have documented the role of maternal autoantibodies in the pathogenesis of this disorder. The true incidence of NLE is not known; however, it is known that NLE accounts for approximately 80% of all cases of CHB, and the incidence of CHB is 1 per 20,000 live births. Therefore, it can be assumed that the incidence of NLE is at least 1 per 12,500 live births.

Neonatal lupus erythematosus: clinical findings and pathogenesis

Neonatal lupus erythematosus is an uncommon disease associated with maternal autoantibodies to proteins of the Ro/La (SSA/SSB) family. The clinical findings most often reported are third-degree heart block and cutaneous lupus lesions, but a significant number of children have cardiomyopathy, hepatobiliary disease, or hematologic cytopenias. The consistent presence of maternal autoantibodies and the transient nature of the disease implicate maternal autoantibodies as the cause of the disease, and developing animal models support the concept that the autoantibodies are pathogenic. Only a minority of babies exposed to the autoantibodies develop disease, however, and mothers and their babies have different disease manifestations. Thus, additional factors are likely to be important in determining disease expression.

Anti-La/SSB antibodies transported across the placenta bind apoptotic cells in fetal organs targeted in neonatal lupus

OBJECTIVE

To determine whether La and/or Ro epitopes on apoptotic cells in fetal organs that are targeted in neonatal lupus syndrome (NLS) are accessible for binding by autoantibodies in vivo, we traced the fate of transplacental autoantibodies in a murine passive transfer model.

METHODS

Pregnant mice at day 15 of gestation (E15) were injected intraperitoneally with human anti-Ro/La-positive sera or control sera, and transplacental transfer of human autoantibodies was tested by enzyme-linked immunosorbent assay with recombinant antigens. Multiple cryostat sections at the level of the heart of E17 fetuses were visualized simultaneously for human IgG binding and apoptosis (TUNEL) under confocal microscopy. Serial paraffin sections of E17 and E19 fetuses were examined for histologic evidence of inflammation.

RESULTS

Human IgG anti-52-kd Ro, anti-60-kd Ro, and anti-La autoantibodies were transported efficiently into the fetal circulation. Human IgG-apoptotic cell complexes were detected in the heart (atrial trabeculae and atrioventricular node), skin, liver, and newly forming bone of fetuses from mothers injected with anti-Ro/La sera but not control sera. The IgG binding was fetal-specific and organ-specific; transplacental autoantibodies did not bind to apoptotic cells in the fetal thymus, lung, brain, or gut. The complexes were not associated with an inflammatory reaction. Injection of mothers with affinity-purified anti-La autoantibodies (but not anti-Ro/La Ig depleted of anti-La) revealed an identical location of IgG binding to apoptotic cells in the fetuses.

CONCLUSION

This is the first study to demonstrate that transplacental anti-La autoantibodies bind specifically to apoptotic cells in selected fetal organs in vivo, similar to the organ involvement in NLS. We hypothesize that additional factors are required to promote proinflammatory clearance of IgG-apoptotic cell complexes and subsequent tissue damage.

Oxidative stress mediates cell surface expression of SS-A/Ro antigen on keratinocytes

Exposure to ultraviolet radiation exacerbates the skin lesions of autoimmune diseases, and is known to induce cell surface expression of SS-A/Ro antigen on keratinocytes in vitro. Following up on recent reports on ultraviolet-B (UVB)-induced oxidative stress, we examined the role of oxidative stress in the surface expression of SS-A/Ro antigen on human keratinocytes. First, the exclusive induction by UVB irradiation of the 52-kDa protein (Ro52) but not of the 60-kDa protein (Ro60) of SS-A/Ro antigen was demonstrated by means of indirect immunofluorescence. The surface expression of Ro52 induced by UVB irradiation was concentration-dependently inhibited by N-acetyl-L-cysteine, an antioxidant. Furthermore, surface expression of Ro52 was similarly induced by diamide, a chemical oxidant. We next used Hoechst 33342 staining and the TUNEL assay to demonstrate that a low dose (20 mJ/cm(2)) of UVB did not induce apoptosis but induced the surface expression of Ro52. Moreover, zVAD-fmk, a pan-caspase inhibitor, did not inhibit UVB-induced surface expression of Ro52 even at a high dose (200 mJ/cm(2)) of UVB, which was sufficient to induce apoptosis in keratinocytes in the absence of zVAD-fmk. Taken together, we concluded that UVB-induced surface expression of Ro52 on keratinocytes is mediated by oxidative stress through a pathway other than apoptosis.

Neonatal lupus: clinical features, therapy, and pathogenesis

Neonatal lupus is a disease characterized by one or more of the following findings: congenital heart block, cardiomyopathy, cutaneous lupus lesions, hepatobiliary disease, and thrombocytopenia. Accumulating evidence indicates that the disease is probably caused by maternal autoantibodies, particularly autoantibodies of the Ro family. While often initially asymptomatic, mothers tend to develop symptoms of connective tissue disease. This review discusses the recent advances in the understanding of neonatal lupus, its clinical features, therapy, and pathogenesis.

SS-56, a novel cellular target of autoantibody responses in Sjögren syndrome and systemic lupus erythematosus

Certain autoimmune disorders, including Sjögren syndrome (SS) and systemic lupus erythematosus (SLE), are characterized by autoantibodies against the Ro/SSA and La/SSB cellular antigens. Although the implication of these autoantibodies in disease pathogenesis is still unclear, it is believed that the aberrant responses against autoantigens may extend to other proteins that are not yet well defined. In an attempt to analyze the regulated gene expression in lymphocytes by an HIV-suppressive immunomodulator, we have identified and cloned a novel gene encoding a 56-kDa protein, named SS-56, which is structurally related to the 52-kDa Ro/SSA antigen. The new protein showed primarily perinuclear cytoplasmic localization, and recombinant SS-56 was found to react in ELISA with sera from most patients with SS or SLE. Western blot analysis confirmed the autoantigenic nature of native SS-56 in extracts from HeLa cells. Interestingly, the incidence of antibodies to SS-56 was associated with visceral complications in SLE, and roughly half of the 17 SS or SLE patients with no detectable antibodies to SSA and SSB antigens presented measurable antibodies against recombinant SS-56. Thus, SS-56 represents a new member of the SS family of autoantigens and could become an additional and important diagnostic marker for SS and SLE.

Phototesting in lupus erythematosus: a 15-year experience

It has long been observed that sun exposure can induce or exacerbate skin lesions in patients with certain forms of lupus erythematosus. Despite the frequency of photosensitivity in these patients, the mechanism by which ultraviolet radiation alters the pathogenic course of this disease remains poorly understood. After development of standardized test methods, our group demonstrated in 1986 that skin lesions in patients with lupus erythematosus can be experimentally reproduced by UVA and UVB irradiation. In the following years, phototesting has received much attention as a valid model to study photosensitivity of different forms of lupus erythematosus and the pathogenetic mechanism of this disease. Further investigations have also made it possible to find genetic and immunologic factors associated with photosensitivity and have helped to identify the pathophysiologic steps involved in the induction of such skin lesions. We present phototesting results and clinical correlations of more than 400 patients with different forms of lupus erythematosus and discuss the recent advances in provocative phototesting.

Association of neutropenia in systemic lupus erythematosus (SLE) with anti-Ro and binding of an immunologically cross-reactive neutrophil membrane antigen

SLE is associated with the production of autoantibodies to self-constituents. In particular, certain ribonucleoprotein particles are targeted. Despite the multitude of autoantibodies produced and the remarkable concentrations of these antibodies in the sera of SLE patients, there have been little data that the autoantibodies found in SLE are involved in the pathogenesis of disease or its manifestations. The present work demonstrates that anti-Ro (or SSA) is associated with granulocytopenia, binds the surface of granulocytes and fixes complement to this membrane surface. Binding is a property of anti-Ro Fab fragments and can be inhibited by 60-kD Ro. However, the antigen bound on the surface of granulocytes is a 64 000 mol. wt protein that is a novel autoantigen in SLE. As suggested by inhibition studies, sequence identity between 60-kD Ro and eight tandem repeats in the 64-kD antigen may be responsible for the observed serologic cross-reactivity. These data imply that anti-Ro antibodies that also bind the 64-kD protein mediate neutropenia in patients with SLE.

Immunization of mice with human 60-kd Ro peptides results in epitope spreading if the peptides are highly homologous between human and mouse

OBJECTIVE

Immunization with peptide fragments of autoantigens may lead to an immune response at both the T and B cell level that is directed not only at the immunogen, but also at the autoantigen from which the peptide came. In addition, a complex multicomponent particle may become the target of this expanded immune response. The purpose of this study was to determine the ability of several different peptides from 60-kd Ro to induce expansion of the immune response to the Ro/La RNP particle.

METHODS

We immunized BALB/c mice with 3 different oligopeptides from human 60-kd Ro (or, SSA).

RESULTS

Animals immunized with peptides either identical to or differing by only 1 amino acid developed autoimmunity to the entire Ro RNP particle. Animals immunized with a human peptide highly divergent from the corresponding mouse sequence developed an immune response to the immunogen only and showed little evidence of epitope spreading. Furthermore, these mice did not have antibodies that bound the poorly conserved mouse homolog peptide, and the antibody response to this peptide did not include IgG1.

CONCLUSION

These data indicate that B lymphocytes specific for the self-peptide that is homologous to the immunogen are a critical determinant for spreading of the immune response to other components of self.

The relationship between facial annular erythema and anti-SS-A/Ro antibodies in three East Asian women

A distinct annular erythema developed on the cheeks of three East Asian women who had anti-SS-A/Ro (SSA) antibodies. The erythema was characterized by a wide, elevated border and central pallor. Histologically, there was a coat-sleeve-like infiltration of lymphocytes around the blood vessels, appendages, and secretory gland cells in the dermis. Immunohistological analysis clarified that the majority of infiltrating lymphocytes were CD4-positive T cells. Abnormal expression of HLA-DR antigens in the perivascular, appendage, and secretory gland cells in the dermis was also observed. The differential diagnosis of the three patients lay between Sjögren syndrome (SjS), Sjögren/systemic lupus erythematosus overlap syndrome and an asymptomatic clinical state. These results are consistent with recent findings of major histocompatibility complex class II expression on target organs in various autoimmune diseases. Based on these findings, erythema appears to represent a broad cutaneous manifestation of these diseases. Furthermore, the presence of SSA antibodies, aberrant HLA-DR expression, and sun exposure may be responsible for the development of erythema.

Detection of anti-Ro/SSA and anti-La/SSB autoantibody-producing cells in salivary glands from patients with Sjögren's syndrome

OBJECTIVE

To investigate and identify the presence of cells producing anti-Ro/SSA and anti-La/SSB autoantibodies in salivary glands from patients with Sjögren's syndrome (SS).

METHODS

Submucosal salivary gland biopsy samples from 10 SS patients (8 with and 2 without circulating Ro and La autoantibodies) and 14 control subjects were evaluated. Frozen tissue sections were immunostained by an avidin-biotin complex technique, using biotinylated recombinant Ro and La proteins as detection reagents. Autoantibody levels in SS patient sera were analyzed by enzyme-linked immunosorbent assay.

RESULTS

Cells producing autoantibodies to the Ro 52-kd, Ro 60-kd, and La proteins were recorded in 8, 6, and 7 of the 10 SS patient biopsy samples, respectively. Samples from the 2 SS patients without circulating Ro and La autoantibodies were negative for these autoantibody-producing cells, as were all control biopsy samples. A strong positive correlation between the presence of autoantibodies in sera and the presence of autoantibody-producing cells in glandular biopsy tissues was evident. The number of autoantibody-producing cells and the serum autoantibody levels were also correlated (r(s)=0.94, P < 0.0001).

CONCLUSION

Using a novel technique, we have demonstrated the presence of Ro and La autoantibody-producing cells in salivary gland biopsy tissues from patients with SS. These findings indicate that anti-Ro/ SSA and anti-La/SSB autoantibodies are produced and are present at sites of inflammation and indicate their potential involvement in the autoimmune exocrinopathy of this disease.

The significance of the 'dust-like particles' pattern of immunofluorescence. A study of 66 cases

Subacute cutaneous lupus erythematosus (SCLE) is a marker of a unique subset of lupus erythematosus patients. A 'dust-like particles' direct immunofluorescence (DIF) staining pattern, which consists of fine granular particles of immunoglobulin(s) scattered through the epidermis and the cellular infiltrates of the dermis, was reported to be specific for SCLE. In this study, we assessed the real specificity of this staining pattern, which had not yet been evaluated. We systematically searched for the dust-like particles staining pattern among the 4374 skin biopsy specimens submitted for direct cutaneous immunofluorescence during a 7-year period (1989-96). The corresponding patient records were reviewed. Dust-like particles were observed in 66 samples originating from 60 patients. Only 53% of the patients had SCLE. The remaining patients had systemic lupus erythematosus with visceral involvement (17%), discoid lupus erythematosus (3%), mixed connective tissue disease (2%). Sjögren syndrome (2%) and other diseases. Eighty-five per cent of the patients had connective tissue disease. Seventy-seven per cent of the patients were positive for antinuclear antibodies, but only 36% were positive for anti-Ro (SSA) antibodies. This study shows that the dust-like particles staining pattern is not specific for SCLE, but is highly suggestive of connective tissue disease. The nature of the antigen responsible for the immunoglobulin deposition and the prognostic significance of this DIF pattern remain to be established.

In Vitro Stimulation of C1s Proteolytic Activities by C1s-Presenting Autoantibodies from Patients with Systemic Lupus Erythematosus

Anti-C1s autoantibodies (IgG forms), which recognize the conjunction of C1s heavy chain and light chain (C1s-presenting autoantibodies) from patients with systemic lupus erythematosus (SLE), have been found to stimulate C1s enzymatic activities. This is due to acceleration of the proteolytic hydrolysis of the synthetic substrate C1-1 by C1s, enhancement of the complex formation of C1s with its natural pseudosubstrate, C1 inhibitor (C1 inh), and promotion of proteolytic activation of its natural substrate, C4. Seven of fifteen samples from patients with SLE were found to contain such autoantibodies. The hydrolysis of the synthetic substrate C1-1 catalyzed by C1s in 25 to 27 min in the presence of anti-C1s autoantibodies was equivalent to the hydrolysis of C1-1 catalyzed by C1s alone or C1s with control IgG from healthy sera in 110 min, approximately fourfold faster than the reaction in the absence of anti-C1s autoantibodies. Densitometry scanning data showed that the formation of the C1s-C1 inh complex in the presence of anti-C1s autoantibodies was three to four times greater than that with control IgG. It was also noticed that the autoantibodies convert almost all of the latent forms of C1s to an active form that binds to C1 inh. Another group of Western blots showed that C1s cleaved C4 α-chain three times faster in the presence of autoantibodies than of control IgG. It is likely that the overconsumption of complement components is common in the pathogenesis of tissue damage occurring in SLE.

Subacute cutaneous lupus erythematosus versus systemic lupus erythematosus: diagnostic criteria and therapeutic implications

BACKGROUND

The nosologic position of subacute cutaneous lupus erythematosus (SCLE) is controversial. More than four American Rheumatism Association (ARA) criteria for systemic lupus erythematosus (SLE) are found in a proportion of patients diagnosed as having SCLE; thus such cases could be classified as SLE.

OBJECTIVE

Our purpose was to determine whether ARA criteria for SLE are helpful in differentiating SCLE from SLE and whether cutaneous and visceral changes, immunologic findings, and photosensitivity provide a basis for diagnosis of SCLE.

METHODS

A cohort of 143 patients (79 with SCLE, 58 with SLE, and six with overlapping features of SCLE and SLE) was studied clinically, histologically, and immunologically as well as by phototesting. The patients were observed for up to 10 years, and the course of the disease and response to therapy were evaluated in each group.

RESULTS

SCLE differed from SLE by cutaneous changes, significantly less frequent kidney involvement, serositis and arthritis, and the rare presence of double-stranded DNA, U1RNP, and Sm antibodies characteristic of SLE. Ro(SS-A) and La(SS-B) antibodies were detected with similar frequency, and photosensitivity was not related to the presence of Ro antibody. In contrast, photoreproduction (appearance of LE lesion in irradiated area) was significantly more frequent in patients with SCLE. The course of SCLE in older patients was less severe than in younger patients, and aggressive therapy was usually not required.

CONCLUSION

Patients with SCLE (although the majority fulfill more than four ARA criteria for SLE) show significant differences from those with SLE in terms of cutaneous and visceral involvement, immunologic findings, photosensitivity, course of the disease, and the requirement for therapy. Therefore SCLE should be recognized as a separate subset. However, cases of overlapping SLE and SCLE suggest a close relation.

B cells and autoantibodies in the pathogenesis of lupus nephritis

Although autoantibodies and autoantibody-producing B cells are crucial for the initiation of lupus nephritis, their precise role in the development of the nephritic lesions is incompletely understood. This article summarizes the results of recent work in our laboratory related to this area. They indicate that not all autoantibodies are pathogenic. Furthermore, among the pathogenic subset, individual immunoglobulins produce clearly distinguishable immune deposit patterns in specific glomerular locations and this is associated with different disease profiles (i.e., inflammation, proteinuria). The variation in immune deposit formation induced by the individual autoantibodies are reminiscent of the different lesions in lupus patients, and they appear to be related to differences in the reactivity of autoantibodies with specific glomerular antigens. Thus, it appears that the predominant interaction in a given individual influences the morphologic and clinical expression of disease. Autoantibody-producing B cells also influence the activation of autoreactive T cells that infiltrate the kidney to produce vasculitis and interstitial nephritis, and the potential mechanisms responsible for this phenomenon are discussed.

Receptor-mediated cellular entry of nuclear localizing anti-DNA antibodies via myosin 1

A unique subset of anti-DNA antibodies enters living cells, interacts with DNase 1, and inhibits endonuclease activity, before their nuclear localization and subsequent attenuation of apoptosis. We now report that endocytosis of these immunoglobulins is mediated by cell surface binding to brush border myosin (myosin 1). Cellular entry and internalization via this unique receptor provides initial contact for entry and sorting these immunoglobulins to translocate to the nuclear pore and enter the nucleus, interact with DNase 1 within the cytoplasm, or recycle back to the cell surface. This internalization pathway provides clues to the translocation of large proteins across cell membranes and the functional effects of intracellular antibodies on cytopathology. This is the first demonstration that brush border myosin functions as a specific cell surface receptor for internalization of large proteins.

Cutaneous lupus erythematosus during the neonatal and childhood periods

Cutaneous lupus erythematosus may be related to maternal autoantibody production in the neonatal lupus syndrome, or may occur later in childhood, with or without findings of systemic lupus erythematosus (SLE). In the first section, we will discuss the transient, passively transferred neonatal disease, and in the second, we will discuss the persistent, actively acquired forms of lupus erythematosus in childhood.

The penetrating potential of autoantibodies into live cells in vitro coincides with the in vivo staining of epidermal nuclei

We have previously demonstrated that IgG autoantibodies derived from SLE patients are capable of penetrating into nuclei of living COLO-16 cells, in vitro. To address the possible correlation in Lupus Erythematosus (LE) between the in vivo ANA binding to nuclei of epidermal cells and the presence of intranuclear penetrating antibodies in sera of those patients, 25 consecutive patients were studied. Out of 25 skin biopsies, 11 specimens (8 of SLE and 3 of DLE) showed by immunofluorescent microscopy extensive in vivo presence of IgG in epidermal nuclei, whereas all sera of these patients stained nuclei of living COLO-16 cells, in vitro. Such penetration was also observed in additional 6/25 sera of patients, but with in vivo negative biopsies. This in vitro nuclear binding, which was unrelated to clinical symptoms of patients or their serological autoantibody profile and titer, was reproduced following cross-linking of intracellular protein by PLP fixation. Likewise, western blotting (immunoblotting) analysis, demonstrated the intranuclear presence of IgG in all in vitro intranuclear IgG staining sera. Furthermore, this in vitro presence, which neither affects cell viability nor DNA synthesis, is time-dependent and of a transient nature: nuclear staining disappears within 48 h following removal of the penetrating sera from medium. In conclusion, since the COLO-16 in vitro assay mirrors exactly the in vivo situation, and because of its higher sensitivity, it provides an excellent tool for the study of non-degraded autoantibody penetration into the nuclei of living cells.