Pathogenesis of Anti-Ro/SS-A Autoantibody-Associated Cutaneous Lupus Erythematosus

Antimalarial lichenoid tissue reactions in patients with pre-existing lupus erythematosus

Recently a number of cases of drug induction or exacerbation of lupus erythematosus (LE) specific skin disease have been described in the literature. Many of the responsible medications are also known for their ability to induce a lichenoid tissue reaction. Aminoquinoline antimalarials are currently the first line of therapy in cutaneous LE specific skin disease. Lichenoid tissue reactions are among the most common cutaneous side effects of aminoquinolone antimalarials. We report three cases of aminoquinolone antimalarial induced or exacerbated LE specific skin disease. We also review the pathophysiology of LE specific skin disease and propose a mechanism by which induction of the lichenoid tissue reaction may result in Koebnerization of LE specific skin lesions.

Pathogenesis of cutaneous lupus erythematosus: common and different features in distinct subsets

The term 'cutaneous lupus erythematosus' (CLE) comprises several related autoimmune skin disorders, defined as 'specific' skin manifestations of lupus erythematosus (LE). The spectrum of clinical presentation of CLE is wide, reaching from mild erythema to disseminated scarring skin lesions. There is increasing knowledge concerning the pathogenesis of LE skin lesions and it has been shown that a complex network of cutaneous cytokines, chemokines and adhesion molecules orchestrate and promote tissue injury observed in LE skin lesions. However, a complete understanding of the diverse pathophysiological mechanisms in the different CLE subsets does not exist. Here we review the main pathological features described in CLE patients against the background of the clinical diversity of different CLE subtypes.

A case of neonatal lupus erythematosus showing transient anemia and hepatitis

Neonatal lupus erythematosus (NLE) is an autoimmune disease that is associated with transplacental passage of maternal autoantibodies that are reactive to SSA/Ro and SSB/La antigens. Cardiac involvement, hematologic abnormality and hepatic disease may occur in the infants suffering with NLE, in addition to the characteristic skin lesions. We report here on a case of NLE in a 4-week-old female infant who was born to an asymptomatic mother, and the baby displayed the characteristic clinical and histological features of cutaneous NLE with transient anemia and hepatitis. Both the infant and mother were positive for anti-SSA/Ro and anti-SSB/La. There have been 18 case reports of NLE in the Korean literature, including 7 case reports in the dermatological field. We describe herein another case of NLE that showed transient anemia and hepatitis, and we also review the case reports of NLE in the Korean literature.

Identification of type I interferon-associated inflammation in the pathogenesis of cutaneous lupus erythematosus opens up options for novel therapeutic approaches

Cutaneous lupus erythematosus (CLE) is one of the most common dermatological autoimmune disorders worldwide. Recently, several studies provided evidence for a pathogenic role of type I interferons (IFNs) in this disease. Plasmacytoid dendritic cells are major type I IFN producers in CLE skin lesions. Type I IFNs are able to induce the expression of several proinflammatory chemokines, including CXCL9 and 10, and enhance the cytotoxic capacity of infiltrating cells. Additionally, adhesion molecules and chemokine receptors, such as intercellular adhesion molecule-1, cutaneous lymphocyte antigen, E-selectin, CCR4 and CXCR3, are involved in the recruitment of potentially autoreactive lymphocytes into the skin. Here, we review the role of type I IFNs, adhesion molecules and chemokine receptors in CLE and discuss options for novel therapeutic approaches.

Anti-La/SSB antiidiotypic antibodies in maternal serum: a marker of low risk for neonatal lupus in an offspring

OBJECTIVE

The anti-La/SSB response to major B cell epitopes of La/SSB can be blocked by an active idiotypic/antiidiotypic network, which can be identified using synthetic complementary epitopes deduced from the sequence of the major B cell epitopes of the molecule. This study evaluated the role of this network in pregnant women with anti-Ro/SSA and/or anti-La/SSB antibodies in the development of neonatal lupus syndrome (NLS).

METHODS

Sixty-three serum samples collected from anti-Ro/anti-La-positive women during pregnancy or within 6 months after delivery were obtained from the Research Registry for Neonatal Lupus and the PR Interval Dexamethasone Evaluation study. These samples, as well as 30 sera from healthy individuals, were tested in a blinded manner by enzyme-linked immunosorbent assay against synthetic peptides corresponding to major B cell epitopes and complementary epitopes of La/SSB.

RESULTS

Sera from mothers giving birth to a healthy child and having no history of a child with NLS exhibited higher antiidiotypic antibody activity compared with mothers carrying a child with NLS (P < 0.0001) or mothers giving birth to a healthy child but who previously gave birth to a child with NLS (P = 0.0151). Sera from mothers of healthy children, which exhibited no apparent epitope activity against amino acids 349-364, revealed a significantly greater frequency of hidden anti-349-364aa epitope responses, blocked by antiidiotypic antibodies, as compared with sera from women pregnant with an affected child (P = 0.0094).

CONCLUSION

The presence of antiidiotypic antibodies to autoantibodies against La/SSB may protect the fetus by blocking pathogenic maternal autoantibodies. Testing for these antiidiotypic responses may be useful in predicting a decreased risk of NLS.

Comparison of Different Test Systems for Simultaneous Autoantibody Detection in Connective Tissue Diseases

The serological diagnosis of connective tissue diseases (CTDs) is based on the analysis of circulating autoantibodies to cytoplasmic and nuclear proteins (extractable nuclear antigens [ENAs]). The determination of autoantibody specificities supports the clinical diagnosis of the type of CTD and also often the prognosis of the disease. The former indirect immunofluorescence (IIF) technique still provides a useful screening method that currently is supplemented by a range of different techniques allowing the exact determination of single autoantibody specificities. These ENA profiling techniques include ELISA, immunoblotting, line-blot assays, and flow cytometric bead-based multiplex assays. The novel line immunoassay (LIA) from Mikrogen has been introduced in a recent study as a suitable technique for the simultaneous detection of autoantibodies in a routine clinical laboratory, providing comparable results as ELISA and ELiA (both from Pharmacia Diagnostics) (see Damoiseaux et al., this volume). In this study, LIAs from three different manufacturers were performed in 30 serum samples from patients with dermatological manifestations and 27 samples from SLE patients with renal involvement. The line assays from Mikrogen (recomLine ANA/ENA), Innogenetics (Inno-Lia ANA Update), and Imtec (ANA-LIA) were compared for antigen composition, handling, and statistical analysis including sensitivity and concordance. Autoantibody frequencies detected by the Mikrogen, Innogenetics, and Imtec line assays were 14.0%, 19.3%, and 15.8% for RNP; 14.0%, 22.8%, and 14.0% for Sm; 26.3%, 31.6%, and 40.3% for SSA; 3.5%, 12.3%, and 14.0% for SSB; and 3.5%, 14.0%, and 10.5% for histones. Our studies show that the line assay format is an easy-to-use, sensitive, and specific method for ENA antibody detection in human sera.

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.

Pneumocystis carinii mimicking neonatal lupus erythematosus-related pneumonitis

Neonatal lupus erythematosus (LE) is a rare disease associated with the transplacental passage of maternal autoantibodies to infants who manifest congenital heart block, skin disease, and less commonly, hematologic and hepatic disease. Pulmonary disease is a rare manifestation of neonatal LE and has presented as transient pneumonitis. In this report we describe an infant with neonatal LE who had the classic skin and hematologic findings of the disease in addition to pulmonary disease which might be attributed to neonatal LE-related pneumonitis, but in fact was caused by a concomitant Pneumocystis carinii infection. This case demonstrates the importance of looking for other causes of pulmonary disease in neonatal LE patients.

Neonatal lupus syndrome: the heart as a target of the immune system

Neonatal lupus erythematosus (NLE) is an auto-immune disease related to systemic lupus erythematosus (SLE). Unlike SLE it is not a spontaneous syndrome but rather an acquired one. In NLE the most common disease manifestations are a transient cutaneous lesion and cardiac conduction disturbances. The cutaneous lesions and other non-cardiac manifestations of NLE are transient and disappear about six months after birth, at the time when maternal antibodies disappear from the neonatal circulation. This fact suggests that maternal antibodies may cross the placenta leading to an inflammatory reaction in the fetal tissues. NLE is the principal cause of atria-ventricular block, when it is not associated with congenital birth defects. All the clinical studies to date correlate the heart block in NLE with the presence of certain types of circulating maternal antibodies, against the Ro/SSA nuclear proteins, in the serum of the newborn. In this paper we discuss animal models that have been developed by our and others groups to study the participation of the anti-Ro/SSA antibodies in the pathogenesis of the cardiac conduction blockades that occur in NLE.

Subacute cutaneous lupus erythematosus associated with cinnarizine and thiethylperazine therapy

We report the case of a woman who developed subacute cutaneous lupus erythematosus (SCLE) after exposure to the sun while taking cinnarizine and thiethylperazine. The patient recalled that 10 years previously, a similar eruption had appeared after sunbathing, while she was taking only cinnarizine. SCLE development in this patient was probably drug related and there is some evidence that cinnarizine played an important pathogenic role.

Ultraviolet-A1 (340-400 nm) irradiation therapy in systemic lupus erythematosus

Ultraviolet-A1 (UV-A1) wavelengths have been found effective in mitigating signs and symptoms of disease activity in systemic lupus erythematosus (SLE) but studies have been uncontrolled. To rigorously assess the effectiveness and safety of daily low-dose UV-A1 irradiation as a therapeutic agent in this disorder we enrolled 26 women with SLE in an 18-week two-phase study. During the initial six-week prospective, double-blind, placebo-controlled phase, the patients were divided into two groups; Group A was exposed to 60kJ/m2 of UV-A1 (340-400 nm) irradiation within a sunbed five days a week for three weeks and Group B was exposed for an equal amount of time to visible light of greater than > 430 nm (placebo). Each group was then crossed over for exposure to the other source for three weeks. During the second phase-2 weeks-patients and physicians were unblinded and patients were irradiated with progressively decreasing levels of UV-A1 only. Twenty-five patients completed the six-week placebo-controlled phase of the study and eighteen patients participated for the entire 18 weeks. In Group A the systemic lupus activity measure (SLAM) score improved significantly after three weeks of five-day-a-week UV-A1 irradiation (P < 0.05), regressing to baseline during the three weeks of placebo irradiation. Improvement recurred and progressed with six weeks of three-day-a-week UV-A1 irradiation (P < 0.05). Group B patients responded negligibly to the three weeks of visible light, more sharply to UV-A1, and as with Group A, maximally to the six weeks of three-day-a-week UV-A1 (P < 0.01). With twice- and then once-weekly UV-A1 irradiation the SLAM scores worsened slightly. All patients decreased their drug use. Anti-double-stranded DNA antibodies (anti-dsDNA) decreased significantly (P < 0.05) and anti-nuclear antibodies non-significantly. Side effects were negligible. Visible light had no significant effect. In conclusion, low-dose UV-A1 irradiation effectively, comfortably, and without apparent toxicity diminished signs and symptoms of disease activity in SLE.

Cytomegalovirus infection induces expression of 60 KD/Ro antigen on human keratinocytes

To investigate the effect of human cytomegalovirus (CMV) infection on the expression of Ro autoantigen in human keratinocytes, the binding of anti-Ro peptide antibodies (anti-60 KD/Ro, anti-52 KD/Ro and anti-calreticulin) to cultured human keratinocytes was detected by fixed cell enzyme-linked immunoassay (ELISA), immunofluorescence, flow cytometry (FACS) analysis and immunoblotting. There was a significant increase in the binding of anti-60 KD/Ro antibody but not anti-52 KD/Ro or anti-calreticulin antibody to the surface of cultured keratinocytes at 24 h after CMV infection compared with uninfected cells, by ELISA and immunofluorescence. Surface binding of anti-60 KD/Ro was found in 71.2% (+/- 5.5%) of CMV-infected cells compared with 26.2% (+/- 4.1%) of untreated cells (P < 0.05) by FACS analysis. Similar observations were made with a human serum which contained anti-60 KD/Ro antibodies. Immunoblotting was used to analyse total cellular 60 KD/Ro antigen expression in keratinocytes infected with CMV or without infection. No increase in the intensity of the 60 KD band was found in extracts of the CMV-infected cells, suggesting that the 60 KD/Ro antigen is redistributed from the cytoplasm to the cell surface after viral infection. The effects of CMV infection on cell cultures were compared with those of ultraviolet B (UVB) irradiation. The 60 KD/Ro, 52 KD/Ro and calreticulin were all induced on the UVB-irradiated cell surface but not significant synergistic effect of UVB and CMV was found. This study provides evidence that CMV infection induced 60 KD/Ro antigen expression on the surface of human keratinocytes, suggesting that CMV may play a role in development of skin lesions in systemic lupus erythematosus (SLE).

Impact of ultraviolet irradiation on expression of SSA/Ro autoantigenic polypeptides in transformed human epidermal keratinocytes

SSA/Ro autoantibodies are frequently found in various autoimmune disorders including subacute cutaneous and neonatal lupus erythematosus. SSA/Ro patient sera precipitate a ribonucleoprotein complex consisting of multiple polypeptides and small RNA molecules (hY RNA). Such sera react in Western blot with at least four antigenically distinct proteins having molecular weights of 52-60 kD. Several laboratories have reported increased binding of anti-SSA/Ro patient serum to viable cultured human epidermal keratinocytes following UVB irradiation. However, it is currently unknown which SSA/Ro molecule(s) might be responsible for this increased antibody binding to UVB irradiated keratinocytes. To address this question, we studied the effect of UVB irradiation on the expression of three different polypeptide components of the SSA/Roautoantigen complex (60 kD SSA/Ro, 52 kD SSA/Ro, and 46 kD SSA/Ro (calreticulin) in A431 cells, a transformed human epidermal keratinocytes cell line. Total cellular and cell surface expression of each SSA/Ro antigenic polypeptide was examined by a whole cell ELISA and FACS using rabbit anti-synthetic peptide antisera as probes. Our results suggest that both total cellular and cell surface calreticulin, but not the 60 and 52 kD SSA/Ro polypeptides, is increased after 100 J/M2 of UVB irradiation, indicating that perturbed calreticulin expression may be primarily responsible for the UVB-induced increased binding of anti-SSA/Ro to keratinocytes. These results suggest that calreticulin could be a critical component of the SSA/Ro ribonucleoprotein complex that is involved in the pathogenesis of anti-SSA/Ro-associated photosensitive LE skin lesions.

Neonatal lupus erythematosus

We present a case of neonatal lupus erythematosus (NLE) in a black infant presenting with symmetrical depigmented macules on the face resembling vitiligo. NLE is a rare condition affecting newborn infants of mothers who have connective tissue disease, with or without autoantibodies to extractable nuclear antigens Ro (SS-A), La (SS-B) or ribonucleoproteins. Infants present with cutaneous lesions or congenital heart block or both. The skin lesions are usually annular and erythematous and transient and resemble those of subacute cutaneous lupus erythematosus. The presentation of this patient was therefore striking.

La (SS-B)-positive neonatal lupus erythematosus: report of a case with unusual features

Neonatal lupus erythematosus is most often associated with autoantibodies against Ro and La antigens. Rarely, neonatal lupus erythematosus occurs in the absence of Ro antibody. We present a case of La antibody-positive neonatal lupus erythematosus with unusual features.

Molecular characterization of the Ro/SS-A autoantigens

Molecular techniques have recently revealed that there are several immunologically distinct Ro/SS-A antigens. Three genes encoding putative Ro/SS-A protein antigens with calculated masses of 46, 52, and 60 kD have been isolated. The encoded amino acid sequence of each is quite dissimilar. The 46-kD antigen is calreticulin (CR), a highly conserved calcium-binding protein that resides predominately in the endoplasmic reticulum where it may be involved in protein assembly. Although CR has recently been confirmed to be a new human rheumatic disease-associated autoantigen, its relationship to the other components of the Ro/SS-A ribonucleoprotein has become somewhat controversial owing predominately to the fact that recombinant forms of calreticulin have not displayed the same pattern of autoantibody reactivity possessed by the native form of this protein. The 52-kD antigen most likely resides in the nucleus and may be involved in the regulation of gene expression. The cellular location and function of the 60-kD antigen is uncertain but studies indicate that it is a RNA-binding protein. The 46- and 60-kD antigens share homology with foreign polypeptides, suggesting that an immune response initially directed against a foreign protein may give rise to the autoimmune response directed at cross-reacting self proteins.

Avian scleroderma: evidence for qualitative and quantitative T cell defects

T cell activation is dependent upon calcium influx and protein kinase C activation, with subsequent lymphocyte proliferation dependent upon IL-2. Abnormalities in T cell proliferation, including abnormal calcium influx and defective protein kinase C activation, have been identified in aged mice and humans and many autoimmune diseases including diabetes, lupus and scleroderma. Since UCD line 200 chickens, which spontaneously develop a scleroderma-like disease, have both thymic defects and a diminished peripheral blood lymphocyte response to IL-2, we have further investigated T cell function in these birds. Interestingly, line 200 T cells respond poorly in vitro to a variety of diversely acting T cell mitogens including concanavalin A, phytohemagglutinin and anti-chicken CD3 monoclonal antibody. Moreover, they do not respond well even to phorbol myristate acetate in conjunction with ionomycin. Addition of exogenous IL-2-containing supernatant concurrently with mitogenic stimulation also had no significant effect. Analysis of intracellular free calcium demonstrated that the lymphocytes from diseased birds had a reduced influx of calcium (or release for intracellular stores) following stimulation. These data clearly reflect a unique defect in T cell activation associated with avian scleroderma. Analysis of chicken CD3, CD4 and CD8 expression revealed a 39% decrease in peripheral blood CD4+ cells in scleroderma birds, although this decrease was not sufficient to explain the 80-90% decrease observed in proliferation assays and calcium influx. Our data support the hypothesis that avian scleroderma is mediated via abnormal function of lymphocyte co-stimulatory molecules or intracellular calcium regulators.