The recognition of human 60-kDa Ro ribonucleoprotein particles by antibodies associated with cutaneous lupus and neonatal lupus

IL-33/ST2 Activation Is involved in Ro60-Regulated Photosensitivity in Cutaneous Lupus Erythematosus

Interleukin- (IL-) 33 contributes to various inflammatory processes. IL-33/ST2 activation participates in systemic lupus erythematous via binding to the receptor of Suppression of Tumorigenicity 2 protein (ST2). However, whether IL-33/ST2 interferes with the nosogenesis of cutaneous lupus erythematosus (CLE) has not been reported so far. Herein, we proposed to disclose the impacts on IL-33/ST2 activation and Ro60 on CLE and their potential implications in the photosensitization of CLE cells. IL-33, ST2, and Ro60 in CLE patients' skin lesions were detected. Murine keratinocytes stimulated with or without IL-33 were irradiated by ultraviolet B (UVB), and the levels of Ro60 and inflammation markers were determined. Keratinocytes were cocultured with J774.2 macrophages and stimulated with IL-33 for analysis of chemostasis. The results identified that IL-33, ST2, and downstream inflammation markers were significantly upregulated in CLE lesions with Ro60 overexpression. Additionally, IL-33 treatment promoted the upregulation of Ro60 induced by UVB treatment in murine keratinocytes. Moreover, IL-33 stimulates keratinocytes to induce macrophage migration via enhancing the generation of the chemokine (C–C motif) ligands 17 and 22. Meanwhile, the silencing of ST2 or nuclear factor-kappa B (NF-κB) suppression abolished IL-33-induced upregulation of Ro60 in keratinocytes. Similarly, the inhibition of SOX17 expression was followed by downregulation of Ro60 in keratinocytes following IL-33 stimulation. In addition, UVB irradiation upregulated SOX17 in keratinocytes. Conclusively, the IL-33/ST2 axis interferes with Ro60-regulated photosensitization via activating the NF-κB- and PI3K/Akt- and SOX17-related pathways.

Complement-4 deficiency in a child with systemic lupus erythematosus presenting with standard treatment-resistant severe skin lesion

The complement system is of great importance in systemic lupus erythematosus. Complete genetically determined deficiencies are with few exceptions reported for the various complement proteins, and most of the deficiency states are rare. Deficiencies of the factors in the classical pathway are also associated with development SLE and SLE-like disorders. Most of the patients with lupus present skin involvement. Approximately, 75-95% of patients with cutaneous lupus erythematosus respond to antimalarial therapy and/or topical glucocorticosteroids. Immunosuppressive agents are usually considered a second-line approach in patients with resistant disease. In this study, we present the clinical features and determine the molecular basis responsible for the complete C4A and C4B deficiencies in a lupus patient presented subacute cutaneous lupus erythematosus and resistance to treatment.

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.

Differential tissue targeting of autoimmunity manifestations by autoantigen-associated Y RNAs

OBJECTIVE

To assess the Y RNAs, a family of homologous RNAs that bind to the Ro autoantigen, for the ability to contribute to autoimmune disease by activating RNA-responsive Toll-like receptors (TLRs).

METHODS

Using cell lines expressing or stably transfected with TLR-3, TLR-7, or TLR-8, we determined the patterns of RNA-specific TLR activation by in vitro transcripts of all of the known murine and human Y RNAs. Next, 8-10-week-old female mice were exposed to a single 50-microg subcutaneous injection of mouse Y1 or mouse Y3 RNA, and the effects were observed.

RESULTS

Y RNA family members differed in their TLR reactivities. Both human and mouse Y3 RNAs, but not other human or mouse Y RNAs, prominently induced TLR-3 activation. Although most human and mouse Y RNAs activated TLR-7 efficiently, mouse Y3 RNA and human Y5 RNA did not. Single subcutaneous injections of mice with either mouse Y1 RNA or mouse Y3 RNA induced or inhibited lymphoid infiltrates in different target organs based on the Y RNA and TLR status of the mouse used. Mouse Y1 RNA induced kidney lesions in TLR-3-intact mice but not in TLR-3-knockout mice. In contrast, mouse Y3 RNA treatment was associated with nephritis in TLR-3-knockout mice but not in TLR-3-intact mice. Sialoadenitis developed in untreated TLR-3-/- mice and in TLR-3-/- mice treated with mouse Y3 RNA, but sialoadenitis was not present in TLR--/-) mice treated with mouse Y1 RNA.

CONCLUSION

Y RNAs can induce innate immune responses and influence clinical manifestations of autoimmunity, suggesting that they are relevant to syndromes of anti-Ro autoimmunity. Distinct patterns of tissue targeting can be seen after exposure to different Y RNAs, in a pattern that correlates with the innate immune signals they induce. Thus, the balance of innate immune signals induced by exposure to endogenous Y RNAs may help determine the nature of the clinical syndrome in anti-Ro autoimmunity.

Mycophenolate sodium for subacute cutaneous lupus erythematosus resistant to standard therapy

BACKGROUND

Approximately 75-95% of patients with cutaneous lupus erythematosus respond to antimalarial therapy and/or topical glucocorticosteroids. Immunosuppressive agents are usually considered a second-line approach in patients with resistant disease.

OBJECTIVES

This was a prospective, nonrandomized, open pilot study to evaluate the efficacy of mycophenolate sodium monotherapy in patients with recalcitrant subacute cutaneous lupus erythematosus (SCLE).

METHODS

Monotherapy with oral enteric-coated mycophenolate sodium 1440 mg daily was given for a total of 3 months. Treatment outcome was evaluated by means of a validated clinical score for cutaneous lupus erythematosus, the Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI), as well as 20-MHz ultrasound measurements and colorimetry. Safety assessment included the monitoring of adverse effects and clinical laboratory parameters.

RESULTS

Ten patients with active SCLE resistant to at least one standard therapy were included in the trial. Mycophenolate sodium led to a remarkable improvement of skin lesions, resulting in a significant decrease of the mean +/- SD CLASI from 10.8 +/- 6.0 at the beginning to 2.9 +/- 2.6 at the end of therapy. Clinical improvement was confirmed by ultrasonographic assessments and colorimetry. No serious side-effects were noted.

CONCLUSIONS

Mycophenolate sodium is beneficial and safe in the treatment of patients with SCLE that failed standard therapy. However, these preliminary data must be confirmed by randomized controlled trials including a larger sample size.

Practical evaluation of methods for detection and specificity of autoantibodies to extractable nuclear antigens

Detection and specificity of autoantibodies against extractable nuclear antigens (ENA) play a critical role in the diagnosis and management of autoimmune disease. Historically, the detection of these antibodies has employed double immunodiffusion (DID). Autoantibody specificity was correlated with diagnoses by this technique. Enzyme immunoassays have been developed by multiple manufacturers to detect and identify the specificity ENA autoantibodies. To address the relationship of ENA detection by DID and enzyme immunoassay, the performances of five immunoassays were compared. These included two DID and three enzyme-linked immunoassays (ELISA) (both screening and individual antigen profile kits). The sample set included 83 ENA-positive, antinuclear-antibody (ANA)-positive specimens, 77 ENA-negative, ANA-positive specimens, and 20 ENA- and ANA-negative specimens. Sensitivity and specificity were calculated by two methods: first, by using the in-house DID result as the reference standard, and second, by using latent class analysis, which evaluates each kit result independently. Overall, the results showed that the ELISA methods were more sensitive for detection of ENA autoantibodies than DID techniques, but presence and/or specific type of ENA autoantibody did not always correlate with the patient's clinical presentation. Regardless of the testing strategy an individual laboratory uses, clear communication with the clinical staff regarding the significance of a positive result is imperative. The laboratory and the clinician must both be aware of the sensitivity and specificity of each testing method in use in the clinical laboratory.

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.

Neonatal lupus: clinical features and management

Neonatal lupus is an uncommon autoimmune disease manifested primarily by cutaneous lupus lesions and/or congenital heart block. Maternal autoantibodies of the Ro/La family are present in virtually every case, although only approximately 1% of women who have these autoantibodies will have a baby with neonatal lupus. The cutaneous lesions of neonatal lupus may be present at birth, but more often develop within the first few weeks of life. Lesions are most common on the face and scalp, often in a distinctive periorbital distribution. Lesions tend to resolve in a few weeks or months without scarring. The most common cardiac manifestation of neonatal lupus is complete heart block. Heart block typically begins in utero during the second or third trimester. In some cases, heart block begins as first- or second-degree block and then progresses to third-degree block. Complete heart block, once established, appears to be irreversible. In some cases, cardiomyopathy occurs together with complete heart block. Most cases have been noted at birth, but delayed dilated cardiomyopathy has been reported. There have been a few cases of endocardial fibroelastosis occurring in the absence of congenital heart block. Hepatobiliary disease occurs in about 10% of cases. Three types of hepatobiliary disease have been observed: liver failure occurring at birth or in utero, transient conjugated hyperbilirubinemia occurring in infants, or transient transaminase elevations occurring in infants. Hematologic disease, consisting of thrombocytopenia, neutropenia, or anemia, occurs in about 10% of cases. It is common for children with neonatal lupus not to have the full expression of disease, but rather to have only one or two organ systems involved. The diagnosis rests largely on the finding of compatible clinical manifestations plus maternal autoantibodies to Ro and/or La, or, in a few cases, to U1 ribonuclear protein. Although the pathogenesis has not been conclusively established, accumulating evidence, including evidence from animal models, implicates autoantibodies in the pathogenesis of the disease. Therapeutic interventions include attempts at prevention, early intervention, and treatment of well established disease, mainly through the use of systemic corticosteroids. Optimal therapy has yet to be determined. The long-term prognosis for children who have had neonatal lupus is still under investigation, but some children who had neonatal lupus have developed other autoimmune diseases later in childhood. About half of the mothers are asymptomatic at the time of presentation of the child, but some of these women eventually develop symptoms of autoimmune disease.

Keratinocytes from patients with lupus erythematosus show enhanced cytotoxicity to ultraviolet radiation and to antibody-mediated cytotoxicity

Keratinocyte cytotoxicity is an important component of the immunopathology of photosensitive lupus erythematosus, and antibody-dependent cell-mediated cytotoxicity (ADCC) has been shown to be an important mechanism by which autoantibodies, especially those specific for SS-A/Ro, can induce keratinocyte damage in models of photosensitive lupus. We provide further evidence that keratinocytes from patients with photosensitive lupus show significantly greater ultraviolet radiation (UVR)-induced cytotoxicity, and that ADCC of these targets is especially enhanced by autologous patient's serum or by anti-SS-A/Ro+ sera. Keratinocytes from normal uninvolved skin of 29 patients with cutaneous lupus erythematosus (LE) were grown in cell culture and tested as targets in cytotoxicity experiments in vitro. Cultured keratinocytes from patients with systemic lupus erythematosus (SLE) and subacute cutaneous lupus erythematosus (SCLE) showed significantly greater cytotoxicity following UVR treatment than did keratinocytes from normal adult controls or from neonatal foreskins (P < 0.01). The same cultures also showed greater UVR-induced binding of IgG from fractionated anti-SS-A/Ro+ preparations. ADCC experiments were also performed using keratinocytes cultured from patients with SLE, SCLE, discoid lupus erythematosus (DLE), and normal controls. When keratinocytes were incubated in autologous serum plus a standard mononuclear cell effector population, the percentage of ADCC observed was significantly greater in cultures containing keratinocytes and sera from the SLE and SCLE patients (P < 0.001). When cultured keratinocytes were added to different IgG antibody probes, plus standard mononuclear effector populations, greater ADCC was seen using the anti-SS-A/Ro probe and keratinocytes from patients with SLE or SCLE. With normal human neonatal keratinocyte targets, the anti-SS-A/Ro probe induced greater ADCC than that seen with anti-ssDNA or normal human serum. We have shown that keratinocytes from patients with some forms of lupus erythematosus (SLE and SCLE) show greater cytotoxicity in vitro when irradiated with UVR, and greater susceptibility to ADCC whether the antibody source is their own serum or an anti-SS-A/Ro probe.

Spectrum and clinical significance of autoantibodies against transfer RNA

OBJECTIVE

To characterize the clinical features of patients who have autoantibodies against transfer RNA (tRNA) or tRNA-associated proteins.

METHODS

Sera from 1,472 patients with suspected systemic rheumatic disease were screened by RNA immunoprecipitation of HeLa cell extracts. The specificities of the antibodies that precipitated tRNAs were further analyzed by immunoprecipitation using deproteinized RNAs and 35S-methionine-labeled HeLa cell extracts, followed by immunoblotting.

RESULTS

Forty-one serum samples (2.8%) were found to immunoprecipitate tRNAs. Thirteen patients were identified as having previously defined anti-aminoacyl-tRNA synthetase antibodies (anti-histidyl-tRNA synthetase in 4 patients, anti-threonyl-tRNA synthetase in 1, anti-alanyl-tRNA synthetase in 3, anti-glycyl-tRNA synthetase in 4, and anti-isoleucyl-tRNA synthetase in 1). All 13 patients had myositis and/or interstitial pneumonitis. Sera from the remaining 28 patients immunoprecipitated previously unidentified tRNAs, including 13 serum samples that bound deproteinized cognate tRNA; 24 of the 28 patients met criteria for either systemic lupus erythematosus (SLE) or Sjögren's syndrome (SS). In addition, nonerosive polyarthritis, leukocytopenia, rheumatoid factor, and characteristic annular or papulosquamous recurrent erythema were noted in these patients; however, renal involvement was rare. Sera from 16 of these 28 patients also contained anti-Ro/SSA and/or anti-La/SSB antibodies. While 189 patient sera precipitated Ro/SSA and/or La/SSB-associated RNAs but not tRNA, only 12 of the patients (6.3%) developed skin lesions (P=0.0009, odds ratio 8.85).

CONCLUSION

Novel autoantibodies against tRNAs or tRNA-associated proteins were identified in 28 sera. These autoantibodies appear to be distinct from anti-aminoacyl-tRNA synthetase antibodies and are associated with SLE and SS. The presence of anti-Ro/SSA and/or anti-La/SSB along with anti-tRNA antibodies is more strongly associated with recurrent erythema than is the presence of anti-Ro/SSA or anti-La/SSB alone.

Determination of antibodies to extractable nuclear antigens by commercial kits: a multicenter study

Several enzyme immunoassays for serum antibodies to extractable nuclear antigen have recently become available. The aim of this study was to evaluate the results obtained with: (1) the same kit under different conditions; (2) different enzyme immunoassays; (3) Western blot and enzyme immunoassays. Twenty-five sera from patients with autoimmune disorders were tested in five different laboratories by one Western blot and four enzyme immunoassay commercial kits. The different methods produced comparable qualitative results. However, semiquantitative evaluation, based on a cut-off value (index), yielded different results due both to laboratory conditions and to the kits employed. Standardization of commercial products and methods should be improved so that the results of different laboratories can be compared and large-scale and follow-up studies conducted. Western blot analysis could also be useful to analyze complex reactivities, although greater experience is necessary to interpret these results correctly.

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.

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.