Association of a promoter polymorphism of tumor necrosis factor-alpha with subacute cutaneous lupus erythematosus and distinct photoregulation of transcription

Cutaneous lupus erythematosus: understanding of clinical features, genetic basis, and pathobiology of disease guides therapeutic strategies

Cutaneous features of the protean disease lupus erythematous (LE) constitute 4 of 11 diagnostic criteria for systemic lupus erythematosus (SLE) and are exhibited by approximately 3/4 of patients during the course of their disease. Because the pathogenesis of LE is multifactorial and polygenic, many of the details of the pathogenesis remain unclear. We review here the clinical features of cutaneous lupus and recent genetic data that elucidate potential candidate genes for both cutaneous lupus erythematosus (CLE) and SLE. We discuss advances in elucidating the autoimmune pathogenesis of CLE and SLE. Furthermore, promising experimental therapies based on these advances are reviewed in the context of B cell directed therapies, T cell directed therapies, disruption of B and T cell interactions, cytokine directed therapies and finally, end-effector targeted therapies.

Failure of physiologic doses of pure UVA or UVB to induce lesions in photosensitive cutaneous lupus erythematosus: implications for phototesting

BACKGROUND

Phototesting studies in cutaneous lupus erythematosus have yielded variable results, with most trials reporting photo-induction of lesions by both UVA and UVB in substantial numbers of patients.

OBJECTIVES

To determine the minimal erythema dose in patients with subacute cutaneous lupus erythematosus (SCLE) and controls.

PATIENTS/METHODS

We phototested nine patients with SCLE and 14 skin type-matched controls, using repetitive dosing of UVA1 and UVB, but with filters that removed most of the shorter UVC and longer infrared and visible light. In addition, DNA was isolated from anticoagulated blood to genotype the TNF-alpha 308 region in each patient and control.

RESULTS

We were unable to demonstrate a difference in minimal erythema dose (MED) between patients and controls, or any correlation of MED with either TNF genotype or systemic drug therapy for SCLE. In addition, no SCLE skin lesions were induced in the nine patients with either UVA or UVB, and one patient cleared a skin lesion after low-dose UVA1 irradiation.

CONCLUSIONS

The potential role of wavelengths outside the UVA and UVB range in the photo-induction of cutaneous lupus skin lesions needs to be investigated, and there is a need to standardize phototesting equipment and procedures for patients with cutaneous lupus erythematous.

Tumour necrosis factor alpha is expressed in refractory skin lesions from patients with subacute cutaneous lupus erythematosus

OBJECTIVES

To investigate whether tumour necrosis factor alpha (TNFalpha) is expressed in subacute cutaneous lupus erythematosus (SCLE) skin lesions.

METHODS

The in situ expression of TNFalpha in refractory lesional and non-lesional skin biopsy specimens from patients with SCLE was analysed using an immunohistochemical approach. At the time of biopsy these patients were receiving treatment with systemic medications such as antimalarial agents, immunosuppressive drugs, and thalidomide. Expression of TNFalpha was also evaluated in cutaneous lesions of patients with other inflammatory and neoplastic skin diseases as controls.

RESULTS

The data showed that refractory lesional skin tissue from patients with SCLE displays a strongly positive distribution of TNFalpha, particularly within the epidermis. No prominent staining was seen in non-lesional skin from the same group of patients or in cutaneous lesions from the control group.

CONCLUSIONS

These findings suggest that TNFalpha is localised and produced by epidermal cells within SCLE skin lesions and support its potential role in the pathogenesis of SCLE. The tissue localisation of TNFalpha may represent a potential therapeutic target providing a new perspective in the treatment of refractory skin lesions in patients with SCLE.

Kutaner Lupus erythematodes

Cutaneous lupus erythematosus (CLE) is a heterogenous disorder with a wide range of skin manifestations. Therefore, it has been difficult to develop a unifying concept for classifying CLE from the dermatologic perspective in the past. In 2004, the classification system was updated and includes now acute CLE (ACLE), subacute CLE (SCLE), chronic CLE (CCLE), and intermittent CLE (ICLE). Additional rarely described variants are not listed as separate entities but are included in the classical forms. Diagnosis of the different subtypes of CLE is made by considering genetic, clinical, histopathologic, and immunoserologic findings, with a systematic analysis of individual criteria. In the past years, the etiology and pathogenesis of CLE has been subject of intensive research and it has been shown by several groups that exogenous factors, such as ultraviolet light and drugs, can induce CLE. The first part of this review will enable the reader to identify the various clinical manifestations of CLE and to employ characteristic criteria to assess differential diagnostic considerations.

GCF2/LRRFIP1 represses tumor necrosis factor alpha expression

Tumor necrosis factor alpha (TNF-alpha) is an important mediator of inflammation, apoptosis, and the development of secondary lymphoid structures. Multiple polymorphic microsatellites have been identified in and around the gene, and there are also multiple single-base pair biallelic polymorphisms in the introns and promoter. The TNF-alpha -308 promoter polymorphism is a G-to-A transition which has been statistically associated with various autoimmune disorders. Some studies have found that it may directly mediate the increased transcription of TNF-alpha in some circumstances. This study characterizes proteins interacting at the polymorphic promoter site. Affinity purification of binding proteins and confirmatory chromatin immunoprecipitation assays were used to identify the proteins. Electrophoretic mobility shift analyses and surface plasmon resonance were used to define binding characteristics. Proteins interacting at this site include GCF2/LRRFIP1 and Ets-1. GCF2/LRRFIP1 appears to act as a repressor and occupies the -308 site in cells that do not make TNF-alpha. Cells competent to produce TNF-alpha have Ets-1 bound to the -308 promoter site. Active transcription is accompanied by NF-kappaB and c-Jun binding to the proximal promoter. Thus, dynamic changes on the TNF-alpha promoter, particularly at the -308 site, accompany the transition from repressed to active transcription. GCF2/LRRFIP1 is the first TNF-alpha repressor identified.

Differential effect of IL10 and TNF{alpha} genotypes on determining susceptibility to discoid and systemic lupus erythematosus

OBJECTIVE

To ascertain the possible involvement of functional interleukin 10 (IL10) and tumour necrosis alpha (TNFalpha) cytokine promoter polymorphisms on the susceptibility to discoid and systemic lupus erythematosus (DLE, SLE), and their associations with immunological features.

METHODS

Single nucleotide polymorphisms of the IL10 (-1082, -819, and -592) and TNFalpha (-308) genes were determined using allele specific probes in 248 lupus patients and 343 matched controls. To assess functional significance of genotypes, basal mRNA cytokine levels were quantified in 106 genotyped healthy controls by real time RT-PCR. Specific autoantibodies and cutaneous manifestations were analysed in SLE patients and associated with functional genotypes.

RESULTS

After analysing the distribution of IL10 and TNFalpha transcript levels according to promoter genotypes in healthy individuals, patients and controls were classified into functional single and combined genotypes according to the expected high or low constitutive cytokine production. High TNFalpha genotypes (-308AA or AG) were associated with SLE independently of IL10 alleles, whereas the risk of developing DLE and the prevalence of discoid lesion in SLE were higher in the high IL10/low TNFalpha producer group (-1082GG/-308GG). Cytokine interaction also influences the appearance of autoantibodies. Antibodies against Sm are prevalent among low producer patients for both cytokines, a genotype not associated with lupus incidence, whereas low IL10/high TNFalpha patients have the highest frequency of antibodies to SSa and SSb.

CONCLUSIONS

IL10/TNFalpha interaction influences susceptibility to DLE and the appearance of specific autoantibodies in SLE patients, whereas high TNFalpha producer genotypes represent a significant risk factor for SLE.

Neonatal lupus: basic research and clinical perspectives

Neonatal lupus, although quite rare, carries a significant mortality and morbidity when the fetal heart is the targeted organ. Anti-SSA/Ro-SSB/La antibodies are present in more than 85% of mothers whose fetuses are identified with congenital heart block (CHB) in a structurally normal heart, but the risk for a woman who has the candidate antibodies to have a child who has CHB is approximately 2%. Although the precise pathogenic mechanism of injury remains unknown, it is clear that the antibodies alone are insufficient to cause disease, and fetal factors are likely contributory. In vivo and in vitro evidence supports a pathologic cascade, involving apoptosis of cardiocytes, surface translocation of Ro and La antigens, binding of maternal autoantibodies, secretion of profibrosing factors (eg, tumor growth factor ) from the scavenging macrophages, and modulation of cardiac fibroblasts to a myofibroblast-scarring phenotype. The spectrum of cardiac abnormalities encompasses varying degrees of block identified in utero and late-onset cardiomyopathy. Better echocardiographic measurements that identify first-degree block in utero may be the optimal approach for pregnant women at risk; prophylactic therapies, including treatment with intravenous immunoglobulin, await larger trials.

Ultraviolet-B recruits mannose-binding lectin into skin from non-cutaneous sources

Mannose-binding lectin (MBL) is an integral part of the innate immune system and functions as an opsonin by binding to pathogens and certain apoptotic cells to promote their uptake by phagocytes. We recently identified an association of low-producing MBL polymorphisms with adult dermatomyositis (DM). Our model is that MBL deficiency leads to a defect in the clearance of apoptotic debris in the skin, thereby predisposing to photosensitive autoimmune disease. In this study, we sought to determine whether MBL binds within the epidermis, and to determine its source, and potential function of this binding. We demonstrated that the MBL is present in irradiated, but not in non-irradiated skin, and in irradiated skin it is bound to apoptotic keratinocytes (KC). We found that MBL is not made by KC, showing indirectly that it comes from an exogenous source, despite the fact that other complement components are made by KC and upregulated by ultraviolet irradiation. Finally, we demonstrated that non-KC-derived MBL bound to apoptotic KC in vitro and increased the uptake of these cells by dendritic cells. We hypothesize that MBL may facilitate non-inflammatory clearance of apoptotic debris in patients with photosensitive forms of DM.

Clinical manifestations of cutaneous lupus erythematosus

The skin findings seen in lupus erythematosus can present with either lupus-specific or lupus-nonspecific findings, with lupus-specific skin disease showing findings histopathologically distinct for cutaneous lupus erythematosus. Lupus-specific skin diseases include chronic cutaneous, subacute cutaneous, and acute cutaneous lupus erythematosus. The types of skin lesions in each group are clinically distinct and recognizing the specific subsets helps in prognosticating the likelihood of underlying systemic lupus. A number of medications are associated with cutaneous lupus, in particular with subacute cutaneous lupus erythematosus. Lupus nonspecific skin lesions are not histopathologically distinct for cutaneous lupus and/or may be seen as a feature of another disease process. Nonspecific disease-related skin lesions are frequently seen in patients with SLE, usually in the active phase of the disease. The current ACR classification criteria for SLE include four somewhat overlapping dermatologic criteria, butterfly rash, discoid lupus, photosensitivity, and oral ulcers and thus patients can be classified as having SLE with only skin manifestations.

Subacute cutaneous lupus erythematosus: 25-year evolution of a prototypic subset (subphenotype) of lupus erythematosus defined by characteristic cutaneous, pathological, immunological, and genetic findings

Subacute cutaneous lupus erythematosus (SCLE) represents a widespread, photosensitive, nonscarring, nonindurated form of lupus erythematosus (LE)-specific skin disease. SCLE lesions are associated with a distinctive immunogenetic background including the production of Ro/SS-A autoantibodies. Individuals who have SCLE skin lesions as a component of their presenting illnesses represent a distinctive subset (subphenotype) of LE that enjoys a good prognosis with respect to life-threatening systemic manifestations of LE. SCLE skin lesions can be triggered by a number of different drugs the majority of which are capable of producing photosensitivity drug reactions in nonlupus patients. Single agent or combination aminoquinoline antimalarial therapy will suffice for 75% of SCLE patients. The remaining 25% will require other forms of systemic antiinflammatory therapy (e.g., diaminodipenylsulfone (Dapsone), thalidomide) or systemic immunosuppressive-immunomodulatory therapy. The etiopathogenesis of SCLE skin lesions is thought to result from four sequential stages: (1) inheritance of susceptibility genes (HLA 8.1 ancestral haplotype [C2, C4 deficiency, TNF-alpha-308A polymorphism], C1q deficiency); (2) loss of tolerance/induction of autoimmunity (ultraviolet light, photosensitizing drugs/chemicals, cigarette smoking, infection, psychological stress); (3) expansion/maturation of autoimmune responses (high levels of autoantibodies (Ro/SS-A), immune complexes, autoreactive T-cells); and (4) tissue injury/disease induction resulting from various autoimmune effector mechanisms (e.g., direct T cell-mediated cytotoxicity, antibody-dependent cell-mediated cytotoxicity).

Increased expression of the novel proinflammatory cytokine high mobility group box chromosomal protein 1 in skin lesions of patients with lupus erythematosus

OBJECTIVE

To investigate the role of the novel cytokine high mobility group box chromosomal protein 1 (HMGB-1) in the pathogenesis of cutaneous lupus erythematosus (CLE).

METHODS

Punch biopsy specimens of lesional and unaffected skin from 10 patients with CLE and 3 healthy control subjects were investigated. Immunohistochemical staining for HMGB-1, tumor necrosis factor alpha (TNFalpha), and interleukin-1beta (IL-1beta) was performed on consecutive sections. Analysis of single-nucleotide polymorphisms of -308 TNF was performed on DNA extracted from peripheral blood mononuclear cells.

RESULTS

An altered expression of HMGB-1 was observed both in the epidermis and in the dermal infiltrates of lesional skin. Expression of HMGB-1 in the epidermis and dermis was increased (P < 0.01 and P < 0.001, respectively, versus unaffected skin), and translocation to the cytoplasm as well as the extracellular presence of secreted HMGB-1 were found. Increased levels of TNFalpha and IL-1beta were also observed in the dermal infiltrates of lesional skin (P < 0.01 and P < 0.05, respectively, versus unaffected skin). The carrier frequency of the -308A TNF polymorphism was 80% in patients with subacute CLE, but this was not related to higher expression of TNFalpha in biopsy specimens from the CLE group.

CONCLUSION

The high amount of extracellular HMGB-1 observed in skin lesions indicates that HMGB-1 is involved in the inflammatory process of CLE. TNFalpha and IL-1beta may form a proinflammatory loop with HMGB-1, since they can induce the release of each other. The extracellular HMGB-1 observed by immunostaining of the epidermis indicates that keratinocytes may be an as yet unrecognized source of secreted HMGB-1, underscoring the role of the target organ in the rheumatoid autoimmune inflammatory process.

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.

Photosensitivity in lupus erythematosus

BACKGROUND

Lupus erythematosus is a systemic disease process that may manifest with a variety of internal and cutaneous findings. Photosensitivity is one the most common manifestations of lupus erythematosus. In patients with lupus erythematosus, there is a relationship between exposure to ultraviolet light, autoantibodies, genetics and other factors in the development of photosensitivity.

METHODS

Literature was reviewed on the topics of lupus erythematosus and photosensitivity discussed together and separately. The suggested mechanisms for their relationship were reviewed and analyzed.

RESULTS

Photosensitivity's relationship to and influence on the systemic manifestations of lupus remain to be defined. Mechanisms for photosensitivity might include: modulation of autoantibody location, cytotoxic effects, apoptosis induction with autoantigens in apoptotic blebs, upregulation of adhesion molecules and cytokines, induction of nitric oxide synthase expression and ultraviolet-generated antigenic DNA. Tumor necrosis factor alpha also seems to play a role in the development of photosensitivity.

CONCLUSION

The basis for photosensitivity in lupus has yet to be fully defined. It is more commonly associated with subacute and tumid lupus erythematosus than with other variants. Anti-Ro antibodies appear to relate to photosensitivity. Tumor necrosis factor alpha polymorphisms appear to be important in some variants of lupus with photosensitivity. There is no sine qua non antibody or mutation of photosensitivity in lupus. In patients with lupus, more work needs to be done to define the mechanisms of photosensitivity.

Update on human systemic lupus erythematosus genetics

PURPOSE OF REVIEW

Susceptibility to systemic lupus erythematosus (SLE) has a genetic component. In recent years, nine complete genome scans using family collections that differ greatly in ethnic compositions and geographic locations have identified several strong, confirmed SLE susceptibility loci. Evidence implicating individual gene polymorphisms (or haplotypes) within some of the linked intervals has been reported. This review highlights recent findings that may lead to the identification of putative genes and new insights in the pathogenesis of SLE.

RECENT FINDINGS

Eight of the best-supported SLE susceptibility loci are 1q23, 1q25-31, 1q41-42, 2q35-37, 4p16-15.2, 6p11-21, 12p24, and 16q12. These are chromosomal regions exhibiting genome-wide significance for linkage in single studies and suggestive evidence for linkage in other samples. Linkage analyses conditioning on pedigrees in which one affected member manifesting a particular clinical condition have also yielded many chromosomal regions linked to SLE. The linked interval on chromosome 6p has been narrowed to 0.5 approximately 1.0 Mb (million basepairs) of 3 MHC class II containing risk haplotypes in white subjects. Cumulative results have shown that hereditary deficiencies of complement component C4A (a MHC class III gene) confer risk for SLE in almost all ethnic groups studied. The FcgammaR genes (located at 1q23) have been convincingly demonstrated to play an important role in susceptibility to SLE (and/or lupus nephritis). The evidence for the intronic single nucleotide polymorphism of program cell death gene 1 (PDCD1 at 2q37) to confer susceptibility is promising but not yet compelling. Within several established susceptibility loci, evidence for association of positional candidate genes is emerging.

SUMMARY

Further replications of linkage and association are the immediate task. The respective contribution of each susceptibility gene, relationships between genotypes and phenotypes, and potential interactions between susceptibility gene products need to be elucidated. This line of investigation is now well poised to provide novel insights into how genetic variants can affect functional pathways leading to the development of SLE.

Bullous subacute cutaneous lupus erythematosus

We describe a 59-year-old woman, with a history of autoimmune disease and disseminated uterine leiomyosarcoma, who developed a photoaggravated, blistering skin eruption. An initial rash, at the outset of treatment with chemo- and radiotherapy, resembled erythema multiforme. Review of the original skin biopsy showed it to be subacute cutaneous lupus erythematosus. There were no systemic symptoms or signs to suggest systemic lupus erythematosus. The much later photoaggravated rash consisted mainly of bullae and eventual epidermal denuding which resembled toxic epidermal necrolysis. We propose that the clinical and histological diagnosis is one of bullous subacute cutaneous lupus erythematosus in a patient with no other features of systemic lupus erythematosus.

Regulation of inflammation

Inflammation is part of the response to infection. It is often considered to be part of the innate response to infection, but it plays a significant role in molding the adaptive response. Conserved pathways that have evolved to contain the infection and mold the ensuing adaptive response can cause deleterious effects when dysregulated. In this review, the various roles of TNFalpha will be discussed. Its pleomorphic effects require complex regulatory strategies. Our work has focused on the role of TNFalpha in autoimmune diseases and the regulation of its expression by transcription factors and chromatin remodeling.

Tumor necrosis factor-alpha and interferon-gamma polymorphisms contribute to susceptibility to oral lichen planus

Most lymphocytes in the lamina propria of oral lichen planus (OLP) lesions express and secrete interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha), whereas they do not secret interleukin-4 and -10 or transforming growth factor-beta. We analyzed whether the polymorphisms of several cytokines may influence the susceptibility to OLP. Cytokine typing was performed by a sequence-specific PCR assay. Thirteen cytokine genes with 22 single-nucleotide polymorphisms were studied. IFN-gamma UTR 5644 genotype frequencies showed a significant increase in number of T/T homozygotes in OLP patients compared with controls (40.9 vs. 22.9%; p=0.0022). Moreover, in OLP patients, the frequency of the -308A TNF-alpha allele was higher than in the controls (21.6 vs. 9.3%; p < 0.05) causing a significantly increased frequency of the genotype G/A in OLP (43.2 vs. 14.3%; p=0.0002). Because in patients with mucocutaneous lichen planus (LP), the frequency of the -308A TNF-alpha allele was more than double the values in the pure OLP patients (40.9 vs. 15.1%; p=0.003), the -308G/A TNF-alpha genotype showed a significantly higher frequency in patients with mucocutaneous LP than in patients with pure OLP (81.8 vs. 30.3%, p=0.003). In conclusion, we suggest that genetic polymorphism of the first intron of the promoter gene of IFN-gamma may be an important risk factor to develop oral lesions of LP, whereas an increase in the frequency of -308A TNF-alpha allele may best contribute to the development of additional skin involvement.

Lupus erythematosus induced by medications, ultraviolet radiation, and other exogenous agents: A review, with special focus on the development of subacute cutaneous lupus erythematosus in a genetically predisposed individual

Exogenous agents implicated in or suspected of precipitating subacute cutaneous lupus erythematosus (SCLE) and lupus erythematosus (LE) are reviewed. An illustrative case of environmentally induced SCLE is presented. A previously healthy 30-year male homozygous for the tumor necrosis factor-alpha (TNF-alpha) 308. A promoter allele developed SCLE after spending several hours removing fertilizer- and pesticide-containing hay from an agricultural barn in the springtime. The cutaneous eruption soon resolved, only to reappear 3 weeks later on the day the patient re-entered the barn. An environmental agent present in the barn, coupled with springtime ultraviolet light, likely triggered the disease in this immunogenetically susceptible individual.

Photosensitivity in rheumatic diseases

There have been a number of recent advances in the genetic understanding of photosensitive rheumatic diseases, especially subacute cutaneous lupus erythematosus and dermatomyositis. These advances support the concept that increased numbers of ultraviolet light-induced apoptotic cells in skin lead to a supra-threshold concentration of antigenic peptides. The current genetic data suggest that increased keratinocyte apopotosis can result from increased amounts of TNF-alpha that induce apoptosis due to a ultraviolet light-sensitive TNF promoter polymorphism or to decreased clearance of apototic cells due to polymorphisms associated with decreased serum levels of collectins such as C1q and mannose-binding lectin. These diseases are frequently oligogenic, and other yet to be elucidated genes will, in individual patients, lead to increased numbers of apoptotic cells associated with these cutaneous autoimmune diseases. In the presence of specific MHC class I and II genes, antigen-presenting cells initiate a primary immune response that leads to cutaneous, and likely systemic, autoimmune disease.

Genetic association of cutaneous neonatal lupus with HLA class II and tumor necrosis factor ?: Implications for pathogenesis

OBJECTIVE

Cutaneous neonatal lupus resembles subacute cutaneous lupus erythematosus (SCLE), and photosensitivity is a common symptom. Tumor necrosis factor alpha (TNFalpha) release by ultraviolet light-exposed keratinocytes may be exaggerated in SCLE patients who have the haplotype TNFalpha -308A;DRB1*03. Accordingly, this study was undertaken to seek genetic and histologic evidence for a role of TNFalpha in the pathogenesis of cutaneous neonatal lupus.

METHODS

DNA was isolated from 83 children (22 with rash, 35 with congenital heart block [CHB], 26 unaffected siblings) and 58 mothers from the Research Registry for Neonatal Lupus.

RESULTS

The -308A allele (associated with higher TNFalpha production), HLA-DRQB1*02, and HLA-DRB1*03 were each present in the majority of children with rash (64%, 68%, and 64%, respectively). The frequency of all 3 6p alleles occurring together in 1 individual was greater in children with rash than in children who had either CHB or no manifestation of neonatal lupus (59% versus 30%; P = 0.02). This association with neonatal lupus rash was equivalent to published findings in a cohort of patients with SCLE, but significantly greater than the association in patients with discoid lupus erythematosus. Prominent TNFalpha staining in the epidermis was observed in lesional skin from 3 children with rash, but not in skin from a healthy neonate.

CONCLUSION

Taken together, the finding of a genetic predisposition to generate increased levels of TNFalpha following tissue injury and the histologic demonstration of TNFalpha in the target organ support the notion that this inflammatory cytokine plays a role in the pathogenesis of cutaneous neonatal lupus. Furthermore, the results of these studies provide evidence of a biologic link between neonatal lupus and the rash of SCLE.

Homozygous single nucleotide polymorphism of the complement C1QA gene is associated with decreased levels of C1q in patients with subacute cutaneous lupus erythematosus

We report an association between a non-familial form of photosensitive Lupus-specific skin disease, subacute cutaneous lupus erythematosus (SCLE), and a new single nucleotide polymorphism (SNP) in the C1QA gene. We also describe an association between this SNP and lower levels of serum C1q. This SNP consists of adenine replacing the third guanine in the codon for aminoacid residue Gly70 (position excludes the 22 amino acid leading peptide) that is located in the second exon of the C1QA gene. We have designated this SNP C1qA-Gly70GGA (the GenBank sequence at this location is C1qA-Gly70GGG). A survey of 19 SCLE patients showed that 11 (58%) were homozygous for C1qA-Gly70GGA SNP, seven (37%) were heterozygous, and only one patient (5%) was homozygous for the GenBank sequence. In contrast, only 13 of 62 (21%) normal controls were homozygous for the C1qA-Gly70GGA SNP, 41 (66%) controls were heterozygous and eight (13%) controls were homozygous for the GenBank sequence. Thus, the C1qA-Gly70GGA SNP is strongly associated with SCLE (P-value = 0.005 by chi-square analysis with Yates correction). This SNP would traditionally be classified as clinically silent as it does not encode a different amino acid. However, our studies have suggested that this SNP appears to be associated with a functional abnormality of C1q expression since its presence correlates inversely with serum levels of C1q antigenic protein in both SCLE patients and normal controls. The mechanism by which this phenotypic change is associated with the translationally silent (synonymous) ClqA-Gly70GGA genetic variation is currently unknown.

Cytokine polymorphisms and histologic expression in autopsy studies: contribution of TNF-alpha and TGF-beta 1 to the pathogenesis of autoimmune-associated congenital heart block

Although Abs to SSA/Ro-SSB/La are necessary for the development of congenital heart block (CHB), the low frequency suggests that fetal factors are contributory. Because CHB involves a cascade from inflammation to scarring, polymorphisms of the TNF-alpha promoter region and codons 10 and 25 of the TGF-beta gene were evaluated in 88 children (40 CHB, 17 rash, 31 unaffected siblings) and 74 mothers from the Research Registry for Neonatal Lupus (NL). Cytokine expression was assessed in autopsy material from two fetuses with CHB. Significantly increased frequency of the -308A (high-producer) allele of TNF-alpha was observed in all NL groups compared with controls. In contrast, the TGF-beta polymorphism Leu(10) (associated with increased fibrosis) was significantly higher in CHB children (genotypic frequency 60%, allelic frequency 78%) than unaffected offspring (genotypic frequency 29%, p = 0.016; allelic frequency 56%, p = 0.011) and controls, while there were no significant differences between controls and other NL groups. For the TGF-beta polymorphism, Arg(25), there were no significant differences between NL groups and controls. In fetal CHB hearts, protein expression of TGF-beta, but not TNF-alpha, was demonstrated in septal regions, extracellularly in the fibrous matrix, and intracellularly in macrophage infiltrates. Age-matched fetal hearts from voluntary terminations expressed neither cytokine. TNF-alpha may be one of several factors that amplify susceptibility; however, the genetic studies, backed by the histological data, more convincingly link TGF-beta to the pathogenesis of CHB. This profibrosing cytokine and its secretion/activation circuitry may provide a novel direction for evaluating fetal factors in the development of a robust animal model of CHB as well as therapeutic strategies in humans.

Progressive cutaneous sarcoidosis responding to anti-tumor necrosis factor-alpha therapy

We describe a patient with widespread and progressive cutaneous sarcoidosis who was successfully treated with anti-tumor necrosis factor-alpha monoclonal antibody, infliximab, suggesting that inhibition of tumor necrosis factor-alpha may be useful as targeted treatment in cutaneous sarcoidosis.

IL-12 completely blocks ultraviolet-induced secretion of tumor necrosis factor alpha from cultured skin fibroblasts and keratinocytes

Interleukin-12 is an important regulator of other cytokines. Although interleukin-12 is considered to act primarily on lymphocytes, provoking a shift from T helper 2 to T helper 1 cells and an increase in lymphocyte-derived tumor necrosis factor alpha, we hypothesized that interleukin-12 might also affect tumor necrosis factor alpha secretion from skin cells. In this study, keratinocytes were treated with ultraviolet-B, ultraviolet-A, or sham irradiation, without or with exogenous interleukin-12. Remarkably, the exogenous interleukin-12 totally blocked ultraviolet-B-induced tumor necrosis factor alpha production. Both ultraviolet-A and ultraviolet-B were capable of inducing interleukin-12 production. To determine the molecular mechanism of this effect, we used a chloramphenicol acetyl transferase reporter under the control of a 1.2 kb fragment of the wild-type (-308G) human tumor necrosis factor alpha promoter and found significant suppression of promoter activity with interleukin-12. Studies using the -308A variant of the human tumor necrosis factor alpha promoter showed much higher promoter activity overall, but also a greater sensitivity to suppression by interleukin-12. The mechanism did not involve blockage of the interleukin-1 receptor, because interleukin-12 did not suppress interleukin-1-mediated induction of collagenase mRNA. To determine the role of endogenous interleukin-12, we found that anti-interleukin-12 antibodies enhanced ultraviolet-B-induced tumor necrosis factor alpha secretion. Thus, interleukin-12 strongly inhibits tumor necrosis factor alpha production by noninflammatory skin cells, mostly or entirely through inhibition of gene transcription via an element within the first 1.2 kb of the tumor necrosis factor alpha promoter. The result is a shift in tumor necrosis factor alpha production from noninflammatory cells to T helper 1 cells. Because tumor necrosis factor alpha is central to the pathogenesis of several photosensitive skin diseases and certain forms of immune suppression, interleukin-12 may have important physiologic, pathophysiologic, and therapeutic roles.

TNFalpha inhibition in MRL/lpr mice ameliorates pulmonary but not renal disease

TNFalpha inhibition has a clearly beneficial effect in a number of arthritides and in Crohn's disease. The exact mechanism of action is uncertain with studies showing inhibition of chemokines, inhibition of adhesion molecule expression, and improved T-cell function. Unlike most therapeutic interventions for autoimmune disease, TNFalpha inhibition appears to act on specific pathologic processes. It is not known how wide-spread these TNFalpha-mediated pathologic processes are. Efforts to expand the use of TNFalpha inhibition have had notable successes but have been disappointing in other disorders. We hypothesized that TNFalpha-mediated pathologic processes might play a significant role in the end-organ effects seen in SLE. We modeled SLE by using MRL/lpr mice and treated with two types of TNFalpha inhibitor. Pulmonary disease was significantly improved in the treated groups compared to controls. In contrast, renal disease was unaffected suggesting that in lupus, where multiple organs are affected, different pathologic processes may be mediating the end-organ damage. This has important implications for designing therapeutics for SLE.

Mannose binding lectin (MBL) polymorphisms associated with low MBL production in patients with dermatomyositis

One theory for the pathophysiology of photosensitive autoimmune skin diseases is that photoinduction of tumor necrosis factor alpha (TNFalpha) secretion leads to keratinocyte apoptosis and translocation of previously sequestered cellular antigens that then activate the immune system. We previously found an association of the overproducing TNFalpha-308 A variant with adult dermatomyositis and with subacute cutaneous lupus erythematosus. Here we focused on mannose binding lectin (MBL), which is one of several proteins involved in clearance of apoptotic cells and could thereby lessen photosensitive autoimmunity. We examined three variant MBL polymorphisms associated with decreased MBL protein (Asp54, Glu57, and the LX promoter polymorphism) in adult dermatomyositis, subacute cutaneous lupus erythematosus, and discoid lupus, and controls. The variant Asp54 allele was positively associated with adult dermatomyositis in a dose-responsive fashion (p=0.0004), as was the Glu57 allele (p=0.004). None of the three variant MBL alleles considered individually was significantly associated with either subacute cutaneous lupus erythematosus or discoid lupus. In adult dermatomyositis patients homozygous for the wild-type TNFalpha-308G allele (GG), i.e., presumably without elevated TNFalpha production, 69% had at least two of the MBL polymorphisms, versus 20% of healthy GG controls (p=0.0011). Combinations of low-producing MBL variants were over-represented in adult dermatomyositis in a dose-responsive fashion (p=0.0002). In adult dermatomyositis patients with one variant TNFalpha-308 A allele (GA), 46% had at least two MBL polymorphisms, versus 7% of GA controls (p=0.0077). Thus, low-producing MBL genes are very strongly associated with adult dermatomyositis. Our model is that genetic polymorphisms leading to overproduction of apoptotic keratinocytes and then impaired clearance of these cells contribute to the pathogenesis of adult dermatomyositis, a photoinduced autoimmune skin disease.

Antimalarials in cutaneous lupus erythematosus: mechanisms of therapeutic benefit

Antimalarials are arguably the best modality currently available for treating patients with cutaneous lupus erythematosus (LE). Although antimalarials have been used for decades in treating cutaneous LE, the precise mechanisms by which they provide therapeutic benefit are not well defined. The putative mechanisms by which antimalarials might provide therapeutic benefit to patients with cutaneous LE include a number of interrelated anti-inflammatory and immunosuppressive effects that include photoprotection, lysosomal stabilization, suppression of antigen presentation, and inhibition of prostaglandin and cytokine synthesis. If we had a more precise understanding of how antimalarials provide therapeutic benefit in cutaneous LE we might gain better insight into the pathogenic mechanisms of LE and ways of developing better therapies for afflicted patients.

Associations of tumor necrosis factor alpha and HLA polymorphisms with adult dermatomyositis: implications for a unique pathogenesis

We recently reported that the -308A tumor necrosis factor alpha promoter polymorphism is associated with the photosensitive disorder subacute cutaneous lupus erythematosus and mediates an exaggerated tumor necrosis factor alpha response to ultraviolet B. We now sought to examine the association of this polymorphism with adult dermatomyositis, a photosensitive disease that exhibits some features in common with subacute cutaneous lupus erythematosus. Fifty adult patients with dermatomyositis and 239 healthy, race-matched controls were examined for the -308A tumor necrosis factor alpha polymorphism and the more common -308G allele. The frequency of the -308A allele was 0.27 in the entire dermatomyositis group, versus 0.14 in the controls (p = 0.003, chi2 2 x 2 table). Caucasians were the only racial/ethnic group in our study large enough to allow separate statistical analysis (47 dermatomyositis, 223 controls). The frequency of the -308A allele was 0.26 for dermatomyositis and 0.14 for controls (p = 0.014). Caucasians are known to exhibit a linkage disequilibrium between -308A and HLA-DR3, which we previously found to be significantly enhanced in subacute cutaneous lupus erythematosus patients. In contrast, we now found no increase in the association of -308A and HLA-DR3 in Caucasians with dermatomyositis compared to controls. Consistent with this observation, the association of these two genes in dermatomyositis was significantly less than we previously reported in Caucasians with subacute cutaneous lupus erythematosus (p = 0.016). We conclude that the tumor necrosis factor -308A polymorphism is associated with dermatomyositis, which suggests a pathophysiologic contribution from ultraviolet-induced production of tumor necrosis factor alpha, similar to subacute cutaneous lupus erythematosus. The differences in linkage with HLA-DR3, as well as several divergent clinical features, indicate that there are also fundamental mechanistic differences between dermatomyositis and subacute cutaneous lupus erythematosus.

Evolution of transcription factor binding sites in Mammalian gene regulatory regions: conservation and turnover

Comparisons between human and rodent DNA sequences are widely used for the identification of regulatory regions (phylogenetic footprinting), and the importance of such intergenomic comparisons for promoter annotation is expanding. The efficacy of such comparisons for the identification of functional regulatory elements hinges on the evolutionary dynamics of promoter sequences. Although it is widely appreciated that conservation of sequence motifs may provide a suggestion of function, it is not known as to what proportion of the functional binding sites in humans is conserved in distant species. In this report, we present an analysis of the evolutionary dynamics of transcription factor binding sites whose function had been experimentally verified in promoters of 51 human genes and compare their sequence to homologous sequences in other primate species and rodents. Our results show that there is extensive divergence within the nucleotide sequence of transcription factor binding sites. Using direct experimental data from functional studies in both human and rodents for 20 of the regulatory regions, we estimate that 32%-40% of the human functional sites are not functional in rodents. This is evidence that there is widespread turnover of transcription factor binding sites. These results have important implications for the efficacy of phylogenetic footprinting and the interpretation of the pattern of evolution in regulatory sequences.

Cutaneous lupus erythematosus: a review

This article will review and update information about the pathogenesis, clinical presentation, diagnosis, and treatment of cutaneous lupus erythematosus. Lupus erythematosus (LE) can present as a skin eruption, with or without systemic disease. Cutaneous LE is subdivided into chronic cutaneous LE, subacute cutaneous LE and acute LE. The prevalence of systemic lupus erythematosus (SLE) is 17-48/100,000 population worldwide. Skin disease is one of the most frequent clinical complaints of patients suffering from SLE. It has been found to occur in up to 70% of patients during the course of the disease. The most frequent mucocutaneous manifestations of SLE are malar rash (40%), alopecia (24%), and oral ulcers (19%). It has been suggested that risk factors that are more likely to signal transition of cutaneous into systemic LE are high ANA titers (> 1:320) and the presence of arthralgias. CLE patients who exhibit these symptoms should be monitored closely, since they may be at increased risk to develop SLE.

Dermatomyositis: an overview of recent progress with emphasis on dermatologic aspects

Important points regarding DM and C-ADM are as follows: C-ADM is a working functional designation for patients having the skin-only and skin-predominant subsets of DM, amyopathic DM, and hypomyopathic DM. C-ADM seems to have approximately 10% the incidence of classic DM in whites and possibly a higher incidence in Asians. Some patients who present with C-ADM, with or without subclinical laboratory abnormalities, can slowly progress to develop symptomatic muscle weakness over a period of years, whereas others go for 10 to 20 years and longer without the appearance of muscle weakness. C-ADM patients are at risk for potentially life-threatening complications of classic DM, such as interstitial lung disease, which may occur in up to 10% of C-ADM patients. This risk seems to be even greater in some ethnic subgroups (e.g., Japanese). C-ADM patients may also be at increased risk for internal malignancy and until further studies are carried out to confirm the statistical significance of this association, all such patients should have a thorough evaluation for internal malignancy, identical to the approach currently used in classic DM patients. Dermatologists are in the best position initially to diagnose C-ADM patients and can contribute greatly to their overall management and quality of life. Ongoing vigilance is required, however, for complications that can arise in C-ADM patients including potentially fatal interstitial lung disease, internal malignancy, delayed onset of muscle weakness from myositis, and complications of systemic drug therapy. Topical therapy with broad-spectrum sunscreens, anti-inflammatories, and antipruritics should be maximized during the initial management of the cutaneous manifestations of either classic DM or C-ADM. Single-agent or combined aminoquinoline antimalarial therapy represents the safest initial form of systemic therapy for DM-specific skin disease occurring in any clinical setting; however, this approach tends to be less effective in general than for cutaneous LE. There is a theoretical rationale for and limited preliminary successful anecdotal experience with the use of anti-TNF-alpha therapy in refractory cases of classic DM and C-ADM. Cautious systematic clinical trials in this area should be considered.

Genetic epidemiology: systemic lupus erythematosus

Systemic lupus erythematosus is the prototype multisystem autoimmune disease. A strong genetic component of susceptibility to the disease is well established. Studies of murine models of systemic lupus erythematosus have shown complex genetic interactions that influence both susceptibility and phenotypic expression. These models strongly suggest that several defects in similar pathways, e.g. clearance of immune complexes and/or apoptotic cell debris, can all result in disease expression. Studies in humans have found linkage to several overlapping regions on chromosome 1q, although the precise susceptibility gene or genes in these regions have yet to be identified. Recent studies of candidate genes, including Fcgamma receptors, IL-6, and tumour necrosis factor-alpha, suggest that in human disease, genetic factors do play a role in disease susceptibility and clinical phenotype. The precise gene or genes involved and the strength of their influence do, however, appear to differ considerably in different populations.