Subacute cutaneous lupus erythematosus-immunogenetic associations

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.

Immunology of cutaneous lupus erythematosus

The cause and effect between ultraviolet light and cutaneous lupus erythematosus (CLE) is clear. In LE patients indeed, photosensitivity is one of the major diagnostic criteria of the systemic form of lupus erythematosus. This strong clinical association has led to the postulate that abnormal photosensitivity participates in the pathogenesis of cutaneous lesions in LE. What is not clear is how the ultraviolet radiation (UVR) induces cutaneous lesions in susceptible individuals despite the fact that profound effects of UVR on the cellular components of the skin have been extensively studied. The whole scenario is complicated by the relationship between sunlight and the cutaneous immune system. Pronounced effects of UVR on the cutaneous immune response further complicate the understanding of photosensitivity in LE. In addition, the network of cutaneous cytokines, chemokines, and adhesion molecules has become increasingly intricate, thus contributing to the genetic substrate of each individual, and to the tremendous complexity of the pathogenesis of CLE.

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.

Human Ro60 (SSA2) genomic organization and sequence alterations, examined in cutaneous lupus erythematosus

BACKGROUND

The Ro 60 kDa protein (Ro60 or SSA2) is the major component of the Ro ribonucleoprotein (Ro RNP) complex, to which an immune response is a specific feature of several autoimmune diseases. The genomic organization and any sequence variation within the DNA encoding Ro60 are unknown.

OBJECTIVES

To characterize the Ro60 gene structure and to assess whether any sequence alterations might be associated with serum anti-Ro antibody in subacute cutaneous lupus erythematosus (SCLE), thus potentially providing new insight into disease pathogenesis.

METHODS

The cDNA sequence for Ro60 was obtained from the NCBI database and used for a BLAST search for a clone containing the entire genomic sequence. The intron-exon borders were confirmed by designing intronic primer pairs to flank each exon, which were then used to amplify genomic DNA for automated sequencing from 36 caucasian patients with SCLE (anti-Ro positive) and 49 with discoid LE (DLE, anti-Ro negative), in addition to 36 healthy caucasian controls.

RESULTS

Heteroduplex analysis of polymerase chain reaction (PCR) products from patients and controls spanning all Ro60 exons (1-8) revealed a common bandshift in the PCR products spanning exon 7. Sequencing of the corresponding PCR products demonstrated an A > G substitution at nucleotide position 1318-7, within the consensus acceptor splice site of exon 7 (GenBank XM001901). The allele frequencies were major allele A (0.71) and minor allele G (0.29) in 72 control chromosomes, with no significant differences found between SCLE patients, DLE patients and controls.

CONCLUSIONS

The genomic organization of the DNA encoding the Ro60 protein is described, including a common polymorphism within the consensus acceptor splice site of exon 7. Our delineation of a strategy for the genomic amplification of Ro60 forms a basis for further examination of the pathological functions of the Ro RNP in autoimmune disease.

Polymorphic light eruption and the HLA DRB1*0301 extended haplotype are independent risk factors for cutaneous lupus erythematosus

Recent evidence suggests that polymorphic light eruption (PLE) is an inherited photosensitivity disorder which may predispose to cutaneous lupus erythematosus (LE). In this study we examine the relative risk (RR) attributable to the presence of PLE, together with the effect of the major histocompatibility complex (MHC) in the development of cutaneous LE. Eighty-five Caucasian patients with annular subacute cutaneous LE (SCLE) and discoid LE (DLE) were recruited, together with 102 first degree relatives and 200 healthy local Caucasian controls. Symptoms suggestive of PLE were elicited in patients and relatives, and human leukocyte antigen (HLA) typing determined by PCR-SSP. Standard association analysis and family transmission disequilibrium testing (TDT) were then used to compare the HLA frequencies between groups. We found a significant (P < 0.05) association of the HL4 A*01, B*08, DRB1*0301 extended haplotype with both SCLE and DLE and also significant association of DLE with the HLA A*03, B*07, DRB1*15 haplotype, with a possible protective effect in SCLE for HLA B*44 and DRB1*04 (P=0.002 and 0.001 respectively). Association was observed between PLE and cutaneous LE (P < 0.001), but not between PLE and any HLA allele. From these figures we estimate, for the general population, that the RR of developing SCLE given the presence of (a) PLE, (b) DRB1*0301 and (c) both PLE and DRB1*0301 is 3.37, 5.45 and 12.03, respectively. For DLE, equivalent RRs are 3.11, 2.15 and 6.94. In conclusion, these data imply the involvement of both PLE and HLA DRB1*0301 in the development of SCLE and DLE. They form a basis for examining the genetic architecture of photosensitivity, some aspects of which may be common to both cutaneous LE and PLE.

Molecular genetics of cutaneous lupus erythematosus

The cutaneous forms of lupus erythematosus (LE) are true complex traits, susceptibility to which is determined by multiple factors. Good evidence exists for both genetic and environmental components to this complexity. Several different experimental techniques have found the strongest genetic associations with cutaneous LE to include sequence polymorphisms of genes encoding HLA, TNF-alpha and complement molecules, particularly in anti-Ro-positive patients. Abnormal expression of multiple other cytokines, adhesion molecules and cellular proteins (such as Ro and La) points towards a range of candidate genes that are currently being examined in cutaneous LE. Combinations of specific polymorphisms of genes encoding these immunoregulatory molecules may determine individual susceptibility to LE.

Cutaneous lupus erythematosus

Lupus erythematosus (LE) has many different clinical manifestations including a variety of cutaneous findings. Some of the cutaneous manifestations are not specific for LE, such as photosensitivity reactions, oral ulcers, alopecia, urticaria, vasculitis, vesiculo-bullous lesions, acral changes, cutaneous mucinoses, and cutaneous calcinosis. Other findings are specific for LE in that they are found only in patients who have lupus erythematosus. These LE-specific disorders include acute cutaneous LE, subacute cutaneous LE, and several forms of chronic cutaneous LE, including discoid LE. Skin biopsies are often helpful in differentiating LE-specific skin lesions from other disorders that can mimic them. Photoprotective measures and a number of drugs are useful in treating cutaneous LE.

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

Ultraviolet irradiation stimulates keratinocytes and dermal fibroblasts to release cytokines involved in apoptosis and immunomodulation, such as tumor necrosis factor-alpha and interleukin-1alpha. Recent work has associated the -308A polymorphism of the human tumor necrosis factor-alpha promoter with systemic lupus erythematosus and adverse outcomes in several infectious diseases. To explore the role of this polymorphism in ultraviolet-induced disease, we used two approaches. First, we examined its prevalence in individuals with different ultraviolet sensitivity. Compared with healthy controls, there was a substantially increased prevalence of -308A in subacute cutaneous lupus erythematosus, an extremely photosensitive form of cutaneous lupus erythematosus, but not in discoid lupus erythematosus, a less photosensitive form. Next, to examine molecular regulation by tumor necrosis factor -308A, cultured 3T3 fibroblasts were transiently transfected with chloramphenicol acetyl transferase reporter constructs under the control of either -308A or the wild-type -308G promoter. Without added interleukin-1alpha the two constructs produced similar baseline chloramphenicol acetyl transferase activity and similar responses to ultraviolet. The responses to interleukin-1alpha, a photoinduced cytokine, were markedly different: interleukin-1alpha without ultraviolet produced a 15-fold increase in chloramphenicol acetyl transferase transcription from the -308A construct without affecting the wild-type -308G. Interleukin-1alpha plus ultraviolet B caused a remarkable 300-fold increase in -308A chloramphenicol acetyl transferase transcription over baseline, while increasing the wild type to <15% of this level. These results indicate a clear difference between the two promoters, including a striking synergy between ultraviolet B and added interleukin-1alpha in the induction of transcription by the tumor necrosis factor-alpha -308A promoter. Overall, our findings indicate a strong linkage between the -308A polymorphism and subacute systemic lupus erythematosus, which is likely to directly contribute to the photosensitivity of these patients.

Anti-Ro(SS-A) antibody positive Sjögren's/lupus erythematosus overlap syndrome

Unlike anti-Ro(SS-A) antibody positive subacute cutaneous lupus erythematosus (SCLE) patients, anti-Ro(SS-A) antibody positive lupus patients with Sjögren's syndrome (SS/LE) appear to have a more guarded prognosis. Our studies indicate these SS/LE patients have an increased frequency of pulmonary, neurological, and renal disease compared to SCLE patients.

Significance of the anti-Ro (SS-A) antibody in evaluation of patients with cutaneous manifestations of a connective tissue disease

The anti-Ro(SS-A) antibody is arguably the most important antibody determination except for antinuclear antibodies in evaluation of patients suspected of having lupus erythematosus. During the past 25 years, studies have established the importance of this antibody in the evaluation of patients with atypical lupus erythematosus, who have a photosensitive dermatitis as the presenting sign. The purpose of this review is to demonstrate the utility and the necessity of this antibody determination in the evaluation of all patients with cutaneous manifestations who are suspected of having a connective tissue disease.

One hundred anti-Ro (SS-A) antibody positive patients: a 10-year follow-up

To explore further the varied clinical expression of anti-Ro(SS-A) antibody positive patients and to determine the outcomes of these patients, we followed 100 anti-Ro(SS-A) antibody positive patients, originally seen at the Johns Hopkins Medical Institutions in 1982 and 1983, over a 10-year period. The results of this study indicate that anti-Ro(SS-A) antibody positive patients have a diverse clinical presentation and that the anti-Ro(SS-A) antibody response generally persists for years. Some of these patients appear to have a static disease process for years. However, 65% (51, including 13 deaths, of 78 patients) of the patients for whom we had follow-up data had a chronic (10 years or greater) progressive disease process. Black patients, in general, have an earlier onset of disease and may have a more severe disease than white patients. At least 25% of our anti-Ro(SS-A) antibody positive patients demonstrated a dynamic change in clinical presentation with the development of Sjögren syndrome and/or a progressive "rheumatoid-like" arthritis. Interstitial pulmonary disease, central nervous system disease, and vasculitic insults occur frequently in these patients. Renal disease occurred in 19 anti-Ro(SS-A) positive patients, and in 47% of these renal disease patients, no anti-DNA antibodies (dsDNA or ssDNA) were detected. Cutaneous manifestations are prominent in anti-Ro(SS-A) antibody positive patients with lupus. Photosensitivity and a malar dermatitis were the most common features. Twenty percent of lupus patients had discoid lesions, and 20% had SCLE lesions. Based on this study, we believe that anti-Ro(SS-A) antibody positive patients should be routinely evaluated for the emergence of systemic features. Since these systemic features are at least in part, if not solely, the result of inflammation, early treatment with steroids and/or immunosuppressive agents may minimize the damage and influence in a positive manner the significant morbidity and mortality observed in some anti-Ro(SS-A) antibody positive patients.

Neonatal lupus erythematosus: discordant disease expression of U1RNP-positive antibodies in fraternal twins--is this a subset of neonatal lupus erythematosus or a new distinct syndrome?

Neonatal lupus erythematosus (NLE) is an uncommon disease that is manifested by cutaneous lesions, cardiac conduction defects, or both, that appear in utero or shortly after birth. In approximately 95% of patients, anti-Ro antibody (Ro[SS-A]) has been identified and has become the serologic marker for NLE. Since 1987 there have been four reported cases of Ro- and anti-La antibody (La[SS-B])-negative, U1RNP antibody-positive, NLE. Our affected twin, as well as all other infants with U1RNP-positive NLE, had cutaneous lesions similar to those in Ro-positive NLE, although they lacked systemic abnormalities, including cardiac conduction defects. HLA typing of mothers with infants with U1RNP-positive NLE revealed the presence of HLA-DR4, DQw1, or DQw3 phenotypes. Our typing confirms these findings. As with Ro-positive NLE, no distinct HLA associations were demonstrated in the infants. Unlike Ro-positive mothers, all mothers with a U1RNP-positive infant with NLE had connective tissue disease at the time of the diagnosis and had a different spectrum of disease. We describe the clinical, serologic, and immunogenetic findings in the first reported case of U1RNP-positive NLE in dizygotic twins in whom the NLE disease expression was discordant.

Subacute cutaneous lupus erythematosus

Gilliam recognized subacute cutaneous lupus erythematosus (SCLE) as a lupus-specific eruption that identifies a unique subset of lupus erythematosus. These patients were noted to have prominent photoaggravated skin disease and often had musculoskeletal complaints, but generally did not develop significant systemic disease. SCLE patients were later found to have other distinctive features, including the frequent presence of anti-Ro antibodies, and enrichment for the human histocompatibility antigens (HLA) B8 and DR3. In the 13 years of published reports of SCLE patients following the initial study by Sontheimer et al (Subacute cutaneous lupus erythematosus: a cutaneous marker for a distinct lupus erythematosus subset. Arch Dermatol 115:1409-1415, 1979) a number of additional observations regarding SCLE patients have been made. These have included the recognition that SCLE may be associated with other rheumatic diseases, and that photoactive medications may induce lesions of SCLE. Areas of controversy concerning SCLE include conflicting studies regarding the histopathology of SCLE as compared to discoid lupus erythematosus (DLE), as well as the frequency of detection of anti-Ro antibodies in SCLE patients. Recent interesting studies of SCLE include a description of a unique pattern of immunoglobulin G (IgG) deposition on direct immunofluorescence, which may indicate the binding of anti-Ro antibodies to keratinocytes in vivo.

Anti-Ro(SS-A) HLA-DR3-positive women: the interrelationship between some ANA negative, SS, SCLE, and NLE mothers and SS/LE overlap female patients

During the past 15 years, the clinical spectrum associated with the anti-Ro(SS-A) antibody response has been defined. Various clinical presentations, including subacute cutaneous lupus erythematosus, the neonatal lupus syndrome, the Sjögren's syndrome/lupus erythematous overlap syndrome, and primary Sjögren's syndrome, have been detected in association with the anti-Ro(SS-A) response. The anti-Ro(SS-A) antibody response is associated with the HLA-DR2 and HLA-DR3 phenotypes. There is now a good deal of evidence to suggest that many anti-Ro(SS-A)-positive HLA-DR3 women are genetically closely related, sharing in common an enriched frequency of the HLA-DR3-linked B8, DQw2, and DRW52 phenotypes. DNA sequence studies have confirmed this genetic relationship. These studies have led us to the following conclusions. 1) The HLA-DR2 and HLA-DR3 associations with systemic lupus erythematosus and the HLA-DR3 association with Sjögren's syndrome are related to the anti-Ro(SS-A) antibody response and not to the clinical disease expression. 2) HLA-DR3 anti Ro-positive female patients with first-degree Sjögren's syndrome, subacute cutaneous lupus erythematosus, or Sjögren's syndrome, or who are asymptomatic, are immunogenetically closely related even though the clinical presentations are strikingly different. All these HLA-DR3 anti-Ro(SS-A) antibody-positive women are at risk to give birth to a child with the neonatal lupus syndrome.

The clinical genetics of lupus

Genetic aspects of lupus are reviewed, including recognition of genetic and clinical heterogeneity, genetic factors in the aetiology and heritability of disease, reproductive implications and genetic counselling of patients. Despite a large literature on the genetic epidemiology and immunogenetics of lupus, it remains difficult to apply the results of laboratory findings to the circumstances of individual patients. Generally, lupus is not transmitted as a simple Mendelian trait, and genetic counselling is based on the multifactorial model of disease aetiology with interaction of multiple genetic and environmental factors. Further studies are needed to clarify the heritability of lupus and improve the data for recurrence risk prediction in lupus families.