Acetylation phenotypes and environmental chemical exposure of people with idiopathic systemic lupus erythematosus

Association Between Cigarette Smoking and Systemic Lupus Erythematosus: An Updated Multivariate Bayesian Metaanalysis

OBJECTIVE

The association between cigarette smoking and the risk of systemic lupus erythematosus (SLE) remains a matter for debate. Additionally, the effect of the change of smokers' demographics on the risk of development of SLE over time has not been formally addressed. We aimed to examine the association between cigarette smoking and the risk of SLE by performing an updated metaanalysis.

METHODS

A literature search using keywords including "lupus," "smoking," "cigarette," "environmental," "autoimmune," and "connective tissue disease" was performed in computerized databases to identify studies addressing the relationship between cigarette smoking and SLE occurrence. A Bayesian metaanalysis was conducted by computing the log-OR between current and never smokers, and between former and never smokers. The average log-OR (subsequently converted to OR) and their corresponding 95% credible intervals (CrI) were calculated. The effect of publication time, sex, and age of patients with SLE on the effect sizes was examined by multivariate metaregression.

RESULTS

Data aggregation of 12 eligible studies comprising 3234 individuals who developed SLE and 288,336 control subjects revealed a significant association between SLE occurrence and current smoking status (OR 1.54, 95% CrI 1.06-2.25), while only a non-significant trend was demonstrated between SLE occurrence and former smoking status (OR 1.39, 95% CrI 0.95-2.08). Publication time, sex, and the mean age of patients with SLE did not explain the heterogeneity of the effect sizes.

CONCLUSION

Current smoking status is associated with risk of SLE. Sex and age of patients with SLE had no significant effect on the risk of SLE over time.

Impact of tobacco smoking upon disease risk, activity and therapeutic response in systemic lupus erythematosus: A systematic review and meta-analysis

Systemic lupus erythematosus (SLE) is a complex disease with variable presentations, course and prognosis. Published studies present conflicting data regarding the impact of cigarette smoking on SLE risk, disease activity, clinical manifestations and treatment response. We performed a comprehensive literature search using Medline, EMBASE and the Cochrane Collaboration database, and hand searches of relevant bibliographies. All original studies investigating the relationship between smoking and SLE were included in TABALUP. Two investigators systematically extracted data from the relevant studies. When possible, meta-analyses were performed. The meta-analysis of 9 case-controls studies show an increased risk of SLE in current-smokers compared to never-smokers (OR: 1.49 [95%CI: 1.06-2.08]), while former-smokers were not at increased risk of SLE. Data on passive smoking remains scarce and controversial. Pooled analysis studies did not find an over-risk of anti-dsDNA, anti-Sm or anti-SSA positivity according to smoking status. Tobacco smoking significantly reduced the therapeutic effectiveness of hydroxychloroquine in cutaneous lesions (pooled OR 0.53; 95%CI: 0.305-0.927) and belimumab in systemic manifestations (HR 0.10; 95% CI 0.02-0.43). In addition to its usual adverse effects, cigarette smoking is a risk factor of SLE and negatively influences the course of the disease and its treatment. We believe that smoking cessation should be one of the main target of physicians treating SLE patients.

Smoking under hypoxic conditions: a potent environmental risk factor for inflammatory and autoimmune diseases

Autoimmune disease management presents a significant challenge to medical science. Environmental factors potentially increase the risk of developing inflammatory and autoimmune diseases, such as multiple sclerosis, rheumatoid arthritis, and lupus. Among various environmental stresses, cigarette smoke and hypoxia have both been reported to lead to an enhanced risk of inflammatory and autoimmune diseases.In this review, we shed light on all reported mechanisms whereby cigarette smoke and a hypoxic environment can induce inflammatory and autoimmune diseases and discuss how hypoxic conditions influence the cigarette smoke-induced threat of inflammatory and autoimmune disease development.Cigarette smoke and hypoxia both lead to increased oxidative stress and production of reactive oxygen species and other free radicals, which have various effects including the generation of autoreactive pro-inflammatory T cells and autoantibodies, reductions in T regulatory (Treg) cell activity, and enhanced expression of pro-inflammatory mediators [e.g., interleukin-6 (IL-6), interleukin-4 (IL-4) and interleukin-8 (IL-8)]. Accordingly, smoking and hypoxic environments may synergistically act as potent environmental risk factors for inflammatory and autoimmune diseases. To our knowledge, no studies have reported the direct association of cigarette smoke and hypoxic environments with the risk of developing inflammatory and autoimmune diseases.Future studies exploring the risk of autoimmune disease development in smokers at high altitudes, particularly military personnel and mountaineers who are not acclimatized to high-altitude regions, are required to obtain a better understanding of disease risk as well as its management.

Cigarette smoking and autoimmune disease: what can we learn from epidemiology?

Cigarette smoking has been causally linked to the development of multiple autoimmune diseases, including rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, Graves' hyperthyroidism, and primary biliary cirrhosis, among others. We review the known biologic effects of cigarette smoke, in particular its actions on the immune system, and the epidemiologic evidence associating smoking with increased risk of each of these autoimmune diseases. Interactions between cigarette smoking and genetic and immunologic factors, such as the human leukocyte antigen (HLA)shared epitope, rheumatoid factor, anti-cyclic citrullinated peptide antibodies, and anti-double stranded DNA antibodies, may point to mechanisms in disease pathogenesis.

Smoking and the risk of systemic lupus erythematosus: an updated systematic review and cumulative meta-analysis

Published articles reported controversial results about the association of smoking with the risk of systemic lupus erythematosus (SLE). A meta-analysis was performed to assess the aforementioned association and arrive at a more precise estimate of effect. A comprehensive search was performed to identify case-control or cohort studies (from 1990 to 2015) of the aforementioned association. The I (2) statistic was used to examine between-study heterogeneity. Fixed or random effect model was selected based on heterogeneity test among studies. Publication bias was estimated using Egger's regression asymmetry test. A total of 12 published articles with 13 studies were finally included in our meta-analysis. Results showed that the pooled odds ratio (OR) for SLE risk was 1.56 (95% confidence interval (CI) = 1.26-1.95) among current smokers compared with nonsmokers. For ex-smokers versus nonsmokers, the pooled OR for SLE risk was 1.23 (95% CI = 0.93-1.63). Subgroup analysis by geographic location and cumulative meta-analysis were also analyzed. In conclusion, our meta-analysis suggested that smoking increased the risk of SLE. Further studies are needed to confirm this result.

Cigarette smoking, alcohol consumption and risk of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex multisystem autoimmune disease whose pathogenesis is thought to involve both genetic and environmental factors. It is possible that common environmental exposures, such as cigarette smoking and alcohol consumption, might modify risk of disease development in certain individuals. Here we aim to review the epidemiologic evidence related to the association of cigarette smoking, alcohol consumption and the risk of developing SLE. A growing body of evidence suggests that cigarette smoking confers a short-term increased risk of SLE in genetically susceptible individuals. On the other hand, alcohol consumption in moderate doses may have a protective effect against the development of SLE, although this is still debated. We also have reviewed proposed mechanistic explanations underlying the role of cigarette smoking and alcohol consumption in SLE pathogenesis.

Epigenetic regulation of cytokine expression in systemic lupus erythematosus with special focus on T cells

Epigenetic events play a central role in the priming, differentiation and subset determination of T lymphocytes. Through their influence on chromatin conformation and DNA-accessibility to transcription factors and RNA polymerases, epigenetic marks allow or prevent gene expression and control cellular functions including cytokine expression. CpG-DNA methylation and post-translational modifications to histone tails are the two most well accepted epigenetic mechanisms. The involvement of epigenetic mechanisms in the pathogenesis of systemic lupus erythematosus (SLE) has been suggested by the development of lupus-like symptoms by individuals who received procainamide or hydralazine treatment resulting in a reduction of CpG-DNA methylation. To date, a growing body of literature indicates that the deregulation of cytokine expression through epigenetic disturbances can result in altered immune responses and autoimmune reactions. Over the past decade, various global and regional epigenetic alterations have been reported in immune cells from patients with SLE and other autoimmune disorders. More recently, the molecular mechanisms that result in epigenetic disturbances have been addressed, and deregulated transcription factor networks have been demonstrated to mediate epigenetic alterations in B and T lymphocytes from SLE patients. A better understanding of the molecular events that contribute to epigenetic alterations and subsequent immune imbalance is essential for the establishment of disease biomarkers and identification of potential therapeutic targets.

Increased risk of chronic obstructive pulmonary disease in patients with systemic lupus erythematosus: a population-based cohort study

BACKGROUND

There is increasing evidence that autoimmune disease is associated with development of chronic obstructive pulmonary disease (COPD). We aim to assess the relationship between systemic lupus erythematosus (SLE) and COPD risk in a nationwide population.

METHODS

We conducted a retrospective cohort study using the catastrophic illness registry of the Taiwan National Health Insurance Research Database (NHIRD). We identified 10,623 patients with SLE newly diagnosed between 2000 and 2010. Each patient was randomly frequency-matched with four people without SLE on age, sex, and index year from the general population. Both cohorts were followed up until the end of 2010 to measure the incidence of COPD. The risk of COPD was analyzed using Cox proportional hazards regression models including age, sex, index year and comorbidities.

RESULTS

The overall incidence rate of COPD was 1.73-fold higher in the SLE cohort than in the control cohort (17.4 vs. 10.1 per 10,000 person-years, 95% CI = 1.62-1.84). Age related analysis showed increased incidence of COPD with age in both SLE and control cohorts. However, adjusted HR maximum was observed in the youngest age group (adjusted HR: 4.33, 95% CI, 2.39-7.85) while adjusted HR minimum was witnessed in the oldest age group (adjusted HR: 1.19, 95% CI, 0.85-1.22).

CONCLUSION

Patients with SLE have a significant risk of developing COPD than the control population. Based on the findings from this study, it can be hypothesized that in addition to cigarette smoke SLE may be a determining factor for COPD incidence. However, further investigation is needed to corroborate this hypothesis.

Sex-specific environmental influences on the development of autoimmune diseases

Sex differences in autoimmune diseases are evolutionarily tied to the fact that the female immune system is confronted with intense alterations during menstrual cycles, pregnancy and childbirth. These events may be associated with breaches in the mucosal epithelial layers that are shielding us from environmental factors. Associations between environmental agents and autoimmune diseases have been described extensively in prior studies. Little evidence, however, exists for sex-specific environmental effects on autoimmune diseases. In this review, we summarize studies involving this often-neglected aspect. We give examples of environmental factors that may influence the sex bias in autoimmunity. We conclude that most studies do not give insight into sex-specific environmental effects due to the influence of gender-selective social, occupational or other exposures. Prospective studies are needed in order to determine true sex-biased environmental influences. Finally, humanized murine models might aid in better understanding the mechanisms involved in sex-specific environmental effects on autoimmune diseases.

Cigarette Smoking, Alcohol Consumption, and Risk of Systemic Lupus Erythematosus: A Case-control Study in a Japanese Population

Objective.

Cigarette smoking may be associated with increased risk of systemic lupus erythematosus (SLE), whereas the role of alcohol consumption is unknown. We examined the association between SLE risk and smoking or drinking.

Methods.

We investigated the relationship of smoking and drinking compared to SLE risk among 171 SLE cases and 492 healthy controls in female Japanese subjects. Unconditional logistic regression was used to compute OR and 95% CI, with adjustments for several covariates.

Results.

Compared with nonsmoking, current smoking was significantly associated with increased risk of SLE (OR 3.06, 95% CI 1.86–5.03). The higher the level of exposure to cigarette smoke, the higher the risk of SLE. Inhalation was also associated with increased SLE risk (OR 3.73, 95% CI 1.46–9.94 for moderate inhalation; OR 3.06, 95% CI 1.81–5.15 for deep inhalation). In contrast, light/moderate alcohol consumption had a protective effect on SLE risk (OR 0.38, 95% CI 0.19–0.76). As for beer, the risks for non-beer drinkers and beer drinkers were similar. This also applies to alcoholic beverages other than beer.

Conclusion.

Our results suggest that smoking was positively associated with increased SLE risk whereas light/moderate alcohol consumption was inversely associated with SLE risk, irrespective of the type of alcoholic beverage. Additional studies are warranted to confirm these findings.

Epigenetics in lupus

Accumulating epidemiological, clinical, and experimental evidence supports the conclusion of a critical role of epigenetic factors in immune programming. This understanding provides the basis for elucidating how the intricate interactions of the genome, epigenome, and transcriptome shape immune responses and maintain immune tolerance to self-antigens. Deciphering the precise contribution of epigenetic factors to autoimmunity, and in particular to lupus, has become an active research area. On one hand, it is well established that environmental factors have an impact on the epigenome and, therefore, on the transcriptional and translational machinery of specific cell types; on the other, the environment also plays an important role in the severity of lupus and other autoimmunity diseases. Determining how epigenetics "connects" the environment to cell biology and to autoreactivity will be key for advancing our understanding in this field and, possibly, for developing novel preventive strategies.

Cigarette smoking and systemic lupus erythematosus: A smoking gun?

Cigarette smoking is one of many environmental exposures, including infectious agents, silica exposure, hormonal and dietary factors, hypothesized to be linked to the development of SLE. Cigarette smoke contains hundreds of potentially toxic components, including tars, nicotine, carbon monoxide, polycyclic aromatic hydrocarbons among others. Whether cigarette smoking increases the risk of developing SLE remains controversial. To date, three case-control studies have reported significantly increased odds ratios for the development of SLE in smokers, while six others have not found a clear association. A meta-analysis statistically combining the effect estimates from the available studies, revealed a modestly increased risk posed by current smoking (RR 1.5 [95% CI 1.09, 2.08]), but no increased risk associated with past smoking. The strengths and weaknesses of these data and potential implications are discussed.

Cigarette smoking, N-acetyltransferase 2 polymorphisms and systemic lupus erythematosus in a Japanese population

Cigarette smoking may be associated with an increased risk of systemic lupus erythematosus (SLE), but the underlying mechanism of this association remains unclear. N-acetyltransferase 2 (NAT2) is highly variable and detoxifies aromatic amines, an important class of carcinogens in tobacco smoke. Individuals who possess homozygous polymorphic alleles have a slower rate of metabolic detoxification of aromatic amines. We investigated the relationship of the NAT2 polymorphism to the risk of SLE with special reference to the interaction with cigarette smoking among 152 SLE cases and 427 controls in a female Japanese population. NAT2*4, NAT2*5B, NAT2*6A and NAT2*7B alleles were detected with polymerase chain reaction–restriction fragment length polymorphism. Individuals carrying the *4/*4 genotype are rapid acetylators, whereas those with homozygous non-*4 genotypes have a slow acetylator phenotype. Cigarette smoking was associated with an increased risk of SLE (odds ratio [OR] = 2.26; 95% confidence interval [CI] = 1.46–3.50). The slow acetylator genotype of NAT2 was significantly associated with an increased risk of SLE (OR = 2.34, 95% CI = 1.21–4.52) compared with the rapid acetylator genotype. A gene-environment interaction was suggested, with a combination of the NAT2 slow acetylator genotype and smoking conferring significantly higher risk (OR = 6.44, 95% CI = 3.07–13.52; attributable proportion due to interaction = 0.50, 95% CI = 0.12–0.88), compared with the NAT2 rapid acetylator genotype and no history of smoking. This study suggests that, in this Japanese population, the NAT2 slow acetylator status may be a determinant in susceptibility to SLE.

What can epidemiology tell us about systemic lupus erythematosus?

Systemic lupus erythematosus (SLE) is an often-severe autoimmune rheumatic disease most commonly diagnosed in women in their childbearing years. It is thought to develop when genetically predisposed individuals are exposed to one or more environmental triggers. This review outlines the epidemiologic evidence for several putative risk factors including cigarette smoke, hormonal and reproductive factors, environmental silica and infectious exposures, as well as many yet to be identified. We also review the evidence for factors associated with increased disease activity and adverse outcomes in SLE. We review the literature on the epidemiology of SLE, its distribution, potential risk factors for its onset and for adverse outcomes. The information considered in this review was gathered through extensive review of the literature. Online Pubmed literature searches, previous reviews of the epidemiology of SLE and original studies were employed. Epidemiologic studies have helped to identify some of these potential risk factors, including exogenous hormone use, cigarette smoking, infections such as Epstein-Barr virus (EBV) and crystalline silica exposure, but many more have yet to be studied. These exposures may interact with multiple genetic factors in determining susceptibility to SLE. While epidemiologic research has contributed an enormous amount to our understanding of the disease and its pathogenesis, there are many more avenues of epidemiologic research that deserve to be pursued.

Environment and systemic lupus erythematosus: an overview

Systemic lupus erythematosus (SLE) is an autoimmune disease of unknown etiology that manifests as a pleomorphic systemic disease mainly affecting females. The variety of autoantibodies found in the serum of patients indicate that SLE is an autoimmune disease, but the mechanisms leading to the aberrant responses are not clearly understood although it is thought that a number of genetic and environmental factors may be involved. Environmental (or non-genetic) exposures could include infectious agents, chemicals or other compounds capable of modulating immune responses such as occupational/environmental pollutants or drugs, and behavioural factors such as smoking and diet. Environmental exposures may lead to the production of autoreactive T cells and autoantibodies, the stimulation of pro- and antiinflammatory cytokines, and target end-organ damage, but are not so convincing as agents causing SLE. Exposure to viruses increases antibody titres, but these may be the result of polyclonal B cell activation. The amount and timing of exposure to different environmental factors may play a significant and complex role in the pathogenesis of SLE and other autoimmune diseases. A better understanding of the etiopathogenetic mechanism of SLE is required in order to clarify the multiple interactions between environmental exposures and genetic factors.

Effect of Cigarette Smoke on Autoimmunity in Murine and Human Systemic Lupus Erythematosus

Several studies have found that smoking cigarettes is a risk factor for systemic lupus erythematosus (SLE). To examine this issue in a mouse model, we subjected pre-autoimmune MRL-lpr/lpr mice for 4 weeks to cigarette smoke to provide standardized smoke effluents equivalent to moderate or to heavy smoking habits for people. The spontaneous production of IgG anti-chromatin but not IgM anti-chromatin, anti-denatured DNA, or rheumatoid factor antibodies was lower in mice exposed to 250 mg/m3 particulates from mainstream smoke, and this suppression of autoimmunity was sustained for 8 weeks (p < 0.02). In contrast to control mice anti-chromatin activity in smoke-exposed mice began to increase in 16-week-old mice, reaching levels at 6 months that were two- to three-fold higher than controls for IgG (p < 0.03) and 10-fold higher for IgM (p < 0.001). There was no significant effect on total IgG or IgM. In newly diagnosed SLE patients, smoking was negatively correlated with IgG anti-DNA antibodies (p < 0.03). However, of nine patients who discontinued smoking prior to diagnosis, eight had elevated IgG anti-DNA compared to 29/79 never smokers and 9/31 smokers (p < 0.01 compared to former smokers). Inhaled cigarette smoke appears to have a long-lasting immunosuppressive effect on T-cell-dependent autoimmune responses, although autoantibodies increase to supra-elevated levels after the suppressive effect has abated.

Occupational and environmental exposures as risk factors for systemic lupus erythematosus

Although genetic susceptibility plays a strong role in the etiology of systemic lupus erythematosus (SLE), recent research has provided new evidence of the potential influence of environmental factors in the risk for this disease. This paper describes epidemiologic and experimental research pertaining to occupational and environmental sources of exposure to respirable crystalline silica, solvents and pesticides, and two "lifestyle" factors (smoking and hair dye use). As has been seen with other systemic autoimmune diseases (eg, systemic sclerosis and rheumatoid arthritis), a series of epidemiologic studies, using different designs in different settings, have demonstrated relatively strong and consistent associations between occupational silica exposure and SLE. The type and quality of exposure assessment is an important consideration in evaluating these studies. Recent experimental studies examined the effect of trichloroethylene exposure in MRL+/+ mice, but to date there have been few epidemiologic studies of solvents and SLE. There are numerous avenues with respect to environmental factors in SLE that need additional research.

Cigarette smoking and the risk of systemic lupus erythematosus: a meta-analysis

OBJECTIVE

Existing studies present conflicting evidence for the role of cigarette smoking as a risk factor in the development of systemic lupus erythematosus (SLE). We performed an extensive search of the medical literature for all studies examining this relationship, and performed a meta-analysis to arrive at a more precise estimate of effect.

METHODS

We performed a computerized literature search for all studies (in all languages), using Medline and EMBASE (1966 to present) and the Cochrane Collaboration database, and completed hand searches of relevant bibliographies and abstracts of conference proceedings. Several investigators systematically extracted data from the relevant studies. Unpublished data were obtained from the author of one abstract. Studies were examined in aggregate for heterogeneity and publication bias. The relationships of current smoking and past smoking (prior to the onset of SLE) to development of SLE were analyzed separately.

RESULTS

Fifty-two studies were identified and chosen for detailed review. Of these, 9 (7 case-control and 2 cohort studies) were appropriate for inclusion in our meta-analyses. For current smokers compared with nonsmokers, the odds ratio (OR) for development of SLE was significantly elevated (OR 1.50, 95% confidence interval [95% CI] 1.09-2.08). Former smokers, compared with nonsmokers, did not demonstrate an increased risk of SLE (OR 0.98, 95% CI 0.75-1.27). Several subgroups were also analyzed.

CONCLUSION

Our meta-analysis of the 7 existing case-control and 2 cohort studies revealed a small but statistically significant association between current smoking and development of SLE. However, no association between past smoking and development of SLE was observed.

Calculating the etiology of systemic lupus erythematosus

Objective was to clarify the etiology and pathogenesis of systemic lupus erythematosus (SLE). Drug-induced lupus (DIL) and SLE are both found in humans, are exacerbated by the same viruses or drugs, and they are both more common in slow acetylators. Thus, DIL can be used as a model for SLE and the Adhami equation of DIL can be applied to SLE. Polyamines are the only possible link between the viral and amine hypotheses of SLE pathogenesis. Based on the Adhami equation, polyamines can explain the actual annual incidence of SLE in the general population. Putrescine is a very weak SLE-causing agent, while spermine and spermidine contribute equally in triggering SLE. The positively charged polyamines bind to negatively charged internucleosomal DNA and change its conformation from B (non-immunogenic) to Z (immunogenic). This is the major contribution of polyamines in triggering SLE. The other effects of polyamines are only secondary. Apoptosis is a necessary step in SLE pathogenesis, because it causes the internucleosomal fragmentation of DNA and exposes Z-DNA to the immune system (due to cell death). The next step is the production of anti-DNA antibodies, followed by other SLE phenomena. Polyamines not only cause SLE, but they are also important in sustaining the disease. Other endogenous and exogenous amines have additive effects with polyamines and may contribute in exacerbating SLE. When SLE is in the active phase, polyamine levels are higher as compared to remissions. Fluctuations in polyamine levels due to diet, metabolic factors, infections, intestinal flora, etc. or the presence of other amines may explain the course of SLE, characterized by remissions and exacerbations. Acetylcysteine is a drug that can be completely metabolized to acetyl groups. As such, this drug is proposed as the ideal acetyl donor for the acetylation of polyamines and other SLE-triggering compounds. Clinical trials will be necessary to test the role of acetylcysteine in the etiologic treatment of SLE.

CONCLUSIONS

Changes in DNA conformation by polyamines are the first step in SLE pathogenesis. Many genetic and environmental factors may increase or decrease the effects or levels of polyamines, causing SLE exacerbations or remissions. Viruses and other infectious agents may cause SLE by producing polyamines or by increasing the levels of endogenous polyamines. The major autoimmune diseases are characterized by remissions and exacerbations and not by a continuously progressive course, as commonly believed. Consequently, they are not sustained by internal vicious cycles, but by the initial triggering agent(s). While the conventional treatment of autoimmune disorders is important in minimizing tissue damage, the neutralization of their etiology may be important in curing and preventing autoimmunity.

A predictive equation for drug-induced lupus

Objective was to quantify the chemical mechanisms of drug-induced lupus (DIL), and to make the data of different authors comparable between them. I have used seven assumptions as a starting point, based on empirical evidence; then an equation is drawn, describing the relationship between the quantity of the drug taken by the patient(s) and the probability of DIL appearance. The DIL-causing potential of each chemical group is a measurable intrinsic characteristic of that group, and the probability of DIL appearance is directly proportional to the total dosage of the drug in question.

CONCLUSIONS

DIL is a syndrome that can be readily quantified and, as such, could be used as a model for idiopathic Systemic Lupus Erythematosus. On the other hand, the equation drawn here could be used to predict the lupus-inducing potential of many compounds that have not yet been studied. Other authors are encouraged to find similar equations in other drug-induced syndromes.

Pathogenesis of systemic lupus erythematosus

The exact patho-aetiology of systemic lupus erythematosus (SLE) remains elusive. An extremely complicated and multifactorial interaction among various genetic and environmental factors is probably involved. Multiple genes contribute to disease susceptibility. The interaction of sex, hormonal milieu, and the hypothalamo-pituitary-adrenal axis modifies this susceptibility and the clinical expression of the disease. Defective immune regulatory mechanisms, such as the clearance of apoptotic cells and immune complexes, are important contributors to the development of SLE. The loss of immune tolerance, increased antigenic load, excess T cell help, defective B cell suppression, and the shifting of T helper 1 (Th1) to Th2 immune responses leads to B cell hyperactivity and the production of pathogenic autoantibodies. Finally, certain environmental factors are probably required to trigger the disease.

Hair dye treatment use and clinical course in patients with systemic lupus erythematosus and cutaneous lupus

The etiological role of hair dye treatment (HDT), some of them such as permanent hair dyes containing aromatic amines, in the development of SLE has been previously ruled out. However, the possible influence of HDT use on the course and prognosis of lupus patients has been assessed only in one short-term study. Since HDT is very extensive among the population, the knowledge of this possible negative effect may be very important. Thus, the aim of this study was to assess the long-term influence of several HDTs on the course and clinical severity of patients with both systemic lupus erythematosus (SLE) and cutaneous lupus (CL). In this longitudinal case series study, 91 SLE patients and 22 CL patients were prospectively studied from October 1988 to May 2000. They were divided into three groups: (a) non-HDT users--patients who have never used HDT (n = 65); (b) P-HDT users--HDT permanent type users, alone or in combination with other types of HDT (n = 28); (c) non P-HDT--users of other treatments different from permanent tinting (bleach, lowlights, etc; n = 20). In each patient we determined: (1) number of flares/year in SLE patients and worsening of cutaneous lesions for CL; (2) Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) damage index; (3) predominant damaged organs/systems according to the HDT use and type of HDT; and (4) subjective impression about the disease evolution in relation to HDT use. No significant differences were found with respect to flares/year and SLICC/ACR damage index between the study groups. Non-HDT group presented more renal involvement and serositis than both HDT-user groups. No patient related the HDT use to the worsening of his disease. Therefore, in this study no evidence of an association between the long-term use of several types of HDT and the clinical activity and course of SLE and CL was found.

Environmental epidemiology and risk factors for autoimmune disease

It has long been recognized that environmental influences play an important role in the risk of developing chronic rheumatic disease. Defining specific pathogenic environmental mediators that may trigger the development or progression of autoimmune disease remains a focus of increasing investigative effort. Factors promoting disease may not be identical to factors that influence the severity or progression of the disorder. Human monozygotic twin studies, animal studies, and genetic models demonstrate that genetic influences strongly determine whether one will develop autoimmunity, however, genes affecting the metabolism of exogenous agents that may trigger disease expression have only recently drawn attention. In this article the authors review recent reports that advance our understanding of previously recognized environmental risk factors and challenge accepted beliefs that increased estrogenic exposures predate the incidence of autoimmune disorders, systemic lupus erythematosus in particular.

Update on the epidemiology of systemic lupus erythematosus: new spins on old ideas

Systemic lupus erythematosus is a serious autoimmune disease of obscure etiology with a propensity for widespread organ involvement. Its manifestations range from ephemeral symptoms to life-threatening events such as thromboses and strokes. Although once considered rare, SLE now appears to be relatively common in certain subsets of the population. Considerable publicity for this disorder as a "silent killer" has heightened public awareness and may have contributed to the increases in the number of individuals reporting this diagnosis in surveys. Epidemiologic studies face numerous challenges in disease classification and case ascertainment. Despite this, such studies have increased in size and number, and have generated novel etiologic hypotheses, ranging from environmental pollutants to viral infections.

Systemic lupus erythematosus (SLE) and hair treatment: a large community based case-control study

OBJECTIVE

To investigate the association of hair treatment, including permanent and non-permanent dyes, bleach, highlights and lowlights on the development of systemic lupus erythematosus (SLE).

METHODS

150 SLE patients and 300 controls from Nottingham, UK were interviewed in a case-control study. Controls were matched to cases for gender and year of birth. All patients met at least four of the American Rheumatology Association criteria for SLE. Controls were randomly selected from the Nottingham Family Health Services Authority register. Information was collected via an interview-administered questionnaire concerning demographic variables and hair treatment.

RESULTS

For hair treatment no significant associations were observed between ever using permanent colouring, non-permanent colouring, bleach or lowlights, and disease. Nevertheless a significant association (OR 0.55, 95% CI 0.31-0.95) was observed between 'ever having' used highlights and disease with cases having used highlights less frequently than their healthy counterparts. No significant differences were observed in duration of usage of hair bleach, permanent colouring, non-permanent colouring, highlights and lowlights between cases and controls.

CONCLUSIONS

Hair treatment or duration of hair treatment usage is not significant in the aetiology of SLE. Although patients with SLE were less likely in this study to have highlights than controls, for all other hair treatments no differences were observed.

Rheumatologic manifestations of gastrointestinal diseases

One of the most significant extraintestinal manifestations of gastrointestinal diseases is rheumatologic disorders. The gastrointestinal diseases with rheumatologic manifestations can be divided into two major categories: intestinal disorders and disorders of the liver, biliary tree, and pancreas. The cause of diseases in each of these categories is different. Although intestinal permeability and immune responsiveness are frequently implicated in disorders of the intestine, diseases of the liver, biliary tree, and pancreas usually involve the production of autoantibodies, cytokines, or enzymes. Treatment of rheumatologic complications frequently involves therapy directed at the underlying gastrointestinal disease.

Hair dye use and the risk of developing systemic lupus erythematosus

OBJECTIVE

To investigate the role of hair dye use in the etiology of systemic lupus erythematosus (SLE).

METHODS

Participants included 106,391 women enrolled in the Nurses' Health Study, a prospective cohort study. The subjects were ages 30-55 years in 1976, and were free from SLE and any other connective tissue disease at the time of enrollment. In 1976, 1978, 1980, and 1982, subjects were classified as never-users or ever-users of permanent hair dye, based on self-report. Incidence rates of SLE meeting American College of Rheumatology classification criteria were ascertained and confirmed by chart review.

RESULTS

Compared with never-users of permanent hair dye, the age-adjusted relative risks (RR) for the development of SLE among ever-users (n = 85 cases) was 0.96 (95% confidence interval [95% CI] 0.63-1.47). Duration of hair dye use was not related to risk of SLE. Women with 15 or more years of use had no increased risk (RR = 0.92, 95% CI 0.46-1.83). There was no relationship between frequency of use or time since first use and risk of SLE. The results were similar when less stringent criteria for SLE were used.

CONCLUSION

We found no evidence that permanent hair dye use, age at first use, frequency of use, or duration of use is associated with the development of SLE.

New environmental agents associated with lupus-like disorders

An increasing number of environmental agents are being investigated as possible risk factors in the etiology of certain connective tissue disorders. Exposure to a variety of therapeutic agents, foods and dietary supplements, occupational and other toxic exposures, and infectious agents has been associated with the onset of lupus-like disorders. The mechanisms by which these agents might induce lupus remain unknown but may involve alteration of cellular components or activation of the immune system. Individual host susceptibility factors, including pre-existing organ dysfunction and particular metabolic enzyme or immunogenetic phenotypes, may also be important risk factors for development of environmentally-associated lupus-like disorders. Awareness of the many environmental agents implicated with lupus and related disorders, and dissection of their pathogenetic mechanisms through appropriate case-controlled investigations, may identify additional toxic agents and may lead to a better understanding of the idiopathic lupus syndromes.

Breast silicone implants and risk of systemic lupus erythematosus

The uncertain safety of breast implants has been a major controversy of late, both in the lay press and in the scientific literature. A case-control study had been performed in the Philadelphia metropolitan area during 1985-1987 to investigate potential risk factors for systemic lupus erythematosus (SLE). A total of 219 eligible cases who met the American Rheumatism Association criteria for SLE were identified from the medical practices of cooperating rheumatologists in the area; 195 (89%) of these were enrolled in the study. Friends of the cases, matched to the cases on sex and age (+/- 5 years) served as controls. For the current investigation, conducted during June 1992 through September 1992, we attempted to re-contact each of these individuals. Using a short telephone interview, we asked each subject to provide information on any surgery that they may have had prior to the index date, i.e. the year of diagnosis of SLE in the cases and the same year for the age-matched friend controls. Specific questions were asked about plastic surgery in general and breast implants in particular. 148 (75.9%) of the 195 SLE cases being sought and 111 (77.6%) of the 143 controls being sought agreed to be re-interviewed for this study. Only 1 (0.8%) out of 133 female SLE cases reported having had a breast implant, 8 years prior to the diagnosis of SLE. This compared to 0 out of the 100 female friend controls (Fisher exact one-tailed p-value = 0.57).(ABSTRACT TRUNCATED AT 250 WORDS)