Complement system protein C4 and susceptibility to hydralazine-induced systemic lupus erythematosus

Drug-induced lupus erythematosus in childhood: Case-based review

BACKGROUND

Drug-induced lupus erythematosus (DILE) is the development of lupus-like syndrome following a drug exposure. DILE has been reported less frequently among children than adults.

METHODS

In this study, we present four children with DILE and similar published cases through a systematic literature review.

RESULTS

We report four children (three girls and one boy) who developed DILE associated with the use of topiramate, doxycycline, etanercept, and ethosuximide. Three of them were positive for anti-histone antibodies. In all patients, the drug was discontinued and symptoms resolved completely. The literature review revealed 48 articles describing 61 children with DILE. In the evaluation of 65 patients (our 4 patients and 61 patients from the literature), the most frequently reported drugs associated with DILE were ethosuximide (n = 13) and minocycline (n = 12). Fever (n = 33), arthralgia (n = 31), rash (n = 30), and arthritis (n = 29) were the most common clinical manifestations. Antinuclear antibody (ANA) was positive in 93.5% of patients and anti-histone antibodies were detected in 72.2% of the patients. As for treatment, the responsible drug was discontinued in all patients, and corticosteroids were initiated in 53.3%. Improvement was achieved in 92.0% of patients.

CONCLUSION

For children presenting with SLE features, proper drug history is crucial since DILE may be more frequent than anticipated. An association of the relevant drug with the symptoms, and resolution of symptoms on drug withdrawal provides evidence for the diagnosis of DILE.

Mendelian randomization study on causal association of FAM210B with drug-induced lupus

OBJECTIVE

Due to the complexity of drug-induced lupus (DIL) pathogenesis, more susceptibility factors need to be discovered. FAM210B is a new mitochondrial protein whose function has not been fully elucidated. This study will explore whether there is a correlation between FAM210B and the risk of DIL.

METHODS

At first, we extracted three FAM210B genetic variants from the GTEx database (n = 948), and extracted their corresponding genome-wide association study (GWAS) summary statistics from DIL (101 DIL cases and 218691 controls). Then, we performed a Mendelian randomization (MR) study to evaluate the causal association of the expression of FAM210B with DIL using inverse-variance weighted (IVW), the weighted median, MR-Egger, and MR-PRESSO test.

RESULTS

We successfully extracted three FAM210B single-nucleotide polymorphisms (SNPs) (rs116032784, rs34361943 and rs33923703) from the GTEx_Analysis_v8_eQTL data that can reduce FAM210B expression. The results of the MR analysis showed that genetically reduced expression of FAM210B was significantly associated with increased risk of DIL in European ancestry based on the IVW method (β = 1.037, p = 0.001, odds ratio [OR] = 2.821, 95% confidence interval [CI]:1.495-5.322).

CONCLUSION

MR analysis showed a causal relationship between FAM210B expression and the risk of DIL disease. Our results suggested that FAM210B may be a marker that can mark susceptibility of DIL in the future. It provides evidence for the study of DIL, but its specific mechanism of action in DIL needs to be further studied. Key Points •This is the first MR analysis to examine the association between FAM210B and DIL. •The findings of this study suggested that reduced FAM210B expression is associated with the increased risk of DIL. •FAM210B may be a marker that can mark susceptibility of DIL in the future.

Elevated Antibody Titers to Epstein-Barr Virus and Cytomegalovirus in Patients with Drug-Induced Lupus

Systemic lupus erythematosus (SLE) is an autoimmune disease, which has been associated with Epstein-Barr virus (EBV) and Cytomegalovirus (CMV) infection. Drug-induced lupus (DIL) is a lupus-like disease caused by the intake of therapeutic drugs, which has been estimated to cause approximately 10-15% of lupus-like cases. Although SLE and DIL share common clinical symptoms, there are some fundamental differences between DIL and SLE onset. Moreover, it remains to be examined whether environmental factors, such as EBV and CMV infections, may contribute to the development of DIL. This study focused on examining the possible association between DIL and EBV and CMV infections, by examining IgG titers to EBV and CMV antigens in serum samples by enzyme-linked immunosorbent assays. Antibody titers to EBV early antigen-diffuse and CMV pp52 were found to be significantly elevated in both SLE and DIL patients compared to healthy controls, although no correlation was found for antibodies to the two virus antigens in the respective disease groups. Moreover, total IgG titers were reduced in SLE and DIL serum samples, which may reflect a general lymphocytopenia, which commonly is associated with SLE. The current findings support that EBV and CMV infections may contribute to the development of DIL and that onset of both diseases are related.

Drug-Induced Lupus Secondary to Ethosuximide in Association with Acute Tubulointerstitial Nephritis and Nephrotic Syndrome

Background. Drug-induced lupus (DIL) is an autoimmune phenomenon where the patient develops lupus-like symptoms after exposure to a long-term medication. Case Summary. Here we describe a 10-year-old female with absence seizures who developed a lupus-like syndrome after being on ethosuximide for three months. She presented with nephrotic syndrome (NS) and acute kidney injury. Four weeks prior to presentation, she had been prescribed a seven-day course of oral amoxicillin for submental swelling after dental extraction. Investigations showed high titer of antinuclear antibody (ANA) and anti-double stranded DNA, elevated serum IgE level, and positive Coombs' test, along with positive anti-histone antibodies. Renal biopsy showed features of acute tubulointerstitial nephritis (TIN) and partial podocyte foot process effacement without evidence of lupus nephritis. The patient had an excellent response to the steroid therapy with remission within two weeks. The patient remained in remission for two months as evaluated during the most recent follow-up; the autoimmune antibodies and immunoglobulin E trended down. Ethosuximide has been reported to cause DIL, however its possible association with TIN has not been reported. Although amoxicillin could have caused the TIN and NS in this patient, a possible novel association of ethosuximide with this nephrotic-nephritic presentation (NNP) cannot be ruled out. Conclusions. A renal histology is important to determine the accurate etiology of NNP in patients with DIL. Further studies are necessary to determine any possible causal effect of ethosuximide with NNP.

Hydralazine-Induced Dual Antineutrophil Cytoplasmic Antibody Positive Vasculitis and Nephritis

Drug-induced autoimmunity occurs when exposure to a causative agent leads to serologic or clinical autoimmune responses. Syndromes that may be associated with drug-induced autoimmunity include antineutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) and drug-induced lupus (DIL). When drug-induced autoimmunity involves the kidney, histological patterns of injury include pauci-immune glomerulonephritis (GN), which occurs with AAV, and immune complex-mediated GN, which is associated with DIL. We present a case of hydralazine-induced dual ANCA-positive vasculitis and nephritis.

The Safe Management of Acne Vulgaris in Lupus Erythematosus: A Systematic Review with Evidence-Based Treatment Recommendations

BACKGROUND

To date, there have been no studies that have specifically investigated which medications can and cannot be safely used to treat acne vulgaris in patients who have lupus erythematosus (LE). These patients require a highly individualized treatment approach, as the use of certain acne medications may exacerbate LE symptomology, such as photosensitivity and hypercoagulability.

OBJECTIVE

In this systematic review, we examine safety outcomes associated with commonly prescribed oral acne medications, specifically in the context of LE.

METHODS

A literature search, conducted on PubMed/MEDLINE, revealed 146 studies, of which 13 met the criteria. We assigned a level of evidence to each study and sought to determine evidence-based recommendations for each class of drug; each recommendation was then assigned a corresponding grade.

RESULTS

There were very few high-quality studies available on this topic. Although we determined recommendations based on the existing literature, the grading was occasionally unfavorable due to the low-quality nature of the evidence supporting the recommendation. However, our recommendation against the use of combined oral contraceptive pills and in favor of spironolactone for the treatment of acne, in the setting of LE, received a satisfactory grading (grade A).

CONCLUSION

While no definitive recommendations for the treatment of acne in LE can be made based on the existing quality and quantity of studies available, this article aims to provide a comprehensive overview and analysis of oral acne medication safety in patients with LE, while emphasizing the immense need for higher quality studies and distinct acne treatment guidelines for this vulnerable patient population.

Drug-induced lupus erythematosus: an update on drugs and mechanisms

PURPOSE OF REVIEW

Rapid introduction of newly developed drugs in the absence of clear understanding of the pathophysiologic mechanisms behind drug-induced lupus erythematosus (DILE) can sometimes make DILE difficult to recognize in clinical practice. The purpose of this review is to summarize drugs most recently reported to be involved in DILE and discuss the current landscape of diverse mechanisms involved.

RECENT FINDINGS

A large number of proton pump inhibitor (PPI)-induced subacute cutaneous lupus erythematosus cases have been reported, suggesting a shift over time in the spectrum of drugs implicated in DILE. Twenty-two articles comprising 29 DILE case reports published within the last 2 years are summarized in this review, including 12 (41.4%) systemic DILE. Antitumor necrosis factor (anti-TNF) drugs were the most frequently (41.7%) reported to introduce systemic DILE in these cases. Chemotherapeutic drugs were the most common drug class (54.5%) involved in subacute cutaneous lupus erythematosus, with an observed higher incidence in female patients. Enhanced neutrophil extracellular trap (NET) formation induced by procainamide and hydralazine could be a new mechanism contributing to the pathogenesis of DILE.

SUMMARY

The list of drugs implicated in triggering DILE is expanding as new drugs with novel mechanisms of action are being developed. It is important to recognize culprit drugs that may induce lupus erythematosus, as discontinuation usually results in improvement of drug-induced manifestations. Characterizing the mechanisms involved might help better understand the cause of idiopathic autoimmunity.

Drug-induced lupus: Traditional and new concepts

Drug-induced lupus (DIL) includes a spectrum of drug-induced reactions often characterised by a clinical phenotype similar to that of idiopathic systemic lupus eruthematosus (SLE) but usually lacking major SLE complications. Different drugs may be associated with distinct clinical and serological profiles, and early recognition is crucial. Drugs traditionally associated with DIL include procainamide, hydralazine, quinidine and others, but strong associations with newer agents, such as TNF α (TNFα) inhibitors, are increasingly recognised. The pathogenic mechanisms explaining how drugs that have heterogeneous chemical structure and function lead to autoimmunity are only partially understood. However, it is likely that traditional DIL-associated agents can boost innate immune responses, particularly neutrophil responses, with neutrophil extracellular trap (NET) formation and exposure of autoantigens. Research in the field of DIL is evolving and may provide interesting models for the study of autoimmunity.

Drug-induced lupus: an update

Drug-induced lupus erythematosus (DILE) is a lupus-like illness that has been recognized as an entity under environmentally-induced lupus erythematosus, where other agents such as physical (ultra-violet irradiation), chemical (heavy metals, aromatic amines) and food products (alfalfa sprouts) have been implicated. DILE has been accepted as a side effect of therapy with over 80 drugs since its first description in association with sulfadiazine in 1945. The epidemiology and clinical course of SLE and DILE differ markedly and prognosis is generally favourable in the latter although occasional lifethreatening cases have been reported in the literature. Constant pharmacovigilance is crucial for prompt diagnosis and cessation of offending therapy offers the best outcome. This review discusses the clinical presentation, diagnosis of DILE as well as provides an update on postulated pathogenic mechanisms and an overview of implicated drugs.

Epigenetics changes associated to environmental triggers in autoimmunity

Autoimmune diseases (AIDs) are chronic conditions initiated by the loss of immunological tolerance to self-antigens and represent a heterogeneous group of disorders that affect specific target organs or multiple organs in different systems. While the pathogenesis of AID remains unclear, its aetiology is multifunctional and includes a combination of genetic, epigenetic, immunological and environmental factors. In AIDs, several epigenetic mechanisms are defective including DNA demethylation, abnormal chromatin positioning associated with autoantibody production and abnormalities in the expression of RNA interference (RNAi). It is known that environmental factors may interfere with DNA methylation and histone modifications, however, little is known about epigenetic changes derived of regulation of RNAi. An approach to the known environmental factors and the mechanisms that alter the epigenetic regulation in AIDs (with emphasis in systemic lupus erythematosus, the prototype of systemic AID) are showed in this review.

Drug-induced glomerular disease: immune-mediated injury

Drug-induced autoimmune disease was initially described decades ago, with reports of vasculitis and a lupus-like syndrome in patients taking hydralazine, procainamide, and sulfadiazine. Over the years, multiple other agents have been linked to immune-mediated glomerular disease, often with associated autoantibody formation. Certain clinical and laboratory features may distinguish these entities from their idiopathic counterparts, and making this distinction is important in the diagnosis and management of these patients. Here, drug-induced, ANCA-associated vasculitis, drug-induced lupus, and drug-associated membranous nephropathy are reviewed.

Drug-induced lupus

INTRODUCTION

Drug-induced lupus (DIL) refers to an idiosyncratic side effect of numerous, apparently unrelated, medications, in which symptoms overlap with those of systemic lupus erythematosus. DIL is reversible by discontinuation of the medication. The etiological mechanism underlying DIL is linked to the inherent susceptibility of the adaptive immune system to lapse into auto-reactivity.

AREAS COVERED

Clinical and laboratory features of DIL will be compared with those of idiopathic systemic lupus and with other types of drug reactions with overlapping features. Formerly commonly-used drugs conferred very high risk of developing DIL, although the probability of developing DIL has not been established with most lupus-inducing drugs. Pharmacological or physiochemical properties of the parent compounds are uninformative, but the importance of reactive drug metabolites in initiating autoimmunity will be discussed. As with most systemic autoimmune diseases, the pathogenesis of DIL is complex and obscure. The role of complement and human leukocyte allotypes as well as drug acetylator phenotype inform the underlying mechanism, and several of these non-mutually exclusive concepts will be described.

EXPERT OPINION

The pros and cons of proposed mechanisms for DIL will be discussed in the context of current understanding of autoimmunity and immune tolerance to self.

Protective effects of melatonin in reducing oxidative stress and in preserving the fluidity of biological membranes: a review

Free radicals generated within subcellular compartments damage macromolecules which lead to severe structural changes and functional alterations of cellular organelles. A manifestation of free radical injury to biological membranes is the process of lipid peroxidation, an autooxidative chain reaction in which polyunsaturated fatty acids in the membrane are the substrate. There is considerable evidence that damage to polyunsaturated fatty acids tends to reduce membrane fluidity. However, adequate levels of fluidity are essential for the proper functioning of biological membranes. Thus, there is considerable interest in antioxidant molecules which are able to stabilize membranes because of their protective effects against lipid peroxidation. Melatonin is an indoleamine that modulates a wide variety of endocrine, neural and immune functions. Over the last two decades, intensive research has proven this molecule, as well as its metabolites, to possess substantial antioxidant activity. In addition to their ability to scavenge several reactive oxygen and nitrogen species, melatonin increases the activity of the glutathione redox enzymes, that is, glutathione peroxidase and reductase, as well as other antioxidant enzymes. These beneficial effects of melatonin are more significant because of its small molecular size and its amphipathic behaviour, which facilitates ease of melatonin penetration into every subcellular compartment. In the present work, we review the current information related to the beneficial effects of melatonin in maintaining the fluidity of biological membranes against free radical attack, and further, we discuss its implications for ageing and disease.

Clearance of dying cells and systemic lupus erythematosus: the role of C1q and the complement system

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease of unknown etiology characterized by the presence of pathogenic high-titer autoantibodies to a diverse group of autoantigens. In 88% of patients, autoantibodies are present an average of 3.3 years before diagnosis. Antinuclear, anti-Ro, anti-La, and anti-phospholipid antibodies appear first, followed by anti-DNA, anti-Smith and anti-ribonucleoprotein. These autoantibodies have features of an antigen-driven, T-cell-dependent immune response. Once present, the course of SLE is characterized by disease flares and autoimmune dysregulation. Programmed cell death (PCD), an essential developmental and homeostatic mechanism, is the preferred physiological death processes for cells as well as an important immune response regulator. Appropriate clearance of apoptotic material completes the PCD process, and is essential for regulating of inflammation and maintaining self-tolerance. Early complement proteins are important in protecting humans against the development of SLE and the protective role of C1q and complement in SLE is mainly related to their role in clearance of dying cells. However, the complement system is also an important ingredient in inflammation, which mediates SLE pathogenesis. Thus, the question remains whether complement factors have either a protective or a destructive role, or a combination of both.

Hydralazine-induced ANCA-positive pauci-immune glomerulonephritis: a case report and literature review

We report a case of hydralazine-induced alveolar hemorrhage and anti-neutrophil cytoplasmic antibody (ANCA)-positive pauci-immune glomerulonephritis, with serum anti-histone antibodies present, features not previously described in the literature with this drug. A 50-year-old Caucasian female had hypertension treated with hydralazine 75mg TID for three years, and a lung nodule followed up periodically with chest-computed tomographies. She was admitted to the hospital for hemoptysis and newly discovered diffuse pulmonary ground-glass opacities. Transbronchial lung biopsy showed alveolar hemorrhage. Serum creatinine was 3.5 mg/dL and urinalysis showed 2+blood, 30-50RBC/hpf and red blood cell casts. ANCA against myeloperoxidase were present. Anti-double-stranded DNA, ANA, and anti-histone antibodies were positive. Serum complements were normal. Renal biopsy revealed focal crescentic necrotizing glomerulonephritis with negative immunofluorescence, consistent with pauci-immune ANCA-positive vasculitis. Serum creatinine returned to baseline three days after hydralazine was discontinued, and the hemoptysis resolved after treatment with cyclophosphamide and prednisone was started. We concluded that this case represents a hydralazine-induced small vessel vasculitis rather than an idiopathic one. The possibility of hydralazine-induced vasculitis should be considered when patients treated with hydralazine develop a pulmonary-renal syndrome. Anti-histone antibodies may be present in the absence of full classification criteria of drug-induced lupus.

RETRACTED: Drug-induced lupus erythematosus

Drug-induced lupus is a syndrome which share symptoms and laboratory characteristics with idiopathic systemic lupus erythematosus (SLE). The terms drug-induced lupus (DIL) and drug-induced lupus erythematosus (DILE) are preferred, but other ones are also used-drug-related lupus, lupus-like syndrome and lupus erythematosus medicamentosus. The first case of DILE was reported in 1945 and associated with sulfadiazine. In 1953, it was reported that DILE was related to the use of hydralazine. More than 80 drugs have been associated with DILE. The average age of patients with DILE is nearly twice that of patients with idiopathic SLE. Approximately half the patients with drug-induced SLE are women, compared with 90% of patients with idiopathic SLE. Similarly to idiopathic lupus, DILE can be divided into systemic, sub-acute cutaneous and chronic cutaneous lupus. The syndrome is characterised by arthralgia, myalgia, pleurisy, rash and fever in association with antinuclear antibodies in the serum. The clinical and laboratory manifestations of drug-induced SLE are similar to those of idiopathic SLE, but central nervous system and renal involvement are rare in DILE. Recognition of DILE is important because it usually reverts within a few weeks after stopping the drug. This review discusses the general issues in DILE, such as pathogenic mechanisms, clinical forms and diagnostic criteria, and provides more detailed information for some of the most recent implicated drugs: minocycline, statins, anti-TNF-alpha agents.

The genetics and epigenetics of autoimmune diseases

Self tolerance loss is fundamental to autoimmunity. While understanding of immune regulation is expanding rapidly, the mechanisms causing loss of tolerance in most autoimmune diseases remain elusive. Autoimmunity is believed to develop when genetically predisposed individuals encounter environmental agents that trigger the disease. Recent advances in the genetic and environmental contributions to autoimmunity suggest that interactions between genetic elements and epigenetic changes caused by environmental agents may be responsible for inducing autoimmune disease. Genetic loci predisposing to autoimmunity are being identified through multi-center consortiums, and the number of validated genes is growing rapidly. Recent reports also indicate that the environment can contribute to autoimmunity by modifying gene expression through epigenetic mechanisms. This article will review current understanding of the genetics and epigenetics of lupus, rheumatoid arthritis, multiple sclerosis and type 1 diabetes, using systemic lupus erythematosus as the primary example. Other autoimmune diseases may have a similar foundation.

[Pay close attention to drug-induced lupus]

Drug-induced lupus (DIL) is a lupus-like illness that has been recognized as a side effect of over 80 drugs since its first description in association with sulfadiazine in 1945. The epidemiology and clinical course of idiopathic systemic lupus erythematosus and DIL differ markedly, and prognosis is generally favorable in the latter although occasional life-threatening cases have been reported in the literature. Constant pharmacovigilance is crucial for prompt diagnosis and cessation of offending therapy, hence achieving the best outcome. This review discusses the clinical presentation, diagnosis and treatment of DIL so as to call for vigilance of medical workers.

Drug-induced lupus

Autoantibodies and, less commonly, systemic rheumatic symptoms are associated with treatment with numerous medications and other types of ingested compounds. Distinct syndromes can be distinguished, based on clinical and laboratory features, as well as exposure history. Drug-induced lupus has been reported as a side-effect of long-term therapy with over 40 medications. Its clinical and laboratory features are similar to systemic lupus erythematosus, except that patients fully recover after the offending medication is discontinued. This syndrome differs from typical drug hypersensitivity reactions in that drug-specific T-cells or antibodies are not involved in induction of autoimmunity, it usually requires many months to years of drug exposure, is drug dose-dependent and generally does not result in immune sensitization to the drug. Circumstantial evidence strongly suggests that oxidative metabolites of the parent compound trigger autoimmunity. Several mechanisms for induction of autoimmunity will be discussed, including bystander activation of autoreactive lymphocytes due to drug-specific immunity or to non-specific activation of lymphocytes, direct cytotoxicity with release of autoantigens and disruption of central T-cell tolerance. The latter hypothesis will be supported by a mouse model in which a reactive metabolite of procainamide introduced into the thymus results in lupus-like autoantibody induction. These findings, as well as evidence for thymic function in drug-induced lupus patients, support the concept that abnormalities during T-cell selection in the thymus initiate autoimmunity.

A protective role for innate immunity in systemic lupus erythematosus

Clinical and genetic studies in humans and animal models indicate a crucial protective role for the complement system in systemic lupus erythematosus (SLE). This presents a paradox because the complement system is considered to be an important mediator of the inflammation that is observed in patients with SLE. One current view is that complement provides protection by facilitating the rapid removal of apoptotic debris to circumvent an autoimmune response. In this Opinion article, I discuss an alternative model in which complement - together with other components of the innate immune system - participates in the 'presentation' of SLE-inducing self-antigens to developing B cells. In this way, the complement system and innate immunity protect against responses to SLE (self) antigens by enhancing the elimination of self-reactive lymphocytes.

Drug-induced lupus erythematosus

Among the numerous idiopathic immune-mediated diseases that can be drug-induced, such as pemphigus, psoriasis, lichen, etc, drug-induced lupus is the most widely commented upon and investigated. The terms drug-induced lupus (DIL) and drug-induced lupus erythematosus (DILE) are preferred, but other ones are also used--drug-related lupus, lupus-like syndrome, and lupus erythematosus medicamentosus. This review discusses the general issues in DILE, such as pathogenic mechanisms, clinical forms, and diagnostic criteria, and provides more detailed information for some of the implicated drugs: minocycline, statins, terbinafine, etc.

Patients with systemic lupus erythematosus are deficient in complement-dependent prevention of immune precipitation

OBJECTIVE

A functional deficiency of complement has been implicated but not conclusively demonstrated in the pathogenesis of systemic lupus erythematosus (SLE). To test this, we studied several aspects of complement in 44 patients with SLE, 46 patients with rheumatoid arthritis and 102 blood donors.

METHODS

Prevention of immune precipitation (PIP) was measured by an enzyme immunoassay, levels of C1q, C4 and C3 by rocket immunoelectrophoresis, C4A, C4B and C3d by enzyme-linked immunosorbent assay (ELISA), complement haemolysis (CH50) by standard methods and C4 allotypes by high-voltage agarose electrophoresis and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE).

RESULTS

PIP was significantly reduced in SLE (P<0.001); the defect was revealed by a sensitive assay measuring this function of complement but not by the other tests employed. The patients were clinically well at the time of study, and levels of C3d, which have been shown to correlate with disease activity, were normal. The defect was more common in patients with early disease (P = 0.009), supporting a role in aetiology or early pathophysiology. PIP was positively correlated with levels of C4 (P = 3 x 10(-5)) and in particular the C4A isotype (P = 9 x 10(-10)) whereas C4B was redundant.

CONCLUSIONS

Our results reveal a defect in prevention of immune precipitation in SLE that is apparent at an early stage in the disease and correlates with low levels of C4A. These results indicate that subtle deficiencies of complement may predispose to SLE.

Melatonin reduces phenylhydrazine-induced oxidative damage to cellular membranes: evidence for the involvement of iron

Phenylhydrazine and iron overload result in augmented oxidative damage and an increased likelihood of cancer. Melatonin is a well known antioxidant and free radical scavenger. The aim of this study was to determine whether melatonin would protect against phenylhydrazine-induced oxidative damage to cellular membranes and to evaluate the possible role of iron in this process. Changes in lipid peroxidation and microsomal membrane fluidity were estimated after the treatment of rats with phenylhydrazine (15 mg/kg body weight, daily, 7 days) alone and melatonin or ascorbic acid (15 mg/kg body weight, two times daily, 8 days), or their combination. Additionally, lipid peroxidation was measured in liver homogenates from untreated and melatonin or ascorbic acid-treated rats in vivo and exposed to iron in vitro. Melatonin, but not ascorbic acid, reduced phenylhydrazine-induced lipid peroxidation in vivo in spleen (3.16+/-0.06 vs. 3.83+/-0.12 nmol/mg protein, P<0.05) and plasma (7. 73+/-0.52 vs. 9.96+/-0.71 nmol/ml, P<0.05) and attenuated the decrease in hepatic microsomal membrane fluidity (1/polarization, 3. 068+/-0.007 vs. 3.027+/-0.008, P<0.05). In vitro exposure to iron significantly enhanced the lipid peroxidation in liver homogenates from untreated (3.34+/-0.75 vs. 1.25+/-0.28, P<0.05) or ascorbic acid-treated rats (2.72+/-0.39 vs. 0.88+/-0.06, P<0.05) but not from melatonin-treated rats (1.49+/-0.55 vs. 0.68+/-0.20, NS). It is concluded that free radical mechanisms are involved in the toxicity of phenylhydrazine and that the antioxidant melatonin, but not ascorbic acid, reduces the toxic affects of phenylhydrazine in vivo and of iron in vitro in cell membranes. Therefore, melatonin co-treatment in conditions of iron overload may prove beneficial.

Widespread susceptibility among inbred mouse strains to the induction of lupus autoantibodies by pristane

Unlike other agents associated with drug-induced lupus, the isoprenoid alkane pristane induces autoantibodies pathognomonic of lupus, including anti-Sm, anti-dsDNA, and anti-ribosomal P in BALB/c and SJL/J mice. The susceptibility of other strains of mice to pristane-induced lupus is unknown and is the focus of the present study. Anti-nRNP/Sm, anti-Su, and anti-ribosomal P autoantibodies were produced by most strains of mice surveyed within several months of pristane treatment, although there was marked interstrain variability in their frequencies, levels, and times of onset. In sharp contrast, the production of autoantibodies against the double-stranded RNA binding proteins NF45/NF90/p110 was restricted to B6 and B10.S mice. We conclude that pristane selectively induces lupus-specific autoantibodies in virtually any strain of mouse regardless of its genetic background. However, H-2-linked as well as non-H2 genes influenced the expression of individual autoantibody markers. The widespread susceptibility of pristane-treated mice to lupus autoantibody production and the relatively small effect of MHC are unique features of this chemically induced lupus syndrome, with potential implications for understanding the pathogenesis of autoantibodies in idiopathic human systemic lupus erythematosus.

Clinical correlates, serum autoantibodies and the role of the major histocompatibility complex in French Canadian and non-French Canadian Caucasians with SLE

OBJECTIVE

To investigate the predisposing role of major histocompatibility complex (MHC) genes to autoantibody production and clinical manifestations comparing French Canadian and Non-French Canadian Caucasians with systemic lupus erythematosus (SLE) METHODS: Ninety-one Caucasian patients with SLE were studied. Clinical manifestations, autoantibody expression and HLA-A, B, (serology), DR, DQ and C4A gene deletion (restriction fragment length polymorphism [RFLP] typing) were determined.

RESULTS

Photosensitivity was present in all SLE subjects with anti-Ro antibodies (P=0.001, RR=13.1, CI=1.8, 564). Photosensitivity was further associated with the HLA-A1, C4A gene deletion haplotype. More strikingly, C4A gene deletion was associated with anti-Ro (P=0.008, RR=4.6, CI=1.4, 16.2) and anti-La (P=0.02, RR=11.7, CI=1.4, 549) autoantibodies. This relationship was also significant for anti-Ro antibody in the French Canadian patients (P=0.01, RR=21.3, CI=1.7, 105.3). In contrast, anti-dsDNA autoantibodies were negatively associated with photosensitivity (P=0.02, RR=0.3, CI=0.07, 0.8) and correlated with HLA-DR15 (P=0.006, RR=4.2, CI=1.5, 12.8) and Dw2 (P=0.009, RR=3.9, CI=1.4, 11.9).

CONCLUSION

C4A gene deletion has a previously unrecognized powerful association with anti-Ro and anti-La autoantibodies. These results support the concept of divergent MHC gene associations with autoantibody expression and emphasize the influence of ethnicity on the immunogenetic study of SLE.

Genetic and immunologic studies of patients on procainamide

Forty (40) patients with cardiac arrhythmias receiving procainamide (PA) therapy and 24 patients who were receiving other drugs for their cardiac disorders were investigated for class II HLA phenotypes and their DRB1*04 and DQB1*03 subtypes. Other genetic marker evaluations in the PA patients included: 1) class III MHC C4A and C4B null alleles of complement; and, 2) acetylation phenotype. Twenty (20) of the PA patients were also tested for the ability of their stimulated cells to secrete Interleukin-1 (IL-1 beta) and tumor necrosis factor (TNF alpha). We also examined the spontaneous production of these cytokines by peripheral blood leukocytes (PBL) from patients who were receiving chronic PA treatment. The results revealed no association of acetylation phenotypes with the class II HLA phenotypes nor class III MHC C4 allotypes in these patients. The results did show a significant increase in class III C4 complement allotypes in the PA patients when compared to the controls. The results also showed a significant increase in autoantibodies and DQw3 phenotypes in the PA patient group when compared to control populations. Results of spontaneous IL-1 and TNF production suggested there may be an association of select class II HLA phenotypes in some patients and this may be relevant to host responsiveness to PA treatment.

Tumor Necrosis Factor Constellation Polymorphism and Clozapine-Induced Agranulocytosis in Two Different Ethnic Groups

Genes of the major histocompatibility complex (MHC) are associated with susceptibility to different immune and nonimmune mediated diseases. We had reported that the drug adverse reaction, clozapine-induced agranulocytosis (CA), is associated with different HLA types and HSP70 variants in Ashkenazi Jewish and non-Jewish patients, suggesting that a gene within the MHC region is associated with CA. This study was designed to find common genetic markers for this disorder in both ethnic groups. The tumor necrosis factor (TNF ) microsatellites d3 and b4 were found in higher frequencies in both Jewish and nonJewish patients: 51 of 66 (77%) and 48 of 66 (57%), respectively. Comparisons of these frequencies with those of controls, 28 of 66 (42%) and 18 of 66 (27%), were statistically significant (corrected P value = .001 for the d3 allele and .0005 for the b4 allele). On the other hand, the TNF microsatellite b5 was underrepresented in the group of patients, 9 of 66 (14%), when compared with the control subjects, 43 of 66 (65%) (corrected P value = .0005), probably related to protection from CA. Our results show a strong association of some genetic variants of the TNF loci with susceptibility to CA in two different ethnic groups suggesting involvement of TNF and/or associated gene(s) products in the pathogenesis of this hematologic-drug adverse reaction.

Clinical case report: multiple idiosyncratic adverse effects of antiepileptic drugs in trisomy 9p

We report the case of a mentally retarded 30 y.o. patient with partial trisomy of chromosome 9, affected by epilepsy. Following treatment with antiepileptic drugs (AEDs), the patient developed several rare complications: after beginning therapy with phenytoin, the patient developed pseudolymphoma; after monotherapy with carbamazepine (CBZ), the patient thereafter developed myoclonic jerks of upper and lower limbs upon awakening; after one year of treatment with valproate (VPA) the patient developed clinical and immuno-haematological signs of SLE. Gradual withdrawal of AED, obtained clinical remission. The possibility that the chromosomal abnormality of the patient was responsible for the three rare complications observed during AED therapy is considered.

Valproate-induced systemic lupus erythematosus in a patient with partial trisomy of chromosome 9 and epilepsy

We report a mentally retarded 30-year-old woman with partial trisomy of chromosome 9 (46, XX-6, +der(6)t(6,9)pat) who has had epilepsy since age 11 months. She had been treated with various combinations of drugs. After 1 year of treatment with valproate (VPA) and ethosuximide (ESM), the patient developed arthralgias, muscle weakness, fatigue, and fever. Laboratory examination showed increased sedimentation rate, hypergammaglobulinemia, and high titers of antinuclear antibodies (ANA). The possibility of VPA-induced systemic lupus erythematosus (SLE) was considered. This diagnosis was supported by detection of antihistone antibodies and the HLA-DR4 antigen. VPA dosage was tapered and discontinued, with accompanying resolution of clinical, immunological and hematological signs of SLE 6 weeks after VPA discontinuation. This is the fourth reported case of VPA-induced SLE.

Xenogenetics in multifactorial disease susceptibility

Susceptibility to multifactorial disease includes both genetic and environmental components. These two aspects of susceptibility are interlinked through genetic control of an individual's response to the environment. As a first step in identifying disease susceptibility genes that influence the response of an individual to foreign compounds (xenobiotics), it is necessary to study disorders in which there is an identified environmental trigger. Establishing a DNA resource from individuals with known environmental exposure ('a xenogenetic register') for diseases with an established environmental aetiology is an essential step in beginning to understand how environmental factors contribute to the susceptibility to polygenic diseases. A complementary approach to identification of environmental factors is suggested using a comparison of genetically homogeneous subdivisions of individuals with polygenic diseases where there is no clue to the environmental trigger.

Drug-induced lupus

Drug-induced lupus is a syndrome resembling mild systemic lupus erythematosus which can complicate treatment with certain apparently unrelated therapies. The most common individual agents are procainamide and hydralazine. Drugs less frequently associated with the disease are chlorpromazine, isoniazid, methyldopa, penicillamine, quinidine and sulfasalazine. Whole drug groups have also been implicated, such as the anticonvulsants, beta-blockers, sulfonamides and some of the newer 'biological' agents. The syndrome is characterised by arthralgia, myalgia, pleurisy, rashes and fever in association with antinuclear antibodies in the serum. More serious features of idiopathic lupus such as nephritis and cerebral disease are rare in drug-induced disease. The pathogenesis is unknown but in some cases is thought to be due to interactions between the drug and DNA or histones, rendering them immunogenic. For the biological agents, including interferons and antibodies to tumour necrosis factor-alpha, it has been suggested that it is due to disruption of the cytokine network. Although extremely rare, recognition of drug-induced lupus is important because it reverts within a few weeks of stopping the drug. It is possible that understanding its pathogenesis may shed light on its more serious relative, systemic lupus erythematosus.

Role of genetic factors in drug-related autoimmunity

Although there is evidence to suggest that genetic factors play a major role in the pathogenesis of many of the rheumatic diseases, far less is known of their role in the induction and expression of human autoimmunity resulting from long-term exposure to drugs, chemicals and environmental agents. Pharmacogenetic factors represent an important source of interindividual variation in response to drugs; most research to date has focused on genetic polymorphism of drug metabolism via N-acetylation, S-methylation or cytochrome P-450-catalyzed oxidation. In drug-related autoimmunity, there is limited evidence that the host's genetic background plays a major role beyond the expression of autoantibodies. More recent prospective studies have concentrated on the association of MHC-genes in the expression of autoimmunity and the susceptibility of patients to develop drug-related clinical syndromes.

Genetic, immunologic and biotransformation studies of patients on procainamide

This report represents follow-up observations of a unique long-term study of patients on procainamide (PA) for various cardiac arrhythmias. Serologic and clinical evaluations associated with drug-related autoimmunity were assessed and patients were characterized for factors postulated to influence susceptibility to autoimmunity, including acetylator phenotype, oxidative metabolism of PA, HLA class profile, and production of interleukin-1 (IL-1) and tumor necrosis factor (TNF). Fifty-two percent had IgM and 70% IgG antibodies to total histones; 67% had IgG antibodies to histone H2A/H2B. Patients were equally divided between fast and slow acetylators. N-oxidative metabolism of PA was indicated by the presence of urinary nitroprocainamide, which correlated with elevated titers of antihistone antibodies. There was a significant incidence of the DQw7 split of DQw3 in PA patients when compared to controls, and the frequency of antibodies to total histones and H2A/H2B was significantly increased in the DQw7 patients. C4A*QO and C4B*QO alleles were more frequent in the PA patients than in controls. IL-1 and TNF production was not different in patients compared to controls. These data suggest that certain genetic factors may serve as markers for PA-related autoimmunity.

Possible induction of systemic lupus erythematosus by valproate

Two patients developed clinical and laboratory evidence of systemic lupus erythematosus (SLE) during treatment with valproate (VPA) preparations. The first patient, a 47-year-old man, had fever, malaise, and thrombocytopenia 1 month after VPA was added to phenytoin (PHT) and primidone (PRM). He developed high titers of antinuclear antibodies (ANA) and anti-DNA antibodies, and hypocomplementemia. After discontinuation of PHT and VPA, steroid and immunoglobulin treatment was required for 4 weeks before his condition improved. The second patient, a 28-year-old woman, had been followed for idiopathic leukopenia for 3 years and had previously experienced fever and lymphadenopathy from PHT. After 4 months of divalproex therapy, she developed confusion, joint pain, and a dramatic increase in seizure frequency. She also developed high titers of ANA and anti-DNA antibodies and hypocomplementemia, along with a further decrease in white blood cell (WBC) count. These responded to steroid therapy and withdrawal of divalproex. Three months later, reintroduction of divalproex was followed by a return of ANA in low titer, which resolved after discontinuation. We believe that VPA may have caused true SLE in these patients, one of whom was probably predisposed.