Up-regulation of SLC7A11/xCT creates a vulnerability to selenocystine-induced cytotoxicity

The SLC7A11/xCT cystine and glutamate antiporter has emerged as an attractive target for cancer therapy due to its selective overexpression in multiple cancers and its role in preventing ferroptosis. Utilizing pharmacological and genetic approaches in hepatocellular carcinoma cell lines, we demonstrate that overexpression of SLC7A11 engenders hypersensitivity towards l-selenocystine, a naturally occurring diselenide that bears close structural similarity to l-cystine. We find that the abundance of SLC7A11 positively correlates with sensitivity to l-selenocystine, but surprisingly, not to Erastin, an inhibitor of SLC7A11 activity. Our data indicate that SLC7A11 acts as a transport channel for l-selenocystine, which preferentially incites acute oxidative stress and damage eventuating to cell death in cells that highly express SLC7A11. Hence, our findings raise the prospect of l-selenocystine administration as a novel strategy for targeting cancers that up-regulate SLC7A11 expression.

Rare coding variant analysis in a large cohort of Ashkenazi Jewish families with inflammatory bowel disease

Rare variants are thought to contribute to the genetics of inflammatory bowel disease (IBD), which is more common amongst the Ashkenazi Jewish (AJ) population. A family-based approach using exome sequencing of AJ individuals with IBD was employed with a view to identify novel rare genetic variants for this disease. Exome sequencing was performed on 960 Jewish individuals including 513 from 199 multiplex families with up to eight cases. Rare, damaging variants in loci prioritized by linkage analysis and those shared by multiple affected individuals within the same family were identified. Independent evidence of association of each variant with disease was assessed. A number of candidate variants were identified, including in genes involved in the immune system. The ability to achieve statistical significance in independent case/control replication data was limited by power and was only achieved for variants in the well-established Crohn's disease gene, NOD2. This work demonstrates the challenges of identifying disease-associated rare damaging variants from exome data, even amongst a favorable cohort of familial cases from a genetic isolate. Further research of the prioritized rare candidate variants is required to confirm their association with the disease.

Oral administration of non-absorbable delayed release 6-mercaptopurine is locally active in the gut, exerts a systemic immune effect and alleviates Crohn's disease with low rate of side effects: results of double blind Phase II clinical trial

Therapy for Crohn's disease (CD) with thiopurines is limited by systemic side effects. A novel formulation of fixed-dose, delayed-release 6-mercaptopurine (DR-6MP) was developed, with local effect on the gut immune system and minimal absorption. The aim of this study was to evaluate the safety and efficacy of DR-6MP in patients with moderately severe CD compared to systemically delivered 6-mercaptopurine (Purinethol). Seventy CD patients were enrolled into a 12-week, double-blind controlled trial. The primary end-point was the percentage of subjects with clinical remission [Crohn's Disease Activity Index (CDAI) < 150] or clinical response (100-point CDAI reduction). Twenty-six (56·5%) and 13 (54·2%) subjects from the DR-6MP and Purinethol cohorts, respectively, completed the study. DR-6MP had similar efficacy to Purinethol following 12 weeks of treatment. However, the time to maximal clinical response was 8 weeks for DR-6MP versus 12 weeks for Purinethol. A higher proportion of patients on DR-6MP showed clinical remission at week 8. A greater improvement in Inflammatory Bowel Disease Questionnaire (IBDQ) score was noted in the DR-6MP group. DR-6MP led to a decrease of CD62(+) expression on T cells, implying a reduction of lymphocyte adhesion to site of inflammation. DR-6MP was safer than Purinethol, with significantly fewer adverse events (AEs). There was no evidence of drug-induced leucopenia in the DR-6MP group; the proportion of subjects who developed hepatotoxicity was lower for the DR-6MP. Non-absorbable DR-6MP is safe and biologically active in the gut. It is clinically effective, exerting a systemic immune response with low systemic bioavailability and a low incidence of side effects.

The impact of abdominal computed tomography in a tertiary referral centre emergency department on the management of patients with inflammatory bowel disease

BACKGROUND

Although exposure to diagnostic radiation may be associated with increased risk of malignancy, the use of abdominal CT (ACT) in the last decade has increased for patients in the emergency department (ED).

AIM

To examine the impact of ACT ordered in the ED on management of patients with inflammatory bowel diseases (IBD), as well as to quantify the cumulative effective dose (CED) of radiation received by these patients.

METHODS

A total of 152 patients with Crohn's disease (CD) and 130 patients with ulcerative colitis (UC) that presented to the ED in a tertiary centre between 2009 and 2011 were identified. For patients that had an ACT, chart review assessed if the ACT findings changed clinical management. CED of diagnostic radiation (DR) was calculated for all imaging studies between 1 January 2006 and 30 August 2012.

RESULTS

Abdominal CT use was 49% for CD and 19% for UC. ACTs with findings of penetrating/obstructive disease were 35% for CD. Urgent non-IBD-related diagnoses were found in 13% for CD and 28% for UC (P < 0.05). ACT caused a change in management in 81% of CD and 69% of UC patients. Mean CED from DR was 77.4 ± 63.0 mSv (median 53 mSv) for CD and 67.2 ± 51.0 mSv (median 56 mSv) for UC (P = 0.47). The CED for the 80-month period exceeded 75 mSv in 35% and 36% respectively (P = 0.99).

CONCLUSIONS

Although abdominal CT often changes management of IBD patients in the emergency department, this population carries a very high-risk of radiation exposure. Efforts should be made to decrease this risk by development of low-radiation protocols, and wider use of MRI/ultrasound.

When APS (Hughes syndrome) met the autoimmune/inflammatory syndrome induced by adjuvants (ASIA)

Vaccination of healthy individuals is the most effective approach to protect the public from infections and prevent the spread of many infectious diseases all over the globe. Licensed vaccines are mostly safe, but in rare cases they may be associated with humoral response to self-antigens due to molecular mimicry, epitope spread, bystander activation or polyclonal triggering. Moreover, the clinical picture of autoimmune conditions following post-vaccination is rarer. Nevertheless, anecdotal case reports on the flare of autoimmune response with clinical manifestations were reported. Herein, we discuss this topic in relation to post-vaccination-induced antiphospholipid antibodies following tetanus toxoid vaccine, HBV and influenza associated in rare cases with antiphospholipid syndrome clinical manifestations. We will discuss the possible mechanisms which pertain to ASIA (Shoenfeld syndrome).

Gulf War Syndrome as a part of the autoimmune (autoinflammatory) syndrome induced by adjuvant (ASIA)

Gulf War syndrome (GWS) is a multi-symptom condition comprising a variety of signs and symptoms described in the literature, which not been fully resolved. The various symptoms of the condition include muscle fatigue and tiredness, malaise, myalgia, impaired cognition, ataxia, diarrhoea, bladder dysfunction, sweating disturbances, headaches, fever, arthralgia, skin rashes, and gastrointestinal and sleep disturbances. In addition, excessive chemical sensitivity and odour intolerance is reported. The aetiology of the condition is unclear, but many reviews and epidemiological analyses suggest association with pyridostigmine bromide (PB), certain vaccination regimes, a variety of possible chemical exposures, including smoke from oil-well fires or depleted uranium from shells, as well as physical and psychological stress. Recently, Shoenfeld et al. suggested that four conditions – siliconosis, macrophagic myofaciitis (MMF), GWS and post-vaccination phenomena – that share clinical and pathogenic resemblances, may be incorporated into common syndrome called ‘Autoimmune (Autoinflammatory) Syndrome induced by Adjuvants’ (ASIA). Symptoms and signs of the four conditions described by Shoenfeld et al. show that at least eight out of ten main symptoms are in correlation in all four conditions. Namely, myalgia, arthralgias, chronic fatigue, neurological cognitive impairment, gastrointestinal symptoms, respiratory symptoms, skin manifestations and appearance of autoantibodies. Regardless of the aetiology of GWS, be it exposure to environmental factors or chemical drugs, vaccinations or the adjuvants in them, GWS fits well with the definition of ASIA and is included as part of ‘Shoenfeld’s syndrome’.

Vaccination of patients with auto-immune inflammatory rheumatic diseases requires careful benefit-risk assessment

Will vaccination raise the incidence of autoimmune diseases, what is the impact of increasingly crowded vaccination schedules, the vaccination in age groups and the risk of coincidental temporal association? All these issues are still under debate. However, for the time being, to avoid confusion in the medical community and the media, we have to adhere to guidelines established consensually by experts while ensuring a strict surveillance and reporting possible side effects. Recommendation for vaccination in patients with autoimmune inflammatory rheumatic diseases (AIIRD) based on the currently available evidence and expert opinion were recently formulated by an EULAR task force. Major recommendations for AIIRD include: i) vaccination should ideally be administered during stable disease; ii) influenza vaccination and pneumococcal vaccination should be strongly considered; iii) vaccination can be administered during the use of DMARDs and TNF-inhibitors, but before starting rituximab; iv) live attenuated vaccines should be avoided whenever possible in immunosuppressed patients; v) BCG vaccination is not recommended.

The efficacy of shortening the dosing interval to once every six weeks in Crohn's patients losing response to maintenance dose of infliximab

BACKGROUND

Patients treated with infliximab for Crohn's disease (CD) frequently require intensified dosage due to loss of response. There are scant data regarding the efficacy of shortening the dosing interval to 6 weeks.

AIM

We sought to investigate the efficacy of a once every 6 weeks' strategy compared with dose-doubling.

METHODS

This work was a multicentre retrospective study of infliximab-treated CD patients who required dose escalation. The clinical outcome of patients treated by intensification to 5 mg/kg/6 weeks (6-week group) was compared with the outcome of patients whose infliximab was double-dosed (10 mg/kg/8 weeks or 5 mg/kg/4 weeks).

RESULTS

Ninety-four patients (mean age: 29.8 years) were included in the study, 55 (59%) in the 6-week group and 39 (41%) in the double-dose group. Demographics and disease characteristics were similar between the two groups, although patients with re-emerging symptoms 5-7 weeks postinfusion were more likely to receive 5 mg/kg/6 weeks dosing (OR: 3.4, 95% CI: 1.4-8.8, P < 0.01). Early response to dose-intensification occurred in 69% of patients in the 6-week group and 67% in the double-dose group (P = N.S.). Regained response was maintained for 12 months in 40% compared with 29% of the patients respectively (P = N.S.).

CONCLUSION

In CD patients who lost response to standard infliximab dose, especially when symptoms re-emerge 5-7 weeks postinfusion, shortening the dosing interval to 6 weeks appears to be at least as effective as doubling the dose to 10 mg/kg or halving the infusion intervals to once in 4 weeks.

Cost effectiveness of mass screening for coeliac disease is determined by time-delay to diagnosis and quality of life on a gluten-free diet

BACKGROUND

Coeliac disease is frequently diagnosed after a long delay resulting in increased morbidity and mortality.

AIMS

To define the parameters which have the highest impact on the cost-effectiveness of mass screening for coeliac disease.

METHODS

A Markov model examined a coeliac disease screening programme of the healthy young-adult general population compared with a no-screening strategy. The main outcome measures were quality adjusted life-years (QALYs) and incremental cost-effectiveness ratio (ICER). Effects of variables were examined using sensitivity analyses.

RESULTS

The screening strategy resulted in a gain of 0.0027 QALYs. The ICER of screening vs. no-screening strategy was US$48,960/QALYs. The variables with the largest impact on cost effectiveness were: the time delay from symptom onset to diagnosis, the utility of adherence to a gluten-free diet (GFD) and the prevalence of coeliac disease. Screening would be cost-effective if the time delay to diagnosis is longer than 6 years and utility of GFD adherence is greater than 0.978.

CONCLUSIONS

Our model suggests that mass screening for coeliac disease of the young-adult general population is associated with improved QALYs and is a cost effectiveness strategy. Shortening of the time-delay to diagnosis by heightened awareness of health-care professionals may be a valid alternative to screening.

Adjuvants and autoimmunity

Some adjuvants may exert adverse effects upon injection or, on the other hand, may not trigger a full immunological reaction. The mechanisms underlying adjuvant adverse effects are under renewed scrutiny because of the enormous implications for vaccine development. In the search for new and safer adjuvants, several new adjuvants were developed by pharmaceutical companies utilizing new immunological and chemical innovations. The ability of the immune system to recognize molecules that are broadly shared by pathogens is, in part, due to the presence of special immune receptors called toll-like receptors (TLRs) that are expressed on leukocyte membranes. The very fact that TLR activation leads to adaptive immune responses to foreign entities explains why so many adjuvants used today in vaccinations are developed to mimic TLR ligands. Alongside their supportive role, adjuvants were found to inflict by themselves an illness of autoimmune nature, defined as ‘the adjuvant diseases’. The debatable question of silicone as an adjuvant and connective tissue diseases, as well as the Gulf War syndrome and macrophagic myofaciitis which followed multiple injections of aluminium-based vaccines, are presented here. Owing to the adverse effects exerted by adjuvants, there is no doubt that safer adjuvants need to be developed and incorporated into future vaccines. Other needs in light of new vaccine technologies are adjuvants suitable for use with mucosally delivered vaccines, DNA vaccines, cancer and autoimmunity vaccines. In particular, there is demand for safe and non-toxic adjuvants able to stimulate cellular (Th1) immunity. More adjuvants were approved to date besides alum for human vaccines, including MF59 in some viral vaccines, MPL, AS04, AS01B and AS02A against viral and parasitic infections, virosomes for HBV, HPV and HAV, and cholera toxin for cholera. Perhaps future adjuvants occupying other putative receptors will be employed to bypass the TLR signaling pathway completely in order to circumvent common side effects of adjuvant-activated TLRs such as local inflammation and the general malaise felt because of the costly whole-body immune response to antigen. Lupus (2009) 18, 1217—1225.

Relationships between hypoglycaemia and gastric emptying abnormalities in insulin-treated diabetic patients

We hypothesize that hypoglycaemia in insulin-treated diabetic patients may result from gastric emptying abnormalities causing insulin and food absorption mismatching. We tested gastric emptying in insulin-treated diabetic patients with unexplained hypoglycaemia and without dyspepsia and in diabetic patients without hypoglycaemia, prospectively. Thirty-one diabetic patients with unexplained hypoglycaemic events within 2 h of insulin injection and 18 insulin-treated diabetic patients without hypoglycaemic events underwent gastric emptying breath tests, glycaemic control and autonomic nerve function. Gastric emptying tests were abnormal in 26 (83.9%) and in four (22.2%) patients with and without hypoglycaemia, respectively (P < 0.001). Gastric emptying was significantly slower in hypoglycaemic diabetic patients (t1/2 139.9 +/- 74.1 vs 77.8 +/- 23.3 and t(lag) 95.8 +/- 80.3 vs 32.84 +/- 16.95 min, P < 0.001 for both comparisons; t-tests). A significant association between hypoglycaemic patients and abnormal values of t1/2 and t(lag) was found (P < 0.001). Gastric emptying abnormalities were more frequent in hypoglycaemic patients. We suggest gastric emptying tests for diabetic patients with unexplained hypoglycaemic events.

Anti-Saccharomyces cerevisiae and antineutrophil cytoplasmic antibodies as predictors of inflammatory bowel disease

BACKGROUND AND AIMS

Several antibodies have been reported in the sera of patients with Crohn's disease (CD) and ulcerative colitis (UC). The most commonly described are anti-Saccharomyces cerevisiae mannan antibodies (ASCA) in CD and perinuclear antineutrophil cytoplasm antibodies (pANCA) in UC. Familial clustering of these antibodies has been described, suggesting they might be genetic markers. Our aim was to investigate the presence of these antibodies before the emergence of overt clinical manifestations.

METHODS

Since 1980, the Israeli Defense Force (IDF) Medical Corps Serum Repository has stored serum samples obtained systematically from 5% of all recruits on enlistment, and from the same population on discharge from compulsory military service. We evaluated serum samples obtained from 32 subjects with CD and eight with UC before they were clinically diagnosed, along with samples from matched controls.

RESULTS

ASCA were present in 10/32 (31.3%) CD patients before clinical diagnosis compared with 0/95 (0%) controls (p<0.001). None of the eight patients with serum samples available before diagnosis of UC were ASCA positive. ASCA was positive in 54.5% of patients after diagnosis of CD. The mean interval between ASCA detection and diagnosis was 38 months. In 90% of patients, antibodies were detected in the first available serum sample; therefore, measurements of the average time from the presence of ASCA to diagnosis may be even longer. pANCA were present in 2/8 (25%) patients with available sera before the diagnosis of UC. None of their 24 matched controls were positive (p = 0.014).

CONCLUSIONS

ASCA and pANCA may predict development of inflammatory bowel disease years before the disease is clinically diagnosed.

Discordance between the degree of osteopenia and the prevalence of spontaneous vertebral fractures in Crohn's disease

BACKGROUND

A high prevalence of osteoporosis has been noted in Crohn's disease, but data about fractures are scarce.

METHODS

The relationship between low bone mineral density and the prevalence of vertebral fractures was studied in 271 patients with ileo-caecal Crohn's disease in a large European/Israeli study. One hundred and eighty-one currently steroid-free patients with active Crohn's disease (98 completely steroid-naive) and 90 steroid-dependent patients with inactive or quiescent Crohn's disease were investigated by dual X-ray absorptiometry scan of the lumbar spine, a standardized posterior/anterior and lateral X-ray of the thoracic and lumbar spine, and an assessment of potential risk factors for osteoporosis.

RESULTS

Thirty-nine asymptomatic fractures were seen in 25 of 179 steroid-free patients (14.0%; 27 wedge, 12 concavity), and 17 fractures were seen in 13 of 89 steroid-dependent patients (14.6%; 14 wedge, three concavity). The prevalence of fractures in steroid-naive patients was 12.4%. The average bone mineral density, expressed as the T-score, of patients with fractures was not significantly different from that of those without fractures (-0.759 vs. -0.837; P=0.73); 55% of patients with fractures had a normal T-score. The bone mineral density was negatively correlated with lifetime steroids, but not with previous bowel resection or current disease activity. The fracture rate was not correlated with the bone mineral density (P=0.73) or lifetime steroid dose (P=0.83); in women, but not in men, the fracture rate was correlated with age (P=0.009).

CONCLUSIONS

The lack of correlation between the prevalence of fractures on the one hand and the bone mineral density and lifetime steroid dose on the other necessitates new hypotheses for the pathogenesis of the former.

Osteoporosis in murine systemic lupus erythematosus--a laboratory model

The aim of this study was to assess the skeletal metabolism in a murine model of systemic lupus erythematosus (SLE). MRL/n and MRL/l mice (respectively representing a benign and a malignant form of the disease) were observed from 1.5 to 6.5 months of life. The monthly follow-up included: biochemical and histomorphometrical studies of the femoral bone, serum biochemistry, immunoglobulins and osteocalcin, and histological evaluation of the kidney tissue. The results showed a higher femoral weight (+11.5%), calcium (+4.4%) and protein bone content (+11.4%) and a significantly higher (+77%) phosphorus bone content in the MRL/n group; significantly lower (-48.9%) bone alkaline phosphatase enzymatic activity, lower bone alkaline/acid phosphatase enzymatic activities ratio (-40.8%) and lower (-38.4%) serum osteocalcin values in the MRL/l group (which might suggest reduced bone formation in these animals); markedly smaller trabecular bone volume (BV/TV) in the femoral head (-36.2%) and femoral neck (-39.8%), and smaller cortical and femoral areas in the mid-femoral shaft (-38.8% and -38.1% respectively) in the MRL/l group; higher serum immunoglobulins, increased serum blood urea nitrogen (BUN) and creatinine and a higher index of activity in the kidney histology in the MRL/l group, indicating increased activity of the disease in this substrain. The MRL mice, through their two substrains, may serve as a valuable laboratory animal model for study of the skeletal changes in SLE and of the influence of the disease activity on the skeletal metabolism.

Self-expandable metal coil stents in the treatment of benign esophageal strictures refractory to conventional therapy: a case series

BACKGROUND

Benign, refractory esophageal strictures are an important therapeutic challenge. Metallic self-expandable stents developed to treat malignant strictures have occasionally been used in the treatment of benign stenoses. This is a report of the use of 14 esophageal metallic stents in 10 patients with severe benign strictures.

METHODS

Ten patients with peptic, post-surgical, or post-radiation esophageal strictures were treated with metallic stents. All patients had previously been treated, unsuccessfully, by endoscopic dilatation. Their strictures, although benign, gave rise to the same problems as malignant ones.

RESULTS

In all patients, marked improvement of dysphagia was achieved with the use of metallic stents. They were inserted without early complications except for chest pain in one patient. Late complications were proximal and distal migration (in three patients) and a proximal stricture in one other patient. The best results were achieved in post-radiation strictures.

CONCLUSIONS

Metallic stents can be considered as a therapeutic alternative in selected patients with severe benign esophageal strictures refractory to conventional treatment.

Smitten by a kitten

Mammalian bite wounds are commonly encountered in the emergency department. When patients come early (<8 hours after injury), local infection is not usually evident. At this stage, the issue of providing prophylactic antibiotic therapy arises. We report a complication of a cat bite to the hand in a previously healthy 32-year-old man. This patient did not seek medical treatment immediately after the cat bite, and distinct local infection did not develop. Nevertheless, his course was complicated with acute Staphylococcus aureus endocarditis. We discuss the common pathogens involved in a cat bite infection, including S aureus, and delineate the indications for prophylactic antibiotic therapy after a mammalian bite wound.

The prevalence of chronic diarrhea among diabetic patients

OBJECTIVE

The prevalence of chronic diarrhea in patients with type I and type II diabetes is uncertain, most data being available from tertiary referral centers. We report the prevalence and etiology of chronic diarrhea in 861 heterogeneous diabetic patients attending a primary care diabetic outpatient clinic.

METHODS

All patients attending the clinic were asked to fill in a questionnaire relating to their bowel habits. Patients who fulfilled the criteria for chronic diarrhea underwent a comprehensive workup to define the cause of the diarrhea. Additional parameters were the mean duration of diabetes, hemoglobin-Alc levels, and the presence of autonomic neuropathy.

RESULTS

Chronic diarrhea was diagnosed in 32 patients (overall prevalence of 3.7%). The prevalence of nondiabetic diarrhea was higher among type I diabetic patients than among type II patients (3.29% vs 2.3%), although it did not reach statistical significance. Diabetic diarrhea was more common among type I than type II diabetic patients (5.2% vs 0.4%, respectively, p < 0.01). The most common cause of nondiabetic diarrhea was medication induced (metformin).

CONCLUSIONS

Chronic diarrhea is more frequent in type I diabetic patients. The higher prevalence of diarrhea in this population can be attributed to diabetic diarrhea (which is quite rare in type II patients). The most common cause of nondiabetic diarrhea is drug therapy with metformin.

Spontaneous bacterial arthritis in a cirrhotic patient

Septic arthritis is usually of hematogenous origin and is increasingly being reported in elderly patients, who often have underlying medical conditions such as diabetes or alcoholism. We report a 62-year-old patient with alcoholic liver disease who presented with Escherichia coli bacteremia and septic arthritis in a previously fractured ankle. There are scarce reports of infectious arthritis in cirrhotic patients, but this is the first report of arthritis after a primary enteric bacteremia. We believe that the patient described here developed E. coli bacteremia as a result of bacterial overgrowth and translocation related to alcoholic liver disease and cirrhosis. The resulting bacteremia resulted in the development of infection in the left ankle, which had preexisting disease and was thus vulnerable. This case provides further evidence for the mode of infection being bacteremia in cirrhotic patients. In patients with cirrhosis and fever, a high index of suspicion is required for joint infection as a potential cause of fever or deterioration in the cirrhotic's patient general condition.

Daily and seasonal variations in the concentration of melatonin in the human pineal gland

To elucidate whether pineal melatonin secretion is affected by changes in day length, we determined the concentration of melatonin in human pineal glands obtained at autopsy from 66 male subjects, aged 16-84 years over a period of 12 consecutive months. Based on the time of death, a day-night difference in pineal melatonin levels was evident only in the long photoperiod (April-September) with significantly higher melatonin concentrations occurring at night (2200-1000 h). Nighttime values in the long photoperiod were significantly higher than the nighttime values during the short photoperiod (October-March). During the short photoperiod, the data suggested a possible phase-delay in melatonin secretion. Day-night difference was evident in young subjects (30-60 years), but not in elderly subjects (61-84 years). Elderly subjects had lower total melatonin levels (day and night values) although statistically not significant. Therefore, melatonin levels did not decline with age and when the data were analyzed by age there was no significant day-night difference in melatonin levels. These data indicate that the concentration of melatonin in the human pineal is augmented only during the long photoperiod. The results suggest a partial effect of photoperiod on melatonin secretion in humans. This may result from living in an artificial light environment or due to other nonphotic signals involved in generating melatonin rhythm.

Zygomycotic gangrenous cellulitis in a patient with non-insulin dependent diabetes mellitus

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Modulation of murine systemic lupus erythematosus with peptides based on complementarity determining regions of a pathogenic anti-DNA monoclonal antibody

Experimental systemic lupus erythematosus (SLE) can be induced in naive mice by immunization with a murine monoclonal anti-DNA antibody (mAb), 5G12, that bears a major idiotype designated 16/6 Id. Strain-dependent differences were observed in the proliferative responses of lymph node cells of mice immunized with two peptides based on the sequences of the complementarity determining region (CDR) 1 and 3 of mAb 5G12. The capacity of the peptides to bind to major histocompatibility complex class II molecules correlated with the proliferative responses. Immunization of high responder strains with the CDR-based peptides led to production of autoantibodies and clinical manifestations characteristic to experimental SLE. The CDR-based peptides could prevent autoantibody production in neonatal mice that were immunized later either with the peptide or with the pathogenic autoantibody. Furthermore, the peptides inhibited specific proliferation of lymph node cells of mice immunized with the same peptide, with mAb 5G12 or with the human mAb anti-DNA, 16/6 Id. Thus, the CDR-based peptides are potential candidates for therapy of SLE.