An Experimental Phototherapy Device for Studying the Effects of Blue Light on Patients with Raynaud's Phenomenon

Raynaud's phenomenon (RP) is a condition that causes decreased blood flow to areas perfused by small blood vessels (e.g., fingers, toes). In severe cases, ulceration, gangrene, and loss of fingers may occur. Most treatments focus on inducing vasorelaxation in affected areas by the way of pharmaceuticals. Recently, animal studies have shown that vasorelaxation can be induced by non-coherent blue light (wavelength ~ 430-460 nm) through the actions of melanopsin, a photoreceptive opsin protein encoded by the OPN4 gene. To study this effect in humans, a reliable phototherapy device (PTD) is needed. We outline the construction of a PTD to be used in studying blue light effects on Raynaud's patients. Our design addresses user safety, calibration, electromagnetic compatibility/interference (EMC/EMI), and techniques for measuring physiological responses (temperature sensors, laser Doppler flow sensors, infrared thermal imaging of the hands). We tested our device to ensure (1) safe operating conditions, (2) predictable, user-controlled irradiance output levels, (3) an ability for measuring physiological responses, and (4) features necessary to enable a double-blinded crossover study for a clinical trial. We also include in the Methods an approved research protocol utilizing our device that may serve as a starting point for clinical study. We introduced a reliable PTD for studying the effects of blue light therapy for patients suffering from Raynaud's phenomenon and showed that our device is safe and reliable and includes the required measurement vectors for tracking treatment effects throughout the duration of a clinical study.

The primary cardiomyopathy of systemic sclerosis on cardiovascular magnetic resonance imaging

AIMS

Cardiac disease in systemic sclerosis (SSc) may be primary or secondary to other disease manifestations of SSc. The prevalence of the primary cardiomyopathy of SSc is unknown. Cardiovascular magnetic resonance (CMR) imaging can help accurately determine the presence and cause of cardiomyopathy. We aimed to investigate the prevalence, the CMR features, and the prognostic implications of the primary cardiomyopathy of SSc.

METHODS AND RESULTS

We conducted a retrospective cohort study of consecutive patients with SSc who had a clinical CMR for suspected cardiac involvement. We identified the prevalence, the CMR features of the primary cardiomyopathy of SSc, and its association with the long-term incidence of death or major adverse cardiac events (MACEs): heart failure hospitalization, ventricular assist device implantation, heart transplantation, and sustained ventricular tachycardia. Of 130 patients with SSc, 80% were women, and the median age was 58 years. On CMR, 22% had an abnormal left ventricular ejection fraction, and 40% had late gadolinium enhancement (LGE). The prevalence of the primary cardiomyopathy of SSc was 21%. A third of these patients had a distinct LGE phenotype. Over a median follow-up of 3.6 years after the CMR, patients with the primary cardiomyopathy of SSc had a greater incidence of death or MACE (adjusted hazard ratio 2.01; 95% confidence interval 1.03-3.92; P = 0.041).

CONCLUSION

The prevalence of the primary cardiomyopathy of SSc was 21%, with a third demonstrating a distinct LGE phenotype. The primary cardiomyopathy of SSc was independently associated with a greater long-term incidence of death or MACE.

CONQUER Scleroderma: association of gastrointestinal tract symptoms in early disease with resource utilization

OBJECTIVES

SSc is associated with increased health-care resource utilization and economic burden. The Collaborative National Quality and Efficacy Registry (CONQUER) is a US-based collaborative that collects longitudinal follow-up data on SSc patients with <5 years of disease duration enrolled at scleroderma centres in the USA. The objective of this study was to investigate the relationship between gastrointestinal tract symptoms and self-reported resource utilization in CONQUER participants.

METHODS

CONQUER participants who had completed a baseline and 12-month Gastrointestinal Tract Questionnaire (GIT 2.0) and a Resource Utilization Questionnaire (RUQ) were included in this analysis. Patients were categorized by total GIT 2.0 severity: none-to-mild (0-0.49); moderate (0.50-1.00), and severe-to-very severe (1.01-3.00). Clinical features and medication exposures were examined in each of these categories. The 12-month RUQ responses were summarized by GIT 2.0 score categories at 12 months.

RESULTS

Among the 211 CONQUER participants who met the inclusion criteria, most (64%) had mild GIT symptoms, 26% had moderate symptoms, and 10% severe GIT symptoms at 12 months. The categorization of GIT total severity score by RUQ showed that more upper endoscopy procedures and inpatient hospitalization occurred in the CONQUER participants with severe GIT symptoms. These patients with severe GIT symptoms also reported the use of more adaptive equipment.

CONCLUSION

This report from the CONQUER cohort suggests that severe GIT symptoms result in more resource utilization. It is especially important to understand resource utilization in early disease cohorts when disease activity, rather than damage, primarily contributes to health-related costs of SSc.

Qualitative Interviews to Assess the Content Validity and Usability of the Electronic Raynaud Diary in Patients with Systemic Sclerosis

OBJECTIVE

To better understand the symptoms and impacts of Raynaud phenomenon (RP) in patients with systemic sclerosis (SSc) and to evaluate the content validity and usability of a new electronic patient-reported outcome (PRO) measure for RP: the Raynaud Diary.

METHODS

The Raynaud Diary was developed as a daily eDiary for assessing the number and duration of symptomatic Raynaud attacks; worst pain, numbness, tingling, and discomfort in the fingers; and overall disease severity, captured using the Raynaud's Condition Score. The Raynaud Diary was debriefed in two waves of qualitative interviews with adults with self-reported RP secondary to SSc. All interviews included open-ended questions about participants' experiences of RP.

RESULTS

Participants (N = 39) had a mean age of 55.1 years, and 87% were female. Frequently reported RP symptoms were color change (reported by all participants), numbness (90%), tingling (82%), pain (77%), and discomfort (72%). Common attack triggers included temperature-related factors and stress. Participants reported being unable to be outside or do outdoor activities and had problems gripping objects. All participants demonstrated understanding of the Raynaud Diary instructions. Most participants indicated that they would be able to use the Raynaud Diary to record the worst severity of individual RP symptoms in the previous 24 hours.

CONCLUSION

Patients with RP secondary to SSc bear a heavy symptom burden. The Raynaud Diary is a content valid PRO measure that captures the most frequent symptoms of RP in patients with SSc.

Safety and Efficacy of B-Cell Depletion with Rituximab for the Treatment of Systemic Sclerosis-associated Pulmonary Arterial Hypertension: A Multicenter, Double-Blind, Randomized, Placebo-controlled Trial

Rationale: Systemic sclerosis (SSc)-pulmonary arterial hypertension (PAH) is one of the most prevalent and deadly forms of PAH. B cells may contribute to SSc pathogenesis. Objectives: We investigated the safety and efficacy of B-cell depletion for SSc-PAH. Methods: In an NIH-sponsored, multicenter, double-blinded, randomized, placebo-controlled, proof-of-concept trial, 57 patients with SSc-PAH on stable-dose standard medical therapy received two infusions of 1,000 mg rituximab or placebo administered 2 weeks apart. The primary outcome measure was the change in 6-minute-walk distance (6MWD) at 24 weeks. Secondary endpoints included safety and invasive hemodynamics. We applied a machine learning approach to predict drug responsiveness. Measurements and Main Results: We randomized 57 subjects from 2010 to 2018. In the primary analysis, using data through Week 24, the adjusted mean change in 6MWD at 24 weeks favored the treatment arm but did not reach statistical significance (23.6 ± 11.1 m vs. 0.5 ± 9.7 m; P = 0.12). Although a negative study, when data through Week 48 were also considered, the estimated change in 6MWD at Week 24 was 25.5 ± 8.8 m for rituximab and 0.4 ± 7.4 m for placebo (P = 0.03). Rituximab treatment appeared to be safe and well tolerated. Low levels of RF (rheumatoid factor), IL-12, and IL-17 were sensitive and specific as favorable predictors of a rituximab response as measured by an improved 6MWD (receiver operating characteristic area under the curve, 0.88-0.95). Conclusions: B-cell depletion therapy is a potentially effective and safe adjuvant treatment for SSc-PAH. Future studies in these patients can confirm whether the identified biomarkers predict rituximab responsiveness. Clinical trial registered with www.clinicaltrails.gov (NCT01086540).

Safety and efficacy of abatacept in early diffuse cutaneous systemic sclerosis (ASSET): open-label extension of a phase 2, double-blind randomised trial

BACKGROUND

Abatacept was well tolerated by patients with early diffuse cutaneous systemic sclerosis in a phase 2, double-blind randomised trial, with potential efficacy at 12 months. We report here the results of an open-label extension for 6 months.

METHODS

Patients (aged ≥18 years) with diffuse cutaneous systemic sclerosis of less than 3 years' duration from their first non-Raynaud's symptom were enrolled into the ASSET trial (A Study of Subcutaneous Abatacept to Treat DiffuseCutaneous Systemic Sclerosis), which is a double-blind trial at 22 sites in Canada, the UK, and the USA. Aftercompletion of 12 months of treatment with either abatacept or placebo, patients received a further 6 months ofabatacept (125 mg subcutaneous every week) in an open-label extension. The primary endpoint of the double-blind trial was modified Rodnan Skin Score (mRSS) at 12 months, which was reassessed at 18 months in the open-label extension. The primary analysis included all participants who completed the double-blind trial and received at least one dose of open-label treatment (modified intention to treat). This trial is registered with ClinicalTrials.gov, NCT02161406.

FINDINGS

Between Sept 22, 2014, and March 15, 2017, 88 participants were randomly allocated in the double-blind trial either abatacept (n=44) or placebo (44); 32 patients from each treatment group completed the 6-month open-labelextension. Among patients assigned abatacept, a mean improvement from baseline in mRSS was noted at 12 months (-6·6 [SD 6·4]), with further improvement seen during the open-label extension period (-9·8 [8·1] at month 18). Participants assigned placebo had a mean improvement from baseline in mRSS at 12 months (-3·7 [SD 7·6]), with a further improvement at month 18 (-6·3 [9·3]). Infections during the open-label extension phase occurred in nine patients in the placebo-abatacept group (12 adverse events, one serious adverse event) and in 11 patients in theabatacept-abatacept group (14 adverse events, one serious adverse event). Two deaths occurred during the 12-month double-blind period in the abatacept group, which were related to scleroderma renal crisis; no deaths were recorded during the open-label extension.

INTERPRETATION

During the 6-month open-label extension, no new safety signals for abatacept were identified in the treatment of diffuse cutaneous systemic sclerosis. Clinically meaningful improvements in mRSS and other outcome measures were observed in both the abatacept and placebo groups when patients transitioned to open-label treatment. These data support further studies of abatacept in diffuse cutaneous systemic sclerosis.

FUNDING

Bristol-Myers Squibb and National Institutes of Health.

Risk Factors for Mortality and Cardiopulmonary Hospitalization in Systemic Sclerosis Patients At Risk for Pulmonary Hypertension, in the PHAROS Registry

OBJECTIVE

We sought to identify predictors of mortality and cardiopulmonary hospitalizations in patients at risk for pulmonary hypertension (PH) and enrolled in PHAROS, a prospective cohort study to investigate the natural history of PH in systemic sclerosis (SSc).

METHODS

The at-risk population for PH was defined by the following entry criteria: echocardiogram systolic pulmonary arterial pressure > 40 mmHg, or DLCO < 55% predicted or ratio of % forced vital capacity/%DLCO > 1.6, measured by pulmonary function testing. Baseline clinical measures were evaluated as predictors of hospitalization and death between 2005 and 2014. Cox proportional hazards models were censored at date of PH onset or latest study visit and adjusted for age, sex, race, and disease duration.

RESULTS

Of the 236 at-risk subjects who were followed for a median of 4 years (range 0.4-8.5 yrs), 35 developed PH after entering PHAROS (reclassified as PH group). In the at-risk group, higher mortality was strongly associated with male sex, low %DLCO, exercise oxygen desaturation, anemia, abnormal dyspnea scores, and baseline pericardial effusion. Risks for cardiopulmonary hospitalization were associated with increased dyspnea and pericardial effusions, although PH patients with DLCO < 50% had the highest risk of cardiopulmonary hospitalizations.

CONCLUSION

Risk factors for poor outcome in patients with SSc who are at risk for PH were similar to others with SSc-PH and SSc-pulmonary arterial hypertension, including male sex, DLCO < 50%, exercise oxygen desaturation, and pericardial effusions. This group should undergo right heart catheterization and receive appropriate intervention if PH is confirmed.

Gene-level association analysis of systemic sclerosis: A comparison of African-Americans and White populations

Gene-level analysis of ImmunoChip or genome-wide association studies (GWAS) data has not been previously reported for systemic sclerosis (SSc, scleroderma). The objective of this study was to analyze genetic susceptibility loci in SSc at the gene level and to determine if the detected associations were shared in African-American and White populations, using data from ImmunoChip and GWAS genotyping studies. The White sample included 1833 cases and 3466 controls (956 cases and 2741 controls from the US and 877 cases and 725 controls from Spain) and the African American sample, 291 cases and 260 controls. In both Whites and African Americans, we performed a gene-level analysis that integrates association statistics in a gene possibly harboring multiple SNPs with weak effect on disease risk, using Versatile Gene-based Association Study (VEGAS) software. The SNP-level analysis was performed using PLINK v.1.07. We identified 4 novel candidate genes (STAT1, FCGR2C, NIPSNAP3B, and SCT) significantly associated and 4 genes (SERBP1, PINX1, TMEM175 and EXOC2) suggestively associated with SSc in the gene level analysis in White patients. As an exploratory analysis we compared the results on Whites with those from African Americans. Of previously established susceptibility genes identified in Whites, only TNFAIP3 was significant at the nominal level (p = 6.13x10-3) in African Americans in the gene-level analysis of the ImmunoChip data. Among the top suggestive novel genes identified in Whites based on the ImmunoChip data, FCGR2C and PINX1 were only nominally significant in African Americans (p = 0.016 and p = 0.028, respectively), while among the top novel genes identified in the gene-level analysis in African Americans, UNC5C (p = 5.57x10-4) and CLEC16A (p = 0.0463) were also nominally significant in Whites. We also present the gene-level analysis of SSc clinical and autoantibody phenotypes among Whites. Our findings need to be validated by independent studies, particularly due to the limited sample size of African Americans.

Utility of B-type natriuretic peptides in the assessment of patients with systemic sclerosis-associated pulmonary hypertension in the PHAROS registry

OBJECTIVES

To assess the utility of B-type natriuretic peptide (BNP) and N-terminal pro-BNP (NT-proBNP) in detecting and monitoring pulmonary hypertension (PH) in systemic sclerosis (SSc).

METHODS

PHAROS is a multicenter prospective cohort of SSc patients at high risk for developing pulmonary arterial hypertension (SSc-AR-PAH) or with a definitive diagnosis of SSc-PH. We evaluated 1) the sensitivity and specificity of BNP≥64 and NT-proBNP≥210 pg/mL for the detection of SSc-PAH and/ or SSc-PH in the SSc-AR-PAH population; 2) baseline and longitudinal BNP and NT-proBNP levels as predictors of progression to SSc-PAH and/or SSc-PH; 3) baseline BNP≥180, NT-proBNP≥553 pg/mL, and longitudinal changes in BNP and NT-proBNP as predictors of mortality in SSc-PH diagnosed patients.

RESULTS

172 SSc-PH and 157 SSc-AR- PAH patients had natriuretic peptide levels available. Median BNP and NT-proBNP were significantly higher in the SSc-PH versus SSc-AR-PAH group. The sensitivity and specificity for SSc-PAH detection using baseline BNP≥64 pg/mL was 71% and 59%; and for NT-proBNP≥210 pg/mL, 73% and 78%. NT-proBNP showed stronger correlations with haemodynamic indicators of right ventricular dysfunction than BNP. Baseline creatinine, RVSP > 40 mmHg, and FVC%:DLco% ratio ≥1.8 were associated with progression from SSc-AR-PAH to SSc-PH but no association with individual or combined baseline BNP and NT-proBNP levels was observed. Baseline and follow-up BNP or NT-proBNP levels were not predictive of death, however, a composite BNP/NT-proBNP group predicted mortality (HR 3.81 (2.08-6.99), p<.0001).

CONCLUSIONS

NT-proBNP may be more useful than BNP in the detection and monitoring of PAH in SSc patients, but additional studies are necessary.

Association Between Serum Antibodies to Periodontal Bacteria and Rheumatoid Factor in the Third National Health and Nutrition Examination Survey

OBJECTIVE

Alterations in the microbiome, including the periodontal microbiome, may be a risk factor for rheumatoid arthritis (RA). Most studies that have analyzed this association are relatively small, focus primarily on a single periodontal pathogen (Porphyromonas gingivalis), and are not population based. This study was undertaken to investigate the association between elevated serum levels of IgG antibodies to 19 periodontal species and the prevalence of rheumatoid factor (RF) in a large nationally representative sample of adults.

METHODS

The Third National Health and Nutrition Examination Survey (NHANES-III) is a cross-sectional sample of the noninstitutionalized US population (n = 33,994). Our study population included all dentate participants who were 60 years and older, did not have RA as defined by a modified version of the American College of Rheumatology 1987 criteria, and had complete data for both serum IgG antibodies against periodontal bacteria and serum RF antibody titer (n = 2,461).

RESULTS

Adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) summarizing the relationship between the 19 periodontal serum IgG antibodies and RF seropositivity ranged from 0.53 (95% CI 0.29-0.97) to 1.27 (95% CI 0.79-2.06), and 17 of the 19 observed ORs were <1.0. The ORs for RF seropositivity among participants with elevated Prevotella intermedia (0.53 [95% CI 0.29-0.97]) and Capnocytophaga ochracea (0.54 [0.31-0.95]) IgG levels were statistically significant.

CONCLUSION

Our findings indicate that elevated levels of IgG antibodies to periodontal bacteria are mostly unassociated with RF seropositivity in the nationally representative NHANES-III. Elevated levels of antibodies to P intermedia and C ochracea are associated with lower odds of RF seropositivity.

Mycophenolate mofetil versus oral cyclophosphamide in scleroderma-related interstitial lung disease (SLS II): a randomised controlled, double-blind, parallel group trial

BACKGROUND

12 months of oral cyclophosphamide has been shown to alter the progression of scleroderma-related interstitial lung disease when compared with placebo. However, toxicity was a concern and without continued treatment the efficacy disappeared by 24 months. We hypothesised that a 2 year course of mycophenolate mofetil would be safer, better tolerated, and produce longer lasting improvements than cyclophosphamide.

METHODS

This randomised, double-blind, parallel group trial enrolled patients from 14 US medical centres with scleroderma-related interstitial lung disease meeting defined dyspnoea, pulmonary function, and high-resolution CT (HRCT) criteria. The data coordinating centre at the University of California, Los Angeles (UCLA, CA, USA), randomly assigned patients using a double-blind, double-dummy, centre-blocked design to receive either mycophenolate mofetil (target dose 1500 mg twice daily) for 24 months or oral cyclophosphamide (target dose 2·0 mg/kg per day) for 12 months followed by placebo for 12 months. Drugs were given in matching 250 mg gel capsules. The primary endpoint, change in forced vital capacity as a percentage of the predicted normal value (FVC %) over the course of 24 months, was assessed in a modified intention-to-treat analysis using an inferential joint model combining a mixed-effects model for longitudinal outcomes and a survival model to handle non-ignorable missing data. The study was registered with ClinicalTrials.gov, number NCT00883129.

FINDINGS

Between Sept 28, 2009, and Jan 14, 2013, 142 patients were randomly assigned to either mycophenolate mofetil (n=69) or cyclophosphamide (n=73). 126 patients (mycophenolate mofetil [n=63] and cyclophosphamide [n=63]) with acceptable baseline HRCT studies and at least one outcome measure were included in the primary analysis. The adjusted % predicted FVC improved from baseline to 24 months by 2·19 in the mycophenolate mofetil group (95% CI 0·53-3·84) and 2·88 in the cyclophosphamide group (1·19-4·58). The course of the % FVC did not differ significantly between the two treatment groups based on the prespecified primary analysis using a joint model (p=0·24), indicating that the trial was negative for the primary endpoint. However, in a post-hoc analysis of the primary endpoint, the within-treatment change from baseline to 24 months derived from the joint model showed that the % FVC improved significantly in both the mycophenolate mofetil and cyclophosphamide groups. 16 (11%) patients died (five [7%] mycophenolate mofetil and 11 [15%] cyclophosphamide), with most due to progressive interstitial lung disease. Leucopenia (30 patients vs four patients) and thrombocytopenia (four vs zero) occurred more often in patients given cyclophosphamide than mycophenolate mofetil. Fewer patients on mycophenolate mofetil than on cyclophosphamide prematurely withdrew from study drug (20 vs 32) or met prespecified criteria for treatment failure (zero vs two). The time to stopping treatment was shorter in the cyclophosphamide group (p=0·019).

INTERPRETATION

Treatment of scleroderma-related interstitial lung disease with mycophenolate mofetil for 2 years or cyclophosphamide for 1 year both resulted in significant improvements in prespecified measures of lung function over the 2 year course of the study. Although mycophenolate mofetil was better tolerated and associated with less toxicity, the hypothesis that it would have greater efficacy at 24 months than cyclophosphamide was not confirmed. These findings support the potential clinical effectiveness of both cyclophosphamide and mycophenolate mofetil for progressive scleroderma-related interstitial lung disease, and the present preference for mycophenolate mofetil because of its better tolerability and toxicity profile.

FUNDING

National Heart, Lung and Blood Institute, National Institutes of Health; with drug supply provided by Hoffmann-La Roche and Genentech.

CD4+ Group 1 Innate Lymphoid Cells (ILC) Form a Functionally Distinct ILC Subset That Is Increased in Systemic Sclerosis

Innate lymphoid cells (ILC) are a heterogeneous group of cellular subsets that produce large amounts of T cell-associated cytokines in response to innate stimulation in the absence of Ag. In this study, we define distinct patterns of surface marker and cytokine expression among the ILC subsets that may further delineate their migration and function. Most notably, we found that the subset previously defined as group 1 ILC (ILC1) contains CD4(+) CD8(-), CD4(-) CD8(+), and CD4(-) CD8(-) populations. Although all ILC1 subsets shared characteristics with Th1 cells, CD4(+) ILC1 also demonstrated significant phenotypic and functional heterogeneity. We also show that the frequencies of CD4(+) ILC1 and NKp44(+) group 3 ILC, but not CD4(-) ILC1 or group 2 ILC, are increased in the peripheral blood of individuals with systemic sclerosis (SSc), a disease characterized by fibrotic and vascular pathology, as well as immune dysregulation. Furthermore, we demonstrate that CD4(+) and CD4(-) ILC1 are functionally divergent based on their IL-6Rα expression and that the frequency of IL-6Rα expression on ILC is altered in SSc. The distinct phenotypic and functional features of CD4(+) and CD4(-) ILC1 suggest that they may have differing roles in the pathogenesis of immune-mediated diseases, such as SSc.

Genetic susceptibility loci of idiopathic interstitial pneumonia do not represent risk for systemic sclerosis: a case control study in Caucasian patients

BACKGROUND

Systemic sclerosis (SSc)-related interstitial lung disease (ILD) has phenotypic similarities to lung involvement in idiopathic interstitial pneumonia (IIP). We aimed to assess whether genetic susceptibility loci recently identified in the large IIP genome-wide association studies (GWASs) were also risk loci for SSc overall or severity of ILD in SSc.

METHODS

A total of 2571 SSc patients and 4500 healthy controls were investigated from the US discovery GWAS and additional US replication cohorts. Thirteen IIP-related selected single nucleotide polymorphisms (SNPs) were genotyped and analyzed for their association with SSc.

RESULTS

We found an association of SSc with the SNP rs6793295 in the LRRC34 gene (OR = 1.14, CI 95 % 1.03 to 1.25, p value = 0.009) and rs11191865 in the OBFC1 gene (OR = 1.09, CI 95 % 1.00 to 1.19, p value = 0.043) in the discovery cohort. Additionally, rs7934606 in MUC2 (OR = 1.24, CI 95 % 1.01 to 1.52, p value = 0.037) was associated with SSc-ILD defined by imaging. However, these associations failed to replicate in the validation cohort. Furthermore, SNPs rs2076295 in DSP (β = -2.29, CI 95 % -3.85 to -0.74, p value = 0.004) rs17690703 in SPPL2C (β = 2.04, CI 95 % 0.21 to 3.88, p value = 0.029) and rs1981997 in MAPT (β = 2.26, CI 95 % 0.35 to 4.17, p value = 0.02) were associated with percent predicted forced vital capacity (FVC%) even after adjusting for the anti-topoisomerase (ATA)-positive subset. However, these associations also did not replicate in the validation cohort.

CONCLUSIONS

Our results add new evidence that SSc and SSc-related ILD are genetically distinct from IIP, although they share phenotypic similarities.

Immunochip analysis identifies multiple susceptibility loci for systemic sclerosis

In this study, 1,833 systemic sclerosis (SSc) cases and 3,466 controls were genotyped with the Immunochip array. Classical alleles, amino acid residues, and SNPs across the human leukocyte antigen (HLA) region were imputed and tested. These analyses resulted in a model composed of six polymorphic amino acid positions and seven SNPs that explained the observed significant associations in the region. In addition, a replication step comprising 4,017 SSc cases and 5,935 controls was carried out for several selected non-HLA variants, reaching a total of 5,850 cases and 9,401 controls of European ancestry. Following this strategy, we identified and validated three SSc risk loci, including DNASE1L3 at 3p14, the SCHIP1-IL12A locus at 3q25, and ATG5 at 6q21, as well as a suggested association of the TREH-DDX6 locus at 11q23. The associations of several previously reported SSc risk loci were validated and further refined, and the observed peak of association in PXK was related to DNASE1L3. Our study has increased the number of known genetic associations with SSc, provided further insight into the pleiotropic effects of shared autoimmune risk factors, and highlighted the power of dense mapping for detecting previously overlooked susceptibility loci.

Periodontal disease, tooth loss and incident rheumatoid arthritis: results from the First National Health and Nutrition Examination Survey and its epidemiological follow-up study

AIMS

Infection may be a rheumatoid arthritis (RA) risk factor. We examined whether signs of periodontal infection were associated with RA development in the First National Health and Nutrition Examination Survey and its epidemiological follow-up study.

MATERIAL AND METHODS

In 1971-1974, 9702 men and women aged 25-74 were enrolled and surveyed longitudinally (1982, 1986, 1987, 1992). Periodontal infection was defined by baseline tooth loss or clinical evidence of periodontal disease. Baseline (n = 138) and incident (n = 433) RA cases were defined via self-report physician diagnosis, joint pain/swelling, ICD-9 codes (714.0-714.9), death certificates and/or RA hospitalization.

RESULTS

Adjusted odds ratios (ORs) (95% CI) for prevalent RA in gingivitis and periodontitis (versus healthy) were 1.09 (0.57, 2.10) and 1.85 (0.95, 3.63); incident RA ORs were 1.32 (0.85, 2.06) and 1.00 (0.68, 1.48). The ORs for prevalent RA among participants missing 5-8, 9-14, 15-31 or 32 teeth (versus 0-4 teeth) were 1.74 (1.03, 2.95), 1.82 (0.81, 4.10), 1.45 (0.62, 3.41) and 1.30 (0.48, 3.53); ORs for incident RA were 1.12 (0.77, 1.64), 1.67 (1.12, 2.48), 1.40 (0.85, 2.33) and 1.22 (0.75, 2.00). Dose-responsiveness was enhanced among never smokers. The rate of death or loss-to-follow-up after 1982 was two- to fourfold higher among participants with periodontitis or missing ≥9 teeth (versus healthy participants).

CONCLUSIONS

Although participants with periodontal disease or ≥5 missing teeth experienced higher odds of prevalent/incident RA, most ORs were non-statistically significant and lacked dose-responsiveness. Differential RA ascertainment bias complicated the interpretation of these data.

Anti-fibrillarin antibody in African American patients with systemic sclerosis: immunogenetics, clinical features, and survival analysis

OBJECTIVE

Anti-U3-RNP, or anti-fibrillarin antibodies (AFA), are detected more frequently among African American (AA) patients with systemic sclerosis (SSc) compared to other ethnic groups and are associated with distinct clinical features. We examined the immunogenetic, clinical, and survival correlates of AFA in a large group of AA patients with SSc.

METHODS

Overall, 278 AA patients with SSc and 328 unaffected AA controls were enrolled from 3 North American cohorts. Clinical features, autoantibody profile, and HLA class II genotyping were determined. To compare clinical manifestations, relevant clinical features were adjusted for disease duration. Cox proportional hazards regression was used to determine the effect of AFA on survival.

RESULTS

Fifty (18.5%) AA patients had AFA. After Bonferroni correction, HLA-DRB1*08:04 was associated with AFA, compared to unaffected AA controls (OR 11.5, p < 0.0001) and AFA-negative SSc patients (OR 5.2, p = 0.0002). AFA-positive AA patients had younger age of disease onset, higher frequency of digital ulcers, diarrhea, pericarditis, higher Medsger perivascular and lower Medsger lung severity indices (p = 0.004, p = 0.014, p = 0.019, p = 0.092, p = 0.006, and p = 0.016, respectively). After adjustment for age at enrollment, AFA-positive patients did not have different survival compared to patients without AFA (p = 0.493).

CONCLUSION

Our findings demonstrate strong association between AFA and HLA-DRB1*08:04 allele in AA patients with SSc. AA SSc patients with AFA had younger age of onset, higher frequency of digital ulcers, pericarditis and severe lower gastrointestinal involvement, but less severe lung involvement compared to AA patients without AFA. Presence of AFA did not change survival.

Epitope-specific immunotherapy of rheumatoid arthritis: clinical responsiveness occurs with immune deviation and relies on the expression of a cluster of molecules associated with T cell tolerance in a double-blind, placebo-controlled, pilot phase II trial

OBJECTIVE

Induction of immune tolerance to maintain clinical control with a minimal drug regimen is a current research focus in rheumatoid arthritis (RA). Accordingly, we are developing a tolerization approach to dnaJP1, a peptide part of a pathogenic mechanism that contributes to autoimmune inflammation in RA. We undertook this study to test 2 hypotheses: 1) that mucosal induction of immune tolerance to dnaJP1 would lead to a qualitative change from a proinflammatory phenotype to a more tolerogenic functional phenotype, and 2) that immune deviation of responses to an inflammatory epitope might translate into clinical improvement.

METHODS

One hundred sixty patients with active RA and with immunologic reactivity to dnaJP1 were enrolled in a pilot phase II trial. They received oral doses of 25 mg of dnaJP1 or placebo daily for 6 months.

RESULTS

The dnaJP1 peptide was safe and well-tolerated. In response to treatment with dnaJP1, there was a significant reduction in the percentage of T cells producing tumor necrosis factor alpha and a corresponding trend toward an increased percentage of T cells producing interleukin-10. Coexpression of a cluster of molecules (programmed death 1 and its ligands) associated with T cell regulation was also found to be a prerequisite for successful tolerization in clinical responders. Analysis of the primary efficacy end point (meeting the American College of Rheumatology 20% improvement criteria at least once on day 112, 140, or 168) showed a difference between treatment groups that became significant in post hoc analysis using generalized estimating equations. Differences in clinical responses were also found between treatment groups on day 140 and at followup. Post hoc analysis showed that the combination of dnaJP1 and hydroxychloroquine (HCQ) was superior to the combination of HCQ and placebo.

CONCLUSION

Tolerization to dnaJP1 leads to immune deviation and a trend toward clinical efficacy. Susceptibility to treatment relies on the coexpression of molecules that can down-regulate adaptive immunity.

Toward the early diagnosis of systemic sclerosis: warning signs the practitioner needs to recognize

Systemic sclerosis, or scleroderma, is a rare condition that first presents with symptoms common to many other diseases. Because of this, diagnosing it can be difficult and take time.This article describes warning signs of possible incipient scleroderma as well as tests that can help the primary care provider identify this serious autoimmune disorder.

Positive selection optimizes the number and function of MHCII-restricted CD4+ T cell clones in the naive polyclonal repertoire

T cell receptors (TCRs) on T lymphocytes in an individual bind foreign peptides bound to major histocompatibility complex (MHC) molecules expressed in that individual (designated MHC(A)). Results from radiation bone marrow chimeras and TCR transgenic mice indicate that this complex form of antigen recognition is the result of positive selection of clones with low affinity for self peptide:MHC(A) complexes during development. Here we used a sensitive peptide:MHC tetramer enrichment method to quantify the role of positive selection in the generation of the preimmune polyclonal T cell repertoire in normal individuals. We made the surprising observation that mouse and human naive T cells capable of binding to foreign peptide:MHC(A) were present at the same frequency in hosts that expressed MHC(A) or a different MHC isoform (MHC(B)). However, most of the clones in MHC(B) hosts also recognized self peptide:MHC(A) complexes. When these "alloreactive" T cells were removed from the MHC(B) repertoire via negative selection in an MHC(A) host, the number of foreign peptide:MHC(A)-binding T cells was reduced to one fifth and many of the remaining cells did not respond to the peptide. Therefore, although positive selection on MHC(A) was not required to produce foreign peptide:MHC(A)-binding clones, it had a large effect on selecting responsive clones.

Induction of interferon-alpha by scleroderma sera containing autoantibodies to topoisomerase I: association of higher interferon-alpha activity with lung fibrosis

OBJECTIVE

Peripheral blood cells (PBMCs) from some patients with systemic sclerosis (SSc) express an interferon-alpha (IFNalpha) signature. The aim of this study was to determine whether SSc patient sera could induce IFNalpha and whether IFNalpha induction was associated with specific autoantibodies and/or clinical features of the disease.

METHODS

SSc sera containing autoantibodies against either topoisomerase I (anti-topo I; n = 12), nucleolar protein (ANoA; n = 12), or centromeric protein (ACA; n = 13) were cultured with a HeLa nuclear extract and normal PBMCs. In some experiments, different cell extracts or inhibitors of plasmacytoid dendritic cell (DC) activation, Fcgamma receptor II (FcgammaRII), endocytosis, or nucleases were used. IFNalpha was measured by enzyme-linked immunosorbent assay.

RESULTS

Topo I-containing sera induced significantly higher levels of IFNalpha as compared with all other groups. IFNalpha induction was inhibited by anti-blood dendritic cell antigen 2 (90%), anti-CD32 (76%), bafilomycin (99%), and RNase (82%). In contrast, ACAs induced low levels of IFNalpha even when necrotic, apoptotic, or demethylated extracts were used, despite the fact that CENP-B-binding oligonucleotide containing 2 CpG motifs effectively stimulated IFNalpha. IFNalpha production was significantly higher in patients with diffuse SSc (mean +/- SEM 641 +/- 174 pg/ml) than in those with limited SSc (215 +/- 66 pg/ml) as well as in patients with lung fibrosis than in those without.

CONCLUSION

Autoantibody subsets in SSc sera differentially induce IFNalpha and may explain the IFNalpha signature observed in SSc. IFNalpha is induced by plasmacytoid DCs and required uptake of immune complexes through FcgammaRII, endosomal transport, and the presence of RNA, presumably for interaction with Toll-like receptor 7. The higher IFNalpha induction in sera from patients with diffuse SSc than in those with limited SSc as well as in sera from patients with lung fibrosis suggests that IFNalpha may contribute to tissue injury.

A multicenter, randomized, double-blind, placebo-controlled trial of oral type I collagen treatment in patients with diffuse cutaneous systemic sclerosis: I. oral type I collagen does not improve skin in all patients, but may improve skin in late-phase disease

OBJECTIVE

To investigate the safety and efficacy of oral bovine type I collagen (CI) treatment in patients who have had diffuse cutaneous systemic sclerosis (dcSSc; scleroderma) for <or=10 years.

METHODS

One hundred sixty-eight patients with dcSSc were enrolled in a double-blind, placebo-controlled trial of oral CI (500 microg/day) or placebo administered over 12 months, with a followup visit at month 15. The primary outcome was the modified Rodnan skin thickness score (MRSS). Other clinical and immune system parameters were also assessed.

RESULTS

Intent-to-treat and modified intent-to-treat analyses showed that for the total population of patients with dcSSc, there were no significant differences in the mean change in MRSS or other key clinical parameters between the CI and placebo treatment groups at 12 months or at 15 months. However, in a subanalysis of the available data at month 15, the CI-treated group of patients with late-phase dcSSc experienced a significant reduction in the MRSS compared with that in the placebo-treated patients with late-phase dcSSc (change in MRSS at month 15 -7.9 versus -2.9; P = 0.0063).

CONCLUSION

Although the results from this trial did not meet the primary outcome goals, the findings from exploratory analyses indicated that CI treatment may benefit patients with late-phase dcSSc. This new treatment strategy and preliminary clinical observations in patients with dcSSc need to be corroborated.

Combined analysis of monocyte and lymphocyte messenger RNA expression with serum protein profiles in patients with scleroderma

OBJECTIVE

We attempted to elucidate possible pathogenetic mechanisms in scleroderma by analysis of gene expression patterns of purified monocytes and lymphocytes, as well as protein profiles of cytokines and growth factors.

METHODS

Expression analysis was performed on messenger RNA (mRNA) from cells that had been purified with magnetic beads. Plasma samples from the same patients were used for multiplex cytokine analysis. Potential sources of proteins were also examined by in situ hybridization of skin specimens.

RESULTS

A total of 1,800 genes from monocytes and 863 genes from CD4+ T cells were differentially expressed in scleroderma patients. As observed by other investigators using unfractionated peripheral blood cells from patients with autoimmune connective tissue diseases, the cell type-specific analyses of our scleroderma samples showed expression of genes suggesting the presence of interferon-alpha (IFNalpha), despite the apparent absence of this cytokine in plasma. IFNalpha RNA was, however, expressed at enhanced levels in vascular and perivascular cells in scleroderma skin samples. While levels of interleukin-1alpha (IL-1alpha) and IL-16 were among 10 proteins found to be significantly elevated in scleroderma patients, none of the large panel of plasma cytokines we analyzed correlated with the expression levels of putative IFN response genes.

CONCLUSION

The pattern of up-regulation of mRNA in both the monocytes and CD4 lymphocytes of scleroderma patients, together with the detection of IFNalpha RNA in the microvasculature, suggests that leukocytes respond to this cytokine locally in the vessels. Detection of high levels of IL-1alpha and IL-16 in plasma and the independence of these protein levels from the IFN signature, implicates an independent contribution of other cytokines to immune activation and/or inflammation in scleroderma.

Micro magnetic resonance angiography of the finger in systemic sclerosis

OBJECTIVE

To characterize vascular lesions in SSc disease with high-resolution magnetic resonance angiography (Micro-MRA) of the finger.

METHODS

Eight SSc subjects and eight age- and sex-matched healthy controls were recruited for this study. Among the SSc subjects, the mean +/- s.d. age was 54.5 +/- 4.9 yrs, and the mean +/- s.d. duration of disease was 8.3 +/- 8.4 yrs. The numbers of SSc subjects that had telangiectasia, calcinosis and impaired finger flexion were 3, 2 and 3, respectively. The 2D time-of-flight micro-MRA was performed on a 3T clinical MRI scanner using a custom-designed finger coil with an in-plane resolution of 0.16 x 0.21 mm(2) and slice thickness of 1.2 mm. The data for the proper palmar digital artery lumen area, the number of visible dorsal digital veins and a semi-quantitative vascular score, which evaluates the overall integrity of digital vessels, were independently evaluated by two experienced reviewers who were blinded to the status of the subject.

RESULTS

Micro-MRA detected significant differences in the digital vasculature between SSc subjects and healthy volunteers. The SSc subjects had a significantly decreased digital artery lumen area (0.13 +/- 0.06 vs 0.53 +/- 0.26 mm(2), P < 0.001), a reduced number of digital veins (0.63 +/- 1.06 vs 3.13 +/- 0.99, P = 0.001) and a lowered overall vascular score (1.75 +/- 1.04 vs 3.5 +/- 0.53, P = 0.001). The study also found that both the digital artery lumen area (Pearson's; r = -0.72, P = 0.044) and vascular scores (Spearman's; rho = -0.75, P = 0.047) of the SSc subjects were inversely correlated with the duration of the disease.

CONCLUSIONS

Micro-MRA can be used to identify and quantitatively characterize the vascular disease in SSc fingers. The parameters derived from micro-MRA could potentially be used as prospective biomarkers for clinical evaluation.

Effect of mycophenolate mofetil on pulmonary function in scleroderma-associated interstitial lung disease

OBJECTIVE

We sought to determine the effectiveness of mycophenolate mofetil (MMF) in scleroderma- associated interstitial lung disease (SSc-ILD).

METHODS

We retrospectively identified patients who met criteria for systemic sclerosis, had evidence of SSc-ILD on chest CT, received > 1 g/d of MMF for >or= 6 months, and had pulmonary function data available. Vital capacity (VC) and diffusion capacity of the lung for carbon monoxide (Dlco) at treatment onset were compared with VC and Dlco values 12 months before and 12 months after treatment onset. Twelve-month values were imputed from regression lines generated using all VC and Dlco measurements made in the 24-month period either prior to or following treatment onset.

RESULTS

Among 13 patients who met inclusion criteria, MMF was associated with a significant improvement in VC (mean, + 159 mL; confidence interval [CI], + 30 to + 289 mL; and + 4% of the predicted normal value; CI, + 2 to + 7%) after 12 months of treatment. In contrast, patients had a significant decrease in VC (mean, - 239 mL; CI, - 477 to - 0.5 mL; and - 5% of the predicted normal value; CI, - 11 to - 0.3%) in the 12 months prior to MMF treatment. Dlco did not change significantly during MMF treatment (mean, + 1% of the predicted normal value; CI, - 2 to + 5%) but decreased significantly in the 12 months prior to treatment (mean, - 5% of the predicted normal value; CI, - 10 to - 1%).

CONCLUSION

These retrospective data suggest MMF improves VC in patients with SSc-ILD.

High-dose immunosuppressive therapy and autologous hematopoietic cell transplantation for severe systemic sclerosis: long-term follow-up of the US multicenter pilot study

More effective therapeutic strategies are required for patients with poor-prognosis systemic sclerosis (SSc). A phase 2 single-arm study of high-dose immunosuppressive therapy (HDIT) and autologous CD34-selected hematopoietic cell transplantation (HCT) was conducted in 34 patients with diffuse cutaneous SSc. HDIT included total body irradiation (800 cGy) with lung shielding, cyclophosphamide (120 mg/kg), and equine antithymocyte globulin (90 mg/kg). Neutrophil and platelet counts were recovered by 9 (range, 7 to 13) and 11 (range, 7 to 25) days after HCT, respectively. Seventeen of 27 (63%) evaluable patients who survived at least 1 year after HDIT had sustained responses at a median follow-up of 4 (range, 1 to 8) years. There was a major improvement in skin (modified Rodnan skin score, -22.08; P < .001) and overall function (modified Health Assessment Questionnaire Disability Index, -1.03; P < .001) at final evaluation. Importantly, for the first time, biopsies confirmed a statistically significant decrease of dermal fibrosis compared with baseline (P < .001). Lung, heart, and kidney function, in general, remained clinically stable. There were 12 deaths during the study (transplantation-related, 8; SSc-related, 4). The estimated progression-free survival was 64% at 5 years. Sustained responses including a decrease in dermal fibrosis were observed exceeding those previously reported with other therapies. HDIT and autologous HCT for SSc should be evaluated in a randomized clinical trial.

Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis

BACKGROUND

Glucosamine and chondroitin sulfate are used to treat osteoarthritis. The multicenter, double-blind, placebo- and celecoxib-controlled Glucosamine/chondroitin Arthritis Intervention Trial (GAIT) evaluated their efficacy and safety as a treatment for knee pain from osteoarthritis.

METHODS

We randomly assigned 1583 patients with symptomatic knee osteoarthritis to receive 1500 mg of glucosamine daily, 1200 mg of chondroitin sulfate daily, both glucosamine and chondroitin sulfate, 200 mg of celecoxib daily, or placebo for 24 weeks. Up to 4000 mg of acetaminophen daily was allowed as rescue analgesia. Assignment was stratified according to the severity of knee pain (mild [N=1229] vs. moderate to severe [N=354]). The primary outcome measure was a 20 percent decrease in knee pain from baseline to week 24.

RESULTS

The mean age of the patients was 59 years, and 64 percent were women. Overall, glucosamine and chondroitin sulfate were not significantly better than placebo in reducing knee pain by 20 percent. As compared with the rate of response to placebo (60.1 percent), the rate of response to glucosamine was 3.9 percentage points higher (P=0.30), the rate of response to chondroitin sulfate was 5.3 percentage points higher (P=0.17), and the rate of response to combined treatment was 6.5 percentage points higher (P=0.09). The rate of response in the celecoxib control group was 10.0 percentage points higher than that in the placebo control group (P=0.008). For patients with moderate-to-severe pain at baseline, the rate of response was significantly higher with combined therapy than with placebo (79.2 percent vs. 54.3 percent, P=0.002). Adverse events were mild, infrequent, and evenly distributed among the groups.

CONCLUSIONS

Glucosamine and chondroitin sulfate alone or in combination did not reduce pain effectively in the overall group of patients with osteoarthritis of the knee. Exploratory analyses suggest that the combination of glucosamine and chondroitin sulfate may be effective in the subgroup of patients with moderate-to-severe knee pain. (ClinicalTrials.gov number, NCT00032890.).

Resolution of Hypertensive Encephalopathy and Scleroderma Renal Crisis With an Angiotensin Receptor Blocker

The use of an angiotensin II type-1 receptor blocker for scleroderma renal crisis is controversial. We describe a 46-year-old woman presenting with a seizure secondary to hypertensive encephalopathy as the initial manifestation of scleroderma renal crisis. She had complete resolution of end organ damage with use of an angiotensin II type-1 receptor blocker. There may be a role for angiotensin II type-1 receptor blockers in the setting of scleroderma renal crisis with central nervous system involvement.

Transcript array analysis in rheumatology

Transcript array analysis is a novel technique that examines the expression of thousands of genes simultaneously. Transcript array analyses are being used to clarify the diagnosis and prognosis of malignancies, and to understand the underlying pathogenesis of complex human disorders such as the rheumatic diseases. In this review, the authors will outline the use of transcript arrays to simultaneously assess gene activation of hundreds or thousands of genes, and their potential use in understanding and managing rheumatic disorders. The authors focus on the use of transcript arrays to confirm and refine disease diagnoses, to generate new hypotheses regarding pathophysiology of rheumatic diseases, and to the possible profiling of patients with respect to their likely response to therapies.

Human T-cell leukemia virus type I Tax induces expression of the Rel-related family of kappa B enhancer-binding proteins: evidence for a pretranslational component of regulation

The Tax protein of the human T-cell leukemia virus type I (HTLV-I) serves as a potent transcriptional activator of its own long terminal repeat as well as select cellular genes, including interleukin-2 and the alpha subunit of the interleukin-2 receptor. Tax activation of these two growth-related genes appears to involve the induced nuclear expression of DNA-binding proteins that specifically engage related kappa B enhancer elements present in the 5' regulatory regions of these genes. In human T cells, kappa B enhancer-binding activity has been discerned as an unexpectedly large family of UV cross-linked nucleoprotein adducts, termed p50, p55, p75, and p85. The protein components of each of these DNA-protein adducts have been shown to share structural similarity with the v-rel oncogene product. The p55 adduct is composed of the 50-kDa subunit of NF-kappa B derived from a 105-kDa precursor polypeptide, while the p50 adduct contains a smaller protein that is closely related to NF-kappa B p50. The p75 adduct contains the 65-kDa subunit of NF-kappa B, while the p85 adduct is composed of the human c-rel proto-oncogene product. We now demonstrate that HTLV-I Tax, in the absence of other viral pX gene products, is capable of inducing the nuclear expression of all four of these kappa B-binding proteins in human T cells, with most marked effects involving c-Rel and NF-kappa B p65. Tax induction of the nuclear expression of c-Rel and NF-kappa B p50 is regulated, at least in part, at a pretranslational level involving increases in c-rel and NF-kappa B p105 mRNA expression. To study the pattern of expression of these kappa B-specific proteins in cells infected with the whole HTLV-I, seven cloned HTLV-I-infected T-cell lines were established from the peripheral blood of patients with adult T-cell leukemia. Of note, only three of these seven cell lines produced Tax, and c-rel mRNA and nuclear protein expression was confined to these three cell lines. In contrast, NF-kappa B p50 and NF-kappa B p65 were constitutively expressed in the nuclei of all seven of the HTLV-I-infected cell lines, even in the absence of detectable Tax or other viral gene expression. These findings raise the possibility of an alternate, Tax-independent pathway for the induced nuclear expression of NF-kappa B p50 and NF-kappa B p65 following HTLV-I infection.

Kappa B-specific DNA binding proteins are differentially inhibited by enhancer mutations and biological oxidation

Kappa B (kappa B) enhancer binding proteins isolated from the nuclei of activated human T cells produce two distinct nucleoprotein complexes when incubated with the kappa B element from the interleukin-2 receptor-alpha (IL-2R alpha) gene. These two DNA-protein complexes are composed of at least four host proteins (p50, p55, p75, p85), each of which shares structural similarity with the v-rel oncogene product. Nuclear expression of these proteins is induced with distinctly biphasic kinetics following phorbol ester activation of T cells (p55/p75 early and p50/p85 late). DNA-protein crosslinking studies have revealed that the more rapidly migrating B2 complex contains both p50 and p55 while the more slowly migrating B1 complex is composed of p50, p55, p75, and p85. Site-directed mutagenesis of the wild-type IL-2R alpha kappa B enhancer (GGGGAATCTCCC) has revealed that the binding of p50 and p55 (B2 complex) is particularly sensitive to alteration of the 5' triplet of deoxyguanosine residues. In contrast, formation of the B1 complex, reflecting the binding of p75 and p85, critically depends upon the more 3' sequences of this enhancer element. DNA binding by all four of these Rel-related factors is blocked by selective chemical modification of lysine and arginine residues, suggesting that both of these basic amino acids are required for binding to the kappa B element. Similarly, covalent modification of free sulfhydryl groups with diamide (reversible) or N-ethylmaleimide (irreversible) results in a complete loss of DNA binding activity. In contrast, mild oxidation with glucose oxidase selectively inhibits p75 and p85 binding while not blocking p50 and p55 interactions. These findings suggest that reduced cysteine thiols play an important role in the DNA binding activity of this family of Rel-related transcription factors.

NF-kappa B: a family of inducible and differentially expressed enhancer-binding proteins in human T cells

A sensitive DNA-protein crosslinking approach has been used to characterize four inducible T-cell proteins (50 kDa, 55 kDa, 75 kDa, and 85 kDa) that specifically bind to kappa B enhancer elements. Partial proteolytic mapping revealed a distinct cleavage pattern for three of these proteins. These polypeptides are sequestered as inactive precursors in the cytosol of unstimulated T cells but can be converted into active forms in vivo by phorbol ester stimulation or in vitro by detergent treatment. The induction of these proteins by phorbol ester results in a strikingly biphasic pattern of nuclear expression with the 55-kDa and 75-kDa species appearing within minutes, whereas the 50-kDa and 85-kDa species appear only several hours after cellular stimulation. These data suggest that NF-kappa B-binding activity may not correspond to a single polypeptide but rather a family of at least four inducible and differentially regulated DNA-binding proteins that are expressed with distinct kinetics in human T lymphocytes.

The v-rel oncogene encodes a kappa B enhancer binding protein that inhibits NF-kappa B function

Studies of NF-kappa B suggest that this enhancer binding activity corresponds to a family of at least four proteins (p50, p55, p75, and p85) differentially induced with biphasic kinetics during T cell activation. While p55 and p50 are closely related to the 50 kd DNA binding subunit of NF-kappa B, p75 and p85 exhibit DNA binding properties that distinguish them from this 50 kd polypeptide and its regulatory subunits I kappa B and p65. All four members of this kappa B-specific protein family are structurally related to the v-Rel oncoprotein and one, p85, appears identical to human c-Rel. v-Rel, but not nontransforming v-Rel mutants, binds to the kappa B enhancer and inhibits NF-kappa B-activated transcription from the IL-2 receptor alpha promoter and HIV-1 LTR. These findings suggest a Rel-related family of kappa B enhancer binding proteins and raise the possibility that the transforming activity of v-Rel is linked to its inhibitory action on cellular genes under NF-kappa B control.