Planning Target Volume Margin Quantification of Retroperitoneal Tumors Using Robotic Stereotactic Body Radiotherapy with Spine Tracking

PURPOSE/OBJECTIVE(S)

Stereotactic body radiotherapy treatment (SBRT) is an effective modality for treating primary and oligometastatic malignant lesions. Appropriate planning target volume (PTV) margins are essential when delivering SBRT to maximize target prescription coverage while minimizing dose to surrounding organs-at-risk. Spine tracking uses boney spinal anatomy as a surrogate for tumor localization during treatment delivery on robotic linear accelerator platforms that employ intrafraction kV x-ray imaging. The aim of this study was to quantify the PTV margin needed when spine tracking was used for tumor localization when treating retroperitoneal metastatic lesions with robotic SBRT.

MATERIALS/METHODS

A single institution chart review was performed and identified 16 patients with retroperitoneal tumors treated stereotactically over 19 courses in 103 fractions. Daily cone-beam computed tomography (CBCT) images that were registered based on tumor position at the time of treatment were analyzed. Rigid registrations were re-performed aligning the position of the spine on the CBCT relative to its position on the planning CT. Shifts from the treatment position were recorded and per-patient mean shifts and standard deviations were calculated. Van Herk's margin recipe was used to determine the additional PTV margin required if spine tracking was used instead of soft tissue alignment. Patient tumors were stratified and compared based on proximity to the vertebral column (≤1 cm vs >1 cm) and location within the retroperitoneum (superior vs inferior to the renal artery). Student's t-test was used to compare statistical differences of shifts based on location.

RESULTS

The additional margins calculated by van Herk's margin recipe to adequately cover the target volumes within the 95% isodose surface for 90% of the entire patient cohort in the vertical, longitudinal, and lateral directions were 2.7, 2.8, and 2.8 mm, respectively. When tumors were stratified by proximity to the vertebral column, average longitudinal (p<0.001) and total shifts (p<0.001) were statistically significant. Isometric PTV expansions of 3, 4, and 5 mm would have encompassed 55%, 76%, and 86% of the maximum total shifts for lesions >1 cm from the vertebral column versus 94%, 100%, and 100% for lesions ≤1 cm. When stratified by location within the retroperitoneum, isometric PTV expansions of 3, 4, and 5 mm would have encompassed 82%, 94%, and 100% of the maximum total shifts for lesions superior to the renal artery versus 78%, 94%, and 98% for lesions inferior to the renal artery.

CONCLUSION

When treating retroperitoneal tumors with robotic SBRT, a minimum isometric margin expansion between 3 to 5 mm when creating the PTV is recommended if spine tracking is used for intrafraction tumor localization. Target volumes adjacent to the vertebral column may have PTV margins decreased to ≤4 mm without compromising target coverage.

Modular gene analysis reveals distinct molecular signatures for subsets of patients with cutaneous lupus erythematosus

BACKGROUND

Cutaneous lupus erythematosus (CLE) is a heterogeneous autoimmune disease with clinical sequelae such as itching, dyspigmentation and scarring.

OBJECTIVES

We applied a previously described modular analysis approach to assess the molecular heterogeneity of patients with CLE.

METHODS

Whole-blood transcriptomes of RNA sequencing data from a racially and ethnically diverse group of patients with CLE (n = 62) were used to calculate gene co-expression module scores. An unsupervised cluster analysis and k-means clustering based on these module scores were then performed. We used Fisher's exact tests and Kruskal-Wallis tests to compare characteristics between patient clusters.

RESULTS

Six unique clusters of patients with CLE were identified from the cluster analysis. We observed that seven inflammation modules were elevated in two clusters of patients with CLE. Additionally, these clusters were characterized by interferon, neutrophil and cell-death signatures, suggesting that interferon-related proteins, neutrophils and cell-death processes could be driving the inflammatory response in these subgroups. Three different clusters had a predominant T-cell signature, which were supported by lymphocyte counts.

CONCLUSIONS

Our data support a diverse molecular profile in CLE that further adds to the clinical variations of this skin disease, and may affect disease course and treatment selection. Future studies with a larger and diverse cohort of patients with CLE are warranted to confirm these findings.

Validation of a Metastatic Assay using biopsies to improve risk stratification in patients with prostate cancer treated with radical radiation therapy

Background

Radiotherapy is an effective treatment of intermediate/high-risk locally advanced prostate cancer, however, >30% of patients relapse within 5 years. Clinicopathological parameters currently fail to identify patients prone to systemic relapse and those whom treatment intensification may be beneficial. The purpose of this study was to independently validate the performance of a 70-gene Metastatic Assay in a cohort of diagnostic biopsies from patients treated with radical radiotherapy and androgen deprivation therapy.

Patients and methods

A bridging cohort of prostate cancer diagnostic biopsy specimens was profiled to enable optimization of the Metastatic Assay threshold before further independent clinical validation in a cohort of diagnostic biopsies from patients treated with radical radiotherapy and androgen deprivation therapy. Multivariable Cox proportional hazard regression analysis was used to assess assay performance in predicting biochemical failure-free survival (BFFS) and metastasis-free survival (MFS).

Results

Gene expression analysis was carried out in 248 patients from the independent validation cohort and the Metastatic Assay applied. Ten-year MFS was 72% for Metastatic Assay positive patients and 94% for Metastatic Assay negative patients [HR = 3.21 (1.35–7.67); P = 0.003]. On multivariable analysis the Metastatic Assay remained predictive for development of distant metastases [HR = 2.71 (1.11–6.63); P = 0.030]. The assay retained independent prognostic performance for MFS when assessed with the Cancer of the Prostate Assessment Score (CAPRA) [HR = 3.23 (1.22–8.59); P = 0.019] whilst CAPRA itself was not significant [HR = 1.88, (0.52–6.77); P = 0.332]. A high concordance [100% (61.5–100)] for the assay result was noted between two separate foci taken from 11 tumours, whilst Gleason score had low concordance.

Conclusions

The Metastatic Assay demonstrated significant prognostic performance in patients treated with radical radiotherapy both alone and independent of standard clinical and pathological variables. The Metastatic Assay could have clinical utility when deciding upon treatment intensification in high-risk patients. Genomic and clinical data are available as a public resource.

Screening characteristics for enrichment of individuals at higher risk for transitioning to classified SLE

OBJECTIVE

Further prospective study is needed to elucidate the etiology and natural history of systemic lupus erythematosus development. The clinical complexity of this heterogeneous disease makes study design challenging. Our objective was to ascertain useful screening factors for identifying at-risk individuals for follow-up rheumatologic assessment or inclusion in prospective studies.

METHODS

We attempted to re-contact 3823 subjects with a family history of systemic lupus erythematosus, who did not meet American College of Rheumatology systemic lupus erythematosus classification at a baseline study visit; 436 agreed to follow-up participation an average of 6.3 years after baseline. In total, 56 of these individuals had transitioned to classified systemic lupus erythematosus (≥ 4 cumulative American College of Rheumatology criteria, verified by medical record review) by the time of follow up. Generalized estimating equations assessed associations between our dichotomous outcome of transitioning to systemic lupus erythematosus with baseline characteristics, including ANA positivity, Connective Tissue Disease Screening questionnaire systemic lupus erythematosus score, and number of American College of Rheumatology criteria. We analyzed predictive accuracy of characteristics on transitioning.

RESULTS

ANA positivity, Connective Tissue Disease Screening questionnaire systemic lupus erythematosus score categorization of possible or probable systemic lupus erythematosus, and greater number of American College of Rheumatology criteria at baseline were each associated with transitioning to systemic lupus erythematosus classification. Being ANA positive and having confirmed immunologic criteria at baseline had the highest positive predictive value and specificity for transitioning to systemic lupus erythematosus. American College of Rheumatology Connective Tissue Disease Screening questionnaire systemic lupus erythematosus score categorization of possible or probable systemic lupus erythematosus had a better positive predictive value, negative predictive value, sensitivity, and specificity than ANA positivity.

CONCLUSION

Given limited resources, identifying individuals for follow up based on the systemic lupus erythematosus portion of the Connective Tissue Disease Screening questionnaire could be an efficient way to identify family members at highest risk of disease transition.

Climate research priorities for policy-makers, practitioners, and scientists in Georgia, USA

Climate change has far-reaching effects on human and ecological systems, requiring collaboration across sectors and disciplines to determine effective responses. To inform regional responses to climate change, decision-makers need credible and relevant information representing a wide swath of knowledge and perspectives. The southeastern U. S. State of Georgia is a valuable focal area for study because it contains multiple ecological zones that vary greatly in land use and economic activities, and it is vulnerable to diverse climate change impacts. We identified 40 important research questions that, if answered, could lay the groundwork for effective, science-based climate action in Georgia. Top research priorities were identified through a broad solicitation of candidate research questions (180 were received). A group of experts across sectors and disciplines gathered for a workshop to categorize, prioritize, and filter the candidate questions, identify missing topics, and rewrite questions. Participants then collectively chose the 40 most important questions. This cross-sectoral effort ensured the inclusion of a diversity of topics and questions (e.g., coastal hazards, agricultural production, ecosystem functioning, urban infrastructure, and human health) likely to be important to Georgia policy-makers, practitioners, and scientists. Several cross-cutting themes emerged, including the need for long-term data collection and consideration of at-risk Georgia citizens and communities. Workshop participants defined effective responses as those that take economic cost, environmental impacts, and social justice into consideration. Our research highlights the importance of collaborators across disciplines and sectors, and discussing challenges and opportunities that will require transdisciplinary solutions.

Less than 7 hours of sleep per night is associated with transitioning to systemic lupus erythematosus

Background The role of sleep in the etiology of systemic lupus erythematosus (SLE) has not been well studied. We examined whether sleep duration was associated with subsequent transitioning to SLE in individuals at risk for SLE. Methods Four hundred and thirty-six relatives of SLE patients who did not have SLE themselves at baseline were evaluated again an average of 6.3 (± 3.9) years later. Fifty-six individuals transitioned to SLE (≥ 4 cumulative American College of Rheumatology (ACR) criteria). Sleep duration, medication use and medical history were assessed by questionnaire; ACR criteria were confirmed by medical record review. Vitamin D was measured by ELISA. Generalized estimating equations, accounting for correlation within families, assessed associations between baseline sleep and the outcome of transitioning to SLE. Results Reporting sleeping less than 7 hours per night at baseline was more common in those who subsequently transitioned than those who did not transition to SLE (55% versus 32%, p = 0.0005; OR: 2.8, 95% CI 1.6-4.9). Those who transitioned to SLE were more likely to sleep less than 7 hours per night than those who did not transition to SLE adjusting for age, sex and race (OR: 2.8, 95% CI 1.6-5.1). This association remained after individual adjustment for conditions and early symptoms that could affect sleep, including prednisone use, vitamin D deficiency and number of ACR criteria (OR: 2.0, 95% CI 1.1-4.2). Conclusion Lack of sleep may be associated with transitioning to SLE, independent of early clinical manifestations of SLE that may influence sleep duration. Further evaluation of sleeping patterns and biomarkers in at-risk individuals is warranted.

Impacts of Combined Cooling, Heating and Power Systems, and Rainwater Harvesting on Water Demand, Carbon Dioxide, and NOx Emissions for Atlanta

The purpose of this study is to explore the potential water, CO₂ and NO_x emission, and cost savings that the deployment of decentralized water and energy technologies within two urban growth scenarios can achieve. We assess the effectiveness of urban growth, technological, and political strategies to reduce these burdens in the 13-county Atlanta metropolitan region. The urban growth between 2005 and 2030 was modeled for a business as usual (BAU) scenario and a more compact growth (MCG) scenario. We considered combined cooling, heating and power (CCHP) systems using microturbines for our decentralized energy technology and rooftop rainwater harvesting and low flow fixtures for the decentralized water technologies. Decentralized water and energy technologies had more of an impact in reducing the CO₂ and NO_x emissions and water withdrawal and consumption than an MCG growth scenario (which does not consider energy for transit). Decentralized energy can reduce the CO₂ and NO_x emissions by 8% and 63%, respectively. Decentralized energy and water technologies can reduce the water withdrawal and consumption in the MCG scenario by 49% and 50% respectively. Installing CCHP systems on both the existing and new building stocks with a net metering policy could reduce the CO₂, NO_x, and water consumption by 50%, 90%, and 75% respectively.

The curiously suspicious: a role for Epstein-Barr virus in lupus

While the events initiating the development of autoantibodies in systemic lupus erythematosus (SLE) have not yet been convincingly established, newly developed tools for molecular investigation make such an undertaking increasingly practical. Applied to the earliest events in the sequence culminating in lupus autoimmunity, we present a critical potential role for Epstein-Barr virus (EBV) in the development and perhaps perpetuation of SLE. The expected properties for an environmental risk factor for SLE are found in this virus and the human host response against it. Existing data show the molecular progression to autoimmunity observed in SLE patient sera, the discovery of the first autoimmune epitopes in the Sm and Ro autoantigen systems, and the possible emergence of these autoantibodies from the heterologous antibodies against Epstein-Barr nuclear antigen-1 (EBNA-1). Further, existing data demonstrate association of SLE with EBV infection, even preceding the development of autoimmunity. Finally, the data are consistent with a proposed model of lupus pathogenesis that begins with antibodies to EBNA-1, predisposing to immune responses that develop crossreactive autoantibodies that culminate in the development of SLE autoimmunity.

Genetic association of CD247 (CD3ζ) with SLE in a large-scale multiethnic study

A classic T-cell phenotype in systemic lupus erythematosus (SLE) is the downregulation and replacement of the CD3ζ chain that alters T-cell receptor signaling. However, genetic associations with SLE in the human CD247 locus that encodes CD3ζ are not well established and require replication in independent cohorts. Our aim was therefore to examine, localize and validate CD247-SLE association in a large multiethnic population. We typed 44 contiguous CD247 single-nucleotide polymorphisms (SNPs) in 8922 SLE patients and 8077 controls from four ethnically distinct populations. The strongest associations were found in the Asian population (11 SNPs in intron 1, 4.99 × 10(-4) < P < 4.15 × 10(-2)), where we further identified a five-marker haplotype (rs12141731-rs2949655-rs16859085-rs12144621-rs858554; G-G-A-G-A; P(hap) = 2.12 × 10(-5)) that exceeded the most associated single SNP rs858554 (minor allele frequency in controls = 13%; P = 4.99 × 10(-4), odds ratio = 1.32) in significance. Imputation and subsequent association analysis showed evidence of association (P < 0.05) at 27 additional SNPs within intron 1. Cross-ethnic meta-analysis, assuming an additive genetic model adjusted for population proportions, showed five SNPs with significant P-values (1.40 × 10(-3) < P< 3.97 × 10(-2)), with one (rs704848) remaining significant after Bonferroni correction (P(meta) = 2.66 × 10(-2)). Our study independently confirms and extends the association of SLE with CD247, which is shared by various autoimmune disorders and supports a common T-cell-mediated mechanism.

Smoking is not associated with autoantibody production in systemic lupus erythematosus patients, unaffected first-degree relatives, nor healthy controls

OBJECTIVE

The objective of this paper is to examine whether smoking is associated with autoantibody production in systemic lupus erythematosus (SLE) patients, unaffected first-degree relatives (FDR) of individuals with SLE--a group at increased risk of developing SLE--or unaffected, unrelated controls.

METHODS

Detailed demographic, environmental, clinical, and therapeutic information was collected by questionnaire on 1242 SLE patients, 981 FDRs, and 946 controls in the Lupus Family Registry and Repository; a blood sample was obtained. All sera were tested for multiple lupus autoantibodies by immunofluorescence and luminex bead-based assays. Generalized estimating equations, adjusting for age, gender, and ethnicity and accounting for correlation within families, were used to assess smoking status with the dichotomous outcome variables of positivity for SLE status, positivity of ANA by immunofluorescence (≥1:120), positivity for ≥1 autoantibody by the luminex assay, and positivity for each of the 11 autoantibodies.

RESULTS

Current smoking was associated with being positive for ≥1 autoantibody (excluding ANA) (adjusted OR = 1.53, 95% CI 1.04-2.24) in our subjects with SLE. No association was observed in unaffected FDRs or healthy controls. Former smoking was associated with anti-Ro/SS-A60 in our unaffected FDRs. There was an increased association with anti-nRNP A seropositivity, as well as a decreased association with anti-nRNP 68 positivity, in current smokers in SLE subjects.

CONCLUSIONS

No clear association between smoking status and individual autoantibodies was detected in SLE patients, unaffected FDRs, nor healthy controls within this collection. The association of smoking with SLE may therefore manifest its risk through mechanisms outside of autoantibody production, at least for the specificities tested.

Patients' satisfaction with the healthcare services at a north central Nigerian tertiary hospital

BACKGROUND

This study sought to determine the level of satisfaction of patients with the healthcare services at Federal Medical Centre, Bida (FMCB) Nigeria and the factors associated with patients' satisfaction.

METHODS

The study utilized exit interview of 480 patients, sampled at the 9 service points of the Centre. The questions covered socio-demographic factors and the 3 core elements of healthcare service delivery namely quality, access and interpersonal issues. The evaluation of satisfaction on the 5 point Likert scale were categorized into dissatisfied {very dissatisfied, dissatisfied and Neutral} and satisfied {satisfied and very satisfied}, setting the threshold for satisfaction at a relatively higher level.

RESULTS

On the overall, 78.5% of them were satisfied with the hospital services and 78.3% had their expectations met. Satisfaction was lowest (72.7%) at the revenue section and highest (96.1%) at the maternity section. Nine of every 10 respondents (91.7%) would recommend the facility to a friend. The patients' satisfaction had significant positive correlation with promptness of staff, communication level of staff, staff relationship with patients, environmental cleanliness and comfort facilities. Cost of services and delay in obtaining services had negative but relatively weak correlation with satisfaction.

CONCLUSION

The observed level of patients' satisfaction at FMC Bida is high. This can be maintained and enhanced by improvement in waiting time, sustenance of the satisfactory hospital ambiance and staff attitude/aptitude. However, enlightenment of the hospital patients on the status of the hospital and the nature of services offered is necessary.

Deep calf cavernous haemangioma in a 10 year- old girl: a case report

Haemangiomas are abnormal proliferation of blood vessels in any vascularised tissue. They can be capillary or cavernous varieties. Cavernous are either of cutaneous or deep types. Cavernous when compared with the capillary haemangioma is rare. Rarer still is the deep type of cavernous haemangioma. This is a report of a 10 year old Nigerian girl who presented with a right posterior leg swelling of 8 year duration, size initially was that of a peanut but increased to fill the entire calf region causing pain to the patient as well as cosmetic and anxiety concern to the parents. No preceding history of trauma, no associated systematic symptoms. She had exploratory laparatomy at 1 year of age at a private hospital for an abdominal mass which was excised. Pre-operative plain radiograph, Magnetic Resonance Imaging(MRI), Abdominopelvic ultrasound scan (USS) were done, fine needle aspiration cytology (FNAC) though done was not helpful. Histo-pathology result of excised leg mass confirmed diagnosis; there was a free margin of excision. Post-operatively, clinical improvement was marked.

Common viruses associated with lower pediatric multiple sclerosis risk

BACKGROUND

Because common viruses are encountered during childhood, pediatric multiple sclerosis (MS) offers a unique opportunity to investigate the influence of these viruses on disease susceptibility and the interactions between seroprevalence and select HLA genotypes. We studied seroprevalence for Epstein-Barr virus (EBV), cytomegalovirus (CMV), and herpes simplex virus (HSV) type 1 and HLA-DRB1*1501/1503 status as predictors of pediatric MS.

METHODS

This was a retrospective analysis of prospectively collected demographic, clinical, and biologic data in subjects up to 18 years of age with early MS, control subjects seen at the same regional referral pediatric MS clinics, and additional healthy pediatric control subjects.

RESULTS

Patients with early pediatric MS (n=189) and pediatric control subjects (n=66) were tested. Epstein-Barr nuclear antigen-1 seropositivity was associated with an increased odds of MS (odds ratio [OR] 3.78, 95% confidence interval [CI] 1.52-9.38, p=0.004) in analyses adjusted for age, sex, race, ethnicity, and HLA-DRB1*1501/1503 status. In multivariate analyses including EBV status, a remote infection with CMV (OR 0.27, 95% CI 0.11-0.67, p=0.004) was associated with a lower risk of developing MS. Although a remote infection with HSV-1 was not associated with an increased odds of MS, a strong interaction was found between HSV-1 status and HLA-DRB1 in predicting MS (p<0.001). HSV-1 was associated with an increased risk of MS in those without a DRB1*15 allele (OR 4.11, 95% CI 1.17-14.37, p=0.03), whereas the effect was reversed in those who were DRB1*15-positive (OR 0.07, 95% CI 0.02-0.32, p=0.001).

CONCLUSIONS

These findings suggest that some infections with common viruses may in fact lower MS susceptibility. If this is confirmed, the pathways for risk modification remain to be elucidated.

Epstein-Barr virus nuclear antigen-1 B-cell epitopes in multiple sclerosis twins

BACKGROUND

Compared with quantitative observations, the search for qualitative changes that may characterize the immune response to Epstein-Barr virus (EBV) in multiple sclerosis (MS) has been less intense.

OBJECTIVE

To examine the B-cell epitopes of antibodies against the Epstein-Barr nuclear antigen-1 (EBNA-1) and their relevance for MS, through a study in disease-discordant identical twins.

METHODS

We evaluated the antibodies to all unique, maximally overlapping octapeptides of EBNA-1 in 12 pairs of monozygotic (MZ) twins (9 MS-discordant, 3 healthy), 3 non-twin patients and 2 healthy subjects. All except one of the patients were untreated. The EBV serology of these individuals had been assessed in advance using commercially available and in-house enzyme-linked immunosorbent assay (ELISA) kits, including assays for antibodies against select peptides of EBNA-1: EBNA-72 (GAGGGAGAGG) and EBNA-206 (EADYFEYHQEGGPDGE).

RESULTS

The glycine-alanine rich domain of EBNA-1 was immunodominant in all subjects. Compared with healthy individuals, and similarly to what has been described in infectious mononucleosis (IM) patients, affected co-twins and non-twin patients had a significantly increased response to another EBNA-1 epitope (aa. 401-411).

CONCLUSION

In a study that controls for confounders, our data focus an EBNA-1 specificity that may be associated with MS pathogenesis.

Epitope specificity of myeloperoxidase antibodies: identification of candidate human immunodominant epitopes

Anti-neutrophil cytoplasmic autoantibodies (ANCA) are a common feature of systemic vasculitides and have been classified as autoimmune conditions based, in part, on these autoantibodies. ANCA are subdivided further based on their primary target: cytoplasm (c-ANCA) or perinuclear region (p-ANCA). p-ANCAs commonly target myeloperoxidase (MPO), an enzyme with microbicidal and degradative activity. MPO antibodies are non-specific for any single disease and found in a variety of vasculitides, most commonly microscopic polyangiitis. Despite their prevalence, their role in human disease pathogenesis remains undefined. We sought to characterize the sequential antigenic determinants of MPO in vasculitis patients with p-ANCA. Of 68 patients with significant levels of p-ANCA, 12 have significant levels of MPO antibodies and were selected for fine specificity epitope mapping. Sequential antigenic targets, including those containing amino acids (aa) 213-222 (WTPGVKRNGF) and aa 511-522 (RLDNRYQPMEPN), were commonly targeted with a prevalence ranging from 33% to 58%. Subsequent analysis of autoantibody binding to the RLDNRYQPMEPN peptide was assessed using a confirmatory enzyme-linked immunosorbent assay format, with six patients displaying significant binding using this method. Antibodies against this epitope, along with four others (aa 393-402, aa 437-446, aa 479-488 and aa 717-726), were reactive to the heavy chain structure of the MPO protein. One epitope, GSASPMELLS (aa 91-100), was within the pro-peptide structure of MPO. B cell epitope prediction algorithms identified all or part of the seven epitopes defined. These results provide major common human anti-MPO immunodominant antigenic targets which can be used to examine further the potential pathogenic mechanisms for these autoantibodies.

Anti-neutrophil cytoplasmic antibodies target sequential functional proteinase 3 epitopes in the sera of patients with Wegener’s granulomatosis

Many patients with Wegener’s granulomatosis (WG) have anti-neutrophil cytoplasmic antibodies (c-ANCA). Aside from being a diagnostic marker, these autoantibodies may play roles in disease pathogenesis. Proteinase 3 (PR3) is the primary target of c-ANCA in WG patient sera. Of 60 c-ANCA-positive patients, 10 patients were selected for detailed humoral epitope analysis, contingent upon serum availability, using samples with positive levels of anti-PR3 by enzyme-linked immunosorbent assay (ELISA). Sequential epitope specificities of anti-PR3 antibodies detected by screening the maximally overlapping solid-phase octapeptides of PR3 showed seven major common antigenic targets bound by WG patient sera. These include novel and previously identified sequential PR3 epitopes bound by c-ANCA. B cell epitope prediction algorithms identified all or part of the seven defined epitopes. Several epitopes share sequence and structural proximity with functional sites, including the catalytic triad and proposed binding sites of other potential proteins [PR3 complementary peptide and soluble endothelial protein C receptor (sEPCR)]. Epitope 4 (VVLGAHNVRTQ) had the highest binding prevalence (90%) and epitope 2 (AQPHSRPYMAS) has the highest average reactivity of the antigenic regions. Epitope 4 includes the interaction site between sEPCR and PR3 which may serve as an important interaction to down-regulate inflammation. Epitopes 3, 5 and 7 are in direct proximity to amino acids that form the catalytic triad of the protein. c-ANCA targets both unique and previously known sequential PR3 peptides. This information may prove useful in understanding anti-PR3-mediated disease pathogenesis in systemic vasculitides.

Studies of Filipino patients with systemic lupus erythematosus: autoantibody profile of first-degree relatives

This study surveyed the frequency of autoantibodies among un-affected first-degree relatives (FDRs) of Filipino systemic lupus erythematosus (SLE) patients compared with healthy un-related Filipino controls. The sensitivity, specificity and predictive value of the autoantibodies for SLE diagnosis were also assessed in this Filipino cohort. Filipino patients included in the University of Santo Tomas (UST) Lupus Database and un-affected FDRs were recruited. Healthy controls included those with no known personal or family history of autoimmune disease. The following autoantibodies were tested in all subjects: anti-nuclear antibody (ANA), anti-dsDNA, anti-Ro/SSA, anti-chromatin, anti-thyroid microsome, and anti-cardiolipin antibodies. Participants included 232 SLE patients, 546 FDRs, and 221 healthy controls. Median age of patients was 27 (range 8-66) years with median disease duration of 27.5 (range 1-292) months. Median age of FDRs was 42.0 (range 5-87) years. Compared with healthy controls, there were significantly more FDRs with positive ANA at titers 1 : 40 to 1 : 160 (p < 0.001) and 1 : 320 (p = 0.003), anti-Ro/SSA (4.94% versus 0.45%, p = 0.003), and anti-dsDNA ≥ 5.0 IU/ml (4.58% versus 1.36%, p = 0.031). ANA titer ≥1  :  160, anti-dsDNA, anti-Ro/SSA and anti-chromatin had the highest predictive value for SLE diagnosis. These findings reinforce the role of genetic influence in SLE risk among Filipinos, with a significant proportion of un-affected FDRs of SLE patients testing positive for autoantibodies compared with healthy Filipino controls. A longitudinal observational study in this same cohort will determine which proportion of these un-affected FDRs will evolve into clinical SLE disease in the future.

Complement receptor 2 polymorphisms associated with systemic lupus erythematosus modulate alternative splicing

Genetic factors influence susceptibility to systemic lupus erythematosus (SLE). A recent family-based analysis in Caucasian and Chinese populations provided evidence for association of single-nucleotide polymorphisms (SNPs) in the complement receptor 2 (CR2/CD21) gene with SLE. Here we confirmed this result in a case-control analysis of an independent European-derived population including 2084 patients with SLE and 2853 healthy controls. A haplotype formed by the minor alleles of three CR2 SNPs (rs1048971, rs17615, rs4308977) showed significant association with decreased risk of SLE (30.4% in cases vs 32.6% in controls, P=0.016, OR=0.90 (0.82-0.98)). Two of these SNPs are in exon 10, directly 5' of an alternatively spliced exon preferentially expressed in follicular dendritic cells (FDC), and the third is in the alternatively spliced exon. Effects of these SNPs and a fourth SNP in exon 11 (rs17616) on alternative splicing were evaluated. We found that the minor alleles of these SNPs decreased splicing efficiency of exon 11 both in vitro and ex vivo. These findings further implicate CR2 in the pathogenesis of SLE and suggest that CR2 variants alter the maintenance of tolerance and autoantibody production in the secondary lymphoid tissues where B cells and FDCs interact.

Meta-analysis and imputation identifies a 109 kb risk haplotype spanning TNFAIP3 associated with lupus nephritis and hematologic manifestations

TNFAIP3 encodes the ubiquitin-modifying enzyme, A20, a key regulator of inflammatory signaling pathways. We previously reported association between TNFAIP3 variants and systemic lupus erythematosus (SLE). To further localize the risk variant(s), we performed a meta-analysis using genetic data available from two Caucasian case-control datasets (1453 total cases, 3381 total control subjects) and 713 SLE trio families. The best result was found at rs5029939 (P=1.67 x 10(-14), odds ratio=2.09, 95% confidence interval 1.68-2.60). We then imputed single nucleotide polymorphisms (SNPs) from the CEU Phase II HapMap using genotypes from 431 SLE cases and 2155 control subjects. Imputation identified 11 SNPs in addition to three observed SNPs, which together, defined a 109 kb SLE risk segment surrounding TNFAIP3. When evaluating whether the rs5029939 risk allele was associated with SLE clinical manifestations, we observed that heterozygous carriers of the TNFAIP3 risk allele at rs5029939 have a twofold increased risk of developing renal or hematologic manifestations compared to homozygous non-risk subjects. In summary, our study strengthens the genetic evidence that variants in the region of TNFAIP3 influence risk for SLE, particularly in patients with renal and hematologic manifestations, and narrows the risk effect to a 109 kb DNA segment that spans the TNFAIP3 gene.

Genetic associations of LYN with systemic lupus erythematosus

We targeted LYN, a src-tyosine kinase involved in B-cell activation, in case-control association studies using populations of European-American, African-American and Korean subjects. Our combined European-derived population, consisting of 2463 independent cases and 3131 unrelated controls, shows significant association with rs6983130 in a female-only analysis with 2254 cases and 2228 controls (P=1.1 x 10(-4), odds ratio (OR)=0.81 (95% confidence interval: 0.73-0.90)). This single nucleotide polymorphism (SNP) is located in the 5' untranslated region within the first intron near the transcription initiation site of LYN. In addition, SNPs upstream of the first exon also show weak and sporadic association in subsets of the total European-American population. Multivariate logistic regression analysis implicates rs6983130 as a protective factor for systemic lupus erythematosus (SLE) susceptibility when anti-dsDNA, anti-chromatin, anti-52 kDa Ro or anti-Sm autoantibody status were used as covariates. Subset analysis of the European-American female cases by American College of Rheumatology classification criteria shows a reduction in the risk of hematological disorder with rs6983130 compared with cases without hematological disorders (P=1.5 x 10(-3), OR=0.75 (95% CI: 0.62-0.89)). None of the 90 SNPs tested show significant association with SLE in the African American or Korean populations. These results support an association of LYN with European-derived individuals with SLE, especially within autoantibody or clinical subsets.

Patients with familial and sporadic onset SLE have similar clinical profiles but vary profoundly by race

Few large, multi-ethnic studies have examined the clinical and serologic differences between familial and sporadic SLE patients. Understanding these similarities and differences is critical for interpreting genetic studies and developing therapeutic strategies. We compiled information on 1915 patients with SLE in a large multi-racial cohort, including general demographics, pedigree structure and the specific American College of Rheumatology (ACR) criteria met. One patient was randomly selected from each multiplex family for analysis, yielding 554 European-Americans (EA), 373 African-Americans (AA), 193 Hispanics (HI) and 237 patients of other of mixed races. When comparing familial and sporadic patients stratified by race, lupus erythematosus (LE) cells and arthritis were increased in white familial cases ( P = 5.5 × 10−6 and P = 0.028, respectively), but no other significant differences between familial and sporadic patients were found. We found that there were profound differences in clinical profiles between races. For example, photosensitivity and malar rash were decreased in AA ( P = 1.3 × 10−13 and 1.4 × 10−7, respectively), whereas discoid rash was increased in AA ( P = 5.5×10−6). EA had significantly less renal disease ( P = 5.4×10−13), proteinuria ( P = 4 × 10−12) and anti-Sm ( P = 1.7 × 10−12) than AA or HI. We, therefore, conclude that familial and sporadic onset patients may be treated similarly with respect to clinical and genetic studies.

Hydroxychloroquine sulfate treatment is associated with later onset of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a clinically diverse, complex autoimmune disease which may present with coincident onset of many criteria or slow, gradual symptom accrual. Early intervention has been postulated to delay or prevent the development of more serious sequelae. One option for treatment in this setting is hydroxychloroquine. Using 130 US military personnel who later met ACR SLE criteria, a retrospective study of onset, development and progression of SLE with and without pre-classification hydroxychloroquine (n = 26) use was performed. Patients treated with hydroxychloroquine prior to diagnosis had a longer (Wilcoxon signed rank test, P = 0.018) time between the onset of the first clinical symptom and SLE classification (median: 1.08 versus 0.29 years). Patients treated with prednisone before diagnosis also more slowly satisfied the classification criteria (Wilcoxon signed rank test, P = 0.011). The difference in median times between patients who received NSAIDs before diagnosis, as opposed to those who did not, was not different (P = 0.19). Patients treated with hydroxychloroquine also had a lower rate of autoantibody accumulation and a decreased number of autoantibody specificities at and after diagnosis. These findings are consistent with early hydroxychloroquine use being associated with delayed SLE onset. A prospective, blinded trial testing the capacity of hydroxychloroquine to delay or prevent SLE in high risk populations is warranted.

Genetic association of interleukin-21 polymorphisms with systemic lupus erythematosus

OBJECTIVE

The aetiology of systemic lupus erythematosus (SLE) is incompletely understood. Both genetic and environmental factors are implicated in the pathogenesis of the disease. Herein, we describe genetic association between SLE and polymorphisms in the interleukin (IL)-21 gene. The reported effect of IL-21 on B-cell differentiation into plasma cells and its effect on dendritic cell maturation and T-cell responses make IL-21 an attractive candidate gene for SLE.

METHODS

Three single nucleotide polymorphisms (SNPs) in the IL-21 gene were genotyped in a total of 2636 individuals (1318 cases and 1318 controls matched for age, sex and race). Population-based case-control association analyses were performed.

RESULTS

We found a genetic association with SLE and two SNPs located within the IL-21 gene (rs907715: chi(2) = 11.55, p<0.001; rs2221903: chi(2) = 5.49, p = 0.019). Furthermore, genotypes homozygous for the risk alleles were more frequent than genotypes homozygous for the non-risk alleles in European-American patients as compared to controls (rs907715 (GG versus AA): odds ratio (OR) = 1.66, p = 0.0049; rs2221903 (GG versus AA): OR = 1.60, p = 0.025).

CONCLUSION

Our findings indicate that IL-21 polymorphism is a candidate association with SLE. The functional effects of this association, when revealed, might improve our understanding of the disease and provide new therapeutic targets.

Familial aggregation and linkage analysis of autoantibody traits in pedigrees multiplex for systemic lupus erythematosus

Autoantibodies are clinically relevant biomarkers for numerous autoimmune disorders. The genetic basis of autoantibody production in systemic lupus erythematosus (SLE) and other autoimmune diseases is poorly understood. In this study, we characterized autoantibody profiles in 1,506 individuals from 229 multiplex SLE pedigrees. There was strong familial aggregation of antinuclear antibodies (ANAs), anti-double-stranded DNA (dsDNA), anti-La/SSB, anti-Ro/SSA, anti-Sm, anti-nRNP (nuclear ribonucleoprotein), IgM antiphospholipid (aPL) antibodies (Abs) and rheumatoid factor (RF) across these families enriched for lupus. We performed genome-wide linkage analyses in an effort to map genes that contribute to the production of the following autoantibodies: Ro/SSA, La/SSB, nRNP, Sm, dsDNA, RF, nuclear and phospholipids. Using an approach to minimize false positives and adjust for multiple comparisons, evidence for linkage was found to anti-La/SSB Abs on chromosome 3q21 (adjusted P=1.9 x 10(-6)), to anti-nRNP and/or anti-Sm Abs on chromosome 3q27 (adjusted P=3.5 x 10(-6)), to anti-Ro/SSA and/or anti-La/SSB Abs on chromosome 4q34-q35 (adjusted P=3.4 x 10(-4)) and to anti-IgM aPL Abs on chromosome 13q14 (adjusted P=2.3 x 10(-4)). These results support the hypothesis that autoantibody production is a genetically complex trait. Identification of the causative alleles will advance our understanding of critical molecular mechanisms that underlie SLE and perhaps other autoimmune diseases.

The helical tomotherapy thread effect

Inherent to helical tomotherapy is a dose variation pattern that manifests as a "ripple" (peak-to-trough relative to the average). This ripple is the result of helical beam junctioning, completely unique to helical tomotherapy. Pitch is defined as in helical CT, the couch travel distance for a complete gantry rotation relative to the axial beam width at the axis of rotation. Without scattering or beam divergence, an analytical posing of the problem as a simple integral predicts minima near a pitch of 1/n where n is an integer. A convolution-superposition dose calculator (TomoTherapy, Inc.) included all the physics needed to explore the ripple magnitude versus pitch and beam width. The results of the dose calculator and some benchmark measurements demonstrate that the ripple has sharp minima near p=0.86(1/n). The 0.86 factor is empirical and caused by a beam junctioning of the off-axis dose profiles which differ from the axial profiles as well as a long scatter tail of the profiles at depth. For very strong intensity modulation, the 0.86 factor may vary. The authors propose choosing particular minima pitches or using a second delivery that starts 180 deg off-phase from the first to reduce these ripples: "Double threading." For current typical pitches and beam widths, however, this effect is small and not clinically important for most situations. Certain extremely large field or high pitch cases, however, may benefit from mitigation of this effect.

Coinheritance of two rare genodermatoses (Papillon-Lefèvre syndrome and oculocutaneous albinism type 1) in two families: a genetic study

The co-occurrence of two rare recessive genetic conditions in apparently unrelated individuals or families is extremely rare. Two geographically distant and apparently unrelated families were identified in which individuals were simultaneously affected by two rare recessive mendelian syndromes, Papillon-Lefevre syndrome and type 1 oculocutaneous albinism. The families were tested for mutations in the causative genes, cathepsin C (CTSC) and tyrosinase (TYR), respectively, by direct sequencing. To assess the relationship of the two families, both families were tested for polymorphisms at eight microsatellite markers spanning both CTSC and TYR loci. Independent mutations (c.318-1G-->A and c.817G-->C/p.W272C) were identified in CTSC and TYR, respectively, that were shared by the affected individuals in both families. The two affected genes lie close together on chromosome bands 11q14.2-14.3, and studies with linked genetic markers suggested that the families shared a small chromosomal segment carrying both mutations that had been transmitted intact from a remote common ancestor. The co-occurrence of the two rare diseases in multiple families depends on their shared chromosomal location, but not on any shared pathogenic mechanism.

Quality assurance of a helical tomotherapy machine

Helical tomotherapy has been developed at the University of Wisconsin, and 'Hi-Art II' clinical machines are now commercially manufactured. At the core of each machine lies a ring-gantry-mounted short linear accelerator which generates x-rays that are collimated into a fan beam of intensity-modulated radiation by a binary multileaf, the modulation being variable with gantry angle. Patients are treated lying on a couch which is translated continuously through the bore of the machine as the gantry rotates. Highly conformal dose-distributions can be delivered using this technique, which is the therapy equivalent of spiral computed tomography. The approach requires synchrony of gantry rotation, couch translation, accelerator pulsing and the opening and closing of the leaves of the binary multileaf collimator used to modulate the radiation beam. In the course of clinically implementing helical tomotherapy, we have developed a quality assurance (QA) system for our machine. The system is analogous to that recommended for conventional clinical linear accelerator QA by AAPM Task Group 40 but contains some novel components, reflecting differences between the Hi-Art devices and conventional clinical accelerators. Here the design and dosimetric characteristics of Hi-Art machines are summarized and the QA system is set out along with experimental details of its implementation. Connections between this machine-based QA work, pre-treatment patient-specific delivery QA and fraction-by-fraction dose verification are discussed.

An investigation of the MEK/ERK inhibitor U0126 in acute myeloid leukemia

Blockade of mitogen-activated protein kinase kinase (MEK1/2), part of the extracellular signal-regulated kinase (ERK) or p44/42 mitogen-activated protein kinase (MAPK) pathway, has been shown in some instances to cause apoptosis in leukemic blast cells. This investigation examined the effect of the potent MEK/ERK inhibitor U0126 on apoptosis in acute myeloblastic leukemia (AML) cell lines, and acute leukemic and non-leukemic patient samples. The pro-apoptotic effect of the inhibitor varied across the five cell lines tested (KG1a, HEL, TF-1, MO7e, and THP-1) from highly significant induction of apoptosis to no apparent response. The pro-apoptotic effect of U0126 in the most sensitive cell line, KG1a, appeared to be related to its CD34 positivity. Three of five leukemic bone marrow samples showed considerable sensitivity to the inhibitor and a similar association with CD34 expression was evident. Interestingly, control marrow cells from six non-leukemic patients did not show a significant effect when exposed to U0126. These results suggest that this agent may offer a potential alternative to standard chemotherapy with a particular role in the most primitive types of leukemia, these often being the most resistant to standard chemotherapy.

Rapid clinical progression to diagnosis among African-American men with systemic lupus erythematosus

The initial clinical course of systemic lupus erythematosus (SLE) is variable, ranging from relatively minor manifestations progressing over years to rapid onset of fulminate disease. We sought to identify factors associated with the rapid manifestation of SLE. Chart review of military medical records was used to identify 130 patients who met the American College of Rheumatology classification criteria for SLE. Demographics, clinical criteria date of occurrence, and the date of SLE classification (at least four clinical criteria) met were documented. Prospectively stored serum samples prior to the diagnosis were evaluated for SLE autoantibodies. Median time from the first recorded criteria to diagnosis was significantly shorter in African-American (AA) males compared with AA females and European American (EA) females and males combined. AA males were more likely to have nephritis as their first clinical symptom. Also, less time transpired between the first clinical criterion and SLE diagnosis in AA males with nephritis than in other groups presenting with nephritis. Even when cases presenting with nephritis were excluded, a diagnosis of SLE was made more rapidly in AA males. African-American men progress from initial clinical manifestations to SLE diagnosis more rapidly than other ethnic or gender groups.

Immunization with peptides from 60 kDa Ro in diverse mouse strains

Antibodies binding the Ro (or SSA) and La (or SBB) proteins are commonly found in a high proportion of sera from patients with systemic lupus erythematosus or Sjögren's syndrome. The mechanism by which these autoantibodies arise is not known. Others and we have shown that immunization of nonautoimmune-prone mice with short peptides from the Ro ribonucleoprotein particle can induce autoimmunity to 60 kDa Ro and 52 kDa Ro as well as to the 48 kDa La protein after epitope spreading. We have explored the differences in the epitope spreading after 60 kDa Ro peptide immunization in several strains of mice. There is intra- and intermolecular diversification of the immune response after immunization of DBA/2J animals with a monomer peptide representing the residues 480-494 of the 60 kDa Ro protein, but this peptide does not induce epitope spreading when used as the immunogen in either C57Bl/6J or PL/J mice. Similar to previously studied BALB/c mice, DBA/2J mice have antibodies binding many epitopes of 60 kDa Ro, and some sera bind 52 kDa Ro as well as La. These mice have antinuclear antibody in their sera. These data demonstrate that Ro peptide immunization results in different outcomes depending upon the strain of mouse used. Furthermore, these data suggest that genetic variation is important with regard to responding towards short peptide immunization by epitope spreading.

Selective small antigenic structures are capable of inducing widespread autoimmunity which closely mimics the humoral fine specificity of human SLE

Recent data have suggested that autoantibodies in lupus can progress from simple immunity against a few antigenic structures to a complex response against multiple autoantigens. Our aim was to determine whether these diverse epitope patterns can indeed be generated by antigenic challenge with a single, small structure. Rabbits were immunized with either a 60 kDa Ro peptide commonly antigenic in human systemic lupus erythematosus (SLE) (Ro 274-289) or one which is rarely a humoral target (Ro 500-515). Rabbits immunized with the antigenic peptide (Ro 274-289) not only developed antibodies to multiple epitopes of 60 kDa Ro and La, as has been described, but also produced non-cross-reactive antibodies to the common spliceosomal proteins Sm B' and D1, and nRNP A and C. Rabbits immunized with the Ro 274-289 peptide also mount a progressive, diversified immune response to the sequential antigenic regions of these proteins (60 kDa Ro, Sm B' and D1, nRNP A and C), which is nearly identical to that seen in human SLE. Animals immunized with the nonantigenic peptide Ro 500-515 develop antibodies only to 60 kDa Ro. These results demonstrate that loss of tolerance to select single, small antigenic structures can begin a cascade which virtually recreates, at the epitope level, the humoral autoimmune specificity seen in human SLE.

The genetics of systemic lupus erythematosus stratified by renal disease: linkage at 10q22.3 (SLEN1), 2q34-35 (SLEN2), and 11p15.6 (SLEN3)

Renal disease occurs in 40-75% of systemic lupus erythematosus (SLE) patients and significantly contributes to morbidity and mortality. We used two pedigree stratification strategies to explore the impact of the ACR renal criterion for SLE classification upon genetic linkage with SLE. In both we used SLE as the phenotype. First, we evaluated genome scan data from >300 microsatellite markers in the 75 pedigrees that had at least one SLE affected with the SLE renal criterion. A maximum-likelihood parametric model approach produced a maximum screening LOD score of 3.16 at 10q22.3 in the European-American (EA) pedigrees. The African-American (AA) pedigrees obtained a maximum screening LOD score of 2.58 at 11p15.6. A multipoint sib-pair regression analysis produced P = 0.0000008 in EA at 10q22.3 (SLEN1) and P = 0.000001 in AA at 2q34-35 (SLEN2). A second stratification strategy explored the renal criterion in 35 pedigrees with two or more SLE patients with renal disease and produced a LOD score of 3.34 at 11p15.6 in AA (SLEN3). Sib-pair analysis in these 35 pedigrees revealed P = 0.00003 at 4q13.1 in EA, P = 0.00003 at 11p13 and 0.00007 at 3q23 in AA. Thus, multiple genetic linkages are related to the renal criterion in SLE. Of the significant genetic linkages with SLE described herein, those at 10q22.3 in the EA pedigrees (SLEN1) and at 2q34-35 in the AA pedigrees (SLEN2) have not been previously described.

A genome screen of systemic lupus erythematosus using affected-relative-pair linkage analysis with covariates demonstrates genetic heterogeneity

Systemic lupus erythematosus (SLE) appears to be the consequence of complex genetics and of only partly understood environmental contributions. Previous work by ourselves and by others has established genetic effects on 1q, 2q, 4p, 6p, and 16p using SLE as the phenotype. However, individual SLE affecteds are extraordinarily different from one another by clinical and laboratory measures. This variation may have a genetic basis; if so, it is advantageous to incorporate measures of between-family clinical variability as covariates in a genetic linkage analysis of affected relative pairs (ARPs) to allow for locus heterogeneity. This approach was applied to genome scan marker data from 160 pedigrees multiplex for SLE and containing 202 ARPs. Because the number of potential covariates was large, we used both ad hoc methods and formal principal components analysis to construct four composite covariates using the SLE classification criteria plus age of onset, ethnicity, and sex. Linkage analysis without covariates has detected evidence for linkage at 1q22-24, 2q37, 4p16, 12p12-11, and 17p13. Linkage analysis with these covariates uncovered linkage at 13p11, 17q11-25, and 20q12 and greatly improved evidence for linkage at 1q22-24, 2q37, 12p12-11, and 17p13. Follow-up analysis identified the original variables contributing to locus heterogeneity in each of these locations. In conclusion, allowing for locus heterogeneity through the incorporation of covariates in linkage analysis is a useful way to dissect the genetic contributions to SLE and uncover new genetic effects.

Genome scan stratified by the presence of anti-double-stranded DNA (dsDNA) autoantibody in pedigrees multiplex for systemic lupus erythematosus (SLE) establishes linkages at 19p13.2 (SLED1) and 18q21.1 (SLED2)

Anti-double-stranded DNA (anti-dsDNA) is arguably one of the most specific autoantibodies in systemic lupus erythematosus (SLE). This antibody is associated with more severe SLE and with glomerulonephritis. From 196 pedigrees multiplex for SLE, we selected those that had any SLE affected positive for anti-dsDNA by the Crithidia luciliae kinetoplast imunofluorescence assay. This stratification strategy tested the hypothesis that anti-dsDNA would identify a more genetically homogeneous group of pedigrees, in which previously undetected linkage effects could be established. A genome screen data for linkage to SLE was available at 307 microsatellite markers for this selected group of 71 pedigrees: 37 European-American, 29 African-American, and five others. The most significant results were obtained at 19p13.2 (LOD(max) = 4.93), named SLED1, in the 37 European-American pedigrees using a dominant model with mixed penetrances (92% for females and 49% for males) at 100% homogeneity (theta = 0). A second linkage effect, SLED2, was established in the 29 African-American pedigrees at 18q21.1 (LOD(max) = 3.40) using a recessive model with 100% penetrance (theta = 0.1). Parametric and non-parametric multipoint analyses were performed, which provided further evidence and support of susceptibility genes residing in these regions. In conclusion, two powerful linkages have been detected with SLE based on the presence of anti-dsDNA. These findings show SLE to be a richly complicated disease phenotype that is now ripe for important new discovery through a genetic approach.

Occlusal considerations in periodontics

Periodontal disease does not directly affect the occluding surfaces of teeth, consequently some may find a section on periodontics a surprising inclusion. Trauma from the occlusion, however, has been linked with periodontal disease for many years. Karolyi published his pioneering paper, in 1901 'Beobachtungen uber Pyorrhoea alveolaris' (occlusal stress and 'alveolar pyorrhoea'). (1) However, despite extensive research over many decades, the role of occlusion in the aetiology and pathogenesis of inflammatory periodontitis is still not completely understood.

Epitope mapping using the X-ray crystallographic structure of complement receptor type 2 (CR2)/CD21: identification of a highly inhibitory monoclonal antibody that directly recognizes the CR2-C3d interface

Complement receptor type 2 (CR2)/CD21 is a B lymphocyte cell membrane C3d/iC3b receptor that plays a central role in the immune response. Human CR2 is also the receptor for the EBV viral membrane glycoprotein gp350/220. Both C3d and gp350/220 bind CR2 within the first two of 15-16 repetitive domains that have been designated short consensus/complement repeats. Many mAbs react with human CR2; however, only one currently available mAb is known to block both C3d/iC3b and gp350/220 binding. We have used a recombinant form of human CR2 containing the short consensus/complement repeat 1-2 ligand-binding fragment to immunize Cr2(-/-) mice. Following fusion, we identified and further characterized four new anti-CR2 mAbs that recognize this fragment. Three of these inhibited binding of CR2 to C3d and gp350/220 in different forms. We have determined the relative inhibitory ability of the four mAbs to block ligand binding, and we have used overlapping peptide-based approaches to identify linear epitopes recognized by the inhibitory mAbs. Placement of these epitopes on the recently solved crystal structure of the CR2-C3d complex reveals that each inhibitory mAb recognizes a site either within or adjacent to the CR2-C3d contact site. One new mAb, designated 171, blocks CR2 receptor-ligand interactions with the greatest efficiency and recognizes a portion of the C3d contact site on CR2. Thus, we have created an anti-human CR2 mAb that blocks the C3d ligand by direct contact with its interaction site, and we have provided confirmatory evidence that the C3d binding site seen in its crystal structure exists in solution.

The role of Epstein-Barr virus in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a devastating autoimmune disease with no known cure. Lupus patients suffer from a myriad of clinical symptoms which variably include arthritis, pleuritis, pericarditis, vasculitis, and nephritis. The underlying mechanisms behind these clinical findings and the etiologic events preceding and causing disease onset, however, remain largely unknown. For many years, investigators have suspected that Epstein-Barr virus might somehow be involved in the etiology and/or pathogenesis of systemic lupus. Numerous studies have examined this possibility from various angles and have arrived at different conclusions. This work reviews these historical papers in the context of new results and presents a hypothetical role for this virus as an etiological environmental trigger for SLE.

Tacrolimus is not associated with gingival overgrowth in renal transplant patients

BACKGROUND

Cyclosporin A is used extensively to prevent the rejection of allogenic renal transplants. However, it is associated with a variety of undesirable side effects including gingival overgrowth. Tacrolimus (FK506), has been marketed as an effective alternative immunosuppressant to cyclosporin A and recent subjective reports suggest patients taking it complain infrequently of gingival problems. This clinical investigation was undertaken to confirm whether or not tacrolimus adversely affected the gingival health of renal transplant recipients.

METHODS

Renal transplant patients (RTPs) under the care of the Renal Transplantation Service at the Manchester Royal Infirmary, who had received a renal allograft at least 18 months earlier, were recruited for this study. All but one of the RTPs had been taking tacrolimus since transplantation. The other had commenced tacrolimus therapy two months after receiving her allograft. A hospital based control group was recruited from non transplanted individuals attending the Turner Dental School, Manchester. Each patient underwent a detailed dental assessment and had dental impressions taken. The extent of gingival overgrowth was determined from plaster models.

RESULTS

25 renal transplant recipients and 26 control patients were included in the study. None of the individuals in either the tacrolimus or control groups had clinically significant overgrowth. The patients in the tacrolimus group with the highest overgrowth scores were those also taking calcium antagonists as treatment for hypertension.

CONCLUSION

This study demonstrates that tacrolimus has no adverse effects on the gingival tissues and thus has potential as an alternative immunosuppressant for individuals susceptible to developing cyclosporin A-induced gingival overgrowth.

Role of viruses in systemic lupus erythematosus and Sjögren syndrome

Systemic lupus erythematosus and Sjögren syndrome remain elusive in the description of their underlying etiologic causes and pathogenic mechanisms. Although underlying genetic predisposition appears to contribute to both diseases based on twin and other genetic studies, additional factors must play a role. Over the decades additional factors, such as hormonal influence, UV light, environmental exposures (e.g., silica, solvents), and infectious agents have been postulated to play a role. Over the past few years additional information has been published concerning roles of various infectious agents in both lupus and Sjögren syndrome. Although the understanding of this field is still incomplete, significant advances are being made.

Lupus autoantibodies recognize the product of an alternative open reading frame of SmB/B'

An unusual feature of the gene for the spliceosomal protein SmB/B' is the presence of an unusually long alternative open reading frame (aORF) which could encode 220 amino acids. We cloned and expressed this aORF protein and used immunological assays to determine its antigenicity in patients with systemic lupus. Sera from 10 of 22 (46%) anti-Sm positive lupus patients showed significant binding to the SmB' aORF protein by ELISA while neither the normal controls nor anti-Sm negative lupus patient controls showed significant reactivity. Antigenicity of the SmB' aORF protein was further localized to the C-terminus using a deletion construct. This is the first known example in which the product of an alternative open reading frame acts as an autoantigen in human disease. These results are consistent with the possibility that generation of anti-Sm autoantibodies in a subset of lupus patients is due to abnormal processing and expression of an aORF SmB/B' message, by an as yet unidentified mechanism.

Development of anti-dsDNA autoantibodies prior to clinical diagnosis of systemic lupus erythematosus

Anti-double stranded (dsDNA) antibodies are of considerable diagnostic value and are thought to be involved in the pathogenesis of systemic lupus erythematosus (SLE). Fluctuations in anti-dsDNA antibody levels are also used as markers for disease activity and exacerbations. In this study we sought to evaluate the anti-dsDNA antibody level in serum samples collected before the onset of SLE diagnosis. A total of 130 SLE patients were identified with stored serum samples available prior to diagnosis within the US Department of Defense serum repository. All 633 sera available from these patients were screened for anti-dsDNA antibodies using an enzyme linked immunosorbant assay (ELISA). Within this cohort 55% of cases had detectable anti-dsDNA antibodies prior to SLE diagnosis. The onset of anti-dsDNA antibodies ranged from 9.3 years before to within the same month as diagnosis (with a mean onset 2.7 years before diagnosis). In order to assess for fluctuations in anti-dsDNA levels relative to diagnosis, cases were selected with at least two positive samples, one within 6 months and a second greater than 6 months prior to diagnosis (n = 26). Seven of these cases also had samples available shortly after diagnosis (< or = 6 months) for comparison. Fifty-eight percent of the 26 cases developed a significant rise in anti-dsDNA antibody levels within 6 months of diagnosis. A significant decline in anti-dsDNA levels ensued after diagnosis (and following treatment with corticosteroids) in all seven cases with samples available. Patients with a significant rise in anti-dsDNA antibodies at diagnosis were more likely to have renal disease than those who did not (66.7% compared to 27.3%, chi2 =3.94, P<0.05). These data suggest that anti-dsDNA antibodies are present in SLE patient sera much earlier than previously suspected. In addition, the data are consistent with increases in anti-dsDNA levels contributing to the onset of clinical illness in some patients with SLE.

The influence of transforming growth factor-beta1 gene polymorphisms on the severity of gingival overgrowth associated with concomitant use of cyclosporin A and a calcium channel blocker

BACKGROUND

The purpose of this study was to determine whether the prevalence and severity of gingival overgrowth in renal transplant recipients concomitantly treated with cyclosporin and a calcium channel blocker was associated with functional polymorphisms within the signal sequence of the transforming growth factor-(TGF)beta1 gene.

METHODS

The extent and severity of gingival overgrowth for 164 renal transplant recipients immunosuppressed with cyclosporin A and concomitantly taking a calcium channel blocker since transplant were entered into the study (86 in Manchester, 78 in Belfast). Two biallelic polymorphisms of the TGF-beta1 gene were studied at position +869, codon 10 (leucine to proline substitution), and position +915, codon 25 (arginine to proline substitution).

RESULTS

Subjects who were homozygous for proline at codon 10 had significantly higher overgrowth scores than those who were heterozygous (P= 0.03) or homozygous for leucine (P= 0.01). Subjects who were heterozygous (arginine/proline) at codon 25 had a significantly higher (P= 0.04) gingival overgrowth score than those who were homozygous for arginine. Logistic regression analysis indicated that for codon 25 independent predictors of severe gingival overgrowth were the heterozygous arginine/proline genotype (P= 0.009) and whether the individual was young (P= 0.05).

CONCLUSIONS

Polymorphisms in the TGF-beta1 gene influence the expression of gingival overgrowth in renal transplant recipients concomitantly treated with cyclosporin and a calcium channel blocker. The polymorphism in the TGF-beta1 gene at codon 25 represented an independent genetic determinant of severe gingival overgrowth in the susceptible subjects studied.