Robert M. Rennebohm

Gene copy-number variation and associated polymorphisms of complement component C4 in human systemic lupus erythematosus (SLE): low copy number is a risk factor for and high copy number is a protective factor against SLE susceptibility in European Americans.

Interindividual gene copy-number variation (CNV) of complement component C4 and its associated polymorphisms in gene size (long and short) and protein isotypes (C4A and C4B) probably lead to different susceptibilities to autoimmune disease. We investigated the C4 gene CNV in 1,241 European Americans, including patients with systemic lupus erythematosus (SLE), their first-degree relatives, and unrelated healthy subjects, by definitive genotyping and phenotyping techniques. The gene copy number (GCN) varied from 2 to 6 for total C4, from 0 to 5 for C4A, and from 0 to 4 for C4B. Four copies of total C4, two copies of C4A, and two copies of C4B were the most common GCN counts, but each constituted only between one-half and three-quarters of the study populations. Long C4 genes were strongly correlated with C4A (R=0.695; P<.0001). Short C4 genes were correlated with C4B (R=0.437; P<.0001). In comparison with healthy subjects, patients with SLE clearly had the GCN of total C4 and C4A shifting to the lower side. The risk of SLE disease susceptibility significantly increased among subjects with only two copies of total C4 (patients 9.3%; unrelated controls 1.5%; odds ratio [OR] = 6.514; P=.00002) but decreased in those with > or =5 copies of C4 (patients 5.79%; controls 12%; OR=0.466; P=.016). Both zero copies (OR=5.267; P=.001) and one copy (OR=1.613; P=.022) of C4A were risk factors for SLE, whereas > or =3 copies of C4A appeared to be protective (OR=0.574; P=.012). Family-based association tests suggested that a specific haplotype with a single short C4B in tight linkage disequilibrium with the -308A allele of TNFA was more likely to be transmitted to patients with SLE. This work demonstrates how gene CNV and its related polymorphisms are associated with the susceptibility to a human complex disease.

Development of validated disease activity and damage indices for the juvenile idiopathic inflammatory myopathies: II. The childhood myositis assessment scale (CMAS): a quantitative tool for the evaluation of muscle function

OBJECTIVE To develop, validate, and determine the measurement characteristics of a quantitative tool for assessing the severity of muscle involvement in children with idiopathic inflammatory myopathies. METHODS The Childhood Myositis Assessment Scale (CMAS) was developed from 2 existing observational functional assessment tools to assess muscle function in the areas of strength and endurance across a wide range of ability and ages. The 14 ordinal items included were chosen to assess primarily axial and proximal muscle groups and are ranked with standard performance and scoring methods. Following the development of the CMAS, a training video and written instructions were developed and reviewed by the physicians participating in this study. Subsequently, utilizing a randomized block design, 12 physicians independently scored 10 children (9 with dermatomyositis, 1 with polymyositis; ages 4-15 years) twice in one day (morning and afternoon) on the CMAS. A pediatric physical therapist performed quantitative manual muscle strength testing (MMT) twice on each child (morning and afternoon), including the neck, trunk, and proximal and distal extremity muscle groups. RESULTS The CMAS has a potential range of 0-51, with higher scores indicating greater muscle strength and endurance. The observed mean for the 10 patients was 36.4 (median 44, SD 14.1, observed range 5-51). The total score for the CMAS correlated with the physicians global assessment (by visual analog scale) of disease activity, the MMT score, serum creatine kinase level, and the Juvenile Arthritis Functional Assessment Report score. The score on the CMAS was not correlated with patient age. Interrater reliability (Kendalls coefficient of concordance) ranged from 0.77 to 1.0 for individual items (all P < 0.001), and overall, it was 0.95 (P < 0.001). Intrarater reliability for the individual physicians was measured by correlation of the CMAS scores for each patient on 2 separate evaluations and ranged from 0.97 to 0.99, with an overall correlation for all physicians of 0.98 (all P < 0.001). CONCLUSION The CMAS demonstrated an acceptable range of observed scores, excellent convergent validity, and excellent inter- and intrarater reliability. The CMAS is validated to quantitatively assess muscle function in the areas of strength and endurance in children with idiopathic inflammatory myopathies. It can be used in routine clinical care as well as therapeutic trials.

Susac's syndrome: 1975–2005 microangiopathy/autoimmune endotheliopathy

Susacs syndrome (SS) consists of the clinical triad of encephalopathy, branch retinal artery occlusions (BRAO) and hearing loss. It is due to a microangiopathy affecting the precapillary arterioles of the brain, retina, and inner ear (cochlea and semicircular canals). Women are more commonly affected than men (3:1); the age of onset ranges from 9 to 58 years; but young women between the ages of 20 and 40 are most vulnerable. The encephalopathy is almost always accompanied by headache which may be the presenting feature. Multifocal neurological signs and symptoms, psychiatric disturbances, cognitive changes, memory loss, and confusion may rapidly progress to dementia. The MRI shows a distinctive white matter disturbance that always affects the corpus callosum. The central callosal fibers are particularly vulnerable and central callosal holes develop as the active lesions resolve. Linear defects (spokes) and rather large round lesions (snowballs) sometime dominate the MRI findings, which include cortical, deep gray (70%) and leptomeningeal involvement (33%). Frequently, the lesions enhance and may be evident on diffusion weighted imaging (DWI). The BRAO are best evaluated with fluorescein angiography, which may show the pathognomonic multifocal fluorescence. Gass plaques are frequently present and reflect endothelial damage. Brain biopsy shows microinfarction to be the basic pathology, but more recent pathological studies have shown endothelial changes that are typical for an antiendothelial cell injury syndrome. Elevated levels of Factor VIII and von Willebrand Factor Antigen reflect the endothelial perturbation. Despite extensive evaluations, a procoagulant state has never been demonstrated. SS is an autoimmune endotheliopathy that requires treatment with immunosuppressants: steroids, cyclophosphamide, and intravenous immunoglobulin, usually in combination. Aspirin is a useful adjunct.

Damage Extent and Predictors in Adult and Juvenile Dermatomyositis and Polymyositis as Determined With the Myositis Damage Index

OBJECTIVE We undertook this study to validate the Myositis Damage Index (MDI) in juvenile and adult myositis, to describe the degree and types of damage and to develop predictors of damage. METHODS Retrospective MDI evaluations and prospective assessment of disease activity and illness features were conducted. Patients with juvenile-onset disease (n = 143) were evaluated a median of 18 months after diagnosis; 135 patients were assessed 7-9 months later, and 121 were last assessed a median of 82 months after diagnosis. Ninety-six patients with adult-onset dermatomyositis or polymyositis had a baseline assessment a median of 30 months after diagnosis; 77 patients had a 6-month followup evaluation, and 55 had a final assessment a median of 60 months after diagnosis. RESULTS Damage was present in 79% of juvenile patients and in 97% of adult patients. In juveniles, scarring, contractures, persistent weakness, muscle dysfunction, and calcinosis were most frequent (23-30%) at the last evaluation. In adults, muscle atrophy, muscle dysfunction, and muscle weakness were most frequent (74-84%). MDI severity correlated with physician-assessed global damage, serum creatinine, and muscle atrophy on magnetic resonance imaging, and in juveniles also with functional disability and weakness. MDI damage scores and frequency were highest in patients with a chronic illness course and in adult patients who died. Predictors of damage included functional disability, duration of active disease, disease severity at diagnosis, physician-assessed global disease activity, and illness features, including ulcerations in children and pericarditis in adults. CONCLUSION Damage is common in myositis after a median duration of 5 years in patients with adult-onset disease and 6.8 years in patients with juvenile-onset disease. The MDI has good content, construct, and predictive validity in juvenile and adult myositis.

Genetic Sophistication of Human Complement Components C4A and C4B and RP-C4-CYP21-TNX (RCCX) Modules in the Major Histocompatibility Complex

Human populations are endowed with a sophisticated genetic diversity of complement C4 and its flanking genes RP, CYP21, and TNX in the RCCX modules of the major histocompatibility complex class III region. We applied definitive techniques to elucidate (a) the complement C4 polymorphisms in gene sizes, gene numbers, and protein isotypes and (b) their gene orders. Several intriguing features are unraveled, including (1) a trimodular RCCX haplotype with three long C4 genes expressing C4A protein only, (2) two trimodular haplotypes with two long (L) and one short (S) C4 genes organized in LSL configurations, (3) a quadrimodular haplotype with four C4 genes organized in a SLSL configuration, and (4) another quadrimodular structure, with four long C4 genes (LLLL), that has the human leukocyte antigen haplotype that is identical to ancestral haplotype 7.2 in the Japanese population. Long-range PCR and PshAI-RFLP analyses conclusively revealed that the short genes from the LSL and SLSL haplotypes are C4A. In four informative families, an astonishingly complex pattern of genetic diversity for RCCX haplotypes with one, two, three and four C4 genes is demonstrated; each C4 gene may be long or short, encoding a C4A or C4B protein. Such diversity may be related to different intrinsic strengths among humans to defend against infections and susceptibilities to autoimmune diseases.

Development of validated disease activity and damage indices for the juvenile idiopathic inflammatory myopathies: I. Physician, parent, and patient global assessments. Juvenile Dermatomyositis Disease Activity Collaborative Study Group.

OBJECTIVE To determine the reliability, content validity, and responsiveness of physician global assessments of disease activity and damage in the juvenile idiopathic inflammatory myopathies (IIM), and to investigate concordance among physician, parent, and patient global ratings. METHODS Sixteen pediatric rheumatologists rated 10 juvenile IIM paper patient cases for global disease activity and damage, and assessed the importance of 51 clinical and laboratory parameters in formulating their global assessments. Then, 117 juvenile IIM patients were enrolled in a protocol to examine the relationship between Likert and visual analog scale global assessments, their sensitivity to change, and the comparability of physician, parent, and patient global ratings. RESULTS Pediatric rheumatologists demonstrated excellent interrater reliability in their global assessments of juvenile IIM disease activity and damage (97.7% and 94.7% agreement among raters, respectively), and agreed on a core set of clinical parameters in formulating their judgments. Likert scale ratings correlated with those on a visual analog scale, and both were comparable in responsiveness (standardized response means -0.56 for disease activity, 0.02 [Likert] and 0.14 [visual analog] for damage, measured over 8 months). Parent global ratings of disease activity correlated with physician assessments, but were not colinear (Spearmans correlation [r] = 0.41-0.45). Patient global disease activity assessments correlated with those done by parents (r = 0.57-0.84) and physicians (r = 0.37-0.63), but demonstrated less responsiveness (standardized response means -0.21 and -0.12, respectively, over 8 months). CONCLUSION Physician global assessments of juvenile IIM disease activity and damage demonstrated high interrater reliability and were shown to be comprehensive measures. Both physician and parent disease activity assessments should be considered valuable as quantitative measures for evaluating therapeutic responses in juvenile IIM patients.

Protocols for the Initial Treatment of Moderately Severe Juvenile Dermatomyositis: Results of a Children's Arthritis and Rheumatology Research Alliance Consensus Conference

To use juvenile dermatomyositis (DM) survey data and expert opinion to develop a small number of consensus treatment protocols, which reflect current initial treatment of moderately severe juvenile DM.

The Paediatric Rheumatology International Trials Organisation provisional criteria for the evaluation of response to therapy in juvenile dermatomyositis

To develop a provisional definition for the evaluation of response to therapy in juvenile dermatomyositis (DM) based on the Paediatric Rheumatology International Trials Organisation juvenile DM core set of variables.

Pulmonary Hypertension and Other Potentially Fatal Pulmonary Complications in Systemic Juvenile Idiopathic Arthritis

Systemic juvenile idiopathic arthritis (JIA) is characterized by fevers, rash, and arthritis, for which interleukin‐1 (IL‐1) and IL‐6 inhibitors appear to be effective treatments. Pulmonary arterial hypertension (PAH), interstitial lung disease (ILD), and alveolar proteinosis (AP) have recently been reported with increased frequency in systemic JIA patients. Our aim was to characterize and compare systemic JIA patients with these complications to a larger cohort of systemic JIA patients.

Determining the one, two, three, or four long and short loci of human complement C4 in a major histocompatibility complex haplotype encoding C4A or C4B proteins.

The complex genetics of human complement C4 with unusually frequent variations in the size and number of C4A and C4B, as well as their neighboring genes, in the major histocompatibility complex has been a hurdle for accurate epidemiological studies of diseases associated with C4. A comprehensive series of novel or improved techniques has been developed to determine the total gene number of C4 and the relative dosages of C4A and C4B in a diploid genome. These techniques include (1) definitive genomic restriction-fragment-length polymorphisms (RFLPs) based on the discrete duplication patterns of the RCCX (RP-C4-CYP21-TNX) modules and on the specific nucleotide changes for C4A and C4B isotypes; (2) module-specific PCR to give information on the total number of C4 genes by comparing the relative quantities of RP1- or TNXB-specific fragments with TNXA-RP2 fragments; (3) labeled-primer single-cycle DNA polymerization procedure of amplified C4d genomic DNA for diagnostic RFLP analysis of C4A and C4B; and (4) a highly reproducible long-range-mapping method that employs PmeI-digested genomic DNA for pulsed-field gel electrophoresis, to yield precise information on the number of long and short C4 genes in a haplotype. Applications of these vigorously tested techniques may clarify the roles that human C4A and C4B gene-dosage variations play in infectious and autoimmune diseases.