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PubMed1992

P-31 magnetic resonance spectroscopy in polymyositis and dermatomyositis. Altered energy utilization during exercise.

OBJECTIVE: To explore alterations in energy utilization as a potential etiology for weakness in polymyositis and dermatomyositis (PM/DM). METHODS: P-31 magnetic resonance spectroscopy studies were performed in patients with acute and treated PM/DM and in normal controls, at rest and with exercise. RESULTS: Patients with acute and treated PM/DM showed increased ratios of inorganic phosphate to phosphocreatine (PCr) during exercise, with loss of ATP disproportional to loss of PCr. CONCLUSION: This study demonstrates changes in energy utilization in PM/DM, thus supporting the notion of a metabolic etiology for the weakness associated with these diseases.

Adenosine Triphosphate↗
PubMed1992

Methotrexate treatment of recalcitrant childhood dermatomyositis.

OBJECTIVE: To review the clinical course of 16 children with recalcitrant dermatomyositis (DM), who were treated with oral methotrexate (MTX) in addition to prednisone. METHODS: Sixteen patients with recalcitrant DM who were treated with MTX in addition to prednisone were followed between 1984 and 1990. The patients' clinical responses to treatment, including alterations in muscle strength and muscle enzyme levels, changes in prednisone dosage, and development of toxicity or complications were reviewed retrospectively. RESULTS: All 12 patients who received MTX for at least 8 months regained normal muscle strength. In 11 of the 12, the prednisone dosage could eventually be tapered to < or = 5 mg/day. Complications during MTX treatment required discontinuation of MTX in 5 patients, and were unrelated to the cumulative dose of the drug. Active disease recurred in 5 patients in whom MTX had been discontinued after apparent clinical remission had been achieved. CONCLUSION: MTX, in combination with prednisone, is a useful adjunct in the treatment of recalcitrant childhood DM. However, recurrence of disease after withdrawal of MTX suggests that the drug may have a suppressive, rather than a remittive, effect.

Adolescent↗
PubMed1993

Chlorambucil. An effective corticosteroid-sparing agent for patients with recalcitrant dermatomyositis.

OBJECTIVE: To investigate the effectiveness of oral chlorambucil treatment in patients with dermatomyositis (DM) that is recalcitrant to treatment with prednisone and/or immunosuppressive agents. METHODS: Five patients with recalcitrant DM were treated with oral chlorambucil, 4 mg/day, after discontinuation of the other immunosuppressive agent (azathioprine or methotrexate). Three patients were treated with a combination of prednisone and chlorambucil, and 2 with chlorambucil alone. RESULTS: Beneficial effects were noted within 4-6 weeks in all 5 patients, and corticosteroids were eventually discontinued in 4. Currently, only 1 patient is still receiving therapy; the other 4 have stopped chlorambucil after 13-30 months of treatment, and their disease remains in remission. Minimal chlorambucil toxicity was noted, consisting of leukopenia in 2 patients. CONCLUSION: Our findings suggest that chlorambucil is an effective, corticosteroid-sparing agent for the control of DM.

Administration, Oral↗
PubMed1994

Magnetic resonance imaging and P-31 magnetic resonance spectroscopy provide unique quantitative data useful in the longitudinal management of patients with dermatomyositis.

OBJECTIVE: To evaluate the utility of magnetic resonance imaging (MRI) and P-31 magnetic resonance spectroscopy (MRS) in the longitudinal management of patients with dermatomyositis (DM). METHODS: The study group consisted of 11 patients, including 3 children, all of whom had a clinical diagnosis of DM. A control group of 8 subjects was studied simultaneously. MRI included images as well as calculations of T1 and T2 relaxation times. The P-31 MRS protocol evaluated metabolic status (i.e., inorganic phosphate/phosphocreatine ratios and phosphocreatine and ATP levels) during rest, exercise, and recovery. RESULTS: T2-weighted images of the thigh muscles showed inflammation even when serum creatine phosphokinase levels were in the normal range. Metabolic abnormalities, which were accentuated with exercise, were found in 10 patients. In some individuals, bioenergetic defects preceded other changes and persisted after resolution of inflammation. In general, clinical impressions correlated with MRI/MRS data. CONCLUSION: MRI and MRS provide unique data which are quantitative and which cannot be obtained from routine laboratory tests. These MR evaluations appear to be of value in assessing the status of DM patients during treatment with steroids and immunosuppressive drugs.

Adolescent↗
PubMed1995

Use of magnetic resonance imaging and P-31 magnetic resonance spectroscopy to detect and quantify muscle dysfunction in the amyopathic and myopathic variants of dermatomyositis.

OBJECTIVE: To investigate the use of magnetic resonance imaging (MRI) and P-31 magnetic resonance spectroscopy (MRS) in characterizing the metabolic and functional status of muscles in patients with amyopathic dermatomyositis (DM) and to compare the findings with those in patients with classic myopathic DM. METHODS: Nine patients with amyopathic DM, 11 patients with myopathic DM, and 11 normal individuals were studied. MRI images of thigh muscles were obtained, and T1 and T2 relaxation times were calculated. Biochemical status was quantitated with P-31 MRS, by determining concentrations of phosphate metabolites during rest and exercise. RESULTS: Patients with amyopathic DM showed no muscle inflammation, and MRS data obtained during rest were normal. During exercise at 25% and 50% maximum voluntary contractile force, the MRS data revealed significant differences between amyopathic DM patients and control subjects indicating inefficient metabolism. In contrast, muscles of patients with myopathic DM showed inflammation and metabolic abnormalities even during rest. CONCLUSION: Metabolic deficiencies in patients with amyopathic DM were unmasked by exercise, suggesting that the 2 DM syndromes may share muscle abnormalities. MRI/MRS may be useful in diagnosis and optimization of treatment.

Adult↗
PubMed1995

Analysis of the Mi-2 autoantigen of dermatomyositis.

OBJECTIVE: To determine the biochemical structure and antigenic components of Mi-2 autoantigen, the target of autoantibodies in 15-20% of dermatomyositis patients. METHODS: Immunoprecipitation from 35S-labeled HeLa cell extract, immunoblotting, and purification from bovine thymus by immunoaffinity chromatography. RESULTS: All 46 sera that had anti-Mi-2 autoantibodies demonstrated by immunodiffusion immunoprecipitated a major protein of approximately 240 kd. Additional proteins of 200, 150, 72, 65, 63, 50, and 34 kd appeared to be part of the antigen. Fractions of purified bovine Mi-2 with antigenic activity showed high molecular weight bands comparable with immunoprecipitated HeLa Mi-2. Twenty-four of 47 anti-Mi-2 positive sera reacted with the 240-kd protein by immunoblot against anti-Mi-2 immunoprecipitates. CONCLUSION: Mi-2 antigen consists of multiple proteins, of which the 240-kd protein appears to be the major reactive component.

Adenosine Triphosphatases↗
PubMed1995

The major dermatomyositis-specific Mi-2 autoantigen is a presumed helicase involved in transcriptional activation.

OBJECTIVE: To characterize the complementary DNA (cDNA) and protein sequences of autoantigens recognized by anti-Mi-2 antibodies, using recombinant Mi-2 proteins for improved autoantibody detection. METHODS: A cDNA expression library was immunoscreened, and cDNA isolation, alignment, and sequence analysis were performed. Northern blotting and in situ hybridization techniques were used. A recombinant protein (rMi-2) was synthesized. Immunoprecipitation of 35S-methionine-labeled HEp-2 cell proteins and immunoblotting of rMi-2 and natural nuclear proteins were performed. Immunofluorescence studies were done with anti-Mi-2 positive sera of dermatomyositis (DM) patients, and with human or rabbit antibodies specific for rMi-2. Antibody screening of systemic lupus erythematosus, rheumatoid arthritis, DM, and antinuclear antibody-positive human sera was performed using an rMi-2 protein enzyme-linked immunosorbent assay (ELISA). RESULTS: A major antigen recognized by anti-Mi-2 positive sera of DM patients was found to constitute a 218-kd nuclear protein (218-kd Mi-2) encoded on chromosome 12 and to belong to the SNF2/RAD 54 helicase family. Human and rabbit antibodies that were affinity purified using the recombinant protein reacted with and precipitated a nuclear protein of similar size, which was also recognized by anti-Mi-2 sera. Anti-218-kd Mi-2 antibodies detected by rMi-2 protein ELISA seemed to be mainly restricted to sera from patients with DM. CONCLUSION: The molecular characterization of the 218-kd Mi-2 antigen may contribute to our understanding of autoimmune phenomena in DM. The use of immunoreactive recombinant proteins allows structural and functional studies of the helicase and the development of sensitive and accurate antibody screening tests.

Adenosine Triphosphatases↗
PubMed1995

Lack of detection of enteroviral RNA or bacterial DNA in magnetic resonance imaging-directed muscle biopsies from twenty children with active untreated juvenile dermatomyositis.

OBJECTIVE: To investigate for the presence of increased titers of circulating antibody to putative infectious agents and for detectable viral RNA or bacterial DNA in children with active recent-onset juvenile dermatomyositis (DM). METHODS: Magnetic resonance imaging-directed muscle biopsies were performed in 20 children with active, untreated, recent-onset juvenile DM and in age-matched children with neurologic disease. Sera were tested for complement-fixing antibody to Coxsackievirus B (CVB), influenza A and B, parainfluenza 1 and 3, Mycoplasma pneumoniae, mumps, respiratory syncytial virus, and Reovirus; and by immunofluorescence for IgG antibody to Toxoplasma gondii cytomegalovirus and IgM antibody to Epstein-Barr virus. Muscle from juvenile DM patients and control children, CD-1 Swiss mice with and without CVB1 infection, and viral stock positive for CVB1-6 were tested using reverse-transcriptase polymerase chain reaction with 5 primer sets, 4 probes (1 Coxsackievirus, 3 Enterovirus), and universal primers for DNA. RESULTS: No increased antibody, viral RNA, or bacterial DNA was present in the juvenile DM patients or the control children. CONCLUSION: Juvenile DM may be triggered by unidentified agent(s) in the genetically susceptible host.

Adolescent↗
PubMed1996

Strong association of dermatomyositis-specific Mi-2 autoantibodies with a tryptophan at position 9 of the HLA-DR beta chain.

OBJECTIVE: To characterize the clinical and immunogenetic features of patients with Mi-2 autoantibodies. METHODS: Eighteen adult white patients with Mi-2 antibodies were clinically characterized and compared with 41 Mi-2-negative dermatomyositis (DM) patients. HLA class I and class II typing for DRB alleles was done by microcytotoxicity assay and for DQA and DQB alleles by polymerase chain reaction-based oligotyping. RESULTS: Seventeen of the 18 Mi-2-positive patients had DM. Symptoms of scleroderma, lung involvement, and arthritis were less common in this group than in the Mi-2-negative DM patients; the V-sign rash and nailfold involvement were found more frequently. Mi-2 antibodies were strongly associated with HLA-DR7 (88% versus 24% in healthy controls), HLA-DQA1*0201 (86% versus 23%), and DR7 "homozygosity" (31% versus 0%). A tryptophan residue at position 9 of the HLA-DR beta chain was present in all Mi-2-positive patients (100% versus 62%; homozygous in 81% versus 15%). CONCLUSION: Our results reemphasize the specificity of Mi-2 antibodies for DM, and extend previous reports that Mi-2 antibody production is associated with certain HLA class II antigens. We propose beta 9-Trp as a candidate epitope on the HLA-DR beta chain as a prerequisite for this type of autoimmune response.

Adenosine Triphosphatases↗
PubMed1997

New-onset juvenile dermatomyositis: comparisons with a healthy cohort and children with juvenile rheumatoid arthritis.

OBJECTIVE: To determine, in a case-control study, if patients with new-onset juvenile dermatomyositis (juvenile DM) have increased symptoms prior to onset, exposure to certain environmental conditions, frequency of familial autoimmune diseases, or antibody titers, compared with 2 control groups. METHODS: A structured interview with the families of 80 children with juvenile DM, 40 children with juvenile rheumatoid arthritis (JRA), or 23 healthy children, from the same geographic area as the children with juvenile DM, was conducted. All children's sera were tested for antibody to Toxoplasma gondii, herpes simplex virus (HSV), or coxsackievirus B (CVB). RESULTS: A high proportion of children with juvenile DM had constitutional symptoms 3 months before the disease-onset date (P = 0.013 versus control children). Children with JRA had more relatives with rheumatoid arthritis (P = 0.0001) and pernicious anemia (P = 0.003) than did children with juvenile DM or healthy children. Among children < or =7 years of age, elevated enteroviral titers were more frequent in those with juvenile DM (81%) and in healthy controls (90%) than in those with JRA (64%), suggesting a common environmental exposure. Titers to T gondii, HSV, or CVB 1-6 were normal. CONCLUSION: Frequencies of familial autoimmune disease, exposure to environmental factors, or elevated antibody titers to T gondii, HSV, or CVB are not increased in juvenile DM. Children with juvenile DM do have symptoms of illness 3 months before the disease-onset date, and young patients have elevated enteroviral titers, as do young geographic controls.

Animals↗
PubMed2004

Down-regulation of the aberrant expression of the inflammation mediator high mobility group box chromosomal protein 1 in muscle tissue of patients with polymyositis and dermatomyositis treated with corticosteroids.

OBJECTIVE: High mobility group box chromosomal protein 1 (HMGB-1) is an endogenous nuclear protein that can be translocated to the cytoplasm and then released extracellularly. It can induce tumor necrosis factor and interleukin-1 production in myeloid cells. Increased expression of these 2 cytokines has been observed in muscle tissue of patients with polymyositis (PM) and dermatomyositis (DM). The present study was therefore undertaken to investigate how HMGB-1 is expressed in muscle tissue of patients with myositis and, if so, whether such expression is modulated by prednisolone therapy. METHODS: Muscle biopsy specimens from 5 patients with PM and 4 patients with DM, obtained before and 3-6 months after initiation of prednisolone therapy, were assessed by conventional microscopic evaluation and computerized image analysis, and HMGB-1 expression was investigated by immunohistochemical staining. Muscle biopsy specimens from 7 healthy controls were also studied. RESULTS: Cytoplasmic HMGB-1 expression was detected in infiltrating rounded mononuclear cells, vascular endothelial cells, and muscle fibers of PM and DM patients. Extracellular staining surrounding the inflammatory cells was also observed. After treatment with high-dose prednisolone, cytoplasmic and extracellular HMGB-1 expression was significantly reduced, coinciding mainly with a decreased number of infiltrating inflammatory cells. Cytoplasmic HMGB-1 expression was still evident in endothelial cells and muscle fibers. No HMGB-1 expression was observed in muscle tissue from healthy controls. CONCLUSION: The cytoplasmic and extracellular distribution of HMGB-1 in muscle tissue may indicate an important role of this proinflammatory molecule in the pathogenesis of PM and DM. Furthermore, our findings indicate that systemically administered high-dose corticosteroids selectively down-regulate aberrant expression of HMGB-1 in mononuclear inflammatory cells in vivo.

Adult↗
PubMed2005

Rituximab in the treatment of dermatomyositis: an open-label pilot study.

OBJECTIVE: To test the hypothesis that B cells play a role in the pathophysiology of dermatomyositis (DM) by examining the effect of B cell depletion in patients with symptomatic DM. Patients were treated with rituximab, a CD20+ B cell-depleting monoclonal antibody. METHODS: This was an open-label uncontrolled pilot trial in 7 adult patients with DM, 6 of whom had longstanding illness that was responding inadequately to a number of currently available immunosuppressive agents. All patients received 4 intravenous infusions of rituximab given at weekly intervals. Patients were followed up for up to 1 year without further treatment with rituximab. One patient was lost to followup. The principal efficacy outcome was muscle strength, measured by quantitative dynomometry. RESULTS: All 6 evaluable patients exhibited major clinical improvement, with muscle strength increasing over baseline by 36-113%. Maximal improvements in muscle strength occurred as early as 12 weeks after the initial infusion of rituximab. CD20+ B cells were effectively depleted in all patients by 12 weeks. Four patients experienced a return of symptoms that coincided with the return of B cells before the 52-week end point. Two patients maintained their increased muscle strength at 52 weeks, and 1 of these patients maintained this strength even after the return of B cells. Other symptoms of DM, including rash, alopecia, and reduced forced vital capacity, improved markedly in patients with these symptoms. Rituximab was well tolerated, with no treatment-related severe or serious adverse events during the observation period of this study. CONCLUSION: This small open-label study of DM patients treated with rituximab provided sufficiently encouraging results to justify a more formal evaluation of the value of B cell depletion therapy in the treatment of DM.

Adult↗
PubMed2005

Autoantibodies to a 140-kd polypeptide, CADM-140, in Japanese patients with clinically amyopathic dermatomyositis.

OBJECTIVE: To identify novel autoantibodies specific for dermatomyositis (DM), especially those specific for clinically amyopathic DM (C-ADM). METHODS: Autoantibodies were analyzed by immunoprecipitation in 298 serum samples from patients with various connective tissue diseases (CTDs) or idiopathic pulmonary fibrosis (IPF). Antigen specificity of the sera was further examined by immunoblotting and indirect immunofluorescence (IF). The disease specificity and clinical features associated with the antibody of interest were determined. RESULTS: Eight sera recognized a polypeptide of approximately 140 kd (CADM-140 autoantigen) by immunoprecipitation and immunoblotting. Immunoreactivity was detected in the cytoplasm, and indirect IF revealed a granular or reticular pattern. Anti-CADM-140 antibodies were detected in 8 of 42 patients with DM, but not in patients with other CTDs or IPF. Interestingly, all 8 patients with anti-CADM-140 antibodies had C-ADM. Among 42 patients with DM, those with anti-CADM-140 autoantibodies had significantly more rapidly progressive interstitial lung disease (ILD) when compared with patients without anti-CADM-140 autoantibodies (50% versus 6%; P = 0.008). CONCLUSION: These results indicate that the presence of anti-CADM-140 autoantibodies may be a novel marker for C-ADM. Further attention should be directed to the detection of rapidly progressive ILD in those patients with anti-CADM-140 autoantibodies.

Adult↗
PubMed2005

History of infection before the onset of juvenile dermatomyositis: results from the National Institute of Arthritis and Musculoskeletal and Skin Diseases Research Registry.

OBJECTIVE: To obtain data concerning a history of infection occurring in the 3 months before recognition of the typical weakness and rash associated with juvenile dermatomyositis (JDM). METHODS: Parents or caretakers of children within 6 months of JDM diagnosis were interviewed by the registry study nurse concerning their child's symptoms, environment, family background, and illness history. Physician medical records were reviewed, confirming the JDM diagnosis. RESULTS: Children for which both a parent interview and physician medical records at diagnosis were available (n = 286) were included. Diagnoses were as follows: definite/probable JDM (n = 234, 82%), possible JDM (n = 43, 15%), or rash only (n = 9, 3%). The group was predominantly white (71%) and had a girl:boy ratio of 2:1. Although the mean age at onset was 6.7 years for girls and 7.3 years for boys, 25% of the children were < or =4 years old at disease onset. In the 3 months before onset, 57% of the children had respiratory complaints, 30% had gastrointestinal symptoms, and 63% of children with these symptoms of infection were given antibiotics. CONCLUSION: This study provides evidence that JDM affects young children. The symptoms of the typical rash and weakness often follow a history of respiratory or gastrointestinal complaints. These data suggest that the response to an infectious process may be implicated in JDM disease pathogenesis.

Causality↗
PubMed2005

Association between lack of angiogenic response in muscle tissue and high expression of angiostatic ELR-negative CXC chemokines in patients with juvenile dermatomyositis: possible link to vasculopathy.

OBJECTIVE: To investigate the relationship between the vasculopathy of juvenile dermatomyositis (juvenile DM) and the balance between the angiostatic ELR- and angiogenic ELR+ CXC chemokines in the muscle of patients with the disease. METHODS: The expression of 3 ELR- CXC chemokines (interferon-inducible protein 10 [IP-10], monokine induced by interferon-gamma, and interferon-inducible T cell alpha-chemoattractant) and 2 ELR+ CXC chemokines was quantitated in muscle biopsy samples from 7 patients with juvenile DM and 7 healthy children, by real-time polymerase chain reaction. The findings were correlated with various histopathologic features, with particular emphasis on the degree of vasculopathy. Synovial biopsy specimens from patients with juvenile rheumatoid arthritis (JRA) were used for additional comparison. RESULTS: The angiostatic ELR- chemokines were expressed at high levels, while the angiogenic ELR+ chemokines were barely detectable, in most juvenile DM samples. This contrasted sharply with the findings in both normal muscle biopsy specimens and JRA synovial tissue specimens. The expression of the ELR- chemokines in juvenile DM samples correlated with the intensity of mononuclear cell infiltration. Furthermore, the juvenile DM samples with the highest degree of capillary loss had the highest levels of ELR- CXC chemokines. The presence of IP-10 in juvenile DM muscle specimens was confirmed by immunohistochemistry analysis. In addition, immunohistochemical staining of muscle tissue revealed that CXCR3, a receptor utilized by ELR- CXC chemokines, was expressed in vascular endothelial cells. CONCLUSION: Increased expression of the interferon-induced angiostatic ELR- CXC chemokines is a feature of juvenile DM that parallels the degree of vasculopathy in patients with the disease. Collectively, these findings are consistent with a model in which a subset of inflammatory cells secrete angiostatic ligands, which then contribute to a local atrophying effect on the muscle's vasculature via a receptor-mediated process.

Biopsy↗
PubMed2005

Quantitative assessments of the effects of a single exercise session on muscles in juvenile dermatomyositis.

OBJECTIVE: To investigate the short-term effects of exercise on muscle inflammation in children with juvenile dermatomyositis (juvenile DM). Magnetic resonance imaging (MRI), muscle strength, and blood parameters were used as outcome measures. METHODS: Children with active juvenile DM, inactive juvenile DM, and healthy children were assessed for muscle strength (using myometry) and function, and MRI T2-weighted relaxation time measurement; blood was obtained from patients with juvenile DM. A standardized physiotherapy-led exercise program was completed, and the MRI was performed immediately afterwards. All children were reassessed with myometry and MRI at 30 minutes and 60 minutes, and repeat blood tests were performed at 60 minutes for the patients with juvenile DM. RESULTS: Ten children with active juvenile DM, 10 with inactive juvenile DM, and 20 healthy controls completed the study. Muscle inflammation assessed by MRI, myometry, and blood parameters did not change significantly in response to exercise either immediately after or up to 60 minutes after the exercise program in any group. CONCLUSION: In the short term, a single bout of exercise does not change the degree of inflammation within the muscles of children with active or inactive juvenile DM or in healthy children. The data suggest that, at least in this time period, there is no evidence that exercise increases the inflammation within the muscles. We propose therefore that a moderate exercise program is safe for children with juvenile DM.

Child↗
PubMed2005

The effectiveness of treating juvenile dermatomyositis with methotrexate and aggressively tapered corticosteroids.

OBJECTIVE: Childhood dermatomyositis (DM) is often a chronic disease, lasting many years. It has traditionally been treated with long-term corticosteroid therapy; side effects are often seen. For more than a decade, methotrexate (MTX) has been safely used for the treatment of juvenile arthritis. Here, we report use of MTX as first-line therapy for DM, along with aggressively tapered corticosteroids, in an attempt to reduce treatment-related side effects. METHODS: We studied an inception cohort of 31 children with DM who were rigorously followed up in our myositis clinic, and compared them with a control group of 22 patients with incident cases of juvenile DM who received treatment just before we instituted a policy of first-line therapy with MTX. The mean starting dosage of MTX in the study group was 15 mg/m(2)/week. RESULTS: Both groups had similar improvement in strength and physical function; however, the median time during which patients in the study group received corticosteroids was 10 months, compared with 27 months for controls (P < 0.0001). As a result, the cumulative prednisone dose in the study group was approximately half that in the control group (7,574 mg versus 15,152 mg; P = 0.0006). The study group had greater height velocity during the first year of treatment and a smaller increase in the body mass index over the first 2 years. In the control group, the relative risk of cataracts developing was 1.95 (95% confidence interval 1.05-4.17). Side effects of MTX were rarely observed. CONCLUSION: Use of MTX in conjunction with an aggressively tapered course of prednisone may be as effective as traditional long-term corticosteroid therapy for children with DM, while decreasing the cumulative dose of corticosteroids.

Dermatomyositis↗
PubMed2006

Functional index-2: Validity and reliability of a disease-specific measure of impairment in patients with polymyositis and dermatomyositis.

OBJECTIVE: To revise the content of the Functional Index in myositis (FI) and to evaluate measurement properties of a revised FI. METHODS: Previously performed FI (n = 287) were analyzed for internal redundancy and consistency, and ceiling and floor effects. Content was evaluated and a preliminary revised FI was developed. To evaluate the construct validity of the preliminary revised FI, it was compared with isokinetic measurements of muscular strength and endurance, the Myositis Activities Profile, disease impact on general wellbeing, and creatine phosphokinase levels. Minor adjustments were made and the revised FI was investigated for interrater reliability and intrarater reliability over a 1-week period. After this, some minor, additional adjustments were made leading to the final version, FI-2. RESULTS: Five tasks were removed from the original FI due to ceiling effects. Performance pace and number of repetitions were modified for the remaining tasks. A moderate correlation (r(s) = 0.58) was found between the shoulder flexion task of the preliminary revised FI and isokinetic measurements of shoulder flexion endurance. Intraclass correlation coefficient (ICC) for interrater reliability of the revised FI varied from 0.86-0.99 with no systematic differences. ICC for intrarater reliability varied from 0.56-0.99 with systematic differences (P < 0.05) between test and retest in 3 of the tasks. The sit-up task was excluded due to low intrarater reliability resulting in the final 7-item FI-2. There was a good correlation between tasks on the right and left side suggesting that the FI-2 could be performed unilaterally. CONCLUSION: The FI-2 is a valid and reliable outcome measure of impairment for patients with polymyositis or dermatomyositis. It is well tolerated and the unilateral FI-2 requires a maximum of 20 minutes to perform. Further evaluation of sensitivity to change and testing in healthy individuals needs to be conducted.

Activities of Daily Living↗