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To investigate the nature of the inflammatory response in facioscapulohumeral muscular dystrophy (FSHD), we analyzed mononuclear cells in muscle sections obtained from 18 FSHD patients and 8 controls. Monoclonal antibodies reactive for T cells, T cell subsets, B cells, and NK cells were used for cell typing. Macrophages were identified by acid phosphatase reaction. The localization of perforin, granzyme A, MHC-I and -II, dystrophin, and alpha-actinin antigens was also examined. We found that all FSHD patients, both familiar and sporadic cases, had greater amounts of mononuclear cellular infiltrates in muscle than controls, in whose specimens only few extra vascular mononuclear cells were counted. Seventy-two percent (13 of 18) of the patients had more than 50 inflammatory mononuclear cells per 1000 muscle fibers, and 33% (6 of 18) patients had numerous inflammatory cells exceeding 600 per 1000 muscle fibers (1835 +/- 482 SE). Nonnecrotic fibers invaded by mononuclear cells with either T8+, perforin+, or granzyme A+ were not observed in FSHD, while a few degenerating fibers were superficially invaded by T cells and macrophages. Occasional T cells were observed moving through the blood vessel wall. The increased number of necrotic fibers was paralleled by an increased number of inflammatory cells (r = 0.783, P = 0.0001). Genetic analysis, using the probes p13E-11, pFR-1, D4S139, and D4S163, was done in 6 patients (3 familiar, 3 sporadic) who had numerous inflammatory infiltrates. These 6 patients had small (< 28 kb) EcoRI fragments associated with the disease, and the disease was linked to 4q35. These results suggest that, in chromosome 4-linked FSHD: (1) inflammatory changes in muscle are a common histological feature; (2) mononuclear cellular infiltrates may enhance muscle fiber damage; but (3) T-cell-mediated cytotoxicity directed against muscle fibers is unlikely. We speculate that the immune effector mechanism in FSHD is different from that in previously reported inflammatory myopathies and Duchenne muscular dystrophy.

Sporadic inclusion-body myositis is the most common progressive muscle disease of older patients. The muscle biopsy demonstrates mononuclear cell inflammation and vacuolated muscle fibers containing paired helical filaments and 6 to 10-nm fibrils, both resembling those of Alzheimer brain, and Congo-red positivity. Hereditary inclusion-body myopathy designates patients cytopathologically similar but without inflammation. In both muscle diseases, prion, and several proteins characteristic of Alzheimer brain--eg, beta-amyloid protein and hyperphosphorylated tau (which normally are expressed mainly in neurons), and apolipoprotein E--are abnormally accumulated in vacuolated muscle fibers, by unknown mechanisms. We now demonstrate in both muscle diseases that prion mRNA is strongly expressed in the vacuolated muscle fibers, which suggests that their accumulated prion protein results, at least partly, from increased gene expression. This, to our knowledge, is the first demonstration of abnormally increased prion mRNA in human disease. Another novel finding is the increased prion mRNA in human muscle macrophages, and both increased prion protein and prion mRNA in regenerating muscle fibers. The latter indicates that prion may play a role in human muscle development.

The intermediate filament nestin is transiently expressed in developing skeletal muscle. In the present investigation, we analyzed by immunohistochemistry the presence of nestin, as well as vimentin and desmin, in skeletal muscle affected by two diseases characterized by various degrees of necrosis and muscle regeneration: Duchenne/Becker muscular dystrophy and myositis. Nestin-positive areas were found in all analyzed muscle biopsies of both diseases. The same areas were, in most cases, also positive for vimentin and stained more intensely for desmin than surrounding myofibers. Only nestin was found specifically in myopathic muscle fibers; vimentin was in addition present in muscle fibroblasts and desmin in all myofibers. The areas staining positive for nestin were typically basophilic, small-diameter myofibers, often with centrally located nuclei. With the interesting exception of a 73-year-old healthy control with abundant ring fibers, nestin was not detected in the muscle of healthy controls. The intracellular distribution of nestin in the myopathic muscle fibers, as well as in the ring fibers, was confined to the vicinity of Z-bands. The presence of nestin protein in myopathic regenerating areas and in ring fibers correlated more closely to the presence of desmin than to vimentin immunoreactivity. Our results suggest that nestin is specifically expressed in newly formed muscle fibers also during regeneration, and that nestin may serve as a useful marker of regenerating muscle fibers in pathological conditions.

Inclusion body myositis (IBM) is one member of a group of disorders known as idiopathic inflammatory myopathies (IIM) in which autoreactive T cells directed against muscle are thought to play a primary role in disease pathogenesis. We have utilized the polymerase chain reaction to determine the pattern of alpha beta T-cell receptor (TCR) variable (V) gene expression in muscle biopsies from 13 IBM patients. In the majority of biopsies, we detected oligoclonal patterns of TCR V gene expression by muscle-infiltrating lymphocytes; an average of six out of the 22 TCR V alpha gene families surveyed and seven out of 24 TCR V beta gene families surveyed were detected per biopsy. While no TCR V alpha gene families were over-represented in our survey, TCR V beta 3 and V beta 6 gene usage was a prominent feature of IBM muscle biopsies. TCR gene expression was characterized further by analysing the junctional sequence composition of both V beta 3 and V beta 6 clones from muscle biopsies of the IBM patients. A large number of structurally diverse V beta 3 and V beta 6 clonotypes were identified from these patients demonstrating a polyclonal pattern of T cell infiltration. These data, while describing prominent TCR V beta 3 and V beta 6 gene detection, do not suggest that a common antigen-driven T-cell response promotes chronic inflammation in muscle of IBM patients.

Perforin (PF) and granzyme A (GA) are candidates suspected of being cytolytic proteins of the granules of cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells. We analysed PF and GA in muscles from patients with inflammatory myopathies. Five cases of polymyositis (PM), two cases of inclusion body myositis (IBM), and five cases of dermatomyositis (DM) were studied immunohistochemically using anti-PF and GA antibodies raised against each synthetic peptide of human PF and mouse GA, together with a panel of monoclonal antibodies reactive for lymphocyte subsets. In PM and IBM, PF positive cells were colocalized with GA positive cells and occasionally invaded into the non-necrotic muscle fibres. The percentage of PF positive cells among the endomysial CD8 positive cell population was 9.9% (PM) and 12.5% (IBM), and the majority of the endomysial CD8 positive cells were alpha/beta T cells. In contrast, in DM, both PF and GA positive cells were very few in all cases. Only few inflammatory cells were CD16+ or CD57+ NK cells among these diseases. Our results suggest that PF and GA are secreted mainly from alpha/beta T cells, and may play a key role in muscle fibre damage in at least some PM and IBM, but not in DM.

The paper reports three cases of myositis. The findings at detailed electroneuromyographic, morphologic and ultrastructural tests were indicative of characteristic vacuole inclusions in the muscular fibers. Two patients had associated neuritic disorders diagnosed neurophysiologically and morphohistochemically. The neuritic component proved aggravating in the course of the disease. Diagnostic myographic and morphological criteria are analyzed which can distinguish myositis with inclusions from other muscular inflammatory disease.

The expression of the myogenic determination gene MyoD1 plays a primary role in the commitment of primitive mesenchymal cells to a striated muscle lineage and is down-regulated during later stages of differentiation. To determine the potential role of this gene in myopathic conditions, we examined its expression by means of immunohistochemical analysis, using a series of muscle biopsies from 14 patients with a variety of primary myopathies and neurogenic disorders. Utilizing the avidin-biotin-complex technique, cryostat sections were stained with monoclonal antibody 5.8 A, which we have previously described as having a high level of specificity for tumors with rhabdomyoblastic differentiation. Of special interest was the observation in 4 of 8 cases of neurogenic atrophy of varying levels of cytoplasmic positivity of muscle fibers, appearing to correlate with their degree of atrophy, in addition to weak nuclear staining. Muscle biopsies from 2 patients with Duchenne's muscular dystrophy and 2 patients with autoimmune inflammatory myopathies demonstrated various levels of nuclear positivity in scattered foci that appeared to correlate with areas of regeneration. A biopsy from a single case of neurogenic atrophy secondary to infantile spinal muscular atrophy (Werdnig-Hoffmann's disease) demonstrated diffuse but relatively weak staining of myofiber nuclei, in contrast to sections of normal striated muscle and muscle biopsies from patients with unexplained myoglobinuria, which exhibited only minimal amounts of staining. These data are compatible with observations that MyoD1 expression is related to electrical activity and muscle regeneration.

We report on the expression of growth associated protein (GAP)43 and neural cell adhesion molecule (NCAM) in congenital fibre type disproportion (CFTD) with myopathological additional signs of interstitial myositis. We assume that sarcolemmal GAP43 in developmental disordered myocytes plays a role in maintenance of growth morphology. In muscular dystrophy light microscopical evaluation reveals no GAP43 immunoreactivity in regenerating fibres. The expression of GAP43 seems to be a characteristic feature of CFTD. The expression of NCAM, particularly in the sarcolemma of small muscle fibres of CFTD, indicates a functional state of permanent partial denervation. Whether the steroid-responsive interstitial myositis is pathogenetically related to CFTD or a coincidental inflammation is not known. Because of the clinical and myopathological data the differential diagnosis of Emery-Dreifuss muscular dystrophy is considered.

In muscle biopsies of 8 sporadic inclusion-body myositis (S-IBM) and 4 hereditary inclusion-body myopathy (H-IBM) patients, vacuolated muscle fibers contained within their vacuoles strongly immunoreactive inclusions with 2 polyclonal and 1 monoclonal antibodies against prion protein (PrP). By light-microscopy, PrP deposits co-localized with beta-amyloid protein (A beta) and ubiquitin (Ub). By immuno-electronmicroscopy, both PrP and A beta were present on amorphous material and on 6-10 nm amyloid-like fibrils; and PrP and Ub co-localized on cytoplasmic twisted tubulofilaments (TTFs) and on amorphous material. Our study provides the first demonstration of abnormally accumulated PrP in pathological tissue other than brain, and it suggests that PrP may play a role in the pathogenesis of IBM.

Ubiquitin has been shown by immunohistochemical studies to be a component of many of the filamentous inclusion bodies that are known in neuropathology. In the current study, we examined the expression of ubiquitin in 14 cases of typical inclusion body myositis, in skeletal muscle specimens from four cases of typical amyotrophic lateral sclerosis, and in muscle specimens from three normal controls. In the cases of inclusion body myositis, rimmed vacuoles were ubiquitin immunoreactive in all cases. Intrasarcoplasmic inclusions were positive in the nine cases that had them. In four cases, there were positive intranuclear inclusions, and in seven, there was homogeneous staining of nuclei. Atrophic fibers and necrotic fibers were positive in 11 and nine cases, respectively. In the cases of amyotrophic lateral sclerosis, atrophic fibers were positive in three cases, and focal nuclear staining was seen in two. In one of the three control cases, a few atrophic fibers had faint sarcoplasmic positivity; no other staining was seen. We conclude that ubiquitin is a component of the inclusions that characterize inclusion body myositis. However, ubiquitin expression in skeletal muscle disease is not pathognomonic of inclusion body myositis.

Although major histocompatibility complex (MHC) class I molecules have been consistently demonstrated on muscle fibers of patients with inflammatory myopathies (IM), results concerning the expression of MHC class II molecules have been conflicting and mechanism of the expression remains to be elucidated. Expression of MHC and neural cell adhesion molecules (N-CAM) was analyzed in 38 cases of IM and in 13 cases of normal and disease controls by the immunocytochemical method. The sarcolemmaL HLA-ABC molecules were seen in all IM cases, and were visualized on the every muscle fiber in 68% of the cases. In contrast, the HLA-DR, -DP, or -DQ expression was seen on scattered fibers in 37%, 11%, 5% of IM cases, respectively. The HLA-DR reactivity was often seen on muscle fibers in the vicinity of infiltrating cells or on the perifascicular fibers. The HLA-DR positive fibers did not express N-CAM, suggesting a degenerating/regenerating process of muscle fibers was not contributory to the aberrant expression of MHC class II molecules. The perifascicular HLA-DR expression was related to the perifascicular atrophy and was more frequent in polymyositis complicated with interstitial pneumonitis. Those results suggest that increased expression of MHC class I molecules precede the aberrant expression of MHC class II molecules, and the perifascicular atrophy might reflect immunopathological processes.

Vacuolated muscle fibers in muscle biopsies of 8 out of 8 inclusion body myositis (IBM) patients, including 2 hereditary patients, manifested increased mRNA for the beta-amyloid precursor protein (beta APP) that contains Kunitz-type protease inhibitor motif. In affected fibers, increased beta APP-mRNA correspond to abnormally accumulated beta APP immunoreactivity (including beta-amyloid protein epitope). In normal human muscle fibers increased beta APP-mRNA was present only at the neuromuscular junctions. Our study (a) suggests that abnormally accumulated beta APP in IBM vacuolated fibers results, at least partly, from increased beta APP generation, and (b) provides the first demonstration of up-regulated beta APP-mRNA in pathologic human tissue other than brain of Alzheimer's disease and Down's syndrome.

Mechanisms to explain the "inoculum effect" have not been elucidated in gram-positive infections. A mouse model of group A streptococcal myositis was used to compare the efficacies of two beta-lactams, penicillin and ceftriaxone, and a protein synthesis inhibitor, clindamycin, at three different inoculum sizes. beta-lactams were more susceptible to inoculum effects than was clindamycin both in vivo and in vitro (P < .05). The large inocula were hypothesized to reach stationary phase of growth sooner than smaller inocula both in vitro and in vivo. The penicillin-binding protein (PBP) patterns from membrane proteins isolated from mid-log-phase and stationary-phase cultures of Streptococcus pyogenes were compared. Binding of radiolabeled penicillin by all PBPs was decreased in stationary cells; however, PBPs 1 and 4 were undetectable at 36 h. Thus, the loss of certain PBPs during stationary-phase growth in vitro may be responsible for the inoculum effect observed in vivo and may account for the failure of penicillin in both experimental and human cases of severe streptococcal infection.

Myositis describes a heterogeneous group of disorders whose main pathologic feature is chronic inflammation of the affected muscles. The association of myositis with other autoimmune diseases, the response to corticosteroid and immunosuppressive therapy, the frequent occurrence of autoantibodies, and the presence of chronic inflammatory cells in the affected muscles of patients with myositis indicate that the myositis syndromes are autoimmune diseases. This review summarizes recent observations on the role of humoral and cellular mechanisms in myositis. During the past year, the most notable contributions included studies on the relationship among autoantibodies and various clinical and epidemiologic features of patients with myositis; further evidence for T-cell involvement in the pathogenesis of myositis; demonstration of amyloid proteins in muscle fibers of patients with inclusion body myositis; and a controlled trial of plasma exchange and leukapheresis in myositis.

In normal muscle, 65-kd heat shock proteins (hsp) were detected on capillary endothelial cells, the mural elements of larger vessels, and some intracellular organelles, probably mitochondria. In the inflammatory myopathies, the 65-kd hsp were detected on inflammatory cells, degenerating and regenerating fibers, and on many but not all nonnecrotic muscle fibers invaded by T cells. The expression of the 65-kd hsp may be an immune-nonspecific response to cellular "stress," but hsp determinants could possibly also serve as autoantigen(s) recognized by autoreactive T cells.

Noninvasive early recognition and treatment of temporomandibular joint dysfunction remains a diagnostic challenge. This pilot study evaluated the use of phosphorus 31 magnetic resonance spectroscopy with magnetic resonance imaging to measure alterations in pH and high-energy phosphate metabolite ratios of muscle that is adjacent to an inflamed temporomandibular joint. Ten New Zealand white rabbits were used in this study. Two animals were used to develop signal acquisition protocols and to ensure that stable baseline data could be measured. In each of the eight animals used in the experiment, one temporomandibular joint was injected with a suspension of silica particles and the contralateral joint served as a control. Data were collected from control and experimental joints on days 0, 7, 14, 21, and 28, after the injection. At the end of the study, temporomandibular joints were block resected and histologically examined to confirm the presence of an inflammatory response. Results indicated that pH and metabolite ratios could be obtained by 31P-magnetic resonance spectroscopy. Changes in pH and some metabolite ratios in experimental joints showed statistical significance (p < 0.001). Differences were seen on day 2 and day 7 (p = 0.040 and p = 0.008, respectively) in the phosphocreatine/alpha-adenosine triphosphate ratios. This contrasts with phosphocreatine/beta adenosine triphosphate ratios that showed significance that began at day 7 (p = 0.022) and continued to day 14 (p = 0.025). Histologic examination indicated that the tissue response within the joint capsule was less than the granulomatous reaction expected.(ABSTRACT TRUNCATED AT 250 WORDS)

In 11 of 11 inclusion-body myositis (IBM) patients, including one hereditary case, vacuolated muscle fibers contained large and multiple small inclusions immunoreactive for beta-amyloid protein (beta AP). All IBM muscle biopsies had characteristic cytoplasmic tubulo-filaments (CTFs) by electron microscopy. None of 14 control muscle biopsies contained the beta AP immunoreactive (IR) inclusions characteristic of IBM. On the light microscopy level, beta AP-IR inclusions colocalized with ubiquitin immunoreactivity. By immunogold electronmicroscopy, beta AP immunoreactivity was localized to a) amorphous, poorly defined structures, b) dense floccular material, c) clusters of loosely packed amyloidlike fibrils 6-8 nm in diameter, and d) poorly defined loose fibrillar structures 6-8 nm in diameter. beta AP immunoreactive structures were often in proximity to CTFs, but CTFs themselves never contained beta AP-IR. Our study provides the first demonstration of beta AP accumulations in abnormal human muscle. This finding suggests that in addition to Alzheimer's disease, Down syndrome, and Dutch-type hereditary cerebrovascular amyloidosis, beta AP may play an important role in the pathogenesis of other diseases, including ones outside the central nervous system, for example, IBM.

Histologic and biochemical anomalies of muscle mitochondria were identified in four patients with predominantly rhizomelic myalgia clinically suggestive of an inflammatory disease but inconsistent biologic evidence of inflammation. This clinical pattern was initially suggestive of atypical polymyalgia rheumatica and could not be ascribed to any other disease. To explain this combination of anomalies, several hypotheses can be put forward, including coincidence, aging, and nonspecific mitochondrial anomalies resulting from immunologic or inflammatory disease. The speculation that these patients have an autonomous syndrome cannot be outruled but should be considered with caution. A therapeutic trial with coenzyme Q is under way.

Two cases of proliferative myositis, four cases of proliferative fasciitis and one mixed form of proliferative myositis and fasciitis have been analyzed in terms of cell differentiation and DNA content. Light microscopically, the lesions were characterized by a mixture of proliferating spindle-shaped cells and uni-, bi- or occasionally multinucleated ganglion cell-like cells. The spindle cells showed ultrastructural features and immunohistochemical properties, including an immunoreactivity for smooth muscle-specific actin, indicative of a myofibroblastic differentiation. The ganglion cell-like cells displayed some resemblance to active osteoblasts ultrastructurally and differed immunohistochemically from the spindle cells by being non-immunoreactive for smooth muscle-specific actin. None of the two cell types showed immunoreactivity for desmin, myoglobin or factor VIII RAG. It is suggested that the two cell types represent different lines of cell differentiation. The cytologic features in smears, as seen in two cases of proliferative fasciitis and one case of proliferative myositis, are considered to be characteristic of these lesions and to permit the diagnosis to be made by fine-needle aspiration. In two of the cases, the lesion was diagnosed only cytologically and thereafter disappeared spontaneously within a month. Cytometric DNA measurements, using two different image analysis systems on Feulgen-stained sections and smears, revealed a "diploid" spindle-shaped cell population with a variable proportion of cells with scattered DNA values. The ganglion cell-like cells differed from the spindle cells by having a broad DNA peak in the diploid region and additional peaks in the tetraploid region, as well as a higher proportion of cells with scattered DNA values compared with those of the spindle-shaped cells. The results of the quantitative DNA analysis are well in keeping with the benign and proliferative nature of these lesions. However, with the technique used here, quantitative DNA analysis, does not distinguish these pseudosarcomatous fibrous lesions from diploid and tetraploid soft tissue sarcomas.

We report a kindred manifesting clinical features and muscle biopsy findings of inclusion body myositis (IBM). In this family, multiple members were affected in two generations with direct male-to-male and female-to-male transmission. This is the first reported instance of autosomal dominant inheritance in IBM, which usually occurs sporadically or, rarely, may be transmitted as an autosomal recessive disorder.

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.

During the course of a systematic study of T cell lines derived from muscle of patients with various inflammatory myopathies, we identified a new form of polymyositis that is mediated by gamma-delta T cells. In the affected patient's muscle CD3+CD4-CD8- gamma-delta T cells surrounded and invaded nonnecrotic muscle fibers in the same way as CD3+CD8+ alpha-beta T cells surround and invade nonnecrotic muscle fibers in inclusion body myositis and other forms of polymyositis. Gamma-delta T cells were extremely rare or absent in muscles and muscle-derived T cell lines in other patients with polymyositis, inclusion-body myositis, dermatomyositis or granulomatous myopathy. This new form of polymyositis has provided us with a unique opportunity to study cytotoxic gamma-delta T cells and their muscle-fiber targets in situ. All muscle fibers expressed HLA-class I antigen and the 65-kD heat-shock protein. The autoaggressive behavior of the gamma-delta T cells is consistent with the hypothesis that in some inflammatory myopathies autoinvasive T cells recognize muscle fiber associated antigen(s). Further studies are needed to define the type of gamma-delta T cell receptor used and the antigen(s) recognized by gamma-delta T cells in this rare type of autoimmune muscle disease.

Inclusion body myositis (IBM) represents a serious debilitating disease of muscle without identifiable cause or treatment. Muscle biopsy specimens have characteristic rimmed vacuoles, varying degrees of inflammation, and, most importantly, cytoplasmic and intranuclear filamentous inclusions of unknown composition. Fresh-frozen sections of muscle biopsy specimens from 24 IBM cases were stained with Congo red dye (pH, 10.5 to 11.0). Control biopsy specimens included polymyositis, dermatomyositis, hereditary vacuolar myopathies of unknown cause, acid maltase deficiency, distal myopathy, oculopharyngeal dystrophy, and chloroquine myopathy. Sections were also immunostained with antibody to transthyretin, human P component, and immunoglobulin light chains. In the vacuolated fibers in IBM, amyloidogenic green-birefringent deposits were seen. Some deposits were delicate and wispy appearing, and others were plaque-like. The size of deposits varied, measuring 1 x 2 to 8 microns, and rarely up to 20 microns in length. The number of amyloid-positive fibers correlated with the number of vacuolated fibers. Similar deposits were seen in one case of distal myopathy and one hereditary vacuolar myopathy. Other control cases were negative for amyloid deposits. Antibody staining for known amyloidogenic proteins was negative. This study demonstrates that the filaments in IBM share properties with amyloid proteins. The location implies that this amyloid material is formed intracellularly, rather than having a systemic derivation. The association of amyloid deposits with autophagic vacuoles in IBM raises the likely possibility that the filaments represent a modification of a normal protein within an acidic degradative vacuolar compartment. An alternative possibility, considering the shared properties of IBM filaments and prions (which include size and amyloidogenic properties), is that IBM represents a human prion disease.(ABSTRACT TRUNCATED AT 250 WORDS)

We described a model of orbital myositis that was induced by 12-0-tetradecanoyl-phorbol-13-acetate (TPA) injection into the superior rectus muscle of New Zealand white rabbits. In this study, in vivo 31P magnetic resonance spectroscopy (MRS) was performed with a 4.7 Tesla Oxford (Oxford Instruments, Oxford, England) magnet to monitor the evolution of muscle inflammation in control animals and the response of this model to external beam radiation. 31P MRS showed a dramatic increase in high-energy phosphorus and phospholipid metabolites 48 hr after TPA injection. These spectra were similar to those from implanted allogenic fibroblasts. Within 18-48 hr after a single dose (400 cGy) or sequential doses (3 days at 400 cGy) of orbital irradiation, reduced extraocular muscle swelling and a significant decrease of all 31P metabolites occurred. A decrease (63 +/- 6%) in the signal-to-noise (S/N) ratio of the control inflamed muscle 31P MR spectra increased by 28 days after inflammation. Two days after single-dose radiation, 31P MR metabolites were significantly lower (58 +/- 5%, P less than 0.012) than control spectra. These postradiation spectra mirror the 28-day control spectra and are consistent with previous histologic data that show decreased fibroblastic activity. Change in 31P MRS was a sensitive indicator of treatment response latency.

We studied four cases of proliferative myositis by the avidin-biotin-peroxidase complex technique, using a panel of 12 antibodies, and by electron microscopy. The aim was to clarify the nature of their constituent cells, specifically the giant ganglion-like cells and spindle cells, and to discuss the implications for histogenesis. In all cases, both cell types showed positive cytoplasmic staining with antibodies to vimentin, actin (C4), and alpha-smooth muscle actin-1, but in only one was there positive staining with desmin. No staining was obtained with factor XIIIa, muramidase, alpha-1-antitrypsin, myoglobin, S-100 protein, CAM 5.2, factor VIII-related antigen, or neuron-specific enolase. By electron microscopy, both types of cells were seen to contain numerous thin filaments, dense bodies, coated and pinocytotic vesicles, active and dilated rough endoplasmic reticulum, few microvilli, and incomplete desmosomal junctions. Our findings imply a myofibroblastic nature for the giant ganglion-like cells and spindle cells. Our observations also support the hypothesis that they are derived from a pericytic cell.

A young patient had an auriculo-ventricular block and a distal myopathy with muscle biopsy findings suggestive of inclusion body myositis. What was most unusual was the presence of numerous sarcoplasmic bodies identified as desmin by electron microscopy and immunocytochemistry. The nosological situation of this condition is discussed.

Alzheimer amyloid precursor proteins (APP) are actively secreted by stimulated human peripheral mononuclear blood leucocytes (PMBLs). Induction of APP transcription, translation and secretion was observed with several T cell mitogens but was highest with phytohemagglutinin. The time course of induction is similar to that reported for IL-2 and IL-2 receptor. We suggest that APP may play an important role in the construction of the immunological network and the differentiation of T cells.

Antibodies directed against neural cell adhesive molecules (NCAM) and in particular a monoclonal antibody recognizing polysialylated isoforms, were used to characterize the expression of these molecules in normal and diseased human muscles. Normal subjects as well as patients with inflammatory, dystrophic and denervating diseases were examined. By immunohistochemistry the main observations were (1) satellite cells expressed the non-sialylated form of NCAMs; (2) regenerative fibers strikingly expressed NCAMs and their sialylated isoforms both on membranes and in the cytoplasm; (3) in denervated muscles, fibers in atrophic groups and some fibers in acute denervation expressed NCAMs on their membrane but not the highly sialylated form; (4) finally, some fibers in myotonic dystrophy and fibers with rimmed vacuoles also expressed NCAMs. Biochemical approaches, using enzymes such as endoglycosidase N and phosphatidylinositol phospholipase C combined with immunoblot analysis allowed visualization of the nature of the expressed isoforms. We have shown that non activated cells, i.e. satellite cells and denervated fibers do not express polysialylated NCAMs. This post-translational modification may be only observed in activated or regenerating fibers. This would parallel the sequence of NCAM expression occurring in normal myogenic pathways.

Cell-mediated immunity has been implicated in the pathogenesis of polymyositis (PM). We conducted a prospective study in which serum levels of soluble interleukin-2 receptors (IL-2R), IL-1 alpha, and IL-2 were correlated with creatine kinase (CK) levels and clinical disease activity. Cytokines and IL-2R were quantitated in 133 serum samples from 14 patients by use of an enzyme-linked immunosorbent assay. In patients with acute PM (9 patients), soluble IL-2R and IL-1 alpha levels were elevated initially, but declined rapidly with therapy. A significant linear relationship was found between soluble IL-2R levels and CK levels. IL-2 was initially detectable in only 3 patients, and it disappeared with therapy in all 3. The levels of cytokines and IL-2R were consistently normal in patients with inactive PM (2 patients). In patients with chronic PM (3 patients), the cytokines and soluble IL-2R levels were normal despite persistently abnormal CK levels and/or muscle weakness. Cellular IL-2R levels correlated positively with serum levels of soluble IL-2R. Our studies substantiate a pathogenic role for cellular immunity in PM, with the finding of activation of lymphocytes. The finding of increased levels of IL-1 alpha demonstrates for the first time that there is monocyte activation in PM. Persistent elevation of CK levels after normalization of the levels of cytokines and IL-2R may be prognostic of impending chronic disease. Serum soluble IL-2R appear to be a sensitive indicator of improvement or exacerbation of disease activity in patients with PM.

A subgenomic cDNA probe with broad specificity for a range of enteroviruses was used to test by an in situ hybridisation technique for the presence of enterovirus specific genomic sequences in muscle biopsy samples obtained from patients with chronic adult myositis. Virus specific RNA sequences were detected in 6/13 (46%) patients with idiopathic polymyositis or dermatomyositis. Control samples obtained from an equal number of patients suffering from other muscle disorders were negative. A monoclonal antibody specific for an enterovirus group was used to probe for viral antigens by indirect immunoperoxidase staining; all biopsy samples from test and control groups were negative.

Two-dimensional gel electrophoresis (2DE) was used to compare the protein composition of human muscle biopsies that were shown by histochemical staining to be deficient in either type 1 or type 2 fibers. Distinct quantitative differences were found in the myofibrillar protein composition of muscle from a 43-year-old woman with proximal limb weakness that showed almost total absence of type 1 fibers and muscle from a 2.5-year-old girl with congenital myopathy in which there was severe lack of type 2 fibers. These data indicate that human type 1 and type 2 muscle fibers express distinct isoforms of myosin light chains and alpha-tropomyosin.

Dissecting aneurysm and stroke are a rare complication of polymyositis. The present report describes an autopsy case of a 53-year-old woman, who suffered from polymyositis accompanied by dissecting aneurysms of right external iliac and right renal arteries, and furthermore, intracerebral hemorrhage. The latter was caused by necrotizing angiitis. The patient had no abnormal anatomical changes such as coarctation of aorta, aortic stenosis, bicuspid aortic valve or Marfan's syndrome. Atherosclerosis in the patient was mild, and cystic medial necrosis of aorta and arteries was not found. Since the patient was attacked by dissections of arteries following long-term steroid therapy, a possibility can be raised that arterial dissection was attributable to steroid treatment besides necrotizing angiitis complicating in polymyositis.

Thirty-one patients with rheumatoid arthritis were consecutively studied for evidence of muscle involvement, using muscle biopsy and electromyography. The patients were initially separated into 4 clinical categories: inactive peripheral joint disease (6 patients); active peripheral joint disease (10 patients); systemic disease and a disproportionately elevated sedimentation rate for the degree of mild synovitis (SERD) (11 patients); or elevated creatinine phosphokinase level (4 patients). In addition to routine histology, muscle tissue was examined for de novo synthesis of IgM and IgM rheumatoid factor, and by indirect immunofluorescence for the presence of immunoglobulin and complement deposits. Our results indicate that: muscle fiber necrosis occurs frequently in patients with rheumatoid arthritis; rheumatoid myositis, defined as muscle fiber necrosis and mononuclear cell infiltration, is a distinct entity and occurs particularly in patients with SERD or an elevated creatinine phosphokinase level; and only muscle from patients with rheumatoid myositis exhibited de novo synthesis of rheumatoid factor and significant quantities of IgM, indicating that local immune events may be important in the pathogenesis of this entity.

Frozen muscle biopsy sections from 13 patients with inflammatory myopathy and from four healthy volunteers were characterized with a double immunohistochemical staining technique, utilizing a panel of antisera to cell surface antigens. The technique enables simultaneous visualization of HLA-DR reactive cells and other cell types, i.e., T lymphocytes. In inflammatory myopathy, large numbers of HLA-DR reactive "macrophage/dendritic" cells were shown. Almost all other inflammatory cells and endothelial cells also expressed HLA-DR, as did the sarcolemma in the vicinity of inflammatory foci. Large numbers of T lymphocytes were detected by alphaLeu-1 antibodies. In most instances, Leu-3a reactive T "helper" lymphocytes dominated over alphaLeu-2a reactive T "suppressor/cytotoxic" lymphocytes. Many T lymphocytes of both phenotypes appeared in close contact with HLA-DR expressing non-T cells. OKM1 and OKT9 antibodies, labeling macrophages and "proliferating" cells, respectively, were common among inflammatory cells. The findings provide basic data that are important for the understanding of inflammatory myopathy.

Thirty-nine human skeletal muscle biopsies from 24 individuals were classified as normal, neuropathic, or myopathic muscle according to classical clinical observations and histopathological properties of the muscles. The content in myosin light chains (LC) of each muscle sample was analyzed by means of a new technique of polyacrylamide gel electrophoresis that gives an improved discrimination, involving isoelectrofocusing of the muscle homogenate for the first dimension and successive migration in a urea-containing gel for the second dimension. Four different LC patterns have been observed in the normal muscles; these four patterns and three different ones have been observed in the pathological muscles. No apparent correlation exists between the myosin LC content and the histochemical fiber typing. It is concluded that the myosin LC are apparently not a useful marker to detect the normality or the pathology of human muscle.

In polymyositis (PM), neither the precise target nor the mechanism of the attack against skeletal muscle have yet been defined. In this study, we report evidence of a pathologic process involving a membrane component of muscle, acetylcholine receptors (AChRs). Our results show that PM patients have significantly reduced AChRs at neuromuscular junctions, averaging 55% below control values (P less than 0.01). Incubation of cultured mammalian muscle cells with sera from PM patients significantly reduced (P less than 0.005) the number of surface AChRs and increased their rate of degradation in 7/8 cases (P less than 0.005). Similar effects were produced by purified IgG from PM patients. These results demonstrate the presence in PM patients of circulating IgG with functional effects on a component of the surface membrane of skeletal muscle. They suggest that PM and myasthenia gravis may have important features in common.

A report is given on a case of proliferative myositis in a 75 year old woman. By fine structural analysis it can be shown, that the characteristic giant cells in proliferative myositis are mesenchymal cells with an intensive protein metabolism. They can be compared to fibroblasts; for a myogenic origin of these cells we found noevidence. Furthermore, various stages in the development and function of the proliferating cells were observed, by which the course of the disease can be expalined.

We studied picornavirus-like inclusions in muscle of a 66-year-old man with chronic polymyositis. Inoculation of a muscle homogenate to suckling mice and VeRo cells failed to detect any virus. After treatment of ultrathin sections with 2% amylase, individual particles that constituted inclusions were digested, as were free glycogen particles in the same section. Particles of the inclusions were stained with periodic acid-thiocarbohydrazide-silver proteinate and alkaline-bismuth, as were glycogen particles. The picornavirus-like inclusions seemed to consist of glycogen particles than form a crystalline arrangement in degenerated muscle fibers.

Thirty-two patients with adult-onset polymyositis uncomplicated by cancer or systemic connective tissue disease were studied. Muscle biopsy specimens were examined with direct immunofluorescence microscopy and results were compared with those in 94 control subjects. Sarcolemmal and sarcoplasmic staining were observed in both groups and considered to be nonspecific. Immune deposits in the muscle microvasculature were present in some cases of systemic lupus erythematosus and dermatomyositis but were not present in polymyositis. Our data suggest that the finding of vascular immunofluorescence excludes the diagnosis of adult polymyositis and implies that the pathogenesis of this disease and other idiopathic inflammatory myopathies may differ.

Muscle biopsies from nine patients with polymyositis, six with muscular dystrophy, six with other muscle diseases and three controls have been studied with a panel of 10 monoclonal antibodies (MoAb) identifying T lymphocytes, HLA-class I antigens, alpha, beta and gamma interferons and interleukin 2 (IL-2). The result confirm that the staining of the sarcolemma with anti-HLA class I antibody is weak or negative, except in areas adjacent to infiltrating leucocytes or where muscle fibre damage is evident. The very similar tissue distribution of alpha, beta and gamma interferons in the polymyositis biopsies supports the hypothesis that interferons are released by the inflammatory infiltrate and induce the class I antigen expression. In contrast, little interferon was demonstrated in the dystrophic muscle implying that class I expression in these disorders must occur by a different mechanism. Little IL-2 was demonstrated in any of the biopsies though some unexplained small dense accumulations were identified by one of the anti IL-2 MoAb.