Polymyositis/dermatomyositis Research Articles

Disordered immune regulation in autoimmune rheumatic diseases. Autologous mixed lymphocyte reactivity in polymyositis/dermatomyositis and systemic lupus erythematosus.

Polymyositis/dermatomyositis (PM/DM) and systemic lupus erythematosus (SLE) are autoimmune disorders of unknown etiology. In order to study whether immunoregulatory abnormalities might be involved in these autoimmune states, the autologous mixed lymphocyte reaction (AMLR) was investigated in patients with either adult PM/DM, childhood DM (CDM), or SLE. The AMLR was found to be significantly depressed in adult PM/DM regardless of disease activity. By contrast, in CDM the AMLR was normal. In SLE, the AMLR was depressed in patients with both active and inactive disease and the responding T cell population appeared to be defective, as shown in a study on a pair of identical twins. These studies thus underscore the existence of a primary immunoregulatory dysfunction in these two autoimmune diseases.

The Frequency of Malignant Neoplasms in Patients With Polymyositis-Dermatomyositis

Seventy-one patients with polymyositis-dermatomyositis (PM/DM) admitted to the Wellesley Hospital Rheumatic Disease Unit (RDU) in Toronto between 1965 and 1980 were followed up to 1981. The frequencies of malignant neoplasms occurring prior to or concurrent with initial RDU admission were compared, using case-control methods, with age- and sex-matched control groups with a diagnosis of any non-PM/DM rheumatic disease (rheumatic disease controls) or osteoarthritis, fibrositis, or fracture (noninflammatory musculoskeletal controls). In a cohort analysis, the incidence of malignant neoplasm subsequent to initial RDU admission in patients with PM/DM was compared with the expected incidence in the Canadian population. Fifteen of 71 patients with PM/DM had an antecedent or concurrent cancer compared with four of 71 rheumatic disease controls and one of 71 noninflammatory musculoskeletal controls. Cohort analysis showed no increase in the number of subsequent malignant neoplasms in patients with PM/DM compared with the age- and sex-matched Canadian population.

Prognostic factors in polymyositis/dermatomyositis. A computer-assisted analysis of ninety-two cases.

An effort was made to identify all patients with polymyositis/dermatomyositis (PM/DM) admitted to hospitals in Israel from 1956-1976. The diagnosis of PM/DM was retrospectively reviewed in 92 (46 definite, 26 probable, and 20 possible) cases. The most common complaints and physical findings in the course of the disease were muscle weakness (86 patients), rash (53 patients), arthritis or arthralgia (39 patients), and dysphagia (35 patients). Elevated serum aldolase levels were found in 64% of the patients for whom data were available; 92% had abnormal electromyogram results, and 60.9% had muscle histopathology consistent with PM/DM. Malignancy was diagnosed in 13 patients. Malignancy, ischemic heart disease, and pulmonary complications were the most common causes of death. The actuarial survival curve was heterogeneous, with an accelerated mortality during the first year after diagnosis and a slower mortality during the following 7 years. Independent unfavorable prognostic signs were: failure to induce remission, leukocytosis, fever, older age, a shorter disease history, and dysphagia.

Childhood Dermatomyositis and Polymyositis

Childhood dermatomyositis has been recognized as a clinicopathologic entity for approximately two decades. Polymyositis in the pediatric age group, as in adults, is not a singly defined entity, as it may occur with or without evidence of one of the collagen vascular diseases. Because of overlap of some features of both disorders the terms "polymyositis" and "polymyositis—dermatomyositis Complex" have sometimes been used to include both of these disorders. INCIDENCE Polymyositis and dermatomyositis are uncommon disorders; even in a referral center, there may be only two or three cases seen per year. The limited number of epidemiologic studies have included both adults and children and have combined several types of inflammatory myopathy. By this imperfect method, the annual incidence of new cases has varied from 1 to 7.7 per million persons. There is an increased incidence in the second and seventh decades of life, with a lower incidence in the third decade. Most reports of dermatomyositis have shown a preponderance of girls. Onset most commonly occurs at school age, but children in their second year of life have been affected. PATHOGENESIS Studies of muscle biopsies from patients with juvenile dermatomyositis have demonstrated that the basic lesion involves the endothelial cells of intramuscular capillaries, arterioles, and veins.

Polymyositis/dermatomyositis and pregnancy.

Eighteen women with polymyositis/dermatomyositis (PM/DM) were studied to determine the possible influences of pregnancy on the disease and the influence of the disease on pregnancy. Before the onset of PM/DM there were 77 pregnancies: 7 (9%) ended in abortion, 2 (2.5%) in perinatal deaths, with a total fetal loss of 11.5%. There were 3 (3.8%) premature newborns that survived. These figures are equivalent to those of the general population. There were 10 pregnancies in 7 patients coinciding with PM/DM, 1 of them with twins; 3 (30%) ended in abortion, 3 (25%) in perinatal deaths, with a total fetal loss of 55%, and 5 (50%) pregnancies ended prematurely. Four of the 7 women had onset of PM/DM during pregnancy, and 3 others with previously inactive disease had an exacerbation during pregnancy. There were no maternal deaths, nor was there any correlation between activity of PM/DM and fetal loss. These results together with those previously reported suggest that pregnancy in PM/DM should be considered high-risk for both the mother and the baby.

Collagen localization in normal and fibrotic human skeletal muscle.

The distribution of types I to IV collagen, types I and III p-N collagen, and fibronectin in human skeletal muscle was studied by immunofluorescence using purified antibodies to those proteins. In normal muscle, types I and III collagen, types I and III p-N collagen, and fibronectin were localized in the endomysium and perimysium. Type IV collagen was restricted to basement membrane. Type II collagen was not present. In Duchenne's musclar dystrophy and dermatomyositis/polymyositis (DM/PM), the prominently increased endomysial and perimysial fibrosis consisted of types I and III collagen, types I and III p-N collagen, and fibronectin. In DM/PM, thickening of the walls of perimysial venular and arteriolar vessels was associated with accumulation of types I and III collagen, types I and III p-N collagen, and fibronectin, as well as type IV collagen. There was no disease-specific accumulation of collagen, p-N collagen, or fibronectin.

Connective Tissue Diseases and the Heart

CONNECTIVE tissue disease is a term used to describe any one of a group of rheumatoid disorders of uncertain cause, which have overlapping clinical manifestations and may share common mechanisms of pathogenesis. The diseases included in the discussion are rheumatoid arthritis, systemic lupus erythematosus (SLE), progressive systemic sclerosis (PSS) (scleroderma), classic polyarteritis nodosa (PAN), polymyositis (dermatomyositis), ankylosing spondylitis, and Reiter syndrome. Acute rheumatic fever and chronic rheumatic heart disease are not discussed. This selection is necessarily arbitrary and is defended only by general familiarity with these diagnostic categories and their recognized potential for producing cardiac and pericardial lesions (Table). Diagnostic criteria and extracardiac manifestations of these diseases are summarized comprehensively elsewhere. 1 The most apparent external clinical manifestations of these disorders typically involve joints and skin. However, cardiac disease occurs as well and plays an important role in determining whether a patient with one of these diseases has a chronic

Radiologic findings in polymyositis—Dermatomyositis involving the pharynx and upper oesophagus

The technique of examination and the radiologic findings in the pharynx and upper oesophagus are described in 6 patients suffering from polymositis or dermatomyositis. The specific localisation of this type of collagenosis makes its radiological differentiation possible from the other dysphagia producing collagenoses such as scleroderma.