Detection of immune complexes in polymyositis

Low serum complements in idiopathic inflammatory myositis: clinical features and impact on the prognosis

This study investigated the clinical features and prognostic relevance of decreased serum complement levels in patients with idiopathic inflammatory myositis (IIM). The clinical information of IIM patients with less than normal serum complement levels (L-Com) and that of those with normal serum complement levels (N-Com) was compared. In patients with interstitial lung disease (ILD), regression analyses were used to investigate the implication of L-Com in their PaO2/FiO2 (P/F) ratio. Prognostic outcomes of ILD were evaluated using the log-rank test. Of 94 IIM patients, 26 with L-Com (median age, 56.0 years) and 68 with N-Com (56.5 years) were included. The prevalence of women was significantly higher in patients with L-Com (92.3%) than in those with N-Com (67.6%). ILD was observed in 17 (65.4%) patients with L-Com and in 46 (67.6%) with N-Com. Among patients with ILD, the P/F ratio was significantly lower in those with L-Com than in those with N-Com. Serum C3 levels were correlated with decreased P/F ratio. Inferior prognosis of ILD was significantly demonstrated in patients with L-Com, especially in those positive for anti-melanoma differentiation-associated protein 5 antibody. L-Com may be implicated in reduced arterial oxygen levels and a poorer prognosis in patients with IIM-related ILD.

Beyond Systemic Lupus Erythematosus and Anti-Phospholipid Syndrome: The Relevance of Complement From Pathogenesis to Pregnancy Outcome in Other Systemic Rheumatologic Diseases

Evidence about the relevance of the complement system, a highly conserved constituent of the innate immunity response that orchestrates the elimination of pathogens and the inflammatory processes, has been recently accumulated in many different rheumatologic conditions. In rheumatoid arthritis, complement, mainly the classical pathway, contributes to tissue damage especially in seropositive subjects, with complement activation occurring in the joint. Data about complement pathways in psoriatic arthritis are dated and poorly consistent; among patients with Sjögren syndrome, hypocomplementemia exerts a prognostic role, identifying patients at risk of extra-glandular manifestations. Hints about complement involvement in systemic sclerosis have been recently raised, following the evidence of complement deposition in affected skin and in renal samples from patients with scleroderma renal crisis. In vasculitides, complement plays a dual role: on one hand, stimulation of neutrophils with anti-neutrophil cytoplasmic antibodies (ANCA) results in the activation of the alternative pathway, on the other, C5a induces translocation of ANCA antigens, favouring the detrimental role of antibodies. Complement deposition in the kidneys identifies patients with more aggressive renal disease; patients with active disease display low serum levels of C3 and C4. Even though in dermatomyositis sC5b-9 deposits are invariably present in affected muscles, data on C3 and C4 fluctuation during disease course are scarce. C3 and C1q serum levels have been explored as potential markers of disease activity in Takayasu arteritis, whereas data in Behçet disease are limited to in vitro observations. Pregnancies in women with rheumatologic conditions are still burdened by a higher rate of pregnancy complications, thus the early identification of women at risk would be invaluable. A fine-tuning of complement activation is required from a physiological progression of pregnancy, from pre-implantation stages, through placentation to labour. Complement deregulation has been implicated in several pregnancy complications, such as recurrent abortion, eclampsia and premature birth; low complement levels have been shown to reliably identify women at risk of complications. Given its physiologic role in orchestrating pregnancy progression and its involvement as pathogenic effector in several rheumatologic conditions, complement system is an attractive candidate biomarker to stratify the obstetric risk among women with rheumatologic conditions.

Muscle biopsy findings predictive of malignancy in rare infiltrative dermatomyositis

OBJECTIVE

The characteristic pathological muscular findings of polymyositis (PM) and dermatomyositis (DM) have been shown to reflect their different pathogeneses. Here, we characterized the muscle biopsy findings of PM and DM patients with or without malignancy.

METHODS

We evaluated the muscle biopsy findings of 215 consecutive PM and DM patients admitted to our hospital between 1970 and 2009. Pathology of the lesion biopsy sections was classified into 3 types: endomysial infiltration-type, perivascular infiltration-type, and rare-infiltrative-type.

RESULTS

There was no difference between the muscle pathology of PM patients with and without malignancy. However, the incidence of rare-infiltrative type muscle pathology in DM patients with malignancy was significantly higher than in those without such tumors (p=0.0345).

CONCLUSION

The incidence of rare-infiltrative type muscle pathology may be a predictive marker of DM with malignancy.

Soluble CD4, CD8 in patients with polymyositis/dermatomyositis

The concentrations of soluble CD4 (sCD4) and soluble CD8 (sCD8) were determined in 64 patients with polymyositis/dermatomyositis (PM/MD). The patients with PM/DM had significantly higher concentrations of sCD8, though the concentrations of sCD4 did not significantly increase. Patients with high concentrations of sCD8 tended to have too high concentrations of soluble interleukin-2 receptor (sIL-2R). The patients with high levels of myogenic enzymes tended to have high concentrations of sCD8. The results of a serial study indicated that the concentrations of sCD8 decreased simultaneously with the decrease of the myogenic enzymes. These results may suggest that the activation of CD8+ cells are related to muscular involvement.

Dermatomyositis and malignancy

In summary, it can be stated that: 1. Dermatomyositis is probably associated with an increased incidence of malignancy. 2. Tumor types found seem to roughly approximate the frequencies of those found in the general population. 3. If present, the malignancy can precede, occur concurrently with, or follow the diagnosis of dermatomyositis. 4. Treatment of associated malignancy may or may not have an effect on myositic or cutaneous disease. 5. Dermatomyositis and associated malignancy may share a common pathogenesis resulting from abnormal immune function. 6. Search for malignancy should be carried out on the basis of abnormal findings on history and physical examination or screening laboratory.

[Dermatopolymyositis: evaluation of 63 patients]

Sixty-three patients with dermatopolymyositis were evaluated from the clinical, laboratory and therapeutical aspects during a period of 15 years: 39 are women and 24 men. The mean age was 36.8 +/- 15.6 years. No correlation was observed between clinical and isolated therapeutics employed; when corticosteroids and cytolytic drugs were used simultaneously, the clinical response was satisfactory. No special fact was seen that can predict the therapeutical response.

Dermatomyositis

Dermatomyositis and polymyositis are related disorders of unknown cause in which immunologic changes may be important. They sometimes overlap with other collagen vascular diseases, and not infrequently are associated with malignancy. The clinical features of the adult and juvenile forms of the disorder and the visceral manifestations of DM-PM are outlined, along with enzymatic, electromyographic, and histologic aids to diagnosis. While the cutaneous lesions often are resistant to treatment, systemic involvement may respond to corticosteroids or to immunosuppressive drugs. Treatment definitely alters the prognosis in cases not associated with malignancy.

Classification of myositis. Correlations between morphological and clinical classifications of inflammatory muscle disease

Insufficient clinical data given to pathologists often hamper the differentiation of inflammatory muscle diseases. Thus we proved the value of a classification based only upon morphological criteria. Among 160 biopsies with myositic pattern (4.9% of a series of 3264 muscle biopsies) we could distinguish the following groups: Interstitial inflammation with only few fibre necroses (17.6%), predominance of fibre necroses with few inflammatory infiltrates (38.1%), small vessel vasculitis (20.0%), arteritis (13.1%), granulomatous myositis (8.8%) and polymorphonuclear leukocytic infiltrates (2.6%). This classification is compared with the used clinical diagnoses. Some special morphological aspects (histometric and immunocytologic examinations, tissue calcification, inclusion bodies, neurogenic atrophies) are analysed and so are some clinical peculiarities (e.g. malignoma-association, differentiation of mixed connective tissue syndrome, drug-induced reactions). The diagnostic value of purely morphologic criteria is restricted. For better diagnostic work a great number of clinical informations is required. Nevertheless, certain morphological patterns give important directions, e.g. to occult malignoma.

Recent advances in the morphology of myositis

Myositis in man may be divided into infectious and non-infectious forms. The myopathologist more often deals with the latter forms which comprise dermatomyositis/polymyositis, inclusion body myositis, mixed connective tissue disease/collagenoses, and granulomatous myopathies. Modern morphological techniques as enzyme-histochemistry, electron microscopy, immunohistology, and morphometry are of different value in various forms of myositis, but are often indispensable techniques in up-to-date diagnostic work up of a myositis.

High single-dose alternate-day corticosteroid regimens in treatment of polymyositis

High single-dose alternate-day prednisolone therapy (ADT) was compared with daily-dose prednisolone therapy (DDT) for treatment of polymyositis. Thirty patients with polymyositis were treated with ADT for an average of 33.9 months. The combined number of improvements was 21 out of 30, a response rate of 70%. Side-effects were very rare and mild. On the other hand, 9 of 17 patients treated with DDT for an average 18.5 months improved, a response rate of 53%. The incidence of side-effects was strikingly higher than with ADT. ADT is therefore strongly advocated for treatment of polymyositis to avoid infectious complications and lessen cushingoid side-effects.

Inflammatory myopathies: Part 1

The inflammatory myopathies have diverse clinical and pathological features and multiple etiologies. Some are confined to a single muscle or group of muscles (e.g., orbital myositis and localized nodular myositis) while others are diffuse. Infective forms may be due to viral, bacterial, fungal, protozoal, or parasitic organisms. Viruses may cause acute self-limited forms of myositis and have been isolated from muscle in some cases of acute rhabdomyolysis and inclusion body myositis. They have also been implicated in some cases of congenital myopathy and in polymyositis and dermatomyositis, but there is no evidence of viral invasion of muscle in these conditions. In polymyositis and dermatomyositis there are derangements in humoral and cellular immune function, and recent evidence suggests an underlying disturbance of immunoregulation. The roles of genetic factors, drugs, and Toxoplasma infection have been under scrutiny. There is increasing recognition of immunological and pathological differences in polymyositis and juvenile and adult dermatomyositis, and in cases with associated connective tissue diseases, suggesting different underlying pathogenetic mechanisms. Inclusion body myositis, eosinophilic myositis, and granulomatous myositis can be separated from the other idiopathic inflammatory myopathies because of distinctive clinical and pathological features and this may also reflect different mechanisms of muscle injury. Recent developments in the treatment of the idiopathic inflammatory myopathies include the use of plasmapheresis and total-body irradiation in cases that are resistant to corticosteroids and immunosuppressive drugs.

Immunogenetic studies of juvenile dermatomyositis. III. Study of antibody to organ-specific and nuclear antigens

Ninety children with definite juvenile dermatomyositis (JDMS), who had been HLA typed, were tested for the presence of tissue or organ-specific antibodies. Sixty had active disease at the time of study. The mean disease duration was 4 years, and 30 had soft tissue calcifications. The following autoantibodies were sought: thyroid, gastric parietal cells, smooth muscle, striated muscle, microsomes, mitochondria, DNA, extractable nuclear antigen, Sm, PM-1, antinuclear antibody (ANA), and rheumatoid factor. Only the ANA and PM-1 were more frequent in patients than in controls (P less than 0.0002 and P less than 0.001, respectively). Higher levels of immune complexes (P less than 0.01) were found in sera from patients with JDMS than in sera from controls and were correlated with the presence of ANA in patients (P less than 0.01). Soft tissue calcification was not associated with any autoantibody or HLA antigen, but with disease duration and activity (P less than 0.001 and P less than 0.05, respectively). There was no association between the occurrence of any autoantibody and the presence of HLA-B8 or DR3 among the white patients with JDMS. The frequency of autoantibodies in 43 full siblings of children with JDMS was not increased. We conclude that children with JDMS, with or without HLA-B8/DR3, do not show evidence of a generalized nonspecific antibody response to tissue antigens. The significance of the increased antibody to nuclear antigens ANA and PM-1 remains to be determined.

Search for autoantibodies to endothelial and smooth muscle cells in patients with multiple sclerosis

The blood-brain barrier (BBB) is disrupted in many of the lesions of multiple sclerosis (MS). Immunologically mediated injury to one of the major components of this barrier, the cerebral capillary, may play a role in the development of the lesion. We therefore examined the sera of 51 cases of MS for the presence of autoantibodies to endothelial and smooth muscle cells, using the indirect immunofluorescent technique. The results were compared to those in other groups of patients with neuroimmunological disorders. We found no anti-endothelial cell antibodies, but autoantibodies to vascular smooth muscle were detectable in 31% of the MS sera tested. They were also present, however, in 30% of sera from cases of myasthenia gravis and in the serum of one of 12 cases of polymyositis. It is considered to be unlikely that antibodies to vascular tissues play any pathogenetic role in multiple sclerosis.

Recent advances in polymyositis

The most typical clinical features of polymyositis (PM), the criteria of diagnosis and principles of treatment are outlined. An inflammatory disease of muscle, PM also frequently affects other organs such as the skin and hence the name dermatomyositis. The principal cardiac symptom is a peculiar disturbance of atrioventricular conduction, correlated with a specific anti-Ro autoantibody, present in 25% of patients. The etiology of PM is as yet unknown, although there is evidence for an autoimmune pathogenesis. It is frequently found in association with other immune-mediated diseases such as myasthenia gravis, pemphigus, immune-complex vasculitis and Sjogren syndrome. Laboratory investigations show hypergammaglobulinemia, a decrease of complement factors C3 and C4 and the presence of circulating immune complexes in 70% of patients. Very frequent, especially in cases of dermatomyositis, is a histologically detectable accumulation of IgG and complement in the walls of the intramuscular venous vessels. Cell-mediated hypersensitivity, emphasised formerly as highly significant in PM, has not been confirmed. The presence of specific antimyoglobin lymphocyto-toxicity, once considered to be the hallmark of muscle degeneration in PM, has been excluded by a number of laboratories. In a personal series of patients with various clinical forms of PM a severe loss of suppressor/cytotoxic lymphocytes was found in the peripheral blood and a relative increase in the first subset. These results support the hypothesis that a serious disturbance of immunoregulation is present in PM and is the cause of a multitude of immunological anomalies, the characterisation of which is under study.

Does Toxoplasma cause polymyositis? Report of a case of polymyositis associated with toxoplasmosis and a critical review of the literature

We report here a case of polymyositis and toxoplasmosis, and review the previous examples of this association. We suggest that in most cases this relationship is due to reactivation of latent infection in an immunocompromised host. Gross immunological aberrations underline the pathogenesis of polymyositis and these predispose the patient to the development of toxoplasmosis. Anti-protozoal therapy is necessary and produces some clinical benefit, but it does not cure the polymyositis.