Myositis specific autoantibodies

Abstract

Recent studies have continued to examine the clinical associations of the group of autoantibodies that occurs predominantly in patients who have myositis (antibodies to aminoacyl-tRNA synthetases, to signal recognition particle [SRP], and to the nuclear helicase Mi-2). The anti-synthetase syndrome has been further studied, and the value of tacrolimus in treatment of the associated interstitial lung disease has been noted. The low frequency of myositis specific autoantibodies in non-myositis neuromuscular disorders has been more clearly demonstrated. The clinical associations of anti-Mi-2 and anti-SRP were further studied, and patients with antibodies without myositis were reported. Evidence suggested that ultraviolet light exposure may influence the expression of dermatomyositis and anti-Mi-2. A new classification for myositis using overlap clinical features and autoantibodies was proposed. A new autoantibody, anti-caDM-140, was described, associated with clinically amyopathic dermatomyositis and interstitial lung disease. The possibility was raised that increased antigen expression in regenerating muscle may help to perpetuate the disease. These antibodies continue to be the subject of active investigation.

Rituximab for the treatment of juvenile dermatomyositis: A report of four pediatric patients

“…This hypothesis is supported by the recurrence of disease coincident with recovery of her 3110 COOPER ET AL peripheral blood B cells 12 months after her first course of rituximab and 14 months after her second course. While the significance of myositis autoantibodies in pediatric patients remains unclear, these antibodies can be useful for classifying disease and predicting outcome in adults with myositis (5,6). Two of the 3 myositis autoantibody-negative patients also had clinical improvement.…”

“…The pathogenesis of juvenile DM remains unclear, although an increasing role of humoral immunity has been suggested by the association of myositisspecific and myositis-associated antibodies with myopathies, including juvenile DM and adult DM (5). While the majority of adults with DM have circulating myositis autoantibodies, Ͻ10% of children with juvenile DM have these autoantibodies, and their significance with regard to clinical diagnosis and disease course is unclear (1,6).…”

The pulmonary histopathologic manifestations of the anti-Jo-1 tRNA synthetase syndrome

“…The most common of these is the antiJo-1 antisynthetase syndrome in which anti-histidyl tRNA synthetase (anti-Jo-1) antibodies are accompanied by clinical arthritis, Raynaud's phenomenon, myositis, mechanic's hands, and interstitial lung disease (ILD). [1][2][3][4][5][6][7][8][9][10] The anti-Jo-1 tRNA synthetase syndrome has a higher incidence of ILD, relative to classical PM/DM, approximating 90% in some series, and the presence of anti-Jo-1 antibodies correlates with poor patient prognosis. [11][12][13][14][15][16][17][18][19][20][21][22] In this report, we studied the pulmonary histopathologic changes of a select group of IIM patients with the anti-Jo-1 tRNA synthetase syndrome, generating the first and largest biopsy study focused on this specific group of patients.…”

Anti-Signal Recognition Particle Myopathy in a Geriatric Patient

“…The slow onset of clinical muscle weakness delayed diagnosis as there were no other signs or symptoms to guide the medical investigation towards an immune-mediated myopathy until the patient presented with rapid progression associated with myalgia. Complete or partial resistance to steroids is a common feature of anti-SRP myopathy [3,4] , and for that reason our patient's initial therapy was a combination of steroids and azathioprine [5] . Other options have been proposed, but no combination has proven better than the others in terms of outcome.…”

“…Anti-SRP autoantibodies may be directed at any of the components of the SRP complex [2] . Despite the rarity of the disorder, all authors describe it as a severe necrotizing immune-mediated myopathy that usually affects middleaged people and is characterized by rapidly progressive proximal and symmetrical muscle weakness, with severe disability occurring within months (sometimes accompanied by dysphagia), elevated creatine kinase (CK) levels (often extremely elevated), no recognizable seasonal pattern, and poor response to steroids or other traditional immunosuppressive therapies [1,4,5] . Histopathologically, it is defined by a necrotizing myopathy with little or no primary inflammation, weak expression of major histocompatibility complex class I (MHC-I), and the presence of particular patterns of complement C5b-9/membrane attack complex deposition [1,3,4] .…”