Polymyositis anti-SRP antibodies and pregnancy about 2 cases.

Anti-SRP myopathy represents 4 to 6% of all the inflammatory myopathies. It has been described since the 80s and its influence on pregnancy and vice versa has been highlighted recently. We report two cases of anti-SRP myopathy associated with pregnancy. In the first case, the initial manifestations of the disease started in post partum and the second case was an anti-SRP myopathy patient before pregnancy. In both cases we objectified outbreaks during post-partum. Pregnancy seems to promote outbreaks. The inactive myopathy seems to presents no serious maternal-fetal complications as well as the usual dose of corticosteroids. The treatment (corticosteroid) during pregnancy is indicated given the risk of worsening during the post-partum.

Heterogeneous clinical spectrum of anti-SRP myositis and importance of the methods of detection of anti-SRP autoantibodies: a multicentric study.

Anti-signal recognition particle (SRP) antibodies are important serological markers for the diagnosis and the prognosis of idiopathic inflammatory myopathy (IIM), especially to distinguish immune-mediated necrotizing myopathy (IMNM). This study was set up to investigate the phenotype associated with anti-SRP antibodies and to evaluate the methods for detecting these antibodies. Clinical and biological data were retrospectively obtained from 60 adult patients with anti-SRP antibodies detected by a dot immunoassay from 12 centers. Thirty-six (60 %) out of these 60 patients suffered from an IIM, and among them, 21 patients were diagnosed as IMNM. Among patients with a definite IIM, proximal weakness and myalgia were prominent symptoms at the time of diagnosis. Only few patients displayed severe extra-muscular symptoms such as cardiac involvement or severe myositis. Mean creatine kinase levels were high for all patients except for two of them. When testing by indirect immunofluorescence (IIF) on HEp2 cells, the fraction of patients displaying the typical anti-SRP fine speckled staining of the cytoplasm was higher in patients with IIM (30/36) (83 %) than in patients with non-IIM (3/24) (12.5 %) (p < 0.0001). Thirty (91 %) out of 33 patients with a positive immunodot and a characteristic IIF cytoplasmic staining suffered from a clinical definite myositis, whereas only 6 (22 %) out of 27 patients with a positive immunodot but a negative cytoplasmic pattern suffered from a myositis (p < 0.00001). This series highlights the strong heterogeneity of anti-SRP positivity that encompassed IMNM and non-IMNM and supports the necessity of considering both IIF and dot immunoassay to confirm the diagnosis of anti-SRP-associated myositis.