Clinical features and therapeutic response of our anti-SRP positive patients with myositis

Introduction: Idiopathic inflammatory myopathies are a group of clinically heterogeneous diseases, which have been classified by myositis specific antibodies recently. The anti-SRP positive subset of this group is characterized by more severe clinical prognosis than other myositis specific antibody positive types. Aim: Our goal was to compare 16 anti-SRP positive patients in the Division of Clinical Immunology, Department of Internal Medicine, University of Debrecen with 16 antibody negative ones. Method: Muscle strength validated in both groups by the manual muscle test proved to be significantly decreased both before and after therapy (x(2) = 0.006 and 0.019) in the anti-SRP positive group. Results: Muscle-specific inflammatory laboratory parameters showed significant difference only in case of LDH-levels after therapy. Both groups showed good clinical response to first line steroid treatment, yet the significantly higher rate of second line administration suggests worse therapeutic response of the antibody positive group. Conclusion: Based on these facts we determined poor clinical prognosis and therapeutic response of the anti-SRP positive group.