antiSRP
Anti-SRP, more commonly written as anti-SRP antibodies, are autoantibodies directed against the signal recognition particle, a ribonucleoprotein complex that guides nascent secretory and membrane proteins to the endoplasmic reticulum. SRP consists of a small RNA scaffold and several protein subunits, with SRP54 being a frequent target. Anti-SRP antibodies are most often identified in a subset of patients with autoimmune myopathy, particularly immune-mediated necrotizing myopathy (IMNM). They are detected in serum as part of autoimmune myopathy panels using assays such as immunoprecipitation, line blot, or ELISA.
Pathophysiology is not fully understood. The presence of anti-SRP antibodies is associated with a necrotizing pattern
Clinically, anti-SRP NAM typically presents with subacute proximal muscle weakness and markedly elevated serum creatine kinase
Diagnosis relies on integrating clinical presentation, elevated CK, muscle biopsy showing necrotizing myopathy, and serologic evidence