Case report
Marked efficacy of a therapeutic strategy associating prednisone and plasma exchange followed by rituximab in two patients with refractory myopathy associated with antibodies to the signal recognition particle (SRP)

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Abstract

We report two patients with myopathy associated with anti-signal recognition particle Ab, refractory to conventional therapy, who were treated with prednisone and plasma exchange, followed by rituximab. A marked response was observed in both patients, with partial to complete recovery of muscle strength, which was sustained.

Introduction

Antibodies to the signal recognition particle (SRP) are detected in 5–6% of patients with idiopathic inflammatory myopathy [1], [2]. Patients with anti-SRP antibodies usually develop severe myopathy with high serum creatine kinase (CK) levels, specific pathological features upon muscle biopsy and usually poor response to corticosteroids (CS) [3], [4]. We here report on the marked efficacy of a combination therapy of corticosteroids (CS) and plasma exchange (PE) followed with rituximab in two patients with severe intractable myopathy associated with anti-SRP Abs.

Section snippets

Case 1

A 20-year-old Malian man presented in 1988 with myalgia, proximal limb weakness and high serum CK. The diagnosis of myositis was made upon muscle biopsy. He had a past history of urinary bilharziosis and hepatitis B and delta viruses co-infection responsible for chronic hepatitis.

He successively received CS, intravenous immunoglobulins (IVIg), CS and PE, cyclosporine A (CyA), intravenous pulse cyclophosphamide (CYC), and mycophenolate mofetil. However, only CyA and the combination of CS and PE

Case 2

A 24-year-old woman from Senegal presented in December 1999 with severe symmetrical proximal weakness, graded at 2/5–3/5 in proximal arms and legs and 1/5 in the neck flexor. Serum CK was high at 10,000 IU/l. Serum anti-nuclear Abs were positive (1:1280), with a cytoplasmic fluorescence. Anti-SRP Abs were identified by immunoblotting. Anti-synthetase Abs were negative. A muscle biopsy revealed many necrotic and regenerating fibres, a single focus of mononuclear cells in the endomysium and MHC

Discussion

Our two patients had typical ‘anti-SRP syndrome’ with severe myopathy, high serum CK, muscle fiber necrosis and regeneration, prominent endomysial fibrosis, little or no inflammation upon muscle biopsy and poor response to conventional treatment [3].

There are several lines of argument for the humoral immune mediated nature of the ‘anti-SRP syndrome’: (i) there is no argument for a CD8+T cell mediated cytotoxicity, since there is a lack of myofiber major histocompatibility complex (MHC) class 1

References (10)

  • R. Brouwer et al.

    Autoantibody profiles in the sera of European patients with myositis

    Ann Rheum Dis

    (2001)
  • A.H. Kao et al.

    Anti-signal recognition particle autoantibody in patients with and patients without idiopathic inflammatory myopathy

    Arthritis Rheum

    (2004)
  • I.N. Targoff et al.

    Antibody to signal recognition particle in polymyositis

    Arthritis Rheum

    (1990)
  • L.A. Love et al.

    A new approach to the classification of idiopathic inflammatory myopathy: myositis-specific autoantibodies define useful homogeneous patient groups

    Medicine (Baltimore)

    (1991)
  • F.W. Miller et al.

    Controlled trial of plasma exchange and leukapheresis in polymyositis and dermatomyositis

    N Engl J Med

    (1992)
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