Rituximab for the Treatment of Refractory Inflammatory Myopathies and Refractory Myasthenia Gravis

Inclusion Criteria:

* For myositis III. Idiopathic myositis

  1. Myositis as defined by the 119th ENMC:

     1. Proximal myopathy with weakness
     2. Subacute or insidious onset over 18 years
     3. Myogenic syndrome on EMG (optional)
     4. Muscle fibre necrosis and regeneration and/or inflammatory cell infiltrate on muscular biopsy
  2. Specific AAbs : anti-synthetases (anti-JO1, anti-PL7, or anti-PL12), or anti-SRP.

     IV. Refractory to the conventional treatments Resistance to conventional treatments is defined as an inadequate response to, or intolerable side effects with conventional treatments, such as corticosteroids, azathioprine, methotrexate, cyclophosphamide, cyclosporine, IgIV and/or plasma exchange. At least one or more of these drugs or therapeutical approaches (used alone or as a combination) must have been unsuccessfully tested before inclusion. Inadequate response is defined as the lack of improvement and/or the degradation of evaluation parameters (defined bellow) despite these conventional therapies, that led to a modification or a reintroduction of treatment.
* For myasthenia III. Generalised MG

Generalised seropositive MG as defined by the Texas Clinical Classification System:

1. Extraocular muscle weakness quantified with MG muscle score (MMS), whose inter and inter observer reproducibility has been demonstrated \[44\].
2. Specific AAbs : anti-AchR IV. Refractory to the conventional treatments Resistance to conventional treatments is defined as an inadequate response to, or intolerable side effects with conventional treatments, such as corticosteroids, azathioprine, methotrexate, cyclophosphamide, cyclosporine, IgIV and/or plasma exchange. At least one or more of these drugs or therapeutical approaches (used alone or as a combination) must have been unsuccessfully tested before inclusion. Inadequate response is defined as the lack of improvement and/or the degradation of evaluation parameters (defined bellow) despite these conventional therapies, that led to a modification or a reintroduction of treatment

Exclusion Criteria:

* Other muscular diseases, such as:

  1. Inclusion body myositis
  2. Macrophagic myofasciitis
  3. Inherited myopathies
* Secondary IM to one other connective tissue disorders

  1. Systemic scleroderma (ARA and/or "LEROY AND MEDSGER" criteria)
  2. Sjögren's syndrome (European criteria)
  3. Systemic lupus erythematosus (ACR criteria)
  4. Rheumatoid arthritis (ACR criteria)
  5. Mixed connective tissue disease (ACR criteria)
* Other myasthenic syndrome, such as:

  1. Non generalised, ocular MG
  2. Lambert Eaton syndrome
  3. MG associated with malignant thymoma
  4. Inherited myasthenic syndrome
* Cancer (or cancer-associated myositis)
* Age \< 18 years
* Pregnancy
* HIV seropositivity
* Evolutive infection (B, C hepatitis, tuberculosis)
* Lack of approved consent