B-cell Depletion Using the Monoclonal Anti-CD20 Antibody Rituximab in Chronic Fatigue Syndrome

B-lymphocyte Depletion Using the Monoclonal Anti-CD20 Antibody Rituximab in Chronic Fatigue Syndrome. An Open Label Phase II Study With Rituximab Induction and Maintenance Treatment

Based on pilot patient observations, and experience from the prior study KTS-1-2008, the investigators anticipate that chronic fatigue syndrome patients may benefit from B-cell depletion therapy using Rituximab induction with maintenance treatment.

The hypothesis is that at least a subset of CFS patients have an activated immune system involving B-lymphocytes, and that prolonged B-cell depletion may alleviate symptoms.

Inclusion Criteria:

• patients with CFS
• age 18-66 years
• informed consent

Exclusion Criteria:

• patients with fatigue, not fulfilling criteria for CFS
• pregnancy or lactation
• previous malignant disease except basal cell carcinoma of skin and cervical carcinoma in situ
• previous major immunological disease, except autoimmune diseases such as diabetes mellitus or thyroiditis
• previous long-term use of immunosuppressive drugs, except steroids e.g. in obstructive lunge disease
• endogenous depression
• lack of ability to comply by the protocol
• multi-allergy with risk of serious drug reaction
• reduced renal function (creatinin > 1.5 x UNL)
• reduced liver function (bilirubin or transaminases > 1.5 x UNL)
• HIV positivity
• evidence of clinically significant infection