We have published a case series of pilot patient observations with B-cell depletion in Chronic Fatigue Syndrome/ Myalgic Encephalopathy (CFS/ME) (Fluge and Mella, BMC Neurol, 2009). Subsequently, we published a small randomized and double-blind phase II study using rituximab induction two infusions two weeks apart (Fluge et al, Plos One, 2011).~We have completed an open label phase II study with 29 patients using rituximab induction and maintenance treatment (six rituximab infusions over 15 months, with follow-up for three years, unpublished).~We hypothesize that a subgroup of patients with Chronic Fatigue Syndrome/ Myalgic Encephalopathy (CFS/ME) have a chronically activated immune system involving B-lymphocytes, possibly a variant of an autoimmune disease, and that patients may benefit from B-cell depletion therapy.~Three substudies will be performed:~Endothelial function: assessment of Flow-Mediated Dilation and skin microcirculation at baseline and repeated during the time interval 17-21 months.~Cardiopulmonary exercise test for two following days: assessment at baseline and repeated during the time interval 17-21 months.~Gastrointestinal function: assessment at baseline and repeated during the time interval 17-21 months.
The hypothesis is that a subgroup of patients with Chronic Fatigue Syndrome/ Myalgic Encephalopathy (CFS/ME) have a chronically activated immune system and may benefit from B-lymphocyte treatment using the monoclonal anti-CD20 antibody rituximab with induction and maintenance treatment.