The hypothesis based on retrospective data is that, the rate of overall response-rate (PR +
CR) at 1 year will be much higher in the rituximab arm (80%) than in the placebo arm
(20%).Thirty four patients (17 in each arm) will be include (amendment n°6 - 15/10/2013) over
a 3 year period (amendment n°3 - 11/12/2012).