The absolute and relative numbers ( percentages ) of CD5 + B cells ( explanatory variables ) were measured longitudinally during 18 months in 197 patients randomized to receive either rituximab ( RTX ) or cyclophosphamide ( CYC ) followed by azathioprine ( AZA ) for the treatment of AAV ( Rituximab in ANCA-Associated Vasculitis [ RAVE ] trial ) .