What about methotrexate? a quick google with methotrexate and B cells brought up several studies. one was about low dose methotrexate lowering B cells in lupus. I recall that in one of the Norweigan studies that some were also on methotrexate with ritux or was it they were non responders to ritux but the addition of methotrexate then turned them into responders??? Methotrexate seems to be a common drug used in auto immune illnesses, maybe useful for a sub set of ME patients?? cheers!!!