I think this may be a case of not seeing the wood for the trees. If rituximab did not kill B cells nobody with B cell lymphoma would have got better - and an awful lot of people have. And they quote a 51% reduction in CD19 count in their blood analysis but when rituximab is used for autoimmune disease we like to see more than 98% depletion of CD19 positive cells. Moreover, that depletion can last long after rituximab levels have sunk away, in rare cases for years. And autoantibodies go down and the B cell growth factor that regulates B cell numbers goes way up, as if there are no B cells. There is no reason to think that rituximab does anything to any other cells, except perhaps a tiny strange population of T cells that have CD20, so I think this looks like a laboratory artefact.