CD4 and autoimmune thrombocytopenic purpura: Rather, the risk of developing Graves disease and immune thrombocytopenia after alemtuzumab is associated with poor thymic T-cell recovery and exaggerated CD4+ T-cell homeostatic proliferation.2 CNS-directed alemtuzumab-induced autoimmunity is also unlikely to be due to numerical differences in B- and T-cell counts.