Mice lacking key inflammatory or anti-inflammatory cytokines respond normally to IVIg treatment of ITP. Control mice (wild-type) and mice lacking the indicated specific proinflammatory cytokines (A), anti-inflammatory cytokines (B), or mice genetically lacking the common cytokine receptor γ chain (C) were rendered thrombocytopenic by daily injection (days 0-3) of antiplatelet antibody as in Figure 1B. On day 2, all mice received 50 mg IVIg (arrow). Mice were bled daily just prior to antiplatelet antibody injection and platelets enumerated as in Figure 1B. The y-axis represents platelet counts; the x-axis, the length of the experiment in days; n = 6 mice per each strain.