To determine whether treatment with rituximab induces HMGB1 release and STAT3 inhibition in vivo, we compared HMGB1 and IL-10 concentrations in the plasma of DLBCL patients before and after treatment with CHOP (n = 24) and R-CHOP (n = 16). The gene discussed is HMGB1; the disease is diffuse large B-cell lymphoma.