SERPINB3 and acute monocytic leukemia: The antiapoptotic serine protease inhibitors Serpin B3 and B4 are significantly induced in acute monocytic leukemia-derived macrophages of the THP-1 lineage infected with the RH strain of T. gondii through activation of STAT6[63], and Serpin B3 and B4 may thus function as cellular factors involved in the parasite's regulation of the apoptosis pathway [64].