The pathogenesis of a wide range of hematological diseases is based on the presence of autoantibodies or circulating immune complexes. Therefore, PEX can play a pivotal role in their therapy (e.g., thrombotic thrombocytopenic purpura, TTP). This chapter will discuss also the conservative treatment in other hematological issues that have become the major treatment option and in which the benefit from PEX is inconclusive (e.g., complement-mediated thrombotic microangiopathy, cmTMA). Additionally, less frequently used apheresis techniques will be reviewed (erythrocytapheresis, RBC exchange, leukocytapheresis, thrombocytapheresis) and their effectiveness in certain hematological conditions.