In most guiidelines is leukopheresisi recommended in cases with neutrophils (myeloblasts) above 100 giga/l and monocytes (monoblasts) above 40. Lymfocytes donť cause leucostasis, so no leukoopherisis is needed. Protocols are machine dependent, so ask the retailer of the separator You use.

The effect is very shortlived, so You need to start chemotherapy simultaneously. In most cases is hydroxyurea + leukopheresis used as pretreatment to lower excessive leucocyte count before starting agresive chemotherapy.

A good book to read, which covers all apheresis metods and indications is Mc Leod - Apheresis

Here are the 2013 guidelines from the American Society for Apheresis. It is well researched and provides recommendations based on published literature with stratification of published literature by strength. http://italkid.org/Guidelines%20on%20the%20Use%20of%20Therapeutic%20Apheresis%20in.pdf