Therapeutic erythrocytapheresis (
TEA) has been used in different diseases such as
polycythemia vera (PV), secondary
erythrocytosis or
hemochromatosis as a process of the less cumbersome but more expensive phlebotomy.
TEA is preferred in emergency conditions such as
thrombocytosis or in conditions such as
porphyria cutanea tarda (PCT) or
erythropoietic porphyria when
plasma exchange (PEX) is often combined with
TEA to reduce extracellular levels of uroporphyrin which contribute to plasma hyperviscosity.
TEA is often combined with
drug therapy that varies from
etoposide in PV to EPO and desferoxamine which are used to mobilize and reduce
iron stores in
hemochromatosis. Benefits from this combination may be more long lasting than expected. Nonetheless for
TEA, there is no standard protocol and, clinical experience with this
therapy remains highly anecdotal. Therapeutic red cell-exchange (TREX) has been used with much interest over the years, starting with the management of hemolytic disease of the newborn and later used to correct severe
anemia in
thalassemia patients thereby preventing
iron overload. It has also been used for the management of complications of
sickle cell disease such as
priapism, chest syndrome,
stroke,
retinal, bone, splenic and
hepatic infarction or in preparation for surgery by reducing HbS to less than 30%. Automated
apheresis has also favored the use of TREX in conditions such as
paroxysmal nocturnal hemoglobinuria and
aniline poisoning, arsenic poisoning, Na
chlorate intoxications and CO intoxications,
hemoglobinopathies,
autoimmune hemolytic anemia, reactions due to ABO incompatibility, in preparation for ABO incompatible
bone marrow transplantation or for preventing
anti-D immunization after the transfusion of D(+) cells to D(-) recipients. Another field of application has been in the emergency management of intraerythrocytic
parasite infections such as
malaria and
babesiosis. Application of TREX may be wide but its real use remains limited. In our personal experience, in 16 years, only 167 TREX procedures have been carried out in a total of 13,747 therapeutic procedures. This represents only 1.21% of the total.