Therapeutic apheresis includes plasma exchange and cytapheresis, which are generally tolerated by healthy donors. However, many minor and a few major risks exist. Insertion of the large IV catheters necessary for apheresis can cause complications (eg, bleeding, infection, pneumothorax). Citrate anticoagulant may decrease serum ionized Ca. Replacement of plasma with a noncolloidal solution (eg, saline) shifts fluid from the intravascular space. Colloidal replacement solutions do not replace IgG and coagulation factors.

Most complications can be managed with close attention to the patient and manipulation of the procedure, but some severe reactions and a few deaths have occurred.

Plasma exchange

Therapeutic plasma exchange removes plasma components from blood. A blood cell separator extracts the patient's plasma and returns RBCs and platelets in plasma or a plasma-replacing fluid; for this purpose, 5% albumin is preferred to fresh frozen plasma (except for patients with thrombotic thrombocytopenic purpura) because it causes fewer reactions and transmits no infections. Therapeutic plasma exchange resembles dialysis but, in addition, can remove protein-bound toxic substances. A one-volume exchange removes about 66% of such components.

To be of benefit, plasma exchange should be used for diseases in which the plasma contains a known pathogenic substance, and plasma exchange should remove this substance more rapidly than the body produces it. For example, in rapidly progressive autoimmune disorders, plasma exchange may be used to remove existing harmful plasma components (eg, cryoglobulins, antiglomerular basement membrane antibodies) while immunosuppressive or cytotoxic drugs suppress their future production.

There are numerous indications (see Table 3: Transfusion Medicine: Indications for Plasma Exchange According to the American Society for Apheresis ). The frequency of plasma exchange, the volume to be removed, the replacement fluid, and other variables are individualized. Low density lipoprotein cholesterol can be removed by plasma exchange with a recently implemented filtration method. Complications of plasma exchange are similar to those of therapeutic cytapheresis.

Table 3
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Indications for Plasma Exchange According to the American Society for Apheresis  Category Plasma Exchange Cytapheresis I. Accepted as 1st-line therapy, either alone or with other treatment ANCA-mediated rapidly progressive glomerulonephritis (Wegener's granulomatosis), on dialysis or with diffuse alveolar hemorrhage Antiglomerular basement membrane antibody disease (Goodpasture's syndrome), on dialysis or with diffuse alveolar hemorrhage Chronic inflammatory demyelinating polyradiculoneuropathy Cryoglobulinemia, severe Focal, segmental glomerulosclerosis, recurrent Guillain-Barre syndrome Hemolytic-uremic syndrome, atypical due to autoantibody to factor H Hyperviscosity in monoclonal gammopathies Myasthenia gravis PANDAS (pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections) Paraproteinemic polyneuropathy with IgG/IgA, IgM (with or without Waldenström's macroglobulinemia) Renal transplantation, antibody-mediated rejection Sydenham's chorea Thrombotic thrombocytopenia purpura Wilson's disease, fulminant Babesiosis, severe: RBC exchange Cutaneous T-cell lymphoma, erythrodermic: Photopheresis Familial hypercholesterolemia (homozygotes): Lipid absorption Heart transplant rejection (prophylaxis): Photopheresis Hyperleukocytosis with leukostasis syndrome: Leukodepletion Sickle cell disease with acute stroke: RBC exchange II. Accepted as 2nd-line therapy, either alone or with other treatment ABO incompatible stem cell or kidney transplant (recipient) Anemia, pure red cell aplasia Antiphospholipid syndrome, catastrophic Autoimmune hemolytic anemia, cold agglutinin disease (life threatening) Hemolytic-uremic syndrome, due to complement factor gene mutation Lambert-Eaton syndrome Multiple sclerosis, acute, unresponsive to corticosteroids Myeloma (cast nephropathy) Neuromyelitis optica Phytanic acid storage disease (Refsum's disease) Rasmussen's encephalitis Red cell alloimmunization in pregnancy (before intrauterine transfusion available) Renal transplantation, desensitization (living donor, due to donor-specific HLA antibody) SLE if severe (eg, cerebritis, diffuse alveolar hemorrhage) Cryoglobulinemia due to hepatitis C: Immuneadsorption Familial hypercholesterolemia (heterozygotes): Lipid absorption Graft vs host disease, skin: Photopheresis Heart or lung transplant rejection (treatment): Photopheresis Inflammatory bowel disease: Adsorptive cytapheresis Malaria, severe: RBC exchange Rheumatoid arthritis, refractory: Immuneadsorption Sickle cell disease with acute chest syndrome: RBC exchange Thrombocytosis, symptomatic: Platelet depletion III. Optimal role of apheresis is not established; decision should be individualized (IRB approval desirable) Acute hepatic failure Aplastic anemia Autoimmune hemolytic anemia, warm Cardiomyopathy, dilated (New York Heart Association class II to IV) Heart transplant rejection (antibody mediated) Hemochromatosis, hereditary Multiple myeloma with polyneuropathy Multiple sclerosis (progressive) Paraneoplastic neurologic syndromes Posttransfusion purpura Progressive systemic sclerosis Thyroid storm Coagulation factor inhibitors: Immuneadsorption Cutaneous T-cell lymphoma, non-erythrodermic: Leukodepletion Graft vs host disease, non-skin: Photopheresis Pemphigus vulgaris: Photophoresis Polycythemia vera or erythrocytosis: RBC depletion IV. Published evidence demonstrates or suggests apheresis ineffective or harmful. Amyloidosis, systemic Amyotrophic lateral sclerosis Burn shock resuscitation Coagulation factor inhibitors Dermatomyositis or polymyositis Hemolytic-uremic syndrome, typical or diarrhea associated Immune thrombocytopenic purpura Inclusion-body myositis Pemphigus vulgaris POEMS (plasma cell dyscrasia with polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, and skin changes) syndrome Psoriasis Rheumatoid arthritis Stiff-person syndrome Dermatomyositis or polymyositis: Leukapheresis Inclusion-body myositis: Leukapheresis ANCA = antineutrophil cytoplasmic antibody; IRB = institutional review board. Data from Szczepiorkowski ZM, Winters JL, Bandarenko N, et al : Guidelines on the use of therapeutic apheresis in clinical practice: evidence-based approach from the apheresis applications committee of the American Society for Apheresis. Journal of Clinical Apheresis 25:83–177, 2010.

Cytapheresis

Therapeutic cytapheresis removes cellular components from blood, returning plasma. It is most often used to remove defective RBCs and substitute normal ones in patients with sickle cell anemia who have the following conditions: acute chest syndrome, stroke, pregnancy, or frequent, severe sickle cell crises. Cytapheresis achieves Hb S levels of < 30% without the risk of increased viscosity that can occur because of increased Hct with simple transfusion.

Therapeutic cytapheresis may also be used to reduce severe thrombocytosis or leukocytosis (cytoreduction) in acute or chronic leukemia when there is risk of hemorrhage, thrombosis, or pulmonary or cerebral complications of extreme leukocytosis (leukostasis). Cytapheresis is effective in thrombocytosis because platelets are not replaced as rapidly as WBCs. One or 2 procedures may reduce platelet counts to safe levels. Therapeutic WBC removal (leukapheresis) can remove kilograms of buffy coat in a few procedures, and it often relieves leukostasis and splenomegaly. However, the reduction in WBC count itself may be mild and only temporary.

Other uses of cytapheresis include collection of peripheral blood stem cells for autologous or allogeneic bone marrow reconstitution (an alternative to bone marrow transplantation) and collection of lymphocytes for use in immune modulation cancer therapy (adoptive immunotherapy).

Last full review/revision July 2012 by Ravindra Sarode, MD