Page 2016 - Hematology_ Basic Principles and Practice ( PDFDrive )

Chapter 118 Hemapheresis 1787

pretransplant plasmapheresis, immunosuppressive medications, and
Cerebrosides low-dose cytomegalovirus immune globulin effectively reduces
Dihexosylceramides donor-specific antibody and isoagglutinin titers with and without
Trihexosyceramides
Globosides posttransplant splenectomy and anti-CD20 treatment. The strength
of donor-specific antibodies is also important and can be determined
Plasma Plasma by titration, but greater sensitivity and specificity may be obtained
exchange exchange using Luminex flow-bead technology. Patients with strong HLA
Nanomole/mL likely to have acute rejection; however, the introduction of peritrans-
antibodies have increased mean bead fluorescence and were more
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plantation apheresis reduced acute rejection from 66% to 7%.
Plasma exchange has also been used to treat patients with focal
segmental glomerulosclerosis, both for primary disease refractory to
standard immunosuppressive therapy and for treatment of patients
with recurrent disease after renal transplantation.
Two immunoadsorption columns have been approved in the
United States for removal of autoantibodies to factor VIII or factor
IX (Immunosorba staphylococcal protein A–agarose column) and
treatment of ITP and rheumatoid arthritis (Prosorba staphylococcal
protein A–silica column). Several case series describe the use of
immunoadsorption for patients with immune inhibitors to factor
0 2 4 6 8 10 12 VIII or factor IX. A phase III, multicenter, sham-controlled random-
Days ized study of staphylococcal protein A column immunoadsorption
shows a significant increase in clinical response in adult patients with
Fig. 118.7 PLASMA EXCHANGE TO REMOVE PLASMA NEUTRAL longstanding rheumatoid arthritis. Sparse published evidence exists
GLYCOLIPIDS IN A PATIENT WITH FABRY DISEASE. The plasma to support the use of immunoadsorption therapy in patients with
lipid recovery curve appears to be biphasic, reflecting initial reequilibration chronic ITP refractory to standard medical management.
from tissue stores and subsequent new synthesis of that glycolipid. Plasmapheresis is effective first- or second-line therapy in selected
patients with certain neurologic disorders. Controlled clinical trials
of plasmapheresis have demonstrated efficacy in at least two of the
Simple plasma exchange may be used in patients with other polyradiculoneuropathies. In Guillain-Barré syndrome, plasmapher-
inherited metabolic diseases, such as Refsum disease. The frequency esis should be considered when patients are unable to walk indepen-
of exchange depends primarily on total body burden, rate of synthesis, dently or require mechanic ventilation. However, IVIg alone may be
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and plasma concentration of the solute to be removed (Fig. 118.7). equally effective and is more readily available. Periodic plasmapher-
Less evidence exists to support a role for repeated treatments in these esis may be necessary in patients with a chronic inflammatory
diseases. demyelinating neuropathy. Because the long-term prognosis varies,
plasmapheresis may be used in conjunction with steroids and IVIg.
Immune Disease Indications and Rapid deterioration may occur upon discontinuation.
MS is a relapsing and progressive disorder with demyelination of
Immunoadsorption Therapies the central nervous system white matter. Patients who present with
acute fulminant demyelination may benefit from early plasma
Plasma exchange appears to have at least a temporary adjunctive role exchange, particularly when they fail to respond to high-dose corti-
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in managing some rheumatic diseases and other immune disorders costeroids. The majority of patients have a relapsing-remitting form
characterized by circulating autoantibodies. Early success was reported of the disease, and plasmapheresis may be of benefit. Unfortunately,
in patients with Goodpasture syndrome, a disorder characterized by for chronic progressive forms of MS, plasma exchange has consistently
a specific pathogenic autoantibody directed against the renal glo- been shown to be ineffective.
merular and pulmonary alveolar basement membrane. Plasmapheresis
has demonstrated similar success in myasthenia gravis, pemphigus,
and Eaton-Lambert syndrome. Although nonselective plasma REPLACEMENT FLUIDS FOR PLASMA EXCHANGE
exchange has been used in a variety of other rheumatic diseases such
as systemic lupus erythematosus (SLE) and rheumatoid vasculitis, The success of therapeutic apheresis procedures seldom depends on
with the exception of treatment of patients with Goodpasture syn- the composition of the replacement solution that is used; the single
drome (in which plasma exchange is considered first-line adjuvant exception is TTP (discussed in the previous section). With therapeutic
therapy), such use remains unproved and should be reserved for plasmapheresis for most other disorders, the primary function of the
circumstances in which a vital organ or life itself is endangered. replacement solution is to maintain intravascular volume. Additional
Selective leukapheresis by Adacolumn technology in a series of requirements include restoration of important plasma proteins,
patients with SLE has shown clinical benefit, but trial interpretation maintenance of colloid osmotic pressure, maintenance of electrolyte
is limited by the uncontrolled nature and small size. balance, and preservation of trace elements lost during a prolonged
In some immune disorders, such as immune thrombocytopenic course of plasmapheresis procedures. In moderately well-nourished
purpura (ITP) and immune inhibitors to coagulation proteins, patients, homeostatic mechanisms normally obviate the need for
plasma exchange may be helpful during a catastrophic event, but in precise plasma replacement, and 5% albumin in normal saline or
general, benefit of nonselective plasma exchange therapy is not combinations of albumin and crystalloid are usually sufficient. Com-
established. monly used is 60% to 80% replacement by colloid, with the crystal-
Plasma exchange appears to be a useful therapeutic option in renal loid component consisting of a combination of normal saline and an
transplant patients threatened with refractory humoral rejection and anticoagulant. Patients with clinical conditions such as hypotension,
is now widely used to overcome ABO and HLA incompatibilities hypoalbuminemia, or preexisting coagulopathies should receive solu-
between renal transplant patients and their only available donors. tions prepared specifically to meet their individual requirements.
Several studies have shown successful reversal of acute humoral rejec- Routine supplementation with calcium, potassium, or immunoglobu-
tion mediated by HLA-specific donor antibody using a combination lins is unnecessary. However, for large-volume apheresis procedures
of plasmapheresis and IV immune globulin (IVIg), which is superior to collect PB-HSPC, IV calcium supplementation is beneficial (dis-
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to high dose IVIg alone. A conditioning regimen consisting of cussed in the following section). Because less than 500 mL is removed