What is the purpose and procedure of plasmaferesis (plasma exchange) in treating medical conditions?

Plasmapheresis (Plasma Exchange): Purpose and Procedure in Medical Treatment

Plasmapheresis is a therapeutic procedure that removes pathogenic substances from the plasma and is indicated for treating specific autoimmune, neurological, and antibody-mediated conditions when conventional therapies fail or in acute, life-threatening situations.

Mechanism and Procedure

• Plasmapheresis is an extracorporeal therapy that separates and removes plasma containing pathogenic elements (such as antibodies or immune complexes) from the patient's blood while returning the cellular components 1
• During the procedure, blood is withdrawn from the patient, plasma is separated from cellular components using either centrifugation or membrane filtration methods, and then discarded 2
• The removed plasma is typically replaced with albumin, fresh-frozen plasma, or crystalloid solutions before being returned to the patient 1
• The procedure is usually performed as a series of treatments (typically 5-6 sessions per patient) depending on the condition being treated 3

Primary Medical Indications

Neurological Disorders

• First-line therapy for severe Guillain-Barré syndrome (grade 3-4) 4
• First-line therapy for myasthenia gravis with significant symptoms 4
• Treatment for severe immune-mediated neuropathies, especially those with rapid progression 4

Renal Conditions

• Recommended for patients with ANCA-associated vasculitis requiring dialysis or with rapidly increasing serum creatinine 1
• Used in anti-glomerular basement membrane (anti-GBM) disease 1
• Beneficial in severe cryoglobulinemia with acute kidney involvement 4

Hematological Disorders

• First-line therapy for symptomatic hyperviscosity due to paraproteinemia 4
• Preventive treatment before rituximab therapy in patients with IgM ≥ 4 g/dL to avoid symptomatic IgM flares 4

Autoimmune Pulmonary Conditions

• Suggested for patients with confirmed autoimmune pulmonary alveolar proteinosis (aPAP) who remain significantly symptomatic despite receiving exogenous GM-CSF and rituximab 1
• Recommended for patients with diffuse pulmonary hemorrhage in ANCA vasculitis 1

Other Autoimmune Conditions

• Used in refractory cases of pemphigus vulgaris when combined with corticosteroids and immunosuppressants 1
• Treatment option for antibody-mediated rejection in cardiac transplantation 1
• Management of severe immunotherapy-related toxicities, particularly neurologic adverse events 1

Clinical Considerations and Limitations

• Plasmapheresis should generally be combined with immunosuppressive medications to prevent rebound antibody production 1
• The procedure removes not only pathogenic elements but also therapeutic drugs, requiring careful timing of medication administration 5
• Not recommended as routine treatment for newly diagnosed pemphigus but may be considered in refractory cases 1
• In pulmonary alveolar proteinosis, higher intensity plasmapheresis regimens may be needed to successfully suppress GM-CSF autoantibodies 1

Safety and Adverse Effects

• Common complications include catheter-related infections, hypotension, and coagulation abnormalities 3
• Mortality associated with plasmapheresis is estimated at 0.05% based on systematic reviews 1
• Removal of important plasma proteins including clotting factors can result in coagulation defects 1
• Plasmapheresis can be associated with hemodynamic shifts, increased infection risk, and thrombosis 1
• When combined with immunosuppressants, there is increased risk of opportunistic infections requiring prophylactic measures 1

Treatment Protocol Considerations

• For most conditions, 5-6 sessions of plasmapheresis are typically performed 3
• Timing is critical when used with other therapies - for example, rituximab should be administered after plasmapheresis since the procedure removes the drug 1
• Different methods (plasma exchange, double filtration, immunoadsorption) may be selected based on the specific condition and therapeutic goals 6
• Replacement fluids must be carefully chosen based on the patient's clinical condition and the specific disorder being treated 7