Is the risk of transmitting a plasma cell clone through blood transfusion to an immunocompromised individual similar to the risk for a transplant patient receiving a kidney from a donor with localized amyloidosis of the oropharynx?

Risks of Plasma Cell Clone Transmission Through Blood Transfusion vs. Organ Transplantation

Yes, there is a theoretical risk of transmitting a plasma cell clone through blood transfusion to an immunocompromised recipient, similar to the risk in transplant patients receiving organs from donors with localized amyloidosis. This risk exists because plasma cells can circulate in the bloodstream at subclinical levels.

Transmission Risk Comparison Between Organ Transplantation and Blood Transfusion

• Blood transfusion has been documented as a potential route for disease transmission, including various infectious agents that may be present in donor blood at subclinical levels 1
• Immunocompromised patients, including transplant recipients, are at increased risk for reactivation and disseminated infection from pathogens transmitted through blood transfusion 1
• The risk of transmitting cellular components (including potentially malignant clones) is higher with non-leukodepleted blood products, as these contain intact donor cells that can interact with recipient leukocytes 2
• Transfusion-associated immunomodulation (TRIM) can occur when donor cells present antigens coated in HLA-DR proteins that interact with recipient leukocytes, potentially allowing for engraftment of abnormal cell lines 2

Mitigating Transmission Risk

For Blood Transfusion:

• Leukodepletion of blood products is recommended for immunocompromised patients to reduce the risk of transmitting cellular components, including potential plasma cell clones 3
• Prestorage leukodepletion is the standard in the United States and many other countries, providing more consistent quality control and reducing transmission risks 3
• Irradiation of blood products with gamma radiation (minimum dose of 25 Gy) prevents transfusion-associated graft-versus-host disease by inactivating viable lymphocytes that could include abnormal plasma cell clones 2

For Organ Transplantation:

• Donor screening protocols are critical but vary with the type of allograft, national standards, and availability of screening assays 4
• Histocompatibility testing and crossmatching help identify donor-recipient combinations likely to yield successful transplants while minimizing immunological risks 1
• Testing for specific disease markers in donors with known conditions (like localized amyloidosis) should be performed to assess transmission risk 1

Special Considerations for Amyloidosis

• AL amyloidosis is characterized by a low-level expansion of an indolent plasma cell clone that produces amyloidogenic light chains 5
• These plasma cell clones could theoretically be transmitted through both organ transplantation and blood transfusion, especially in immunocompromised recipients 5, 6
• The risk may be higher with organ transplantation than with blood transfusion due to:
  • The larger volume of tissue and potential number of cells transferred 4
  • The prolonged engraftment of donor-derived cells in organ transplantation versus the typically shorter lifespan of transfused cells 7

Risk Reduction Strategies

• For patients with known plasma cell disorders (including localized amyloidosis), consider:
  • Using leukodepleted blood products for all transfusions 3
  • Irradiating blood products to inactivate viable lymphocytes 2
  • Regular monitoring of recipients for signs of plasma cell disorders or amyloidosis 8
• For immunocompromised recipients:
  • Consider additional screening of blood donors with history of plasma cell disorders 7
  • Implement enhanced monitoring protocols for early detection of transmitted disease 4

Common Pitfalls and Caveats

• The actual incidence of cell transplant-transmitted disease is unknown and can only be inferred from limited studies 7
• Absence of routine, active surveillance coupled with common failure to recognize or report transmission events means limited data are available on the incidence of allograft-associated disease transmission 4
• The theoretical risk must be balanced against the immediate need for transfusion or transplantation in critically ill patients 1
• While the risk exists, it should not prevent necessary transfusions or transplants when clinically indicated, but rather inform appropriate precautionary measures 1