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Chapter 112 Clinical Considerations in Platelet Transfusion Therapy 1719

TABLE Management of the Platelet-Refractory Patient TABLE Grades of Human Leukocyte Antigen–Matched
112.2 112.4 Platelets
Obtain 10-minute to 1-hour posttransfusion platelet count on two Match Grade Description
occasions. A 4-antigen match (donor and recipient match at
If there is an appropriate increment in platelet count after a single both HLA-A and HLA-B loci)
platelet transfusion, continue to transfuse random platelets and
treat nonimmune factors associated with decreased platelet survival B1U 1 antigen unknown or blank (e.g., donor is: A2, –;
such as sepsis and DIC, discontinue offending drugs, and so on. B5, 27)
If the 10-minute to 1-hour posttransfusion platelet counts demonstrate B1X 1 cross-reactive group a
no platelet increment (or only a marginal increment), obtain the B2UX 1 antigen blank and 1 cross-reactive a
patient’s HLA type and screen the patient for the presence of
anti-HLA antibodies (panel reactive antibody test). C 1 mismatched antigen present
While awaiting HLA antigen typing and antibody screening results, D ≥2 mismatched antigens present
consider transfusion of “fresh” (<3 days old) ABO-matched R Random
platelets. a
The clusters of human leukocyte antigen (HLA) that share antigenic epitopes
If PRA shows less than 20% reactivity, continue with “fresh” can be classified into cross-reactive antigen groups. Antibodies recognizing one
ABO-matched random platelets. HLA molecule within the group cross-react with other members of the same
If PRA shows more than 20% reactivity, obtain anti-HLA antibody group.
specificity. Use the recipient’s HLA typing information to locate Adapted from Brecher ME, editor: Technical manual, ed 15, Bethesda, MD,
2005, American Association of Blood Banks.
grade A or B matched platelet units for transfusion. Avoid
transfusion of platelets containing antigens against which the
recipient has antibodies. Consider recruiting recipient’s family for
platelet donation. The most challenging cases are the rare instances involving
Transfusion of cross match-compatible platelets is an option if there is immune-refractory patients who are actively bleeding and HLA-
a poor response to grade A- or B-matched platelets or if the matched platelets or cross matched platelets are either ineffective or
recipient has antibodies to platelet-specific antigens. unavailable. In such cases, patients are typically transfused with
All HLA-matched or cross-matched platelet units must be irradiated repeated doses of random HLA-incompatible platelets during hemor-
before transfusion to prevent transfusion-associated GVHD. rhagic episodes. The efficacy of this practice is unclear.
DIC, Disseminated intravascular coagulation; GVHD, graft-versus-host disease;
HLA, human leukocyte antigen; PRA, panel reactive antibody.
REFERENCES

1. Levitt J: Standards for blood banks and transfusion services, 29 ed, Bethesda,
TABLE Traditional Platelet Selection Guidelines for 2012, AABB.
112.3 Refractoriness Caused by Alloimmunization 2. Whitaker BI: The 2011 national blood collection and utilization survey
ABO antigens are expressed on platelets. Consider transfusion of report, Washington, DC, 2013, U.S. Department of Health and Human
ABO-matched platelets while awaiting the recipient’s HLA type and Services.
antibody specificity 3. Zou S, Stramer SL, Dodd RY: Donor Testing and Risk: Current
Platelet matching for the recipient’s HLA-A and HLA-B antigens is Prevalence, Incidence, and Residual Risk of Transfusion-Transmissible
important. Agents in US Allogeneic Donations. Transfus Med Rev 26(2):119–128,
Platelet matching for the recipient’s HLA-C antigens is not essential. 2012.
Determine the antigen specificity of recipient’s antiplatelet antibodies 4. Slichter SJ: Leukocyte reduction and ultraviolet B irradiation of platelets
and try to transfuse antigen negative platelets. to prevent alloimmunization and refractoriness to platelet transfusions.
Some HLA antigens may be weakly expressed on platelets. Consider The Trial to Reduce Alloimmunization to Platelets Study Group. N Engl
giving platelets mismatched for those antigens (e.g., HLA-B12 and J Med 337(26):1861–1869, 1997.
its splits B44, B45) 5. Slichter SJ: Factors affecting posttransfusion platelet increments, platelet
If HLA-matched platelets are unavailable, consider transfusion of refractoriness, and platelet transfusion intervals in thrombocytopenic
platelets mismatched for HLA antigens that are serologically patients. Blood 105(10):4106–4114, 2005.
cross-reactive with the recipient’s HLA antigens. 6. Gaydos LA, Freireich EJ, Mantel N: The quantitative relation between
If platelets mismatched for serologically cross-reactive antigens are not platelet count and hemorrhage in patients with acute leukemia. N Engl
effective, matching for HLA-associated antigen systems such as J Med 266(18):905–909, 1962.
Bw4/Bw6 may be helpful. 7. Slichter SJ, Harker LA: Thrombocytopenia: Mechanisms and manage-
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HLA, Human leukocyte antigen.
8. Heckman KD, Weiner GJ, Davis CS, et al: Randomized study of
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using single HLA antigen-coated beads. This information can be used 9. Rebulla P, Finazzi G, Marangoni F, et al: The threshold for prophylactic
to find donors that may be HLA mismatched with the recipient, but platelet transfusions in adults with acute myeloid leukemia. Gruppo
whose platelets lack the antigens to which the patient has specific Italiano Malattie Ematologiche Maligne dell’Adulto. N Engl J Med
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patients may benefit from receiving donor platelets that are cross dence in hematopoietic stem cell transplant recipients: 10,000/L versus
match compatible with the patient’s serum. The major benefit of cross 20,000/microL trigger. Biol Blood Marrow Transplant 8(10):569–576,
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excluded by strict HLA antigen matching. Also, platelet cross match- 11. Gmür J, Burger J, Schanz U, et al: Safety of stringent prophylactic
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