Alloimmunization From Transfusions Follow-up

Updated: Sep 08, 2017
  • Author: Douglas Blackall, MD, MPH; Chief Editor: Michael A Kaliner, MD  more...
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Further Inpatient Care

Delayed hemolytic transfusion reactions

To assess the effectiveness of RBC transfusions, measure hemoglobin levels 1 and 24 hours posttransfusion.

More than 40% of RBC antibodies become undetectable after the first detection, but these antibodies may cause hemolysis upon restimulation. [15]

Maintain accurate records of the antibodies present and consider notifying patients (eg, with a carry-on card) that they have clinically significant alloantibodies.

Refractoriness to platelet transfusions

To assess the effectiveness of platelet transfusions, obtain platelet counts at 1 and 24 hours posttransfusion.

If the specificity of antibodies is identified, keep a permanent record and consider notifying the patient (eg, with a carry-on card).

Consider planning future platelet transfusions in advance by selecting donors who lack the involved antigens.



Delayed hemolytic transfusion reactions

Properly identify blood group alloantibodies prior to transfusion, and select antigen-negative RBCs for transfusion.

Patients with previously identified alloantibodies must be documented in a database, with information shared between institutions, as appropriate. Antigen-negative RBC units should be provided whenever possible, even if corresponding alloantibodies have decreased below detectable levels (to prevent immune restimulation).

Patients with alloantibodies require fully crossmatched (ie, antihuman globulin phase) donor units.

In patients of ethnic minorities who have received multiple transfusions (eg, African-Americans with sickle cell disease), testing for commonly involved antigens (eg, Rh, Kell, Kidd, Duffy) and transfusing antigen-negative units can significantly reduce the frequency of alloimmunization. However, the cost effectiveness of this approach must be considered because most patients who receive multiple transfusions do not form clinically significant alloantibodies. A more cost-effective approach may be to match the ethnic origin of donors and recipients, reserving extensive antigen typing for recipients who have been alloimmunized previously. These patients may also benefit from leukocyte reduced RBCs because leukoreduction appears to decrease the frequency of alloimmunization to RBC antigens, possibly due to decreased stimulation of TH 2 lymphocytes associated with transfusions. [6]

If Rh-positive units (RBCs, platelets, or granulocytes) must be transfused into an Rh-negative recipient, alloimmunization to the D antigen can be prevented by administering intravenous Rh-immunoglobulin (eg, WinRho SD, 10-12 mcg/mL of transfused Rh-positive RBCs). If transfusing a large number of Rh-positive units, the dose of Rh-immunoglobulin may be reduced after removing the antigen load by RBC exchange. [16, 17]

Refractoriness to platelet transfusions

Primary alloimmunization to class I HLA antigens present on platelets requires active donor APCs.

Removing leukocytes by filtration or buffy coat removal or deactivating APCs by ultraviolet-B irradiation reduce the frequency of alloimmunization.

Leukocyte reduction is indicated in all patients who are expected to be transfused repeatedly, especially candidates for bone marrow transplantation. These patients may also benefit from initial HLA typing and transfusions from crossmatched or HLA-matched platelets. [18]

Pooled, random-donor, leukocyte-reduced platelets do not increase the frequency of alloimmunization compared with leukocyte-reduced, single-donor apheresis platelets. [19]

Transfusion of ABO incompatible platelets (ie, donor platelets with A or B antigens reacting with the recipient's A or B antibodies) increases the likelihood of alloimmunization to other platelet antigens and reduces platelet survival. Therefore, ABO-compatible platelets should be provided routinely, as available, to avoid alloimmunization. [20]


Patient Education

Inform patients that they have alloreactive antibodies and educate them about the names of these antibodies (eg, with a wallet carry-on card). Instruct patients to present the carry-on card if they are admitted to a care facility different from that which they usually attend..