Transfusing special populations: Transplant Recipients:
Patients undergoing solid organ or stem cell transplants from non-ABO identical donors pose special serologic challenges for blood transfusion services. The most common abnormality is a grouping discrepancy, meaning that the blood group suggested by the forward group does not match what is suggested by the reverse group (see Module 2 for further discussion of blood grouping).
In patients undergoing solid organ transplants, the discrepancy will most often be seen in the reverse group. Potent immunosuppressant medications or therapeutic plasma exchange procedures may lead to loss of reactivity of the patient’s normal isoagglutinins (anti-A and/or anti-B). For example, the weak reaction against B cells below, in what appears to be a group A patient, would be a typical presentation.
| Anti-A | Anti-B | A1 cells | B cells | Anti-D | Rh-control |
|---|---|---|---|---|---|
| 4+ | 0 | 0 | 1+ | 4+ | 0 |
In addition, the development of passenger lymphocyte syndrome may result in the appearance of a new isoagglutinin of donor origin. For example, the weak reaction against A cells seen in the grouping result below may be due to plasma cells that were transplanted as “passengers” of a group B kidney grafted into a group A patient.
| Anti-A | Anti-B | A1 cells | B cells | Anti-D | Rh-control |
|---|---|---|---|---|---|
| 4+ | 0 | 1+ | 4+ | 4+ | 0 |
Recipients of non-ABO identical stem cell transplants may manifest both of the above phenomena. In addition, however, abnormalities of the forward blood group (typically mixed field reactions) will be seen as the patient’s RBC population transitions to that of the donor. For example, a group O patient who receives a stem cell transplant from a group A donor might present with a blood group like the following:
| Anti-A | Anti-B | A1 cells | B cells | Anti-D | Rh-control |
|---|---|---|---|---|---|
| mf | 0 | 2+ | 2+ | 4+ | 0 |
Patients with abnormalities in both their forward and reverse group can be challenging to interpret; in addition, other causes of grouping discrepancy (as described in Module 2) must be considered as well. Resolving grouping discrepancies can be considered an advanced skill and beyond the scope of these modules; however, it is important to appreciate the special transfusion requirements of patients with these discrepancies, which may be summarized as follows:
- In recipients of both solid organ and stem cell transplants, plasma must be selected that, in addition to being compatible with the patient’s RBCs, will not injure the graft.
- In recipients of stem cell transplants, RBCs must be compatible with both the donor’s and the recipient’s blood group, until it has been confirmed that the donor has completely engrafted.
Knowing the ABO group of a patient’s solid organ or stem cell donor is thus very important both for the interpretation of the blood group, and for the safe selection of blood products.
Next page: Investigating transfusion reactions