A transfusion medicine physician who works in the clinical laboratory of at an academic center in the MidWest US wonders how other laboratories report results of ABO grouping for potential renal transplant patient whose red cells demonstrate Group A1 or demonstrate a subgroup of A. Up to now her clinical laboratory reports such patients as either group A1 or group A sub, without distinguishing between group A2 and the various other subgroups of A. However, the renal transplant group at her hospital now requests that the clinical laboratory differentiate between A2 and A3, and other subgroups of A. Is any other hospital laboratory reporting out the A subgroup of potential renal transplant patients? If so, is there literature that shows the value to differentiate between A2 and A3 in the setting of renal transplantation?

The following comments have been received.

ADDENDA Aug. 3, 2006

1. According to Carol Pancoska Ph.D., Laboratory Director of the New Jersey Sharing Network (attribution used with permission), as background, there has been at least one documented hyperacute rejection of a kidney transplant due to anti-A1 a few years ago. Since then, her practice has been to type donors and recipients for subgroups of A using A1 lectin AND performing a backtype on the recipients' serum using A1, A2, B, and O reagent red cells and an autocontrol with a 15 minute room temperature incubation to detect anti-A1 in the serum of recipients who are a subgroup of A.

In her opinion, the issue is whether the recipient is a subgroup of A and does the recipient have anti-A1 in his/her serum. A recipient who is an A subgroup and has anti-A1 in the serum should not receive an organ from an A1 donor. Also in her opinion, it should be sufficient to report A1, A2 or Asub and anti-A1 present or absent in the case of A subgroups.

ADDENDA Aug. 9, 2006

2. Dr. Laura Cooling of the University of Michigan Hospitals reports that several years ago, at a different institution, she also saw rejection of an A1 kidney by an A2 donor. Unlike the case described in the August 3, 2006 posting to this discussion, the case that she saw was NOT a hyperacute rejection. Rather, the recipient presented with humoral rejection 2-3 months post-transplant. At that time, a new anti-A1 was detected. They were reportedly able to confirm the recipient was A2 and the donor (living-related) was A1. Dr. Cooling would question the need to determine the specific A subgroup (A2, A3, Ax) but it may be prudent to identify transplant candidates who are an A subgroup and therefore have the potential to make an anti-A1.

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Ira A. Shulman, MD
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