MTN’s role in making A2 → B allocation part of the renal allocation system in the US

1991 & 1994 MTN implemented a UNOS-approved kidney allocation variance (modified in 1994) that allowed our
OPO/DSA to allocate kidneys from A2 or A2B deceased donors preferentially into B candidates if they had low anti-A IgG
titers.

1998 MTN presented our A2 to B allocation & clinical data to UNOS minority affairs committee. That set the stage for
their consideration of that allocation system as one way to provide blood group B candidates, who are predominantly
minority candidates, increased access to kidneys. MTN also pointed out that access of B candidates to deceased donor
kidneys could be increased by ≈ 7%/year if kidneys from B donors were no longer allocated into AB candidates.

2000 MTN lab implemented the first (inter-lab) proficiency testing program for anti-A titer testing with other labs who
also did the test. Anti-A (IgG) titer testing is the test done (before transplantation) to predict the likelihood of success of A2
to B or O kidney transplantations.

2001 UNOS policy was implemented nationally whereby kidneys from B deceased donors were no longer allocated to
AB candidates in order to increase access of B candidates to those B kidneys that here-to-for were going to AB
candidates. That change in national kidney allocation policy resulted from MTN’s recommendation to the UNOS minority
affairs committee in 1998 (above). We just showed (2014) that B’s got 10.3% more kidneys because of this change.

2001 MTN gave an updated presentation to the UNOS minority affairs committee (MAC) on the current success of our A2
to B kidney (deceased donor) allocation system. MAC decided to implement a national voluntary variance, based on the
MTN’s experience. MTN wrote the protocol for that national voluntary variance based on our A2 to B variance
experience.

2002 UNOS board approved a national voluntary variance to allow OPO’s (DSA’s) to allocate A2 kidneys into blood
group B candidates in their DSA. Five DSA’s initially participated in that variance and two others joined in 2006. This is
one of only 2 voluntary variances UNOS has ever put into place and the only one now in operation.

2005 The first report on the A2 to B voluntary variance experience was presented at the American Transplant Congress,
Seattle. That was recognized as one of the “what’s hot topics” of the meeting. MTN was a part of that presentation.

2005 MTN presented our allocation and clinical experience in A 2 to B transplantation to the UNOS Kidney allocation
review subcommittee (KARS). Based on those data, as well as the data from the UNOS voluntary variance that we also
presented, KARS proposed that A2 to B allocation be a component of the revised/new allocation algorithm for deceased
donor kidneys they were developing. Subsequent modelings performed by KARS have included the A2 to B allocation
system.

2005 In consultation with the College of American Pathologists implemented the first proficiency testing survey for labs
that test for anti-A titers. Federal regulations [CLIA] mandate that labs participate in proficiency testing for all lab tests.

2006 The second report on the A2 to B voluntary variance experience was presented at the World Transplant Congress in
Boston. MTN was a part of that presentation.

2008, June…Emory University & Georgia is beginning to participate in UNOS voluntary variance they called us for
guidance as they begin to anti-A titer test their 125 B candidates

September, 2008...OPTN/UNOS sent out document, Kidney allocation concepts which defines the new national kidney
allocation system. On page 30-32 is a description of the A2/A2B to B system that will become national practice.

September, 2009…OPTN/UNOS presented to Operations committee a risk analysis of A subgroup errors with one vs. two
typings. Data (A subgroup error rate) used was from an MTN publication. This will be used to justify mandating two A
subgroups be done for A/AB donors (live/deceased).

May, 2010….UNOS presented a poster presentation of that risk analysis of A subgroup errors at American Transplant
Congress, San Diego. MTN was a part of that work as we had published a paper that allowed them to calculate that risk.

2011...MTN is first to describe that a high anti-A IgG titer does not effect kidney function in simultaneous liver and kidney
transplantation because the liver likely adsorbs the A isoaggultinins which protects the kidney.

2013….On Monday, June 24, 2013, the UNOS Board of Directors voted to implement the new kidney allocation
algorithm. One component of that algorithm is A2/A2B → B allocation, when anti-A titers are low. MTN played a
predominant role in getting that allocation system implemented in the United States as illustrated by the above steps.