Page History

Part 1: Since B*15:BPXE = B*15:03/61/74/103 a donor with this codes is a potential allele match for the patient. According to the official WMDA serology/DNA correspondence table, B*15:61 and B*15:74 have a serology of B15/B70 while B*15:03 is B72 and B*15:103 is B70. As a consequence a serology of B15 rules out B*15:03 and this donor is no longer potentially identical (on the allele level). Another explanation could be the limited length of donor lists.Part 2: In the old BMDW serology was ignored when DNA typing was available so B*15:03 was not excluded. The new system does not modify or ignore donor data and respects and relies on the responsibility of the providing registry for its dataand this donor is no longer potentially identical (on the allele level). Another explanation could be the limited length of donor lists.

Background: Unfortunately, for many donors serology was derived from DNA (by using the first field for the serological assignment) and vice versa (by appending “:XX” to the serological assignment) and often eventually both values are reported. In the case discussed, B*15:BPXE probably was translated back into B15 which is most likely wrong. This is a typical and (with certain registries) frequent case but there are many more unexpected DNA-serology correspondences that can give rise to exactly the same situation.

Hap-E Search and ATLAS does not consider binary attributes like gender or CMV for  sorting sorting at all. If you see a rich donor list and prefer, for example,  male male donors you should use the filtering capability of the algorithmsapply the filter to see male donors only.

Rationale: There is no agreed concept for weighing secondary match  criteria criteria like age, gender or CMV against each other. The approach to sort by probability in blocks and then by age plus ad hoc filtering gives the user maximum control of the appearance of the list.

This can happen only if the difference in resolution is not  considered considered sufficiently relevant in the given context by Hap-E Search and ATLAS. Below are some possible (not mutually exclusive) reasons:

1. The allele designations encode for the identical ARD (antigen  recognition domain) and Hap-E Search and ATLAS only matches for the ARD part of the HLA protein complex. For example B*07:ANVB stands for B*07:02/07:61 which both encode for the same ARD (here: exon 2 and 3). Hence Hap-E Search and ATLAS is regarding the codes B*07:02, B*07:61 and B*07:ANVB all as allele matches for each other but might give different matching probabilities for phenotypes containing each of those three codes since haplotypes  involving B*07:02 and B*07:61 are having individual frequencies.
2. The resolution only looks higher but, in fact, is lower (e.g.  B*15:12 currently is only a single allele while B*15:12:01G covers three), identical (e.g. A*80:01, A*80:01:01 and A*80:01:01G cover exactly the same alleles) or not directly comparable since each code is containing some alleles not covered by the other (e.g. comparing  B*07:TDVB and B*07:02:01G the former also covers a lot more variants of  B*07:02 like  B*07:02:02 to B*07:02:05 while it is excluding other alleles like B*07:44 and B*07:49N).
3. The broader code only contains additional alleles which have never  been observed in the population whose haplotype frequencies are used - at least not in a relevant haplotypical context. Their frequency could  also be so low that it is disregarded due to rounding or the 10%  probability grouping explained elsewhere. This applies, in particular,  to all null variants of expressed alleles with identical first two field  designations.

In rare cases the match program cannot decide which of two B locus results are a mismatch, in those cases both  both are given in bold. For example, the patient is B*27:05, 44:03; the donor is B*44:ABYM, 44*AFFK. In this case both multiple allele codes include 44:03 therefore the match program cannot choose between them. See example image below where donor 12 on the search report is being marked as having two HLA-B mismatches, when actually it is only a single mismatch.

The patient's 5 locus phenotype (10/10) cannot be explained by the haplotypes used for probability matching. The algorithm tries to fall back to 4 locus phenotypes (8/8) and 3 locus phenotypes (6/6).

Most likely, the donor's phenotype cannot be explained by the haplotypes used for probabilistic matching.

The probabilities shown in your match results table are based on allele level matching and do not correspond with this particular match typeon all loci.