Sunday, February 04, 2007

Whither immunohematology in AABB's Transfusion?

As a longtime member of AABB, having joined in1975 to get the member rate for attending the annual meeting in Chicago, I have always made it a habit to read the association's journal Transfusion from cover to cover. Typically, the journal sits in the bathroom where it helps time pass when I'm otherwise engaged.

Generally speaking, I find editorials and letters to the editor particularly useful in presenting the big picture of transfusion medicine. Reading the abstracts of all scientific papers, even those that are of minimal interest, may seem to be a time waster, but I believe they help keep me informed of the breadth of the latest research, something that is always prudent for a teacher. Sometimes, if an article is particularly fascinating, the journal makes it onto my night table for restful bedtime reading.

For many years I've been aware that few of my fellow medical technologists read Transfusion from cover to cover. Indeed it's a stellar issue if they read even one article. The most common proffered reasons have been that

  1. almost all articles have nothing to do with their professional practice and
  2. they cannot understand the science of many articles.

The latter reason is largely because many experienced technologists (the profession, like all health professions, is aging) were not trained in molecular genetics.

A very long time ago immunohematology with its antigens, antibodies, and serologic tests was king to blood bank technologists. Blood banking has long since evolved into transfusion medicine, a broad, multidisciplinary field. Now IH is relegated to a section of Transfusion, and a small one at that.

Consider these two articles, the sole papers in the IH section of the Jan. 2007 issue:

1. The molecular diversity of Sema7A, the semaphorin that carries the JMH blood group antigens

  • BACKGROUND: Semaphorin 7A (Sema7A), the protein that carries the JMH blood group antigen, is involved in immune responses and plays an important role in axon growth and guidance. Because previous serologic studies on red blood cells (RBCs) suggested a considerable diversity of Sema7A, the present study was designed to elucidate the complex picture of the molecular diversity of this protein.
  • STUDY DESIGN AND METHODS: The JMH antigen status was determined by serology, flow cytometry, and Western blot. Genomic and transcript analysis of SEMA7A was performed by nucleotide sequencing. Recombinant Sema7A proteins were used for genotype-phenotype correlation. A three-dimensional model of Sema7A was generated for topologic analyses.
  • RESULTS: Our studies on 44 individuals with unusual JMH phenotypes and their family members revealed that aberrant Sema7A expression can be an inherited or an acquired phenomenon and is based on reduced surface expression or qualitative changes in Sema7A. These different phenotypes are caused by variations of the SEMA7A gene or seem to be generated by autoimmune-related or RBC lineage?specific mechanisms. The variant JMH phenotypes were related to the presence of missense mutations in SEMA7A, predicting amino acid changes in the semaphorin domain of Sema7A. Sequence analysis of the variant SEMA7A alleles revealed mutations affecting codons 207 and 460/461. Topologic analyses showed that Sema7A polymorphisms were prominently located on the top and bottom of the semaphorin domain, suggesting a functional relevance of these sites.
  • CONCLUSION: These findings provide a basis with which to delineate the various ligand-binding surfaces of Sema7A.

2. Knops blood group haplotypes among distinct Brazilian populations

  • BACKGROUND: The Knops blood group system consists of antigens encoded by exon 29 of complement receptor 1 (CR1) gene. To better elucidate the complexity of Knops group system, the frequency of six single-nucleotide polymorphisms (SNPs) in three Brazilian populations is determined...
  • .....Design and results omitted to give neurons a break....
  • CONCLUSIONS: In this study, a new SNP substituting serine for asparagine at amino acid 1540 was identified. Moreover 12 haplotypes were identified. The differences in haplotype frequencies strongly suggest that the H1 and H2 might be the ancestral one while the H3 may have originated in Africa and may have fixed there by positive selection.

Are these papers really immunohematology?

Most of my colleagues would say no. How much is understandable to someone with no education in molecular genetics? To some, phrases such as axon growth and guidance, missense mutations, and semaphorin domain may be as meaningful as those generated by the infamous and hilarious Buzz Phrase Projector

The publisher's website says that "Transfusion reports on the latest technical advances, discusses opposing viewpoints regarding controversial issues, and presents key conference proceedings."

The posters from the annual meetings have much to interest working technologists, e.g., serologic studies, educational initiatives, quality management projects, management issues, and more. Why do so few of these studies make it to Transfusion as full research papers?

Moreover, how many articles in Transfusion are relevant to nursing transfusion practice? Some for sure, but enough? Food for thought for another blog....

Cheers, Pat

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