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More on Prekallikrein Deficiency

Here is an comment on Tracy Dixon’s prekallikrein deficiency case from Dr. Tom Exner, Haematex, Sydney, Australia.

Hi, George, thanks for the interesting case; from Australia of all places!  I’ve written up a couple of such cases many years ago. PKK and HMWK-deficient plasmas may be less readily available these days but the antibodies are still around and can be used to prepare deficient plasma just by conservative “spiking” into PNP if not affinity chromatography. Companies such as Precision BioLogic Inc., Affinity Bio, Hyphen BioMed, Stago, Aniara and George King must still be able to supply these products for the curious among us. (Note from George, I was able to find prekallikrein-deficient plasma from Precision BioLogic, but couldn’t find readily available HMWK-deficient plasma from any suppliers.)

It might be interesting to know if different APTT reagents gave different results as the various contact activators may be more or less sensitive to the defect. Ellagic acid is not supposed to be sensitive to PKK deficiency, yet with the ROTEM reagent it was in this case.

Of course the first thing should have been to check out any relatives. One of my cases came from an aboriginal background where the parents were consanguinous and this is quite a common thing in their community. However they do not like being tested for anything, so actual studies on the frequency of Fletcher factor deficiency have not been carried out. I suspect it may be quite high.

As for being an acquired defect; if this is correct it would be well worth reporting. I haven’t heard of such a case before.

Comments (1)
Factor Assays
May 25, 2015 4:37am

Thankyou George & Tom! Just
Thank you George & Tom! Just to clarify that his aPTT performed in February this year in the same lab was 29 seconds, so it appears to be an acquired deficiency. Our QEII laboratory performed mixing studies with both PKK & HMWK deficient plasmas, and confirmed a HMWK deficiency. Inhibitor studies show no inhibitor to HMWK. We know there was liver involvement of his metastatic melanoma, however his other coagulation factors were within the normal range.

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