The meeting was attended by 50-90 members.
Carboxypeptidases, including TAFI
This was a new topic for the subcommittee. Dr. Dirk Hendriks summarized the current state of knowledge on these enzymes, including specificity and physiological location. He discussed assay methods and the inhibitors that were available to identify which enzymes are active in a particular situation. He recommended that the standard nomenclature be adopted, including the recently agreed EC number. Dr. Lazslo Bajzar then addressed the specific topic of TAFI (also known as carboxypeptidase U) and gave information on a functional assay and on a novel ELISA. He presented data on a small group of normal individuals. It was agreed that this topic was of growing interest and that it should be on the program for 1999.Measurements of proteins of the fibrinolytic system in animal models
Dr. Paul Declerck presented an overview of methods suitable for non-human samples, both functional and immunological. Additional information on assays and availability of antibodies was presented from the floor (Dr. HR Lijnen). It was agreed that a written summary of available antibodies should be made available and Paul Declerck offered to prepare this with a view to publication in Thromb. Haemost.Standards for proteins of the fibrinolytic system
Dr. Patrick Gaffney made the case for a new standard for plasmin. He presented data on assignment of a value of 5.3 IU/ml to the new standard. It was agreed that this material should be recommended to the WHO Expert Committee on Biological Standardization. He and Dr. Booth, as Chairman, would discuss its presentation to the Committee with the SSC's presentative to the WHO.
Dr. Gaffney's second topic was on single-chain uPA. A collaborative group had assayed two preparations of this material, one produced in E coli and one in CHO cells. The agreement between all five centres was excellent, but there was a discrepancy in the activity of the CHO product in chromogenic versus clot lysis assays. It was agreed that, in the light of this, it was too early to propose either of these materials as a standard. It was agreed that Dr. Gaffney should offer these two preparations as NIBSC reagents, giving the full data on site of production and activities in both assays. The average data from the collaborative group would be included in the information given.Blood collection for assays of fibrinolysis
Dr. I Walker was unable to be present so Dr. C Kluft summarized a document she had prepared. Since this was of relevance to other subcommittees, he undertook to consult with other interested parties and to bring together a final version of the report to be made available to any member of the subcommittee for eventual publication.Fluctuations in fibrinolysis throughout the menstrual cycle
Dr. C Kluft presented the results of a literature review of this topic. There were strong indications of changes in some components of the system over the menstrual cycle in some studies but no clear changes emerged. Dr. Kluft intends to pursue this topic in further studies but there was little support for making this a subcommittee initiative at this stage, in view of the difficulty of carrying out a sufficiently wide-scale study to achieve a clear outcome.Reports for PGM working group
Dr. C Kluft chaired this session, reporting on the activities of the Project Group on Methods, consisting of Drs. J Gram, J Jespersen, TW Barrowcliffe, PJ Declerck and CW Francis, with Dr. Kluft as chair. He explained that this group was part of general SSC activities that had initially concentrated on fibrinolysis. It aims to examine the methods used to measure particular analytes and to produce reports on the criteria necessary to achieve reproducibility across laboratories. Two such reports, on tPA antigen and plasmin inhibitor, are in preparation.
Dr. B Binder presented a review of methods to measure scuPA. His conclusion was that there was no single analyte measurement of which there was good experience at this stage. It was therefore decided to put the issue of standardization aside until this became available.
Dr. J Sidelaman presented data on plasminogen measurements, showing the wide fluctuations in data achieved in a WHO EQAS initiative. It was decided that several collaborators were required to assay a number of samples and to report back to the subcommittee.The introduction of the IFCC/SSC working party
Dr. C Jackson explained the background to the formation of The Joint Committee on Standardization of Coagulation Effects, comprising Drs. J Jespersen, J Rosing, P Esnouf, G White, TW Barrowcliffe, C Kluft and J Lenahan with Dr. Jackson as Chair. This initiative will impact on the Fibrinolysis Subcommittee in that it will cover some of the issues covered up to now by the PGM.Plans for 1999
It was agreed that topics for the SSC meeting in Washington should include
The meeting finished at 5:15.