Presiding chair was Dr. Francesco Rodeghiero (Vicenza, Italy); all co-chairmen were present.

Attendance was approximately 350.

Dr. A.B. Federici (Italy) reported the final data of the International Registry on Acquired VWD, set up with Dr. J.H. Rand. A document including guidelines for diagnosis and treatment will be submitted to the SSC for publication as an official report.

Dr. J.E. Sadler (U.S.A.) presented the recommendation of the joint ISTH/WHO meeting on VWD held in London, October 12, 1998. WHO and ISTH agreed on the development of joint strategies for epidemiological data collection on the prevalence of VWD in developing countries, for laboratory diagnosis, and for optimal treatment of VWD patients. The Subcommittee on VWF is already active in this field.

Dr. A. Srivastava (India) presented data on the prevalence of VWD in developing countries collected by mailed questionnaires. A new questionnaire for the collection of additional data on the prevalence of VWD in comparison to severe hemophilia A and on the severity of VWD was proposed and approved.

Dr. I. Peake (U.K.) chaired a session on the molecular diagnosis of VWD. Dr. A. Goodeve (U.K.) presented an updated molecular and genetic terminology of VWF and VWD. A consensus document will be prepared in cooperation with other members for approval in the next subcommittee meeting. Dr. J.E. Sadler, on behalf of Dr. D. Ginsburg (U.S.A.), reported on the current status of the electronic database on VWD mutations and polymorphisms. Dr. I. Peake reported on the difficulties of a molecular diagnosis of type 1 VWD. His proposal for a registry of studies on phenotypically and genotypically investigated type 1 VWD patients was approved.

Dr. C. Mazurier (France) chaired the session of the Working Party on the measurement of VWF content in therapeutic products. Dr. A. Hubbard (U.K.) and Dr A. Chang (U.S.A.) reported on the joint NIBSC and FDA study for the identification of a suitable concentrate preparation to be used as a future standard. Dr. T. Barrowcliffe (U.K.)

presented data on potency assignment of the 4th International Standard of FVIII:VWF adopted by WHO. Dr. R. Seitz (Germany) presented two methods for VWF:CBA in concentrates.

Dr. R. Montgomery (U.S.A.) chaired the session of the Working Party on laboratory diagnosis of VWD. Dr. K. Friedman (U.S.A.) reported on an international standardized study of VWD variants. Dr. A.B. Federici presented data on VWF:Rcof, VWF:CBA and on a commercial VWF:Ag "functional" assay in different types of VWD. He also presented data on the use of the above tests for the diagnosis of type 2 VWD. Dr. E. Fressinaud (France) also presented data on the VWF:Rcof/VWF:Ag and FVIII:C/VWF:Ag ratio for the diagnosis of type 2 VWD. Dr. C. Miller (U.S.A.) reported on disproportionately high Factor VIII levels using the 3rd International Plasma Standard and on the problems encountered in VWF:Rcof assay using commercial kits. Dr. E. Favaloro (Australia) reported on the role of VWF:CBA in VWD diagnosis in a multi-laboratory study in Australasia. Dr. Z. Ruggeri (U.S.A.) suggested the term "functional activity" for any VWF measurement be avoided.

Dr. M. Furlan (Switzerland) and Dr. J.P. Girma (France) presented two methods for VWF-cleaving protease assay for use in the clinical laboratory. A new Working Party on the measurement of VWF-cleaving protease was created, under the coordination of Dr. Furlan.

Dr. F. Rodeghiero closed the session presenting the current status of the multicenter study on the validation of diagnostic criteria of type 1 VWD.

SUMMARY OF SUBCOMMITTEE ACTIVITIES

Issues voted:

Submission to the SSC of an official report on diagnosis and treatment of AVWS.

Creation of a new Working Party on the measurement of VWF-cleaving protease.

Creation of a registry of studies on phenotypically and genotypically investigated type 1 VWD patients.

Ongoing projects:

Multicenter, retrospective study for the validation of the diagnostic criteria for type 1 and type 3 VWD.

The Working Party for VWF assay in concentrates will continue to cooperate with FDA and NIBSC to produce an international standard consisting of a stable freeze-dried concentrate calibrated against normal plasma.

Survey on VWD in developing countries.

Proposals for genetic and molecular terminology of VWF/VWD.