Report on the Tenth International Platelet Genotyping and Serology Workshop on behalf of the International Society of Blood Transfusion.

BACKGROUND AND OBJECTIVES

The aims of the 10th International Platelet Serology and Genotyping Workshop were to evaluate the proficiency of platelet immunology determinations.

MATERIALS AND METHODS

There were 40 participants from 25 countries of four continents. Thirty-eight institutions reported results for genotyping, and 38 institutions reported their serological results. For genotyping, EDTA-anticoagulated whole-blood samples were provided (to allow the inclusion of DNA-separation methodology in the analysis) as well as separated DNA of a and b alleles for human platelet antigen (HPA)-1 to -6. For serological evaluations, sera contained allo- and autoantibodies, and for sensitivity testing a standard freeze-dried sample of HPA-5 antibody.

RESULTS

All participants reported HPA-1, -2, -3 and -5 genotyping results; HPA-4 was determined in 29 laboratories and HPA-6 in 21. Results from 16 laboratories were concordant with the majority vote for all allotypes, eight institutions reported one deviation, five laboratories two, and nine laboratories three or more deviations. Twelve institutions had no deviation from the majority vote for HPA antibodies, nine had one, three had two, and 14 had three or more deviations. Most laboratories reported a reactivity of the standard anti-HPA-5b sample with HPA-5b platelets at a dilution of 1:4-1:8. Four laboratories detected anti-Gova in one sample. Seventeen laboratories reported no deviation from the majority vote for pan-reactive platelet antibodies, 12 had one deviation, two had two, and seven had three or more deviations. In addition, seven participants reported antibodies against glycoprotein IV (GPIV), three against glycoprotein V (GPV) and three against CD 109. These results were discussed at a meeting organized jointly with the International Society of Blood Transfusion (ISBT) 2000 Congress.

CONCLUSION

The results for pan-reactive antibodies were heterogeneous with most discrepancies from the majority vote. The provision of sufficient samples for many participants is difficult. Based on the results and discussion it is clear that frequent workshops are needed in the future. Therefore, workshops shall be organized regionally, and each region shall participate with one institution in international workshops. The latter are needed to assure international exchange of experience and quality.