In Focus
PIWP International Platelet Immunology Workshop
Quality and Innovation Excercise for Platelet Laboratories around the Globe
Brian Curtis
Director, Platelet & Neutrophil Immunology Lab Versiti Blood Center of Wisconsin Milwaukee, USA Read bio >
Nuria Nogues
Head of the Immunohematology Reference Laboratory, Banc de Sang i Teixits. Barcelona. Spain
Nurul Munira Yahya
National Blood Center, Kuala Lumpur, Malaysia Read bio >
The primary goal of the PIWP is to “improve diagnostic laboratory testing for the detection and identification of platelet antibodies and antigens”.
The workshop
A major mechanism we have used for over 40 years to accomplish this goal is our biennial International Platelet Immunology Workshop (IPIW)1. Participating labs must apply and meet specific qualifications, including election by member labs, to participate in the workshop. The IPIW typically consists of two parts:
1. Quality Exercise
For this activity, 3-5 human serum samples and matching DNA samples are provided to participant labs. Labs are instructed to perform their routine in-house testing to detect and identify HPA antibodies in the serum samples and determine the HPA genotypes of the DNA samples. Labs then submit their results to the Organizing Lab for compilation and review.
2. Innovation Exercise
This exercise is not graded. It can involve studies of a new method or reagent that the labs evaluate together to verify its utility. Another example is group evaluation of samples submitted from complex serologic cases. By working together as a group through the IPIW, we can often solve these difficult patient cases.
Review and Follow-up
The Organizing Committee reviews the data submitted by all of the participating labs and assists the Organizing Lab to prepare a report of the results that is then distributed to all participants. Laboratories value the opportunity to compare their performance to the other labs. Many labs use the Quality Exercise as part of their proficiency testing program to meet regulatory requirements. The final, approved results are published in Vox Sanguinis. The final report is also discussed at the PIWP Business Meeting and ISBT Congress and at the European Symposium on Platelet & Granulocyte Immunobiology (ESPGI). The ESPGI is a one-of-a-kind gathering of researchers, physicians and laboratorians to discuss about platelets and granulocytes. The 17th ESPGI will be held in September 2024 in the Netherlands: https://sanquinacademy.nl/en/offers/espgi-2024/.
The 22nd IPIW
In 2024, the 22nd IPIW will take place. The innovation exercise will focus on optimizing the detection of antibodies against CD36. Laboratories will receive CD36-specific monoclonal- and human antibodies to perform glycoprotein capture assays to detect antibodies (Figure 1). These assays are required testing in order to detect and identify the antigens targeted by platelet antibodies in patients’ sera. CD36/GPIV is a major 88-kDa platelet membrane protein that is expressed on platelets, macrophages, and capillary endothelium2. Antibodies against CD36 cause fetal & neonatal immune thrombocytopenia, platelet transfusion refractoriness, post-transfusion purpura, and TRALI.2 CD36 is a receptor for platelet adhesion to type V collagen, a receptor for malaria-infected red blood cells and for LDL cholesterol. Approximately 3-10% of individuals in African, Asian, and Middle Eastern populations have little to no expression of CD36 on their monocytes and platelets2, while CD36-deficiency in white populations is rare ~ 0.1%3. Individuals that do not express CD36 can produce antibodies when exposed to the protein by transfusions or pregnancy and these antibodies can cause the aforementioned immune platelet disorders, therefore, it is important that laboratories can detect CD36 antibodies.
Barcelona
The 22nd IPIW be organized by the Immunohematology Laboratory, Banc de Sang i Teixits (BST), Barcelona, and the results will be discussed June 2024 at the 38th International ISBT Congress in Barcelona, Spain. More than 30 PIWP labs from across the world will participate in this workshop! Assisting BST with sample preparation, distribution, and data collection and analysis will be National Blood Centre (Pusat Darah Negara) Malaysian Blood Transfusion Society, Kuala Lumpur, Malaysia, and the Platelet & Neutrophil Immunology Lab at Versiti, Milwaukee, USA. The Institute of Blood Transfusion, Guangzhou Blood Center, Guangzhou, China and Versiti will supply critical reagents in support of the workshop.
Figure 1. Examples of monoclonal antibody capture tests for detection of human/patient antibodies against platelet CD36.
References
- V Kieffel and C Mueller-Eckhardt. Report on the Fifth International Society of Blood Transfusion Platelet Serology Workshop. Transfusion 1993;33:65-69.
- BK Flesch, V Scherer, A Opitz, O Ochmann, A Janson, M Steitz, T Zeiler. Platelet CD36 deficiency is present in 2.6% of Arabian individuals and can cause NAIT and platelet refractoriness. Transfusion 2021;61:1932-1942
- BR Curtis and RH Aster. Incidence of the Naka-negative platelet phenotype in African Americans is similar to that of Asians. Transfusion 1996;36:331-334.
