Skip to main content
2024 AABB Annual Meeting Main banner
Icon Legend
This session is not in your favorites.
This session is in your favorites. Click again to remove it.
Presentation Icons
Live Stream Sessions
Live Stream Sessions

Immunohematology and Genetic Testing (red cells, leukocytes and platelets)

(P-IG-29) Optimization of the MAIPA assay for the specific detection of anti-HPA-15 alloantibodies

Sunday, October 20, 2024
12:00 PM - 1:00 PM  
Background/Case Studies: The monoclonal antibody immobilization of platelets (MAIPA) assay is commonly employed to detect alloantibodies directed against human platelet antigens (HPA). However, discrepancies in MAIPA protocols among platelet immunology laboratories leads to variable detection sensitivity. Furthermore, the low expression and instability of CD109 at the platelet membrane makes the detection of anti-HPA-15 alloantibodies particularly challenging.

Study

Design/Methods: We identified the parameters of a published MAIPA protocol that are most likely to influence the sensitivity of detecting antibodies directed against HPA-15 in sera. For this assay, we used multiple donors homozygote for the HPA-15 position. To compare our results with other platelet immunology laboratories, we used NIBSC’s anti-HPA-15b minimum potency reagent. We aimed to generate a protocol that is time-efficient and can be easily incorporated into a standard working hours schedule.

Results/Findings:

Platelet quantity and serum volume are strongly correlated with the sensitivity of the assay. To a lesser extent, other parameters such as revelation antibody concentration and HRP-TMB reaction time increased the detection of anti-HPA-15 antibodies compared to negative controls.

We also noted that the sensitivity of this assay varies considerably depending on the expression of CD109 on donor platelets.

The final MAIPA protocol exceeds the standards established by the World Health Organization for the detection of anti-HPA-15 directed antibodies.

 

Conclusions: Modifying MAIPA assay parameters and carefully selecting panel platelet donors allows for a sensitive and specific detection of anti-HPA-15 antibodies. Sharing these findings with other platelet immunology laboratories could promote better standardization of the assay thus mitigating the occurrence of false negatives in detecting these elusive antibodies.