Researchers found no statistically significant differences in accuracy between different methods for detecting anti-human platelet antigen (HPA) antibodies responsible for fetal and neonatal alloimmune thrombocytopenia (FNAIT), according to a recently published study in Hematology, Transfusion, and Cell Therapy.
The authors tested the current standard of care for FNAIT diagnosis, Monoclonal antibody immobilization of platelet antigens (MAIPA ) along with the following alternative methods: platelet immunofluorescence test (PIFT) and Luminex platform-driven microsphere-based multiplex assays (Pak-Lx) for anti-HPA detection.
The aim was to compare the sensitivity (ability to identify samples with antibodies) and specificity (ability to identify samples without the antibodies) between the three methods. The study included 100 samples from patients suspected of having antibody-mediated platelet diseases such as FNAIT and post-transfusion purpura.
Researchers compared MAIPA results with the other three methods, observing no statistically significant differences between them. Pax-lyx and PIFT had 94% and 88% concordance with MAIPA, respectively.
“These data suggest that no single method can detect all clinically important antibodies. Therefore, it is advisable that each laboratory develops customized protocols based on their expertise and employs complementary methods for comprehensive patient assessments,” the authors concluded.
Understanding FNAIT diagnostic testing
Platelets, like all other cells in the body, express specific molecules on their surface (antigens), which have the potential to be recognized by specific antibodies. If a pregnant person carries antibodies against HPA antigens expressed on the surface of platelets, these antibodies can cross the placenta, bind to fetal platelets, and start an immune reaction that results in platelet destruction.
Because of this, HPA antibody testing is vital for FNAIT diagnosis and prevention. For years MAIPA has been the method of choice for HPA detection, however the introductions of new technologies call for studies comparing all available options.
“The detection and identification of antibodies have an important role in the diagnosis and prevention of complications in neonatal and fetal alloimmune purpura (FNATP), post-transfusion purpura (PTP), and immune platelet refractoriness (IPR),” the authors wrote.
