Standardized Platelet-Antibody Screening and Identification

Platelet Immunology

Monoclonal Antibody-specific Immobilization of Platelet Antigen (MAIPA) is a qualitative technique for platelet antibody detection and/or identification and is considered to be the gold standard method in the platelet immunology field.

apDia offers all cells, control plasma, reagents and materials necessary to perform the MAIPA procedure. The products are either offered as a complete MAIPA kit or as separate modules allowing ordering reagents for defined steps of the MAIPA procedure:

Platelet-Antibody Screening Cells, Ref. 900001
Platelet-Antibody Identification Panel Cells Kit, Ref. 900002
Control Plasma Kit, Ref. 900003
MAIPA Reagents Kit, Ref. 900004
MAIPA ELISA Detection Kit, Ref. 900005
Complete MAIPA Kit, Ref. 900006

The apDia ready-to-use human Platelet-Antibody Screening Cells & Platelet-Antibody Identification Panel Cells are manufactured by employing a special proprietary production process. The standardized antibody-screening panel allows the sensitive detection of anti-HPA antibodies, while the platelet antibody identification panel offers the ability to reliably identify the antibodies. These apDia thrombocyte reagents are especially recommended for the MAIPA procedure and are advantageous for standardization, handling and workflow organization in the platelet immunology laboratory. The human thrombocytes are typed for HPA-1, -2, -3, -4, -5, -6 and -15. The use of well-characterized thrombocytes offers the ability to standardize the MAIPA: the apDia thrombocyte reagents allow the use of typed cells expressing even rare antigen combinations such as HPA-1(a-,b+)[2,5%] or HPA-5(a-,b+)[less than 1%] for an extended period of time. The stability if the platelet preparations and platelet antigens is guaranteed until indicated expiry date if stored at 2-8°C.
Detection and identification of allo- or auto-antibodies against platelets is indispensable for a targeted therapy of three clinical symptoms in platelet transfusions:

Neonatal/Fetal Allo-Immune Thrombocytopenia (NAIT)

Post-Transfusion Purpura (PTP)

Platelet Refractoriness (PR)

NAIT: Feto-maternal incompatibility of human platelet allo-antigens may induce antibodies to Human Platelet Antigens (anti-HPA) which may lead to a neonatal/fetal allo-immune thrombocytopenia (NAIT/FNAIT). The mother produces antibodies against fetus' antigens inherited from the father. These allo-antibodies (IgG) can cross the placenta, destroy fetal thrombocytes and may induce severe thrombocytopenia. It is most commenly caused by the HPA-1a antigen (80%). NAIT has an estimated incidence of 1/1000 pregnancies and may lead to intra-cerebral bleeding and/or ventriculomegaly. Typing the maternal platelets for the HPA-1a antigen should be performed systematically. Screening and identification of maternal antibodies has to be done for prevention and treatment of such manifestations.
PTP: Post-Transfusion Purpura is an adverse reaction to a blood transfusion due to donor platelet antigens being different from patient platelet antigens. Allo-antibodies destroy the transfused platelets and auto-antibodies destroy the patient's own platelets, leading to a severe form of thrombocytopenia that lasts for several weeks and sometimes even months. It is most commonly caused by the HPA-1a antigen. PTP is most common in HPA-1a negative women who have had multiple pregnancies, while in men PTP may occur after having undergone previous tranfusions. This adverse reaction to blood transfusion typically occurs 10 days following a transfusion. The thrombocytopenia can be treated with therapeutic intravenous immunoglobulin (IVIgG). Other platelet allo-antigens are occasionally implicated in post transfusion purpura.
PR: Long-term application of platelet concentrates may induce anti-HLA and anti-HPA antibodies. These patient antibodies destroy transfused platelets and prevent successful therapy. The use of matched platelets saves valuable resources and costs whilst minimizing concomitant risks of platelet concentrate transfusion such as bacterial or cytokine load. Characterization of the allo-antibodies is an important step in improving the efficacy of platelet transfusion. Of the platelet antigens involved in platelet refractoriness upon platelet transfusion the most prominent allo-immunization is caused by the HPA-5b platelet antigen followed by the HPA-1a allo-antigen. Typing donors and recipients for HPA-1a and HPA-5b antigens is of utmost importance, screening and identification of antibodies has to be done to achieve an effective platelet transfusion treatment.

Do you have a question? Feel free to contact us.