Approach to managing platelet refractory patients

Abstract

The diagnosis of platelet refractoriness is made when at least on two sequential occasions, a 10‐min to 1‐h post‐transfusion, the CCI is less than 5 × 109/l, using ABO‐identical fresh platelets of less than 72 h old. In practice, an increase in the patient's platelet counts of <10 × 109/l after the transfusion can be used. Refractoriness to platelet transfusion can be due to non‐immune and immune causes. Non‐immune causes include sepsis and disseminated intravascular coagulation. Twenty percent of cases have a combination of both immune and non‐immune causes. Immune causes include alloimmunization to human leukocyte antigen (HLA) and/or human platelet antigens(HPA). The pattern of refractoriness and clinical condition may assist in determining the cause. Patients who are likely to receive multiple platelet transfusion should have their post transfusion platelet count estimated. If refractoriness is suspected, HLA typing and antibody investigation should be done. While waiting for the test result and the supply of HLA matched platelets, ABO compatible platelets may be given. Doubling the dose or giving more frequent transfusion maybe necessary in non‐immune cases. Where patient's HLA type is known, an identical or closely identical platelet can be given. Another approach is by giving platelet from donors lacking HLA antigens that correspond to the recipient's alloantibodies. Crossmatched platelets can be given in the absence of typed HLA platelets. Approximately 20–25% cases may be due to platelet‐specific antibodies, and undetected HLA incompatibility, in which case, the patient can be given antigen negative platelet.