What is refractoriness to platelet?

What is refractoriness to platelet?

Platelet refractoriness is defined as a repeated suboptimal response to platelet transfusions with lower-than-expected posttransfusion count increments. Refractoriness can be caused by immune and nonimmune factors, with nonimmune factors (Table 1) responsible for 60% to 80% of cases.

What are HLA platelets?

What is an HLA-matched platelet? Human Leukocyte antigens (HLA) are proteins that are found on most cells in your body including platelets. An HLA-matched platelet is a blood component from a blood donor with an HLA type very similar to your own.

What are cross matched platelets?

Cross-matching platelets is a method of selecting compatible platelets for patients with HT, in particular, in hospitals where access to large panels of HLA-typed platelet donors is limited.

Do platelets express HLA?

This is possible since platelets constitutionally express HLA class I molecules (though in copy numbers that consistently differ among individuals).

How is platelet refractoriness determined?

Diagnosis. Platelet transfusion refractoriness can be defined in several different ways. All measures of platelet refractoriness are defined by the timing of the post-transfusion platelet count, usually 1 hour post transfusion or 24 hours post transfusion or both.

What does refractoriness mean?

Medical Definition of refractoriness : the insensitivity to further immediate stimulation that develops in irritable and especially nervous tissue as a result of intense or prolonged stimulation.

What causes platelet refractoriness?

Platelet refractoriness can be due to immune causes or non-immune causes. Non-immune causes account for over 80% of cases of platelet refractoriness, and sepsis is one of the most common non-immune causes. HLA alloimmunization is the commonest immune cause of platelet refractoriness.

What is HLA antigen?

Human leukocyte antigens (HLA) are genes in major histocompatibility complexes (MHC) that help code for proteins that differentiate between self and non-self. They play a significant role in disease and immune defense. They are beneficial to the immune system but can also have detrimental effects.

Does platelet need cross matching?

Platelet transfusions from RhD-positive donors to recipients with anti-D antibodies do not result in hemolysis, because they contain very few RBCs. Only products containing >2 mL of incompatible RBCs require a serologic crossmatch per AABB standards.

Is cross matching necessary for platelets?

Crossmatching of plasma is not required, since there are no RBCs in these products. Platelets: Platelets are transfused in patients with thrombocytopenia if they are bleeding, if prophylaxis against spontaneous bleeding is required or if a platelet count threshold needs to be surpassed before an invasive procedure.

How is platelet refractoriness diagnosed?

The clinical team must first order 10- to 60-minute posttransfusion platelet counts on 2 sequential transfusions to confirm refractoriness. The next step is a trial of crossmatch-compatible platelets, closely monitored with 10- to 60-minute CCI.

How is platelet refractoriness treated?

General approach to investigation and management of refractoriness

1. Standard practice is to provide unselected or random platelet products (apheresis or pools) for initial platelet transfusion support.
2. If refractoriness is identified, screening for the presence of HLA antibodies is recommended.

What causes the refractoriness of a platelet?

Immune-mediated platelet refractoriness: Immune-mediated refractoriness is due to antibodies made by the patient that recognize an epitope on the transfused platelets, most commonly human leukocyte antigen (HLA) class I.

Is there an AABB guideline for platelet transfusions?

AABB Guideline for Platelet Transfusions The AABB, formerly the American Association of Blood Banks, has developed a guideline on appropriate use of platelet transfusion in adult patients. The new guideline published in the Annals of Internal Medicine emphasises judicious use of the procedure to reduce patient risk and conserve resources.

How is platelet refractoriness related to BMT Pts?

Platelet refractoriness connotes a worse survival Increased exposure to platelet concentrates Increased time spent at critically low platelet concentrations Increased bleeding complications Most common in chemotherapy and BMT pts Kerkhoffs et al. 2008 Toor et al. 2000

What do you need to know about HLA matched platelets?

HLA antigen-negative platelets (HLA matched): Single donor platelets which are collected from a patient whose HLA class I phenotype is compatible with the patient’s HLA antibody panel. Evaluation requested by clinician ≥ 3 platelet transfusions with 1-hr post-transfusion counts < 3 platelet transfusions with 1-hr post-transfusion counts ts Time