Abstract
Background and Objectives
Transfusion of platelet has become one of the main treatments for thrombocytopenic patients to reduce the severity and frequency of bleeding consequences. Failure to attain the desired level of platelets in a patient following platelet transfusion is defined as platelet refractoriness. The purpose of present paper is to review and study the mechanisms involved in the formation of platelet refractory.
 
Materials and Methods
This article reviews the effective factors present in platelet recipients and donors, and considers the characteristics of platelet products that may have impacts on platelet refractoriness. The search is conducted through scientific databases including Science Direct, PubMed, Medline, SID, Scopus, and Magiran by the keywords “Platelet Refractory”, “Alloantibody”, “HLA”, “Platelet Transfusion” and their Persian equivalents. Finally out of about 130 related articles, 97 articles were used for the review.
 
Results
Generally, platelet refractoriness occurs in two ways including immunologic and non-immunologic. The immunologic way is due to alloimmunization against alloantigens as a result of contact with human leukocyte antigens (HLA), Human Platelet Antigens (HPA). Non immunologic conditions such as fever, spleen enlargement and use of certain medications are responsible to 80% of platelet refractory incidence.
 
Conclusions 
Identification of different features and mechanisms in platelet refractoriness including immunologic and non-immunologic factors have an important role in control, prevention and management of the disease.