1. Why should blood stations prepare leukocyte-depleted mixed concentrated platelets?

With the continuous improvement of medical technology, the amount of platelet clinical transfusion has increased year by year. At present, apheresis platelets dominate in China (see figure1). Platelet supply is often in a tight balance and cannot adequately meet clinical needs. With the continuous progress of blood component preparation technology, blood component separator, platelet room temperature preservation bag, platelet special leukocyte removal filter, sterile connection device, etc., make the quality of concentrated platelets prepared by whole blood continuously improve. Collect multiple bags of ABO and RhD type platelet concentrate and complete the white blood cell filtration of platelet components of blood is to white blood cell mixed platelet concentrate, its quality and efficacy can be comparable with the apheresis platelet. Platelets in whole blood are precious blood resources. Cherish the love of blood donors. Blood collection and supply institutions should make full use of this resource. Effective use of blood components is the glorious mission of blood workers. Platelet preparation in China (see Figure 1)

2、What are the preparation methods of white blood cell mixed concentrated platelets?

The methods of preparing leukocyte-depleted mixed concentrated platelets include the white membrane pooling method and the single-portion concentrated platelet pooling method, recommend the white membrane pooling method is used to prepare leukocyte-depleted mixed concentrated platelets.

The white membrane pooling method includes whole blood preservation overnight method and white membrane preservation overnight method. The single-part concentrated platelet pooling method includes immediate pooling filtration method and first preservation and then pooling filtration method. For the specific method and preparation process, please refer to the group standard "T/CAME 11-2020 Preparation and Quality Control of Mixed Concentrated Platelets". The preparation flow chart of white membrane pooling method is shown in Figure 2, and the preparation flow chart of single-part concentrated platelet pooling method is shown in Figure 3.

2、Is there a quality standard for white blood cell mixed concentrated platelets?

The group standard "T/CAME 11-2020 Preparation and Quality Control of Leukocyte-depleted Mixed Concentrated Platelets" has formulated the quality standard of leukocyte-depleted mixed concentrated platelets according to the quality requirements of leukocyte-depleted apheresis platelets in "GB 18469-2012 Quality Requirements for Whole Blood and Component Blood", and introduced 0.5 specifications for platelet therapeutic doses, as shown in Table 1.

1.1　 

Table 1 Quality requirements for leukocyte-depleted mixed platelet concentrate

4. Why should white blood cells in mixed concentrated blood be filtered out?

in the pastThirtyIn the middle of the year, it has been provenPlatelet transfusion-related adverse events were not related to the type of platelet preparation or the number of donors the recipient had contact with, but to whether or not leukocytes were filtered out.Filter out white blood cellsIt can effectively reduce some adverse reactions caused by blood transfusion, such as non-hemolytic febrile reactions (FNHTR), cytomegalovirus (CMV), the main factor leading to ineffective platelet transfusion is leukocyte antigen (HLA) and platelet antigens (HPA) alloimmunization,Leukocyte filtration can effectively reduceHLAPlatelet transfusions caused by alloimmunization are ineffective.Several countries implement extensive leukocyte filtration,As part of the blood safety policy. Filtering white blood cells in platelets before storage can reduce the adverse reactions of blood transfusion, reduce the risk of alloimmunity and the transmission of viruses carried by white blood cells, and prevent the transfusion from being ineffective due to white blood cell antibodies, thereby improving the safety level of blood transfusion.

5. Under what circumstances is it most suitable to transfuse mixed concentrated platelets with white blood cells?

Studies have shown that the leukocyte-depleted mixed concentrated platelets and apheresis platelets have no statistically significant differences in the efficacy of transfusion and the incidence of transfusion reactions, and there is no statistically significant difference in the efficacy of platelet transfusion between patients with blood system diseases and patients with non-blood system diseases. In special clinical situations, such as neonatal immune thrombocytopenia or ineffective platelet transfusion due to platelet alloantibodies, transfusion of matched apheresis platelets is required. In the past 30 years of clinical practice in Europe, leukocyte-depleted mixed concentrated platelets account for about 50% of the total platelets used in clinical practice. They are the main platelet preparation, not only to supplement the deficiency of apheresis platelets.

6. How is the use of leukocyte-depleted mixed concentrated platelets at home and abroad?

US platelet concentrates account for clinical platelet transfusions9％。2013Year, to the white blood cell mixed concentrated platelet France accounted51.6%Germany accounted38.5%Switzerland accounted35%England accounted19.3%. Our country2012~2014Annualapheresis plateletFor111.41The amount of treatment,platelet concentrateFor50.14Ten thousand units, willplatelet concentratePress12The unit is counted as a therapeutic amount,2012~2014Annual whole blood platelet separation3.62%, Apheresis Platelets96.38%.2012~2014Annual red blood cell donation is1909.33Ten thousand units, only2.6%Preparation of whole blood separationplatelet concentrate.

In the past few decades, in vivo and in vitro tests have proved the safety and effectiveness of leukocyte-depleted mixed concentrated platelets, which not only make full use of valuable blood resources, solve the problem of tight balance of platelet supply, but also greatly reduce the economic burden of patients, showing great social benefits. With the promulgation of the 2012 edition of China's national standard "quality requirements for whole blood and blood components" and "technical operation procedures for blood stations", the operation of preparing concentrated platelets in blood stations is more standardized and the quality is more reliable. At present, dozens of blood stations in Jiangsu, Henan, Shanxi, Shaanxi, Zhejiang, Jiangxi, Hunan, Sichuan, Fujian, Guangdong, Inner Mongolia, Gansu and other provinces have provided leukocyte-depleted mixed platelet concentrates for clinical use, which effectively meets clinical needs., Has won the praise of the majority of hospitals and the praise of the health administrative department.

As more and more blood stations join this glorious ranks, hospitals no longer have to worry about the supply of platelets, the blood for treatment of patients is guaranteed, and the safety and health of the people are taken care.