ABSTRACT
Objective To establish a new dialysis washing method for human frozen platelets and to evaluate a new type of washing machine based on dialysis.Methods Twenty bags of platelets(1U)were divided into two groups:centrifugation group and dialysis group.The effect of the washing machine was evaluated by measuring platelet function in vitro.Results After the platelets were treated by the two methods, the recovery rate of dialysis group[(73.57 ± 12.49)%]was significantly better than that of centrifugal group[(62.21 ±7.07)%].The osmotic pressure of dialysis group was 305.8 ±5.27mOsm/kg, compared to 383.2 ±22.00 mOsm/kg in centrifugation group.There was significant differences in the recovery rate and osmotic pressure(P<0.05), but there was no significant difference between dialysis group and centrifugation group in the mean platelet volume[(9.44 ±0.93)vs(9.23 ±0.50)fl], ADP-induced aggregation rate[(20.7 ±8.00)%vs(27.7 ±11.83)%],thrombin-induced platelet aggregation rate[(84.1 ±7.88)%vs(92.9 ±5.28)%], hypotonic shock responses[(19.02 ±4.42)% vs(23.19 ±9.08)%], CD62p activation rate [(16.00 ±9.40)%vs(21.86 ±8.14)%]or apoptosis rate[(46.31 ±10.28)% vs(54.59 ±16.76)%](P>0.05). Conclusion Compared to centrifugation group,the frozen platelet washing machine can not only improve platelet recovery,but also solve the problem of excessive DMSO residues.
ABSTRACT
BACKGROUND: Platelet antigen and antibody tests have been used in platelet immunological disorders, such as neonatal alloimmune thrombocytopenia (NAIT) and post-transfusion purpura (PTP). Mixed passive hemagglutination (MPHA) method has several advantages, including frozen preservation of platelets, ability to differentiate between anti-HLA and platelet-specific antibodies, and quick and easy interpretation without expensive equipment. In this study, we intended to develop the MPHA method using indicator cells of anti-Rh(D) sensitized group O, Rh+ RBCs. METHODS: We made indicator cells sensitized with anti-Rh(D) with various strengths (1:32 to 1:256) and determined the optimal strength. We determined the sensitivity of the MPHA and compared the results using flow cytometry. We observed the changes of the reaction according to the storage time of indicator cells. RESULTS: The optimal sensitization strengths of the indicator cells were 1:192 and 1:256. MPHA showed strong positive results with 1:8,192 diluted positive control, while the detection limit of flow cytometry was 1:128. Until the second week (mean 16 days), the indicator cells showed good results comparable to those of fresh ones. CONCLUSION: We developed the MPHA method using indicator cells of anti-Rh(D) sensitized group O, Rh+ RBCs. We produced the indicator cells in our own laboratory and obtained platelet panels with rare antigen typing using frozen-stored platelets. This technology will be used effectively for detection of platelet antigens and identification of platelet antibodies and also for platelet crossmatching.