Preservation of red blood cell antigenicity in a new storage solution in vitro

Abstract

Introduction: Red blood cell (RBC) storage solution is used for suspending and preserving RBCs for later use in in vitro immunohematology testing. Proper RBC preservation is crucial for obtaining accurate results in RBC phenotyping and pretransfusion antibody screening tests. Haemolysis or RBC antigen degradation during storage can result in inaccurate RBC phenotyping, thereby decreasing the sensitivity of pretransfusion antibody screening and identification assays. The conventional RBC storage solutions usually contain adenosine, adenine, and antibiotics. We designed an RBC storage solution and determined whether it could preserve RBC integrity for 70 days.

Materials and methods: The new storage solution has a different formula from that of the conventional solution-in particular, it is strengthened with polyethylene glycol (PEG). The extent of haemolysis and hemagglutination reactivity of the RBC antigen systems, Rh, Duffy, Kidd, Lewis, MNS, P1, and the rare antigen Mi^a (which has a low prevalence antigen in most parts of the world but a higher prevalence in Taiwan), in the new RBC storage solution was compared with that of the conventionally preserved RBC storage solution.

Results: The RBCs preserved in the new solution for 70 days retained a similar haemolysis grade as those preserved in the control solution for 28 days. Although both solutions largely preserved RBC antigenicity, the decline in RBC hemagglutination scores in new solution often occurred later than that in the control solution in most antigen phenotyping assays, especially labile antigens such as D, P1, and M.

Conclusion: The new solution reduces haemolysis more effectively and preserves antigenicity throughout the 70-day storage period. Moreover, Mi^a antigen is more stable in the experimental group.

Keywords: RBC antigenicity; haemolysis; modified RBC preservation (storage) solution; polyethylene glycol (PEG).

Figure 1.

Hemolysis indexes for RBCs preserved in control and experimental solutions during storage. Depending on the combinations of the screen cell sets and preservation solutions (SI + control, SII + control, SI + experimental, SII + experimental [n = 54 each, 6 (triplicate in two medical centers) x 9(days) = 54]), the experimental solution provide superior protection against hemolysis than control solution. All the results shown in Figure 1 are means and error bars indicate standard deviation.

Figure 2.

(A) SI screen cell antigenicity changes. SI_Ori: SI screen cells preserved in the control solution, SI_Mod: SI screen cells preserved in the experimental solution (the results were all quadruplicated which there were duplicate in two medical centers). SI cell antigenicity changed over time. All antigens remained detectable in both solutions, but the experimental RBC preservation solution had the same or higher agglutination scores during the experiment. The results presented in (A) are means, and error bars (standard variation) are not shown because the repeated results were the same. (B) SII screen cell antigenicity changes. SII_Ori: SII screen cells preserved in the control solution, SII_Mod: SII screen cells preserved in the experimental solution (the results were all quadruplicated which there were duplicate in two medical centers). According to the changes in SII screen cell antigenicity, M and P1 antigens were more prone to lost antigenicity. Compared with the control solution, the experimental solution effectively preserved these antigens. (**: p < 0.01). The results presented in Figure 2B are means, and error bars (standard variation) are not shown because the repeated results were the same.

Figure 3.

Mi^a-positive screen cell antigenicity changes. Mi^a_Ori: Mia-positive screen cells preserved in the control solution, Mi^a_Mod: Mi^a-positive screen cells preserved in the experimental solution (the results were all quadruplicated which there were duplicate in two medical centers) The results presented in Figure 3 are means, and error bars (standard variation) are not shown because the repeated results were the same. The score in both experimental and control solutions decreased by 1 point, but the experimental solution had a higher score from day 35 to day 56.