IN-VITRO AND IN-VIVO EFFECTS OF PRESTORAGE FILTRATION OF APHERESIS PLATELETS

Background: The effect of prestorage filtration on the quality of aphe resis platelet concentrates stored for transfusion is undetermined. St udy Design and Methods: Investigation of 11 plateletpheresis component s used a concurrent paired-study design. On the day of collection, eac h component was equally divided into two suspensions; one half was fil tered, and the other half was not. Each suspension was stored for 5 da ys. In vitro testing was performed on the day of collection (Day 0) fo r cell counts and on Day 5 for measurements of lactate, glucose, blood gases, pH, platelet ATP, hypotonic stress ratio, extent of shape chan ge In response to ADP, tissue necrosis factor alpha, interleukin 8, in terleukin 1 alpha, Interleukin 1 beta, interleukin 6, and platelet sur face glycoproteins by flow cytometry At the end of the 5-day period, a sample was taken from each of the two suspensions, radiolabeled with either Cr-51 or In-111, and transfused concurrently. Posttransfusion s amples were drawn for measurements of recovery and platelet survival a nd for functional assessment of the ex vivo ability of the circulating radiolabeled platelets to aggregate in response to ADP. Results: The apheresis component had a mean platelet yield of 3.2 +/- 0.4 x 10(11) and a white cell yield ranging from 1 x 10(5) to 1 x 10(8), With a med ian of 2 x 10(7). Filtration resulted in a platelet loss of approximat ely 10 percent and a variable 2 to 3 log reduction in white cell conte nt. No significant differences between filtered and unfiltered suspens ions in paired t tests that would likely have an impact on platelet qu ality were observed in the in vitro tests. The in vivo recovery and su rvival were highly similar and not statistically different in filtered and unfiltered paired suspensions: the mean difference was 1.2 +/- 4. 0 percent for recovery and 7.0 +/- 15 hours for survival. The function al assessment by aggregation to ADP showed no difference between filte red and unfiltered suspensions. A small decrease in tumor necrosis fac tor alpha and interleukin 8 was evident in the filtered suspension as compared to levels in the unfiltered suspensions. Conclusion: Prestora ge white cell reduction in apheresis components resulted in WBC reduct ion by several log(10) with no evident adverse effect on platelet viab ility or function.