Evaluation of an ABO antibody immunoadsorption column for reduction of anti-A and anti-B isoagglutinin titers in group O platelet units.

BACKGROUND: Clinical guidelines recommend transfusing ABO-identical platelets where possible. However, the short shelf life of platelets (5-7 days) and stock availability mean ABO-nonidentical platelet transfusions are sometimes unavoidable. Minor ABO-incompatible platelet transfusions carry a risk of hemolysis due to donor anti-A/B antibodies, and high-titer (HT)-negative units are preferred to mitigate this risk. To further mitigate this risk, we investigated whether an ABO antibody immunoadsorption column could reduce anti-A/B titers in group O platelet units while preserving platelet quality.

STUDY DESIGN AND METHODS: Six group O double dose apheresis platelet units were pooled with HT-positive group O plasma and split into three arms: untreated control, single-pass filtration (Glycosorb ABO A/B-column), and double-pass using the same column. Anti A and anti B IgM and IgG titers were measured pre- and post-filtration using a gel card method. Platelet count, platelet volume, coagulation factors, and markers of platelet quality and activation were assessed after filtration and during storage.

RESULTS: Anti-A and anti-B titers were decreased from titers of 128 to ≤4 (IgM) and from 512 to ≤8 (IgG) following a single pass through the immunoadsorption column. Reduced efficacy was observed following a second pass through the same column (≤32 (IgM) and ≤128 (IgG)). Filtration was not associated with substantial platelet loss, although changes in some metabolic and activation markers were observed during storage.

DISCUSSION: The ABO antibody immunoadsorption column effectively reduced anti-A/B titers in group O platelet units and may offer a strategy to increase the availability of low-titer platelets for transfusion.