Intrauterine use of hyperconcentrated platelet concentrates collected with Trima Accel in a case of neonatal alloimmune thrombocytopenia

BACKGROUND: Due to the threat of serious or fatal bleedings, fetuses with neonatal alloimmune thrombocytopenia (NAIT) may need intrauterine platelet (PLT) transfusions. To prevent a volume overload or an ABO minor mismatch, standard PLT concentrates need to be washed to increase the PLT concentration and to reduce the plasma content. Hyperconcentrated single‐donor PLT concentrates (HCPs) are a therapeutic alternative. The first case of NAIT successfully treated with HCPs collected with the Trima Accel (TA; Gambro BCT) is reported. CASE REPORT: A 31‐year‐old woman with a history of NAIT in the preceding pregnancy underwent cordocentesis three times during her third pregnancy (30th, 31st, and 32nd weeks of gestation). NAIT was confirmed by marked fetal thrombocytopenia, a maternal anti‐human PLT antigen (HPA)‐1a–immunoglobulin G (titer 1:128), and the appropriate HPA genotype of the fetus and the parents. On each cordocentesis procedure, a distinct volume of a HPA‐1a‐negative HCP with a PLT concentration of 3 × 10 6 PLTs per µL was transfused resulting in high corrected count increments after 2 hours. The HCPs were transfused within 10 hours after collection. One day after the last cordocentesis procedure, a cesarean section was performed. The newborn did not show any bleeding signs, and the PLT count remained on normal levels and no further PLT transfusions were needed. CONCLUSION: HCPs collected with TA are a useful alternative to washed standard PLT concentrates without the need for further manipulation of the product after collection. Further in vitro and in vivo studies are needed, however, to make definite recommendations for the shelf life of these HCP.