No abstract

Background and Objectives Prediction of haemolytic disease of the foetus and newborn (HDFN) caused by maternal anti‐A/‐B enables timely therapy, thereby preventing the development of kernicterus spectrum disorder. However, previous efforts to establish accurate prediction methods have been only modestly successful. Materials and Methods In a case–control study, we examined 76 samples from mothers and 76 samples from their newborns; 38 with and 38 without haemolysis. The IgG subclass profile of maternal anti‐A and anti‐B was determined by flow cytometry. Samples from newborns were genetically analysed for the A2 subgroup, secretor and FcγRIIa receptor alleles. Results Surprisingly, we found a correlation between the newborn secretor allele and haemolysis (p = 0.034). No correlation was found for FcγRIIa alleles. The A2 subgroup was found only in newborns without haemolysis. Unexpectedly, different reaction patterns were found for maternal anti‐A and anti‐B; consequently, the results were treated separately. For the prediction of haemolysis in A‐newborns, the maternal IgG1 subclass determination resulted in an accuracy of 83% at birth. For B‐newborns, an accuracy of 91% was achieved by the maternal IgG2 subclass determination. Conclusion We improved the prediction of ABO‐HDFN by characterizing maternal anti‐A and anti‐B by flow cytometry and we presented genetic traits in newborns with correlation to haemolysis. We propose a new understanding of A‐ and B‐substances as immunogens that enhance the maternal immune response and protect the newborn, and we suggest that the development of ABO‐HDFN is different when caused by maternal anti‐A compared to maternal anti‐B.

Introduction Pneumatic tube systems (PTS) are frequently used for rapid and cost‐effective transportation of blood samples to the clinical laboratory. The impact of PTS transport on platelet function measured by the Multiplate system and global hemostasis measured by the TEG 5000 was evaluated. Methods Paired samples from healthy adult individuals were obtained at two study sites: Rigshospitalet (RH) and Nordsjællands Hospital (NOH). One sample was transported by PTS and one manually (non‐PTS). Platelet function was assessed by platelet aggregation (Multiplate) and global hemostasis was assessed by a variety of thrombelastography (TEG) assays. Multiplate (n = 39) and TEG (n = 32) analysis was performed at site RH, and Multiplate (n = 28) analysis was performed at site NOH. Results A significant higher agonist‐induced platelet aggregation was found for PTS samples compared to manual transport at site NOH (P < .02, all agonists). No significant difference was found at site RH (P > .05, all agonists). For Kaolin TEG, samples transported by PTS showed a significant lower R‐time and higher Angle (P < .001). No significant differences in MA and LY30 was found (P > .05). ACT of RapidTEG was significantly reduced (P = .001) and MA of Functional Fibrinogen TEG was significantly increased (P < .001) after PTS transport. No significant impact of PTS was observed for TEG assays with heparinase (P > .05). Conclusions Depending on the type of PTS, transportation by PTS affected platelet aggregation measured by Multiplate. Furthermore, PTS alters TEG parameters possibly reflecting coagulation factors. Clinical laboratories should evaluate the effect of the local PTS on Multiplate and TEG results.

The modified dithiothreitol method was able to reduce haemolysis during storage and to detect and identify alloantibodies in the presence of daratumumab.