Centre-based comparison of double versus single prevention strategy on transfusion-transmitted cytomegalovirus in at-risk haemopoietic stem cell transplant patients and a state survey on cytomegalovirus-seronegative ordering practises.

BACKGROUND: Universal leucocyte depletion reduces the risk of transfusion-transmitted cytomegalovirus; however, many clinicians still prescribe cytomegalovirus seronegative units. AIM: Our retrospective study aims to confirm the low risk of transfusion-transmitted cytomegalovirus with leucocyte depletion alone and demonstrate the ongoing variability in cytomegalovirus seronegative transfusion prescribing. METHODS: Over a 9-year period (July 2009-July 2018), occurrences of transfusion transmitted cytomegalovirus in cytomegalovirus seronegative donor/recipient haemopoietic stem cell transplant pairs were compared at one allogeneic haemopoietic stem cell transplant centre providing cytomegalovirus seronegative blood products and leucocyte depletion (double prevention) versus another providing leucocyte depletion only (single prevention). Retrospective chart audit identified patient demographics, blood product exposure and cytomegalovirus infection by polymerase chain reaction. A separate audit examined cytomegalovirus seronegative blood product ordering in a broader range of hospital types. RESULTS: We identified 122 and 66 cytomegalovirus-negative donor/recipient haemopoietic stem cell transplant pairs using double and single transfusion prevention strategy respectively. Transfusion exposure to red cells and pooled platelets was similar, although more apheresis platelets were used in the double prevention group. The cytomegalovirus infection rate was 3 (2.4%) and zero in the double and single prevention groups respectively. Cytomegalovirus seronegative unit ordering was not limited to hospitals with obstetric or neonatal populations, suggesting ongoing reliance of cytomegalovirus seronegative units outside this population. CONCLUSIONS: The analysis suggests a double prevention strategy does not provide additional protection against transfusion-transmitted cytomegalovirus. There is ongoing variability in the acceptance of leucocyte depletion alone despite the low risk of cytomegalovirus infection.

Immature platelet fraction as a predictor of platelet count recovery following allogeneic bone marrow transplantation.

The immature platelet fraction (IPF) is a marker of increased platelet production. An increase in IPF is associated with increased marrow production; therefore, a subsequent increase in a bone marrow transplant recipient during the pancytopenic phase may correlate with platelet recovery and engraftment. We performed a retrospective cohort study and evaluated 32 patients who underwent allogeneic bone marrow transplantation. Patients had platelet count, neutrophil count, platelet transfusion and IPF recorded over a period extending from stem cell infusion, day 0, to day 30. The outcomes analysed were platelet count versus time and IPF versus time to establish the predictive ability of the IPF to determine platelet count recovery. Further analysis was performed to confirm the strength of the correlation and the sensitivity of the IPF in predicting a platelet count greater than 50 at day 30. The IPF was shown to rise 5 days prior to platelet count increase. An IPF rise was also shown to correlate with higher average platelet counts at day 30 of transplant. The utility of the IPF in predicting a platelet count of over 50 at day 30 was strongest between days 11 and 15 with an area under the curve (AUC) of 0.79. An IPF of 2.0 or above had 69% sensitivity and 85% specificity for predicting a platelet count of greater than 50 by day 30. In allogeneic bone marrow transplantation, the IPF is a reliable predictor of platelet recovery. The mean IPF between day 11 and day 15 is the most sensitive in predicting a robust platelet count of greater than 50 by day 30.