Abstract: Twelve trials met the inclusion criteria. One trial is still ongoing, leaving a total of 11 trials eligible involving 653 participants. These trials were conducted between 1978 and 2006 and enrolled participants from fairly comparable patient populations. None of the studies included people with neutrophil dysfunction. Ten studies included only adults, and two studies included children and adults. Ten of these studies contained separate data for each arm and were able to be critically appraised. One study re-randomised people and therefore quantitative analysis was unable to be performed. Overall, the quality of the evidence was very low to low across different outcomes according to GRADE methodology. This was due to many of the studies being at high risk of bias, and many of the outcome estimates being imprecise. All-cause mortality was reported for nine studies (609 participants). There was no difference in all-cause mortality over 30 days between people receiving prophylactic granulocyte transfusions and those that did not (seven studies; 437 participants; RR 0.92, 95% CI 0.63 to 1.36, very low-quality evidence). Mortality due to infection was reported for seven studies (398 participants). There was no difference in mortality due to infection over 30 days between people receiving prophylactic granulocyte transfusions and those that did not (six studies; 286 participants; RR 0.69, 95% CI 0.33 to 1.44, very low-quality evidence). The number of people with localised or systemic bacterial or fungal infections was reported for nine studies (609 participants). There were differences between the granulocyte dose subgroups (test for subgroup differences P = 0.01). There was no difference in the number of people with infections over 30 days between people receiving prophylactic granulocyte transfusions and those that did not in the low-dose granulocyte group (< 1.0 x 1010 granulocytes per day) (four studies, 204 participants; RR 0.84, 95% CI 0.58 to 1.20; very low-quality evidence). There was a decreased number of people with infections over 30 days in the people receiving prophylactic granulocyte transfusions in the intermediate-dose granulocyte group (1.0 x 1010 to 4.0 x 1010 granulocytes per day) (4 studies; 293 participants; RR 0.40, 95% CI 0.26 to 0.63, low-quality evidence). There was a decreased number of participants with bacteraemia and fungaemia in the participants receiving prophylactic granulocyte transfusions (nine studies; 609 participants; RR 0.45, 95% CI 0.30 to 0.65, low-quality evidence). There was no difference in the number of participants with localised bacterial or fungal infection in the participants receiving prophylactic granulocyte transfusions (six studies; 296 participants; RR 0.75, 95% CI 0.50 to 1.14; very low-quality evidence). Serious adverse events were only reported for participants receiving granulocyte transfusions and donors of granulocyte transfusions. In people who are neutropenic due to myelosuppressive chemotherapy or a haematopoietic stem cell transplant, there is low-grade evidence that prophylactic granulocyte transfusions decrease the risk of bacteraemia or fungaemia. There is low-grade evidence that the effect of prophylactic granulocyte transfusions may be dose-dependent, a dose of at least 1.0 x 1010 per day being more effective at decreasing the risk of infection. There is insufficient evidence to determine any difference in mortality rates due to infection, all-cause mortality, or serious adverse events.

Plain-language summary: The evidence is current to April 2015. In this update, 12 trials were identified that compared giving granulocyte transfusions to prevent infections compared to not giving granulocytes to prevent infection. One trial has not yet been completed. Eleven trials containing a total of 653 participants were reviewed. These trials were conducted between 1978 and 2006. Data from one trial were not included in the analyses because patients were included within the trial more than once. Ten studies included only adults, and two studies included children and adults. Six studies reported their funding sources, and all were funded by charities or governments. Giving granulocyte transfusions to prevent infections did not affect the risk of death due to infection, or the risk of death due to any cause. Giving granulocyte transfusions to prevent infections decreased the number of people who had a bacterial or fungal infection in the blood, but did not decrease the number of people having a localised bacterial or fungal infection. It is unknown whether granulocyte transfusions increased the risk of having a serious adverse event because adverse events were only reported in people receiving granulocyte transfusions. The evidence for most of the findings was of very low or low quality. This was because patients and their doctors knew which study arm the patient had been allocated to and two of the studies were not true randomised studies (patients were allocated to the granulocyte transfusion arm if they had a suitable granulocyte donor).