Risks associated with red blood cell transfusions: potential benefits from application of pathogen inactivation

Kleinman, Steve; Stassinopoulos, Adonis

Sepsis resulting from RBC bacterial contamination is rare but does occur. In France, this occurred at a rate of 1 per 2.6 million transfused RBC units from 2000 to 2008; 33 the rate in Germany was 1 in 1.9 million over a similar time frame. 34, 35 In France, all seven septic cases were caused by Gram-negative bacteria, but in only a single case was the isolate (Yersinia enterocolitica) one that is commonly considered to be psychrophilic. 33 In Germany, multiple species of Gram-positive and Gram-negative organisms were reported. 34, 35 In the United States, no RBC-mediated fatalities due to bacterial sepsis have been reported to the FDA in the past 5 years. 36 Analogous to PLTs, it is likely that RBC bacterial contamination occurs more frequently than clinically detected sepsis. 37 As demonstrated in Table 2 , 7% to 15% of RBC cocomponents associated with bacterially contaminated WB-derived PLTs contain bacteria; these data justify the policy of quarantining and either discarding or culturing RBC units associated with culture-positive PLT pools. PI-RBCs may prevent RBC-mediated Gramnegative sepsis as well as any potential deleterious effects from transfused Gram-positive bacteria. 33, [38] [39] [40] [41] Transfusion-transmitted cytomegalovirus (TT-CMV) can be a serious medical complication in specific immunosuppressed populations such as CMV-seronegative hematopoietic stem cell transplantation (HSCT) recipients. 42, 43 Strategies to reduce TT-CMV include the use of leukoreduced (LR) cellular products or CMV serology testing or both. 42, 43 Despite these strategies, there is consensus that TT-CMV residual risk persists. As shown in Fig. 2 , several recent transfusion transmission and/or donorbased PCR studies indicate that per-unit risk is approximately 0.1%. [42] [43] [44] [45] [46] [47] [48] A recent editorial indicated that, in the absence of PI, complex testing algorithms would be needed to reduce this residual CMV risk and would result in substantial loss of transfusable RBC units. 42 Anaplasma phagocytophilum, the agent of human granulocytic anaplasmosis, is an intracellular, Gramnegative bacterium with neutrophil tropism. 49, 50 Nine transfusion-transmitted cases have been reported; in seven cases, the implicated blood product was an RBC. 49, 51 Transmission has occurred with both LR and non-LR RBC units; in one case the unit had been stored for 30 days. Eight of the cases were reported since 2007, The length of the arrows corresponds to the 95% confidence intervals, when reported, or high and low estimates. The overall estimate is depicted with the vertical arrow above the x-axis and takes into account that only the approximately 50% of patients who are CMV seronegative are at risk for acquiring TT-CMV.