A Prospective Clinical Trial of Hemolytic Reaction in Patients With Positive Cold-Reactive Antibodies Following Transfusion of Corresponding Antigen

Allo‐anti‐M: Detection peaks around 2 years of age, but may be attenuated by red blood cell transfusion

“…For patients with allo-anti-M, M antigen-negative red cells were transfused even for cold-reactive anti-M at around 80% of Japanese facilities in our study, and allocated only for 37°C reactivity at the remaining $20% during our study period (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015); Japanese policy has since been updated to specify that compatible RBCs should be transfused when the antibody is reactive at 37°C , based on evidence from a nationwide survey. 18 That anti-M is usually of little clinical significance in transfusion is supported by two Japanese surveys. 18,19 No one developed hemolytic reactions after 41 M antigenpositive RBC transfusions into 14 patients who had cold reactive anti-M. 18 No adverse reactions were reported in 33 patients with anti-M following transfusion of M-positive RBCs (5 clinically relevant by IAT and 28 clinically not relevant by only saline/enzyme methods).…”

“… 18 , 19 No one developed hemolytic reactions after 41 M antigen‐positive RBC transfusions into 14 patients who had cold reactive anti‐M. 18 No adverse reactions were reported in 33 patients with anti‐M following transfusion of M‐positive RBCs (5 clinically relevant by IAT and 28 clinically not relevant by only saline/enzyme methods). 19 Such clinical non‐significance is presumptively attributed to the fact that almost all anti‐M is mainly of IgM class.…”

“…For patients with allo‐anti‐M, M antigen‐negative red cells were transfused even for cold‐reactive anti‐M at around 80% of Japanese facilities in our study, and allocated only for 37°C reactivity at the remaining ~20% during our study period (2001–2015); Japanese policy has since been updated to specify that compatible RBCs should be transfused when the antibody is reactive at 37°C, based on evidence from a nationwide survey. 18 …”