No naturally occurring blood group antibodies were detected in the crossmatching of 25 giant pandas.

The giant panda (Ailuropoda melanoleuca) is a vulnerable species of ursid, endemic to China. With over eight million years of evolution, it is considered a living fossil. Blood transfusion is an important means to treat giant pandas that are critically ill or severely injured, however the blood grouping of giant pandas, as the first element of blood transfusion, has not yet been clarified. Based on immunohematology, the saline-tube test, polybrene test and antigen test were carried out to detect IgM and IgG antibodies in the blood of giant pandas in this study. In parallel, human ABO typing reagent and lectin were used to identify whether the RBCs of giant pandas had a similar antigen as the human ABO blood group system. Here we found that there was no clinically significant agglutination in the crossmatching, indicating that giant pandas most likely lack naturally occurring blood group antibodies, unlike what is observed by incompatibility in humans. And due to the presence of interspecies antibodies, human blood typing reagents could not be used for the identification of giant panda blood types. This finding is of great significance for guiding the clinical blood transfusion of giant pandas. Although this study represents the largest cohort of giant panda blood typing to date, the sample size is still insufficient for species-level blood typing. New findings may emerge, especially as the genetic diversity of the sample increases (such as the introduction of wild populations). A major obstacle currently restricting the study of giant panda blood groupings is the preservation technology of giant panda blood. This requires extensive involvement of engineers and biologists in addition to hematologists.