As a species vulnerable to extinction, the giant panda is the most famous flagship species for the conservation of wildlife and a beloved national treasure of China. Although the species is recovering in the wild, giant pandas are still at risk from both anthropogenic factors and disease outbreaks, especially in the captive population. Therefore, improving the veterinary care, including blood transfusion, is a necessary step to ensure the safety of the species. Given the lack of detectable naturally occurring blood group antibodies suggests that blood transfusions between allogeneic pandas may not have the severe adverse reactions caused by blood group incompatibility as seen in humans. However, crossmatching should not omitted. First, although this study is the largest cohort of giant panda blood typing experiments to date, the sample size is still insufficient for blood typing research on a species, and these samples mainly come from captive populations. As wild populations are introduced and sampling areas expand, new findings in blood types may emerge due to increased genetic diversity. Second, just as was found in humans and dogs, in which the RBC antigens exposed to the immune system after pregnancy or blood transfusion will induce the production of alloantibodies, and re-transfusion may trigger sever transfusion reactions12,14,15. Therefore, before we thoroughly figure out the blood group of giant pandas, we still recommend crossmatching before the allogeneic blood transfusion of giant pandas to avoid unknown adverse risks. In addition, Deng et al. also suggested that giving priority to donors who are healthy, adult, without blood transfusion history, and close relatives can increase the probability of successful matching9.
At the same time, we should recognize that before breakthroughs are made in serological techniques and commercial reagents for giant panda blood typing, developing molecular typing is a beneficial supplement. Molecular blood typing relies on the identification of blood group antigen-coding genes and their polymorphisms. The release of the high-resolution genome of the giant panda provides a good opportunity to achieve this goal16,17. Learning from other species where blood group evidence has been found, and identifying blood type-related genes within the vast giant panda genome, will undoubtedly require extensive involvement of engineers and biologists in addition to hematologists.
The further study of giant panda blood typing requires one key step. We need to determine how to preserve giant panda blood. Collecting large amounts of giant panda blood is time consuming and difficult to arrange. Only when the anticoagulation and storage technology are mature can the blood group antigen maintain its immunogenicity, and then provide conditions for the study of blood groupings and production of specific reagents.
Finally, we should also keep in mind that a compatible crossmatch does not guarantee normal RBC survival, nor does it completely eliminate the risk of transfusion, and it is the responsibility of the veterinary team to remain up-to-date in transfusion practices to prevent transfusion-related complications.
Ethics approval and consent to participate
All methods and animal care procedures in this study were carried out in accordance with the ARRIVE guidelines (https://arriveguidelines.org), involved thorough review and received approval from the Institutional Animal Care and Use Committee of Chengdu Research Base of Giant Panda Breeding, with the assigned approval number 2019010. All methods were performed in accordance with the relevant guidelines and regulations of the People’s Republic of China.