In an emergency situation, when Rh-negative red cells are transfused to an Rh-positive recipient of genotype CDe/CDe, which antibody is likely to develop first?

In the scenario of an emergency transfusion of Rh-negative red cells to an Rh-positive recipient with the genotype CDe/CDe, the development of antibodies is influenced by the presence of specific antigens and the recipient's immune response.

The correct answer is that anti-c is likely to develop first. The recipient's genotype indicates that they possess the C and e antigens but lack the c and D antigens. When Rh-negative red blood cells are transfused, particularly if those cells have the c antigen, the recipient's immune system may recognize the c antigen as foreign. This recognition can trigger the primary immune response, leading to the production of anti-c antibodies.

In contrast, although Rh-positive individuals have already been exposed to the D antigen, transfusing Rh-negative cells does not typically stimulate the production of anti-D antibodies from the recipient. Moreover, antibodies to the other minor antigens (anti-e and anti-E) are less prevalent and thus less likely to develop first in this specific context of transfusion.

This understanding underscores the importance of matching not only for the D antigen but also considering other Rh antigens when planning transfusions, especially under emergency conditions where there may be less opportunity for careful cross-matching.