A donor tested with Rh antisera shows positive for anti-D, anti-C, and anti-c, but negative for anti-E and anti-e. What is the most probable Rh genotype?

In this scenario, the results of the Rh typing using antisera reveal that the donor is positive for anti-D, anti-C, and anti-c, and negative for anti-E and anti-e.

To understand the genotype, we need to analyze the Rh antigens presented. The presence of anti-D indicates the donor expresses the D antigen, which is found in genotypes such as R1 (DCE/dce) and R2 (DCE/DCe). The presence of anti-C and anti-c suggests that the donor has at least one copy of the C antigen and one copy of the c antigen. However, the negative reaction to anti-E and anti-e means that the donor does not have the E or e antigens, which would typically be seen in individuals with certain combinations of alleles.

Given this information, the R1r genotype (where R1 represents the D and C antigens, and r represents the presence of the little c antigen) makes the most sense. This combination allows for the presence of anti-D and the specific C and c antibodies found in the testing.

The other potential genotypes can lead to either the presence of the E antigen or do not account for the combination of C and c antigens properly.