RESUMEN
Rodgers [Rg] and Chido [Ch] are blood-group antigens and they determine the fourthcomponent of human complement C4. Rodgers and Chido are associated with two C4 isotypes [C4A and C4B]. In addition to genotype determination, study on expression of Rg and Chido could be useful in disease studies. DNA was extracted from the whole blood of 60 normal individuals. Then, PCR amplification of C4d gene fragment was followed by restriction digestion. This study demonstrated that the frequency of Ch and Rg in Iranian healthy population was 98.3 and 93.4 percent, respectively. Additionally, 6.6 percent of the studied population showed Chido-positive, Rodger-negative and 1.7 percent showed Rodger-positive, Chido-negative genotype. It may be concluded that upon receiving blood transfusion, 6.6 and 1.7 percent of individuals could produce anti-Rg and anti-Ch antibodies, respectively