C4: Rodgers and Chido typing.

Rodgers (Rg) and Chido (Ch)-typing, by means of haemagglutination inhibition, has been performed on 136 plasma/serum samples selected by or submitted to the 1989 Workshop. All were tested for two Rg and six Ch antigenic determinants and a proportion were also tested for WH. The established interrelationships for the antigenic determinants have been fully supported and previously reported associations with C4 allotypes have been maintained. A second example of the Ch phenotype Ch:-1, 2,-3,4,5-6 was detected in an Italian family with the B3 allotype.