RESUMEN
The human complement C4 electropheresis bands of 171 serem samples were scaned with UltroScan aser Densitometer(LK.B2202),and the ratio of C4A to C4B of(R value)of each sample was calculated.It was found that he R values of samples with C4A~* QO range from 0.068 to 0.429 with an average of 0.228,while the R values of amples with C4B~* QO range from 2.197 to 9.334 with an average of 3.973.The R values of 7 samples with duplicated genes at C4B locus were very small(range from 0.120 to 0.625),and among them,the R values of samples with 4A~*QO were significantly different from that of samples without C4A~* QO.This results indicated that it is reasonable to assignate C4~* QO gene and duplicated gene according to the R value of each sample.In addition,we have found that among the most common C4 phenotype 3,3/1,1,the R values were shown as normal distribution,but the R values of C4 phenotypes 3,3/2,1,3,3/2,2 and 3, 2/1,1 were mostly above 1.0,while the R values of 4,4/2,2 and 4,4/2,1 were mostly below 1.0.The differences between R values of C4 phenotypes in these two groups were signifficant(P