The frequency distribution of HLA-DRB1*04 subtypes among DRB1*04 positive and ACPA-positive or ACPA-negative RA patients by ethnic group.

€,¥,§The frequency of DRB1 genotypes in ACPA subgroups was calculated as the number of ACPA-positive or ACPA-negative rheumatoid arthritis(RA) cases for a specific DRB1 allele (DRB1*04 +)divided by the total number of cases within that ACPA subgroup (Malay :98 DRB1*04+/ACPA-positive cases, 25 DRB1*04+/ACPA-negative cases; Chinese: 64 DRB1*04+/ACPA-positive cases, 13 DRB1*04+/ACPA-negative cases; Indian: 69 DRB1*04+/ACPA-positive cases, 26 DRB1*04+/ACPA-negative cases).