Cloning report of complete coding region of HLA-DRB1*1405 has never appeared in the literature. We have isolated and sequenced it from a B cell line with a DRB1*1405/1502 genotype. The sequence information of this gene and previously published DRB1 genes for the other DR serotypes facilitated us to find that the cytoplasmic domain sequences of DRB1 genes fall into three groups. It is known that antigen presenting cells are differentially activated when products of different MHC class II genes are triggered. Functional analyses would discern if these allelic differences in the cytoplasmic domain are of functional significance.