HLA-DR alpha-Chains. HLA Class II Histocompatibility Antigen, DR alpha Chain . HLA-DR Heavy Chain . HLA-DRA . MHC Class II Antigen DRA . HLA DR Heavy Chain . HLA DR alpha . HLA DR alpha Chain . HLA DR alpha Chains . Heavy Chain, HLA-DR . alpha-Chain, HLA-DR . alpha-Chains, HLA-DR . HLA-DR alpha . HLA-DR alpha-Chain . 0.45