CD4 and acute lymphoblastic leukemia: The negative association of DP1 with BCP ALL may be due to the binding and recognition of TEL-AML1 peptide(s) in children with pre-ALL with this supertype, as discussed elsewhere (Taylor et al, 2008), since a TEL-AML1 junctional peptide has been shown to elicit a DPB1*0501-restricted (DP1) CD4+ T cell response (Yun et al, 1999).