The CDR3 region of the TCR molecule has the highest antigenic specificity and directly binds to the antigenic peptide presented in the context of HLA.27 Garrido et al.28 demonstrated strikingly similar motifs in CDR3 TCR-Vβ13 sequences in 42% of CD4+/TCRαβ+ T-LGL leukemia cases and a clear association with the HLA-DR*0701 genotype. The gene discussed is CD4; the disease is T-cell large granular lymphocyte leukemia.