PTK2B and chronic myelogenous leukemia, BCR-ABL1 positive: In a patient who cleared CML after DLI, the appearance of CD4+ T cells reactive against a polymorphic MHC-II restricted peptide derived from the enzyme protein kinase 2 beta (PTK2B; also known as RAFTK) coincided with the appearance of antibodies directed against the same target, suggesting that the B-cell response was T-cell dependent in this case.37