CD274 and anaplastic large cell lymphoma: Furthermore, BATF3, together with the IRF4 transcription factor, was found to be important for PD-L1 expression in ALK+ ALCL [114], and inhibition of the PD-1/PD-L1 signalling axis in ALK+ ALCL cell lines was found to increase the ability of these cell lines to activate T cells and be killed by NK cells [114].