CD8A and post-transplant lymphoproliferative disease: As LMP1 expression in a latency III B cell cycles between subpopulations that are LMP1hi and highly sensitive to CD8+ T-cell killing and those that are LMP1lo and much less sensitive (10), it will be important to distinguish whether EBNA2+/LMP1− cells within PTLD tumors are LMP1lo latency IIb cells of fixed status or are latency III cells cycling between low and high LMP1 states.