Purging effect of reovirus on DLBCL cells. (A) Cytopathic effect of reovirus on DLBCL cells 48 hours after infection. Purified cells were infected with 40 MOI live virus. Photomicrographs were taken at 48 hours after infection (original magnification, × 200). Significant cytopathic effect indicative of widespread killing was observed in live virus-treated but not in untreated cells. (B) Flow cytometric analysis of DLBCL following reovirus purging. Apheresis product cells were mixed with DLBCL cells (10%) and purged for 2 days with reovirus. Samples were analyzed using region C and lineage gate D (CD10^-CD19⁺) to enumerate κ monoclonal CD10^-CD19⁺ malignant cells (region C + D). Flow count beads were included in the CAL region to calculate absolute counts. (C) Representative histograms of viable DLBCL cells before and after purging with reovirus. Arrow indicates the absence of DLBCL cells.