Fatal outcome of EBV-infected NOG-hCD34 mice with persistent viremia, expansion of CD8⁺ T cells, and hepatosplenomegaly in the absence of B-cell proliferative disorders. (A) Quantification of EBV DNA in the PB of EBV-infected mice. Number at the top of each gray bar represents the number of analyzed EBV-infected mice at each time point. (B) Survival curve. Kaplan-Meier survival curve of mock-infected mice (n = 15) and EBV-infected mice (n = 28) is shown. Statistical significance in the survival rate (P = .000077) between mock-infected mice and EBV-infected mice was determined by log-rank test. (C) The difference in the viremia and the survival rate between male and female recipient mice. (Left) The level of EBV DNA in the PB of EBV-infected male mice (n = 20) and EBV-infected female mice (n = 8). Asterisks represent statistic significance (P < .05 by Welch t test) versus the value obtained from EBV-infected female mice. (Right) Survival curve. Kaplan-Meier survival curve of EBV-infected male mice (n = 20) and EBV-infected female mice (n = 8) is shown. Statistical significances in the survival rate between EBV-infected male mice and EBV-infected female mice until the indicated wpi were determined by log-rank test. (D) Longitudinal analysis on human PBMC composition. PB was routinely collected from mock-infected mice (n = 5) and EBV-infected mice (n = 12) and was analyzed by flow cytometry. Results are presented as the average percentages in human CD45⁺ leukocytes. (E) Hepatosplenomegaly in EBV-infected mice. Representatives of spleens and livers of a mock-infected and 2 EBV-infected mice are shown. Scale bars in panel E represent 5 mm. (F) Human MNC numbers in multiple organs. The cell numbers of CD19⁺ B cells (left) and CD8⁺ T cells (right) in spleen, liver, BM, lung, kidney, and ascitic lavage fluid of mock-infected mice (n = 4) and EBV-infected mice (n = 7) are shown. Asterisks represent statistic significance (P < .05 by Welch t test) versus the value obtained from the mock-infected mice. (G) Immunostaining for CD8, CD68, and CD20. Representatives of spleen (top) and liver (bottom) of EBV-infected mice, respectively, are shown. CD8⁺ cells (left) and CD20⁺ cells (right) are shown in green, CD68⁺ cells (left) are shown in red, and nuclei were shown in blue by staining with Hoechst. (H) In situ hybridization for EBERs. Representatives of spleen (left) and liver (right) of EBV-infected mice were shown. EBERs were shown in brown. Areas enclosed with squares are enlarged in bottom right of the panel. Scale bars in panels G and H represent 50 μm.