IµHABcl6 and IµHABcl6 Ung^−/−Msh2^−/− mice have similar lymphocyte development and develop similar lymphomas. Representative flow cytometric analysis of splenocytes from healthy (n = 3 for each genotype) and sick (n = 6 IµHABcl6 and n = 19 IµHABcl6 Ung^−/−Msh2^−/−) mice. Cells were stained with T-cell (CD3), mature B-cell (B220, IgM), GC B-cell (CD95), and plasma cell (CD138) markers as indicated. For healthy spleens, only the lymphocyte gate is shown. For diseased spleens, cells were ungated.