Lyn^up-Bmutation leads to subtle phenotypic changes. (A) Flow cytometric analysis of CD19⁺ cells in the peripheral blood of WT and Lyn^up-B mice over 1 year. (B) Flow cytometric analysis of CD19⁺ B cells in the spleens of young (<6 months) and old (>6 months) WT and Lyn^up-B mice. (C) Cytokine profile in sera of WT (n = 6) and Lyn^up-B (n = 6) mice. Data represent mean values (pg/mL). IL, interleukin. (D) Kaplan-Meier curves representing the overall survival of WT and Lyn^up-B mice from birth to moribund; P value was calculated by Mantel-Cox log-rank test. PBMC, peripheral blood mononuclear cell.