Considering that the lack of CD2BP2/U5–52K induces T cell lymphopenia in both spleen and lymph nodes (Figures 1B, C, F–I), we wondered whether the ratio between naïve and memory T cells in both CD4+ and CD8+ populations is affected in the absence of CD2BP2/U5–52K. The gene discussed is CD2BP2; the disease is lymphopenia.