Associations between lymphocyte populations in the peripheral blood and serum levels of IL-7 in patients evaluated for ICL. Correlation between CD4⁺ T-cell counts and (A) CD4/CD8 ratio or (B) percentage of immature/transitional (CD10⁺/CD27⁻) B cells. Correlation between serum levels of IL-7 and (C) CD4⁺ T-cell counts or (D) percentage of immature/transitional (CD10⁺/CD27⁻) B cells. The open triangle in panels C and D identify patient 13 in Table S1, who was 85 years old.