The TNF-α/IGFBP-1/IGF-1 axis in regulating B-cell lymphopoiesis in older humans. (A-B) Plasma samples were collected from healthy young or older humans or older patients with lymphoma treated for B-cell depletion (old depleted) (see the Methodology section of NCT00863187). Plasma samples were analyzed for IGF-1 (A) and IGFBP-1 (B) by ELISA. Shown are results for individual patients and group means (indicated by thick solid horizontal line) (n = 9-18 for each group). (C) Peripheral blood B cells were collected from patients from the indicated human cohorts and cultured in vitro for 24 hours. Supernatants were collected and analyzed for TNF-a by ELISA. Shown are results for individual patients and group means (n = 5-6 for each group).