Transitional B cells in patients with IJD treated or not treated with anti–TNF-α. (A-B) Cross-sectional analysis of transitional B cells in healthy controls (n = 4) and patients with IJD treated with TNF-α (IJD-TNF-α, n = 19) or naïve to anti-TNF-α (IJD-NB, n = 14). Blood cells were analyzed by flow cytometry and mature (CD19⁺/CD24^lo/med/CD38^lo/med) and transitional (CD19⁺/CD24^hi/CD38^hi) B-cell frequency was determined. (A) Representative analysis for a single patient from each group gated on CD19⁺ cells. Shown are gates for mature and transitional B cells indicated by arrows. (B) Frequency of transitional B cells. Quantity of transitional B cells was calculated as the fraction of transitional B cells divided by the sum of transitional and mature B cells. Shown are results for individual patients and group means. (C-D) Longitudinal analysis of transitional B-cell ratio of patients with IJD undergoing treatment with anti–TNF-α. (C) Transitional B-cell ratio averages in patient subset (n = 6) analyzed upon initiation of anti–TNF-α therapy and again after 3 months of anti–TNF-α therapy. Results are expressed as mean ± SE. (D) Longitudinal analysis for individual patients with IJD transitional B-cell ratios before and after anti–TNF-α therapy. (E-F) Longitudinal analysis of plasma IGF-1 in patients with IJD undergoing anti–TNF-α therapy. (E) Plasma IGF-1 averages in the patient subset (n = 6) analyzed upon initiation of anti–TNF-α therapy and again after 3 months of anti–TNF-α therapy. Results are expressed as mean ± SE. (F) Longitudinal analysis for individual patients with IJD transitional B-cell ratios before and after anti–TNF-α therapy.