T cells priming with rCD40L treatment in XHM patients. (A) PMBCs (2 × 10⁶) from patients with XHM and normal controls were stimulated with anti-CD3 or SEA or SEB. Cytokine measurements were made at 36 hours by ELISA. Healthy adult controls (n = 20) were used to determine the reference range because pediatric controls were not available. The lower limit of the 95% confidence interval range is represented by the dotted line. Reference range values for TNF-α production are as follows: anti-CD3, 2 343 to 23 968; SEA, 1062 to 6598; and SEB, 1084 to 6198. Reference range for IFN-γ production is as follows: anti-CD3, 1 242 to 17 703; SEA, 3 105 to 11 010; and SEB, 1 421 to 16 354. (B) Intracellular TNF-α and IFN-γ production in CD4⁺ and CD8⁺ T cells after in vitro stimulation with anti-CD3/28 or SEA for 6 hours. After stimulation, PBMCs were fixed, permeabilized, and stained with antibodies for surface markers and intracellular cytokines. Gating on CD3⁺CD8⁺ cells the plots depict surface staining for CD8 and intracellular TNF-α or IFN-γ; CD8⁻ cells are equivalent to CD4⁺ cells.