Examination of OSMR surface expression on T and B cells. (A) Representative flow plots of OSMR (APC) expression of ex vivo–unstimulated CD4⁺ CD8⁺ T cells from one of two healthy controls (HCs) and one P1. (B) Histograms of 5 days anti-CD3/CD28-stimulated CD4⁺ CD8⁺ T cells from P1 showing the OSMR-APC channel. (C) PBMCs (500,000 cells) from HCs were incubated with CpG (ODN 2006, 2 µg/ml) alone (left panel) or CpG (2 µg/ml), BAFF (10 ng/ml), and IL-21 (10 ng/ml) (right panel) in the BCM for various days as shown. The vertical axis of the flow plots shows the progression of CD27, and the horizontal axis of the flow plots shows the OSMR expression.