RNA-sequence analyses of four CD4+ T cell subpopulations (PD-1hi CXCR5-, PD-1hi CXCR5+, PD-1lo CXCR5-, and PD-1lo CXCR5+) obtained by culturing in the presence of cytokines.

PD-1hi CXCR5- T peripheral helper (Tph) cells produce IL-21 and contribute extra-follicular B cell activation in autoimmune diseases. However, it remains unclear what cytokines are required for Tph differentiation. We found that type I IFNs (IFN-alpha and IFN-beta) promote generation of IL-21-producing PD-1+ CXCR5- CD4+ T cells from human naïve CD4+ T cells cultured under IL-12 plus TGF-beta condition. To compare the gene expression pattern of T cells cultured in this condition with blood Tph cells, we performed RNA-seq analysis and showed a Tph-related gene expression pattern similar with that of PD-1hi CXCR5- Tph cells obtained from PBMC of healthy volunteers or patients with systemic lupus erythematosus.