MPPE1 and Arthritis: In contrast, genes upregulated from children whose arthritis remained limited to a few joints were enriched in T cell lineages, including unconventional T cells (MAIT cells and Vd2+ gamma-delta T cells) and CD8+/CD4+ memory cells (T peripheral helper, GZMK+GZMB+ T cells), as well as in CLEC9A+ cDC1 and pDC (Fig. 6F).