MR1 and acquired polycythemia vera: Previous studies addressing TCRβ repertoire diversity in the context of psoriasis have been conducted in whole skin biopsy samples38–40, total peripheral mononuclear cells41 and sorted cutaneous CD4+ T cell effector and regulatory T cells42, CD8+42,43 or CD45+44 T lymphocytes, providing little insight into the TCRβ clonotype diversity of MR1-restricted MAIT cells in PV.