Detailed phenotyping of perivascular and endomysial CD8+ T cell infiltrates in PM and DM identified them to be predominantly memory (CD45RO+) cells [155,157], while infiltrates in PM were also shown to express cytotoxic effector molecules perforin and granzyme B [158,159,160,161,162]. The gene discussed is GZMB; the disease is dermatomyositis.