STIR‐positive FSHD muscle is characterised by lymphocytic infiltrates (Fig 2), particularly endomysial CD8+ and perivascular CD4+ T lymphocytes (Frisullo et al, 2011), with B cells and macrophages in close proximity to CD4+ T cells at perivascular sites (Arahata et al, 1995): cellular distributions with similarities to myositis. Here, CD4 is linked to facioscapulohumeral muscular dystrophy.