Despite this reduction, there was no significant difference in the CD4:CD8 ratios between the groups (P‐value = 0.12, Table 1) but we did observe an expansion of the CD8+ T cells accompanied by altered CD4:CD8 ratios, below or at a value of 1.5, in 33% of IBM patients and 20% of HC (Supplementary figure 2). This evidence concerns the gene CD8A and inclusion body myositis.