MAPT and argyrophilic grain disease: Based on the significant correlation between the stages of GFAs and AGD in all regions demonstrated by univariate and multivariate analyses (Table 4 and Supporting File S3), to explore findings associated with the formation process of GFAs, the change of immunoreactivity of GFAs in the frontal cortex and putamen in AGD cases was examined using a panel of anti‐tau, ubiquitin and p62 antibodies and the Gallyas method after stratification by AGD stage (Figure 5A,B).