CD68 and amyotrophic lateral sclerosis: Interestingly, we found greater infiltration of activated MΦ into the skeletal muscle of patients with slowly progressing ALS, as demonstrated by the inverse correlation between the protein level of expression of the CD68 marker and the rate of disease progression (r= −0.502, p = 0.028) (Fig. 8A), while no correlation was found in the levels of Iba1, a marker of overall macrophages (r = 0.172, p = 0.481) (Fig. 8B).