IL15 and early-onset autosomal dominant Alzheimer disease: Another study identified that IL-15 could also serve as a detrimental pro-inflammatory factor in the brain and showed increased serum IL-15 levels, which can be utilized as a biomarker for Alzheimer's disease since IL-15 has been extensively studied in AD pathophysiology (Rentzos et al., 2006; Bishnoi et al., 2015).