IL15 and posterior cortical atrophy: Remarkably, a highly significant correlation was observed between IL-7 and IL-15 levels in sera from patients with either early stage PCA (p < 0.0001, R = 0.6631, n = 50) or BPH (p < 0.0001, R = 0.6019, n = 40) (Figure 3, panels A.2.