Fig. 7: Lysosomal function and ARG1 increases in activated eosinophils, and lysosomal acidity, CTSL activity correlate with disease severity in humans.

A–I Granulocytes were isolated from the peripheral blood of healthy volunteers (n = 13) and asthmatic patients (n = 23). Lysosome-associated membrane protein (LAMP) 1 (A) and LAMP2 (B) expression, lysosomes acidity (C), CTSL enzyme activity (D), and ARG1 expression (E) in eosinophils. Spearman correlations between lysosomal acidity and forced expiratory volume in one second (FEV1) % pred (F), and FEV1/ forced vital capacity (FVC) (%) (G). Spearman correlations between CTSL enzyme activity and FEV1 % pred (H), and FEV1/FVC (%) (I). Data presented are shown as mean ± SEM (A–E). Statistical analyses were calculated using two-sided unpaired Student’s t test. Data are combined from two independent cohorts of asthmatic patients and healthy controls, with each individual sample representing a distinct biological replicate.