C3 and Alzheimer disease: Proteins uniquely associated with AD were enriched in ‘Apoptotic cleavage of cellular proteins’ (P = 5.5 × 10−5; CASP3, CASP7 and CASP8), ‘Integrin cell surface interactions’ (P = 9.7 × 10−5; ITGA5, ITGB5 and ITGAL) and ‘Neutrophil degranulation’ (P = 1.9 × 10−4; C2, C3, CD44, CD47 and CD59) pathways.