Cluster 5 consisted of five proteins (AMBP, C4A, C4B, RAN, SERPINA10), that were more abundant in Pro rugby players only, and were associated with GO: BP terms, regulation of apoptotic cell clearance (eFDR = 0.0003) and Complement Activation, classical pathway (eFDR = 0.0020) and KEGG pathways associated with Pertussis (eFDR = 0.0001) and Complement and coagulation cascades (eFDR = 0.0010). The gene discussed is C4A; the disease is pertussis.