NCF4 (Neutrophil Cytosolic Factor 4): NCF4 is a component of the NADPH oxidase complex that plays a central role in the body’s immune defence. It helps regulate the assembly and activation of this complex, enabling the production of reactive oxygen species (ROS) during the oxidative burst in phagocytes. This process is vital for destroying engulfed pathogens, and mutations in NCF4 can impair immunity, leading to increased susceptibility to infections.