NCF4 and multiple sclerosis: On a genetic level, Neutrophil Cytosolic Factor 4 (NCF4), which encodes a subunit of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex in neutrophils, has emerged as a genetic susceptibility locus for MS in a recent genome-wide association study by the International Multiple Sclerosis Genetics Consortium (31).