In accordance with the allelic dosage effect observed in Fig 2A, such that TNFSF15 expression increased with more copies of the IBD-protective rs6478109:A allele, heterozygous monocytes stimulated with immune complex or intracellular poly(I:C) showed significant allelic imbalance favoring the protective allele (p 1.09 x 10−6, p 0.0215, respectively, Fig 2C left and middle panels). The gene discussed is TNFSF15; the disease is inflammatory bowel disease.