The second class includes a broad spectrum of immune response genes such as cytokine (IL2, IL4, IL5, IL6, IL10, IL12A, IL12B, IFNA1, IFNA2, IFNA21, IFNB1, IFNG, TNFA, and CSF2) and cytokine receptor genes (IL2RA, IL2RB, IL2RG, IL4R, IL6R, IL6ST, IL10RA, IL10RB, IL12RB1, IL12RB2, IL18R1, IFNAR1, IFNAR2, IFNGR1, IFNGR2, TNFRSF1A, TNFRSF1B, and CSF2RB) regulating Th1, Th2, and inflammatory responses to rubella. The gene discussed is IFNA21; the disease is rubella.