IL4 and neoplasm: For example, IFNγ production by iNKT cells promotes the clearance of pathogens13 and inhibits tumor growth.14,15 On the other hand, iNKT cells shift their functions toward Th2 responses by producing large amounts of IL4 but small amounts of IFNγ,16,17 and this change favors tumor growth,18 but inhibits autoimmune diseases.17,19,20 The mechanisms underlying biased iNKT cell functions are not fully understood.