Considering the fact that TNFAIP3 mutation can be associated with HLH, and that HA20 can be presented with the symptoms of HLH/MAS, the biologic drugs seem to be the most reasonable choice for treatment of HA20 when HA20 is a possible trigger of HLH or is in differential diagnosis. Here, TNFAIP3 is linked to A20 haploinsufficiency.