PRF1 and Familial hemophagocytic lymphohistiocytosis: Two triplet infants have been reported with familial hemophagocytic lymphohistiocytosis related to compound heterozygous perforin mutations and KSHV infection; in these cases, a defective perforin‐granzyme pathway is suggested to have led to reduced viral clearance ability and therefore to the onset of symptoms related to lytic KSHV infection.67