Fig. 1

Timeline of the history of hemophagocytic lymphohistiocytosis (HLH). The figure illustrates the key milestones in the discovery of HLH over the past 80 years. HLH was first described in 1939, and since then, various types of primary and secondary HLH have been defined gradually. Mutations in genes associated with HLH have also been progressively discovered. CHS chédiak-higashi syndrome, GS-2 griscelli syndrome type 2, LPI lysinuric protein intolerance, X-SCID X-linked severe combined immunodeficiency, XLP-1 X-linked lymphoproliferative sisease-1, HPS-2 hermansky–pudlak syndrome 2, XLP-2 X-linked lymphoproliferative disease-2, HIDS hyper-IgD syndrome, MKD mevalonate kinase deficiency, XLA X-linked agammaglobulinemia, ALPS autoimmune lymphoproliferative syndrome