Introduction
HLH, hyperinflammatory disorder
PROLIFERATION, HEMOPHAGOCYTIC LYMPHOHISTIOCYTOSIS, INFLAMMATORY DISORDER
Hemophagocytic lymphohistiocytosis (HLH) is a severe or even fatal hyperinflammatory disorder caused by a hereditary or acquired immunoregulatory abnormality, non-malignant proliferation of lymphocytes and tissue cells, and secretion of numerous inflammatory cytokines. Even with the recommended HLH-94/2004 regimen (Numerous JAK inhibitors, such as ruxolitinib, tofacitinib, baricitinib, and oclacitinib have been utilized for treating inflammatory disorders. Both experimental studies and early clinical reports have indicated that ruxolitinib may have utility in experimental and clinical HLH. Since the first confirmation of activity of ruxolitinib in HLH mouse models by Das et al. and Maschalidi et al. in 2016, an increasing number of publications describing its use in HLH patients (