Limited utility of the HScore in detecting secondary haemophagocytic lymphohistiocytosis in COVID‐19.

Keywords: COVID-19; haemophagocytic syndrome; bone marrow morph EN COVID-19 haemophagocytic syndrome bone marrow morph 686 688 3 08/18/21 20210815 NES 210815 We read with interest the correspondence by Wood I et al i . relating to the limited utility of the HScore in identifying possible cases of secondary haemophagocytic lymphohistiocytosis (sHLH) that may contribute to the excess mortality seen in COVID-19.1 A subset of patients is at risk of developing a markedly dysregulated immune response associated with a "cytokine storm" that strongly resembles the pathological and clinical features of sHLH.2 HLH is a rare immune-mediated hyperinflammatory syndrome characterised by fever, hepatosplenomegaly, cytopenias and several biochemical features. Panels (A) and (B) demonstrate evidence of haemophagocytosis on bone marrow aspirate. gl Discussion This case supports the notion that a distinct inflammatory syndrome accompanies COVID-19 that may be secondary HLH. Limited utility of the HScore in detecting secondary haemophagocytic lymphohistiocytosis in COVID-19. [Extracted from the article]