Haemophagocytic lymphohistiocytosis has variable time to onset following CD19 chimeric antigen receptor T cell therapy.

Two CD19 chimeric antigen receptor (CAR) T cell therapies are now approved by the US Food and Drug Administration for the treatment of relapsed or refractory (R/R) diffuse large B-cell lymphoma (DLBCL) and histological variants: axicabtagene ciloleucel (axi-cel) and tisagenlecleucel (tisa-cel) (Neelapu I et al i , [6]; Schuster I et al i , [9]). Clinically, it remains unclear as to when the HLH features of CRS are significant enough to consider treatment with therapies used for non-CAR T-associated HLH, such as etoposide or methotrexate (Neelapu I et al i , [8]). Our case series suggests that the timing of onset of CAR T-associated HLH may differ between patients, with concern when delayed or recurrent HLH symptoms occur with a rising ferritin level, which is when HLH-directed therapies should be considered. [Extracted from the article]