© 2018 Mac millan Publishers Li mited, part of Springer Nature. All rights reserved. management of CRS. In our experience, both tocilizumab and siltuximab have been effective in the initial management of CRS in adults. Nevertheless, we agree that prospective clinical studies are needed to directly compare the effectiveness of tocilizumab and siltuximab in the treatment of CRS, and have made this statement in our article2. With the FDA approval of tocilizumab for the management of CRS, which was announced while our manu script was in press and being prepared for publication online, we agree that tocilizumab is currently the first-line anti-IL-6 therapy of choice for the treatment of CRS. We also agree with Teachey and colleagues1 that CRS and haemophagocytic lymphohistiocytosis and/or macrophage activation syndrome (HLH/MAS) have overlapping pathologies and clinical manifestations, and have stated so in our article2. Teachey and colleagues1 correctly point out that most patients with grade≥ 2 CRS would meet the published consensus diagnostic criteria for HLH/MAS. Thus, we believe that such criteria are not useful to identify patients who develop ‘fulminant CAR T cell-related HLH/MAS’, who might need therapy beyond that used for the management of CRS. By contrast, using the diagnostic criteria proposed in our article2, we have found that fulminant CAR T cell-related HLH/MAS is observed in only~ 1% of adult patients treated with CAR T cell therapy6. We agree that the treatment of the underlying CRS should be the initial approach to therapy for CAR T cell-related HLH/MAS, and this strategy is reflected in our proposed treatment algorithm2. We also agree that a paucity of data exist on the use of etoposide and intrathecal cytarabine in the setting of CAR T cell-related HLH/MAS and have acknowledged this limitation in our article. We accept that the role of etoposide-based therapy has only been clearly established for primary HLH occurring in children; however, published data do suggest that etoposidebased therapies might also be effective in adult patients with HLH, especially in those with cancer-related or infection-associated HLH13, or those with refractory HLH14. For these reasons, we suggested these therapies can be “considered” 2 only when anti-IL-6 therapy and corticosteroids have been tried and found to be ineffective. Despite the prior experience with intrathecal methotrexate in patients with HLH/MAS involving the central nervous system15, we did not recommend this approach owing to reports of leukoencephalopathy occurring in some patients with CRES after CAR T cell therapy16, 17. Teachey et al. 1 also disagreed with some minor recommendations we made for supportive care of patients treated with CAR T cells. As suggested in our article, the supportive care strategies that we proposed are “considerations” 2 that can be used when deemed necessary for the management of these patients. Such considerations are likely to improve the safety of CAR T cell administration, and minimize morbidity and, possibly, mortality. Teachey and colleagues1 incorrectly suggest that we recommend routine use of filgrastim for all patients with neutropenia. We recommended use of filgrastim for patients with neutropenia who develop fever because there is no reliable way to distinguish fever due to infection from fever due to CRS, and an infection that is not treated appropriately in the setting of CRS and neutropenia might have fatal consequences2. Teachey and colleagues1 also incorrectly state that we recommend telemetry during the entire hospital stay: we recommended telemetry only between the day of CAR T cell infusion and …