Diagnosis and Management of Secondary HLH/MAS Following HSCT and CAR-T Cell Therapy in Adults; A Review of the Literature and a Survey of Practice Within EBMT Centres on Behalf of the Autoimmune Diseases Working Party (ADWP) and Transplant Complications W

Introduction: Secondary haemophagocytic lymphohistiocytosis (sHLH) or Macrophage Activation Syndrome (MAS) is a life-threatening hyperinflammatory syndrome that can occur in patients with severe infections, malignancy or autoimmune diseases. It is also a rare complication of haematopoetic stem cell transplantation (HSCT), with a high mortality. It may be associated with graft vs. host disease in the allogeneic HSCT setting. It is also reported following CAR-T cell therapy, but differentiation from cytokine release syndrome (CRS) is challenging. Here, we summarise the literature and present results of a survey of current awareness and practice in EBMT-affiliated centres of sHLH/MAS following HSCT and CAR-T cell therapy. Methods: An online questionnaire was sent to the principal investigators of all EBMT member transplant centres treating adult patients (18 years and over) inviting them to provide information regarding: number of cases of sHLH/MAS seen in their centre over 3 years (2016-2018 inclusive); screening strategies and use of existing diagnostic/classification criteria and treatment protocols. Results: 114/472 centres from 24 different countries responded (24%). We report estimated rates of sHLH/MAS of 1.09% (95% CI = 0.89-1.30) following allogeneic HSCT, 0.15% (95% CI = 0.09-5.89) following autologous HSCT and 3.48% (95% CI = 0.95-6.01) following CAR-T cell therapy. A majority of centres (70%) did not use a standard screening protocol. Serum ferritin was the most commonly used screening marker at 78% of centres, followed by soluble IL-2 receptor (24%), triglycerides (15%), and fibrinogen (11%). There was significant variation in definition of "clinically significant" serum ferritin levels ranging from 500 to 10,000 μg/mL. The most commonly used criteria to support diagnosis were HLH-2004 (43%) and the H score (15%). Eighty percent of responders reported using no standard management protocol, but reported using combinations of corticosteroids, chemotherapeutic agents, cytokine blockade, and monoclonal antibodies. Conclusions: There is a remarkable lack of consistency between EBMT centres in the approach to screening, diagnosis and management. Further research in this field is needed to raise awareness of and inform harmonised, evidence-based approaches to the recognition and treatment of sHLH/MAS following HSCT/CAR-T cell therapy.

Sandler RD ，Tattersall RS ，Schoemans H ，Greco R ，Badoglio M ，Labopin M ，Alexander T ，Kirgizov K ，Rovira M ，Saif M ，Saccardi R ，Delgado J ，Peric Z ，Koenecke C ，Penack O ，Basak G ，Snowden JA ... -  《Frontiers in Immunology》

Adult macrophage activation syndrome-haemophagocytic lymphohistiocytosis: 'of plasma exchange and immunosuppressive escalation strategies' - a single centre reflection.

Lorenz G ，Schul L ，Schraml F ，Riedhammer KM ，Einwächter H ，Verbeek M ，Slotta-Huspenina J ，Schmaderer C ，Küchle C ，Heemann U ，Moog P ... -  《-》

Macrophage Activation-Like Syndrome: A Distinct Entity Leading to Early Death in Sepsis.

Karakike E ，Giamarellos-Bourboulis EJ 《Frontiers in Immunology》

Hemophagocytic lymphohistiocytosis: An update on pathogenesis, diagnosis, and therapy.

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening state of immune hyperactivation that arises in the setting of genetic mutations and infectious, inflammatory, or neoplastic triggers. Sustained, aberrant activation of cytotoxic CD8+ T cells and resultant inflammatory cytokine release are core pathogenic mechanisms. Key clinical features include high persistent fever, hepatosplenomegaly, blood cytopenia, elevated aminotransferase and ferritin levels, and coagulopathy. HLH is likely under-recognized, and mortality remains high, especially in adults; thus, prompt diagnosis and treatment are essential. Familial forms of HLH are currently treated with chemotherapy as a bridge to hematopoietic stem cell transplantation. HLH occurring in rheumatic disease (macrophage activation syndrome) is treated with glucocorticoids, IL-1 blockade, or cyclosporine A. In other forms of HLH, addressing the underlying trigger is essential. There remains a pressing need for more sensitive, context-specific diagnostic tools. Safer, more effective therapies will arise with improved understanding of the cellular and molecular mechanisms of HLH.

Griffin G ，Shenoi S ，Hughes GC 《-》

Post-hematopoietic stem cell transplant hemophagocytic lymphohistiocytosis or an impostor: Case report and review of literature.

HLH occurring after HSCT is a relatively rare disease. Many conditions may mimic or trigger HLH in post-HSCT period (eg, cytokine release syndrome, engraftment syndrome, graft rejection/failure, acute graft-vs-host disease, infections systemic inflammatory response syndrome/sepsis, and thrombotic microangiopathy). Moreover, this period is usually marked by febrile illness, cytopenia, and a "cytokine storm" leading to elevation of inflammatory biomarkers like ferritin and sCD25. These parameters overlap with the diagnostic criteria for HLH. Such confounding factors make the management of post-HSCT HLH quite challenging. We illustrate this critical issue with case report of a patient who was diagnosed with HLH after allogeneic HSCT for tAML. He received MP and CsA for HLH but VP-16 was not administered due to fear of severe myelosuppression. Fortunately, he responded well to treatment and remains in remission to date. We recommend caution while using HLH-94/HLH-2004 guidelines for the diagnosis and management of post-HSCT HLH. In this article, we pinpoint these issues with a brief review of all the pediatric cases and clinical studies of post-HSCT HLH along with a critical evaluation of its various diagnostic criteria. Finally, based on the limitations of current diagnostic criteria, we suggest a need for formulating disease-specific diagnostic criteria for post-HSCT HLH.

Vatsayan A ，Pateva I ，Cabral L ，Dalal J ，Abu-Arja R ... -  《-》