Toxoplasma-induced hemophagocytic lymphohistiocytosis after haploidentical allogeneic stem cell transplantation.

Hemophagocytic lymphohistiocytosis (HLH) is a disorder of immune regulation, manifested by fever, pancytopenia, hyperferritiniemia, hypertriglyceridemia, and extensive hemophagocytosis involving the bone marrow and spleen. HLH can occur in adults with an underlying hematopoietic malignancy, or with systemic infections. HLH following hematopoietic stem cell transplantation (HSCT) is unusual, and the diagnosis may be challenging particularly because the diagnostic criteria in the HLH-2004 guidelines overlap with common post-transplant complications such as engraftment syndrome, graft-vs-host disease, and infections. HLH is commonly triggered by viral, bacterial and, less commonly, parasitic infections. Following HSCT, patients with latent Toxoplasma infection may develop systemic disease secondary to reactivation, and rarely this may lead to a HLH physiology, with a very high mortality rate. Herein we describe the successful management of disseminated toxoplasmosis associated with life-threatening HLH using tocilizumab and antimicrobial therapy.

Sanchez-Petitto G ，Holtzman NG ，Bukhari A ，Brown M ，Morales MK ，Koka M ，Yared JA ，Dahiya S ，Rapoport AP ，Hardy NM ... -  《-》

Hemophagocytic lymphohistiocytosis induced by Toxoplasma gondii infection diagnosed by a bone marrow biopsy and DNA next-generation sequencing in an allogeneic hematopoietic stem cell transplant recipient.

In the United States, toxoplasmosis following allogeneic hematopoietic stem transplant (allo-HCT) is very rare with a rate only between 0.5% and 2%. The reported rates of hemophagocytic lymphohistiocytosis (HLH) following allo-HCT range between 0.3% and 17%. Secondary HLH due to toxoplasmosis infection is extremely rare. Herein, we report a case of secondary HLH due to toxoplasmosis following allo-HCT. The diagnosis was reached by a bone marrow biopsy and confirmed by DNA next generation sequencing and immunohistochemical (IHC) staining. The IHC staining included CD1a, a stain previously known to react with cells infected by Leishmania, here we show CD1a staining of macrophages infected with Toxoplasma gondii. Our report highlights the utility of bone marrow biopsy in diagnosing parasitic infection underlying HLH in post-transplant settings. The pre-transplant evaluation of patients from low endemic countries, is a great opportunity to obtain a travel history to determine the risks and the preventative measures against opportunistic infections including toxoplasmosis.

Obeid KM ，Grzywacz B ，Ferrieri P ，Arbefeville S ，Slungaard A ，Betts B ... -  《-》

Successful Haploidentical Stem Cell Transplant With Posttransplant Cyclophosphamide for Hemophagocytic Lymphohistiocytosis.

Kohli S ，Rastogi N ，Nivargi S ，Thakkar D ，Katewa S ，Yadav SP ... -  《-》

[Clinical study of haploidentical hematopoietic stem cell transplantation on 15 cases of adult-onset primary hemophagocytic lymphohistiocytosis].

Wang YN ，Wang JS ，Wei N ，Wu L ，Jin ZL ，Wang Z ... -  《-》

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 ... -  《-》