Development of acute lymphoblastic leukemia with translocation (4;11) in a young girl with familial pericentric inversion 12

Genetics of Acquired Cytokine Storm Syndromes : Secondary HLH Genetics

Secondary hemophagocytic lymphohistiocytosis (sHLH) has historically been defined as a cytokine storm syndrome (CSS) occurring in the setting of triggers leading to strong and dysregulated immunological activation, without known genetic predilection. However, recent studies have suggested that existing underlying genetic factors may synergize with particular diseases and/or environmental triggers (including infection, autoimmune/autoinflammatory disorder, certain biologic therapies, or malignant transformation), leading to sHLH. With the recent advances in genetic testing technology, more patients are examined for genetic variations in primary HLH (pHLH)-associated genes, including through whole exome and whole genome sequencing. This expanding genetic and genomic evidence has revealed HLH as a more complex phenomenon, resulting from specific immune challenges in patients with a susceptible genetic background. Rather than a simple, binary definition of pHLH and sHLH, HLH represents a spectrum of diseases, from a severe complication of common infections (EBV, influenza) to early onset familial diseases that can only be cured by transplantation.

Hemophagocytic syndrome in children and adults

Hemophagocytic syndrome, also known as hemophagocytic lymphohistiocytosis (HLH), is a heterogenic syndrome, which leads to an acute, life-threatening inflammatory reaction. HLH occurs both in children and adults, and can be triggered by various inherited as well as acquired factors. Depending on the etiology, HLH can be divided into genetic (i.e., primary) and acquired (i.e., secondary) forms. Among genetic HLH forms, one can distinguish between familial HLH and other genetically conditioned forms of HLH. Acquired HLH can be typically triggered by infections, autoimmune diseases, and malignancies. The most common symptoms of HLH are unremitting fever, splenomegaly, and peripheral blood cytopenia. Some severely ill patients present with central nervous system involvement. Laboratory tests reveal hyperferritinemia (often >10,000 μg/L), increased serum concentration of soluble receptor α for interleukin-2 (>2,400 U/L), hypertriglyceridemia, hypofibrinogenemia, coagulopathy, hyponatremia, hypoproteinemia, and elevated liver transaminases and bilirubin. Prognosis in HLH is very serious. Genetic HLH is always lethal if adequate therapy is not administered. Similarly, severe acquired cases often lead to death without appropriate treatment. Since HLH can be encountered by various specialists in the medical field, basic knowledge of this entity such as diagnostic criteria and treatment should be familiar to all physicians.

Successful treatment of recurrent malignancy-associated hemophagocytic lymphohistiocytosis with a modified HLH-94 immunochemotherapy and allogeneic stem cell transplantation

Acquired hemophagocytic lymphohistiocytosis (HLH) triggered by a known or still to be recognized malignancy is a life-threatening hyperinflammatory syndrome due to massive cytokine release from activated lymphocytes and macrophages. Malignancy-associated HLH (M-HLH) often impedes adequate treatment of malignancy and has the worst outcome compared with any other form of HLH. The incidence of M-HLH is unknown, and there are no published treatment recommendations addressed to this HLH form. Here, we report the case of a young woman with recurrent ALK1-positive anaplastic large T-cell lymphoma and M-HLH successfully treated with a modified HLH-94 protocol, allogeneic stem cell transplantation (alloSCT) and donor lymphocyte infusion (DLI). More than 3 years after DLI, the patient is alive, in complete remission from her malignancy and HLH-free, although suffering from extensive chronic graft-versus-host disease. AlloSCT and, if needed, DLI performed to consolidate remission of malignancy and HLH may have a curative impact on both entities. We propose that when discussing possible treatment options for patients with M-HLH, alloSCT should be considered in eligible individuals.

Hemophagocytic lymphohistiocytosis associated with precursor B acute lymphoblastic leukemia

We report a case of a child with precursor-B acute lymphoblastic leukemia (ALL) who experienced refractory thrombocytopenia and massive splenomegaly during standard induction chemotherapy. He was diagnosed with hemophatocytic lymphohistiocytosis (HLH) during induction. Clinical and laboratory evaluation showed no evidence of infectious cause to HLH. Pancytopenia and HLH persisted after consolidation therapy even with remission from leukemia. After failure to control HLH with ALL-directed therapy and HLH-directed therapy, the patient underwent unrelated donor hematopoietic stem cell transplantation 8 months after diagnosis. He is 34 months post-transplant and in remission from leukemia and HLH.

Precursor B-cell acute lymphoblastic leukemia presenting with hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory syndrome which can be an inherited congenital disorder or can develop secondary to malignancy, infection, or autoimmune disease. Secondary HLH due to malignancy occurs most commonly with T or NK-cell lymphoid neoplasms. HLH with B-cell malignancies is less common and HLH has rarely been described in association with precursor B-cell acute lymphoblastic leukemia (B-ALL). We report three cases of HLH associated with B-ALL and review 17 cases of ALL-associated HLH previously reported in the literature.

Hemophagocytic syndrome preceding acute myeloid leukemia with der t [7:17][q12; q11], monosomy, 17 and 5p-

Hemophagocytic syndrome (HS) is a severe and acute proliferative process of histiocytes, often associated with infection or malignancy. No consistent clonal abnormality has been reported in HS. We report a case of a child presented with HS, who progressed later to acute myeloid leukemia (AML)-M4, associated with a clonal evolution, from normal to a complex karyotype consisting of t [7:17] and deletions in chromosomes 7, 17, and 5. This is the second report of involvement of 7q rearrangement in a child with HS that has progressed to AML. Additional studies are required to establish the association reported here, between HS with progression to AML and chromosome rearrangements that involve chromosome 7q.

Constitutional chromosome aberrations as pathogenetic events in hematologic malignancies

A predisposition to tumor development is associated with some constitutional chromosomal abnormalities. Investigations of families with an apparent hereditary cancer and constitutional chromosome rearrangements have led to the molecular identification of tumor suppressor genes. Under the somatic mutation theory for the development of cancer, two mutational events are required. The first step may be a constitutional event and the second an acquired genetic mutation. Cytogenetic studies were performed on 5633 bone marrow specimens from patients with hematologic malignancies from a single institution. Fifty cases of constitutional chromosome aberrations were detected. Data collected from the literature and from our series are reviewed and compared with the incidence of specific constitutional chromosome aberrations in the newborn population. Possible mechanisms that may predispose individuals with constitutional chromosome aberrations to the development of a hematologic malignancy are reviewed.

Inversion of chromosome 12 and lineage promiscuity in hematologic malignancies

Rearrangements of the short arm of chromosome 12 are among the most common aberrations found in hematologic malignancies, including myelodysplastic syndromes, acute myelocytic leukemias, acute lymphoblastic leukemias, and non-Hodgkin lymphomas. We report on a group of 46 patients with a variety of myelocytic and lymphoid malignancies, all with an inversion of chromosome 12. Both pericentric and paracentric inversions occurred. The identified hotspots for breakage were p13 and q24. These correspond to gene-rich areas of known chromosome instability. The inv(12) is difficult to detect and may be misinterpreted as a partial deletion by routine cytogenetics. Fluorescence in situ hybridization studies revised the G-banding interpretations of a deleted 12p in some cases to an inversion. The inv(12) may occur as the sole abnormality in both myelocytic and lymphoid malignancies, suggesting lineage promiscuity as seen with MLL and ETV6 gene disruptions. The majority of patients with the inv(12) had complex karyotypic changes that predicted a poor prognosis. Of the 24 patients with known clinical follow-up, many were refractory to chemotherapy and overall survival was short.