Acute myeloid leukemia following etoposide therapy for EBV-associated hemophagocytic lymphohistiocytosis: a case report and a brief review of the literature

Background

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening disorder characterized by prolonged fever, cytopenia, hepatosplenomegaly, rash, icterus, and other neurological symptoms. Successful treatment of HLH by etoposide has improved outcomes for children with HLH. However, the development of treatment-related acute myeloid leukemia (t-AML) after the usage of this drug is a concern.

Case presentation

We report a case of acquired EBV-triggered HLH with progression to t-AML following etoposide therapy with cytogenetic abnormality for t (11; 19) (q23; p13) resulting in MLL gene fusion. The development of t-AML was detected 23 months after HLH diagnosis.

Conclusions

Although the successful treatment of HLH by etoposide has improved outcomes for children with HLH, t-AML is a serious complication of topoisomerase II inhibitor therapy and is characterized by the presence of gene rearrangement. This study suggests that HLH patients undergoing therapy with HLH-2004 protocol need monitoring for future malignancy, especially in the initial 2 to 3 years.

Adult haemophagocytic syndrome

Haemophagocytic syndromes (haemophagocytic lymphohistiocytosis) have a wide range of causes, symptoms, and outcomes, but all lead to a hyperinflammatory response and organ damage--mainly reported in paediatric patients, but reports of adult presentation are increasing. Analysis of the genetic and molecular pathophysiology of these syndromes have improved the understanding of the crosstalk between lymphocytes and histiocytes and their regulatoty mechanisms. Clinical presentations with a broad differential diagnosis, and often life-threatening outcome, complicate the management, which might include supportive intensive care, immunosuppressive and biological treatments, or haemopoietic stem cell transplantation. Insufficient knowledge of these syndromes could contribute to poor prognosis. Early diagnosis is essential to initiate appropriate treatment and improve the quality of life and survival of patients with this challenging disorder.

Therapy-related myeloid neoplasms in 39 Korean patients: a single institution experience

Background

Therapy-related myeloid neoplasms (t-MN) occur as late complications of cytotoxic therapy. This study reviewed clinical and cytogenetic characteristics of patients with t-MN at a single institution in Korea.

Methods

The study subjects included 39 consecutive patients diagnosed with t-MN. Each subject's clinical history of previous diseases, treatments, and laboratory data was reviewed, including cytogenetics. The primary diagnosis was hematologic malignancy in 14 patients and solid tumor in 25 patients.

Results

Therapy-related acute myeloid leukemia (t-AML, 66.7%) was found to be more common than therapy-related myelodysplastic syndrome (t-MDS). Primary hematologic malignancies that were commonly implicated included mature B-cell neoplasm and acute leukemia. Breast cancer was the most common primary solid tumor. The mean time interval from cytotoxic therapy initiation to t-MN detection was 49 months. Chromosomal aberrations were observed in 35 patients, and loss of chromosome 5, 7, or both accounted for 41% of all cases. Balanced rearrangements occurred in 13 patients; these patients showed shorter latency intervals (mean, 38 months) than patients with loss of chromosome 5 or 7 (mean, 61 months).

Conclusions

In this study, we determined the clinical and cytogenetic characteristics of Korean patients with t-MN. Although our results were generally consistent with those of previous reports, we found that t-MN resulting from de novo leukemia was common and that t-AML was more common than t-MDS at presentation. Multi-institutional studies involving a larger number of patients and additional parameters are required to investigate the epidemiology, genetic predisposition, and survival rate of t-MN in Korea.

Myelodysplastic syndrome (MDS) as a late stage of subclinical hemophagocytic lymphohistiocytosis (HLH): a putative role for Leptospira infection. A hypothesis

It is proposed that hemophagocytic lymphohistiocytosis (HLH) and myelodysplastic syndromes (MDS) may be temporally distinct phases of pathophysiologically related disease processes. A significant subgroup of MDS may develop from subclinical HLH. In that case, HLH-like disease would chronically proceed with little disease activity or under occasional flares only, until it first becomes clinically apparent at the MDS stage. At the MDS stage, however, HLH activity may be easily overlooked by histological or cytogenetic means, since hemophagocytosis has fallen already largely silent. Current treatment options for HLH, like high-dose intravenous immunoglobulins (IVIG), may turn out to be helpful in MDS patients as well. In rare and extreme cases, Leptospira infection causes severe and life-threatening HLH. Thus, this proposal also implies that an insufficient, dysfunctional or misdirected immunological response to Leptospira infection may lead to MDS in the long run in a significant number of cases, which have not been recognized as Leptospira -triggered events in the first place. Infections by agents other than Leptospira may lead to subclinical HLH-like disease with MDS as a late stage as well.

Secondary hemophagocytic lymphohistiocytosis and severe sepsis/ systemic inflammatory response syndrome/multiorgan dysfunction syndrome/macrophage activation syndrome share common intermediate phenotypes on a spectrum of inflammation

In an effort to attain earlier diagnoses in children with hemophagocytic lymphohistiocytosis (HLH), the International Histiocyte Society has now broadened their diagnostic criteria to no longer differentiate primary (HLH) and secondary hemophagocytic lymphohistiocytosis (SHLH). Five of the following eight diagnostic criteria needed to be met: 1) fever, 2) cytopenia of two lines, 3) hypertriglyceridemia and/or hypofibrinogenemia, 4) hyperferritinemia (>500 microg/L), 5) hemophagocytosis, 6) elevated soluble interleukin-2 receptor (CD25), 7) decreased natural killer-cell activity, and 8) splenomegaly can also commonly be found in patients with sepsis, systemic inflammatory response syndrome (SIRS), multiorgan dysfunction syndrome (MODS), and macrophage activation syndrome (MAS). Nevertheless, the therapeutic options for these are radically different. Chemotherapy and bone marrow transplant have been used for treatment of HLH/SHLH, whereas antibiotics and supportive treatment are used in severe sepsis/SIRS and MODS. MAS is treated with limited immune suppression. Outcomes are also different, SHLH has a mortality rate around 50%, whereas pediatric septic shock and MODS have a mortality of 10.3% and 18%, respectively, and severe sepsis in previously healthy children has a mortality rate of 2%. MAS has a mortality rate between 8% and 22%. Because SHLH and severe sepsis/SIRS/MODS/MAS share clinical and laboratory inflammatory phenotypes, we recommend extreme caution when considering applying HLH therapies to children with sepsis/SIRS/MODS/MAS. HLH therapies are clearly warranted for children with HLH; however, a quantitative functional estimate of cytotoxic lymphocyte function may be a more precise approach to define the overlap of these conditions, better identify these processes, and develop novel therapeutic protocols that may lead to improved treatments and outcomes.

Hemophagocytic lymphohistiocytosis and other hemophagocytic disorders

Hemophagocytic disorders result when critical regulatory pathways responsible for the natural termination of immune/inflammatory responses are disrupted or overwhelmed. Hemophagocytic disorders reflect pathologic defects that alter the normal crosstalk between innate and adaptive immune responses, and compromise homeostatic removal of cells that are superfluous or dangerous to the organism. Although hemophagocytic disorders are considered rare, increased awareness of these conditions has led to more frequent diagnoses, more rapid initiation of life-saving treatments, and new insights into the molecules and pathways involved in natural immune down-regulation. Furthermore, improved understanding of the immunologic abnormalities revealed by hemophagocytic disorders informs potential new treatments for life-threatening multisystem organ dysfunction related to sepsis in the intensive care unit setting and severe cases.