Flow Cytometric Findings in Hemophagocytic Lymphohistiocytosis

Abstract

Hemophagocytic lymphohistiocytosis (HLH) is an often fatal hyperinflammatory syndrome. HLH may be inherited, but it more commonly arises secondary to Epstein-Barr virus (EBV) or other infections, hematologic malignancies, or rheumatologic diseases. We identified 17 patients diagnosed with HLH who had flow cytometric analysis of peripheral blood or bone marrow performed at the time of diagnosis. Two patients had primary HLH, and the others had HLH secondary to EBV infection, hematologic malignancies, rheumatologic conditions, or tuberculosis. The marrow typically showed a reactive lymphocytosis and a marked left shift in myelopoiesis regardless of the etiology. Qualitative abnormalities were also found in several cases, including T-cell abnormalities in the majority of the EBV-associated HLH cases. While not specific, flow cytometric findings in HLH are different from the findings in uninvolved marrow samples, and care should be taken not to overinterpret immunophenotypic findings in these cases as indicative of a primary marrow disorder or lymphoma.

Diagnostic dilemmas in HLH: Can T‐cell phenotyping help?

“…compared T‐cell phenotype patterns among patients with proven genetic primary HLH and patients with secondary HLH. Consistent with prior reports and clinical practice in some centers , HLA‐DR expression was able to differentiate patients with HLH from controls. Notably, the authors observed that an optimal diagnostic cut‐off of HLA‐DR expression percentage of 14% among CD8 + T cells and 5% among CD4 + T cells offered sensitivities and specificities ranging from 83 to 98%.…”

Haemophagocytic lymphohistiocytosis: A fulminant syndrome associated with multiorgan failure and high mortality that frequently masquerades as sepsis and shock

“…Reports on the role of flow cytometry in diagnosing HLH on bone marrow aspirates show promise and may assist in increasing the pick-up rate. [1,24] It is hoped that this case series raises awareness of adult acquired HLH in intensivists, oncologists, physicians and infectious disease experts.…”

Marrow Assessment for Hemophagocytic Lymphohistiocytosis Demonstrates Poor Correlation With Disease Probability

“…[1][2][3][4] HLH is a group of disorders that include familial and acquired forms of the syndrome and macrophage activation syndrome that is associated with certain autoimmune diseases. [1][2][3]5 The acquired form of HLH is associated with infections, especially with Epstein-Barr virus, and malignancies, particularly peripheral T/NK-cell or anaplastic large cell lymphomas, and certain medications used for conditions such as systemic lupus erythematosus.…”