title: 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.
authors.affiliation: Pathology, The Johns Hopkins Medical Institutions, Baltimore, MD, USA.
authors.forename: Chad M
authors.initials: CM
authors.lastname: McCall
authors.forename: Shiyama
authors.initials: S
authors.lastname: Mudali
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Arceci
authors.forename: Donald
authors.initials: D
authors.lastname: Small
authors.forename: Shirley
authors.initials: S
authors.lastname: Fuller
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Gocke
authors.forename: Milena
authors.initials: M
authors.lastname: Vuica-Ross
authors.forename: Kathleen H
authors.initials: KH
authors.lastname: Burns
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Borowitz
authors.forename: Amy S
authors.initials: AS
authors.lastname: Duffield
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D016208:Databases, Factual; D020031:Epstein-Barr Virus Infections / Q000150:complications / Q000473:pathology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007223:Infant; D051359:Lymphohistiocytosis, Hemophagocytic / Q000473:pathology* / Q000821:virology; D008297:Male