title: Diagnostic dilemmas in HLH: Can T-cell phenotyping help?
abstract: The diagnosis of hemophagocytic lymphohistiocytosis (HLH) can be a difficult one, and the distinction between primary versus secondary HLH can be particularly challenging during the early stages of diagnosis. This distinction is important to make as primary HLH requires allogeneic hematopoietic cell transplantation for a definitive cure. Flow cytometric screening tests for many of the genetic forms of HLH are available. However, not all patients with primary HLH are captured by these screening tests, due to the fact that no screening test is 100% sensitive, and additionally, some patients with "primary" forms of HLH may have mutations in genes which are yet to be discovered. In this issue of the European Journal of Immunology, Ammann et al. [Eur. J. Immunol. 2017. 47: 364-373] compare T-cell phenotype patterns among patients with primary and secondary HLH, and find that assessment of T-cell activation and differentiation may assist with the diagnosis of HLH. Furthermore, this phenotypic analysis has the potential to help make the important distinction between primary and secondary HLH.
authors.affiliation: Division of Bone Marrow Transplantation and Immune Deficiency, Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Marsh
mesh_terms: D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology*; D051359:Lymphohistiocytosis, Hemophagocytic; D009154:Mutation; D013601:T-Lymphocytes / Q000276:immunology
keywords: HLA-DR; Hemophagocytic lymphohistiocytosis; Perforin; Primary HLH; Secondary HLH; T-cell activation