Send to

Choose Destination
Blood. 2018 May 3;131(18):2016-2025. doi: 10.1182/blood-2017-10-812503. Epub 2018 Mar 16.

Human CTL-based functional analysis shows the reliability of a munc13-4 protein expression assay for FHL3 diagnosis.

Author information

Department of Pediatrics, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Department of Molecular and Cellular Biology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.
Department of Pediatrics, School of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan.
Laboratory for Integrative Genomics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan.
Kazusa DNA Research Institute, Kisarazu, Japan; and.
Department of Pediatrics, Graduate School of Medicine, Ehime University, Toon, Japan.


Familial hemophagocytic lymphohistiocytosis (FHL) is the major form of hereditary hemophagocytic lymphohistiocytosis (HLH); as such, it requires prompt and accurate diagnosis. We previously reported that FHL type 3 (FHL3) can be rapidly screened by detecting munc13-4 expression in platelets using flow cytometry; however, the reliability of the munc13-4 expression assay for FHL3 diagnosis is unclear. Regardless of the type of UNC13D mutation, all reported FHL3 cases examined for the munc13-4 protein showed significantly reduced expression. However, the translated munc13-4 protein of some reportedly disease-causing UNC13D missense variants has not been assessed in terms of expression or function; therefore, their clinical significance remains unclear. The aim of this study was to determine the reliability of a munc13-4 expression assay for screening FHL3. Between 2011 and 2016, 108 HLH patients were screened by this method in our laboratory, and all 15 FHL3 patients were diagnosed accurately. To further elucidate whether munc13-4 expression analysis can reliably identify FHL3 patients harboring missense mutations in UNC13D, we developed an alloantigen-specific cytotoxic T lymphocyte (CTL) line and a CTL line immortalized by Herpesvirus saimiri derived from FHL3 patients. We then performed a comprehensive functional analysis of UNC13D variants. Transient expression of UNC13D complementary DNA constructs in these cell lines enabled us to determine the pathogenicity of the reported UNC13D missense variants according to expression levels of their translated munc13-4 proteins. Taken together with previous findings, the results presented herein show that the munc13-4 protein expression assay is a reliable tool for FHL3 screening.

Supplemental Content

Full text links

Icon for HighWire
Loading ...
Support Center