Accuracy of flow cytometric perforin screening for detecting patients with FHL due to PRF1 mutations

To the editor: Mutations in PRF1 , which encodes perforin, were discovered to cause familial hemophagocytic lymphohistiocytosis (FHL) in 1999 and account for 20% to 50% of all FHL cases.[1][1][⇓][2][⇓][3][⇓][4][⇓][5]-[6][6] Flow cytometric detection of perforin in peripheral blood natural