“…In GATA2 de ciency, reduced cytotoxicity of NK cells and speci c loss of CD56bright NK subpopulation have been demonstrated, which is associated with impaired differentiation of cytotoxic active NK cells [17] .GATA2 gene defects lead to a decrease in the number and activity of NK cells [17] .In this paper, 3 cases with GATA2 gene defect have observed a decrease in the activity of NK cells, which is consistent with previous reports.It is easy to speculate that the lack of NK cell number and function disrupts the immunomodulatory role of NK cells, making patients with defective GATA2 gene more susceptible to HLH. Thus, HLH may re ect not only impaired infection control, but also a genetic predisposition to excessive in ammation.Degranulation damage of cytotoxic T lymphocytes (CTL) and NK cells was detected by CD107a analysis.As previously reported, quantitative detection of CD107a on the surface of CTL is highly sensitive and speci c for the diagnosis of HLH with granular exocytosis genetic disorders [13,18,19] .In this paper, except for 1 of the 3 patients with GATA2 gene defect who did not undergo CD107a detection, the NK and CTL cell levels of ΔCD107a decreased in the other 2 patients, as shown in Table 2.Given the progression of bone marrow failure, allo-HSCT is the only treatment for GATA2 de ciency [12,20] .The only possible cure for patients with GATA2 gene de ciency combined with HLH is allo-HSCT.…”