Flt3L is a specific marker of GATA2 mutation. (A) Flt3L was measured by ELISA in the serum of unaffected relatives with WT GATA2 (n = 13), individuals with GATA2 mutation (n = 24), patients with other PID (n = 11), and MDS patients (n = 11). For patients with GATA2 mutation, the clinical score (0 or 1 to 4) is indicated. (B) The relationship between Flt3L and the development of MDS (n = 24). (C) Relationship between Flt3L and clinical score, excluding patients with MDS (n = 18). (D) Decline in DCs/monocytes, B cells, and NK cells with increasing clinical score (n = 24). (E) Relationship between cell counts, Flt3L, and clinical stage (n = 24; shaded regions indicate normal ranges and asterisks indicate P values for Spearman correlation coefficients). (F) Elevation of Flt3L mRNA detected by Q-PCR in GATA2 patients compared with controls, and relationship between serum Flt-3L and percentage of CD3 (ie, T cells in PBMCs). *P < .05; **P < .01; ***P < .001. Q-PCR, quantitative polymerase chain reaction.