Munc13-4 expression in control and FHL NK cells. Cell extracts from polyclonal NK cells of healthy donors (H1, H2), patients with FHL3 (UPNs 237, 336, 293, 180), and patient with FHL2 (UPN 314) were analyzed by Western blot with anti–Munc13-4 antibody. Blots were reprobed with antiactin antibody. Molecular weight standards are shown on the left (kDa).