Perforin expression and granule polarization of patients with FHL compared with control subjects. Polyclonal activated NK cells derived from healthy donor (A,D,G,J) and patients with FHL3 (UPN 336; B,E,H,K) and with FHL2 (UPN 314; C,F,I,L) were analyzed by flow cytometry (A-C) and confocal microscopy (D-L). Filled curves indicate perforin expression, whereas open curves indicate isotypic control (A-C). Confocal staining of perforin (green) and cathepsin D (red) (D-F) or cathepsin D (red) and tubulin (green) (G-L) is analyzed in isolated NK cells (D-I) or conjugates between NK and target 221 (J-L). Bar indicates 10 μm.