Fig. 1.

Presence of neutrophil extracellular traps and antineutrophil cytoplasmic antibodies associated with vasculitides using DIF and IHC.

a through f, and i, DIF. a. Area of vasculitis, showing deposits of FITC-conjugated anti-human fibrinogen within dermal vessels (red arrows). b. Intra-cytoplasmic deposits of FITC-conjugated antihuman C1q within epidermal cells (red arrow). c. Positive p-ANCAs (yellow arrow) using FITC-conjugated anti-human IgG. The nuclei are counterstained in red with TO-PRO-3 dye (blue arrow); vessel autoreactivity is displayed in green utilizing the FITC-conjugated anti-human IgG (white arrow). d. Positive p-ANCAs (yellow arrows) in the dermis utilizing FITC-conjugated anti-human IgG antibodies. The nuclei are counterstained in red with TO-PRO-3 (blue arrows). e, Same as d, but at higher magnification, and without nuclear counterstaining. f. Shows a detail of the p-ANCA antigen(s) in the epidermis and the NETs (yellow arrows). g IHC staining with collagen IV shows strong reactivity to the BMZ, as well as around the superficial dermal vessels (brown stain) (aqua arrows). h. H & E staining demonstrating leukocytoclastic vasculitis with fibrinoid necrosis (blue arrow). .i, DIF, and g, deposits of nuclear dust (yellow) on some superficial vessels utilizing FITC-conjugated anti-human IgA antibodies (yellow arrows). The blue arrows show the nuclei counterstained with TO-PRO-3. j An IHC stain using anti-CD34 on the vascular area in i, and showing strong, fragmented endothelial expression of this molecule (aqua arrows). k, IHC stain utilizing myeloperoxidase (red arrows). l. IHC CD31 antibody shows fragmented endothelial cells (red arrows).