Immune reactivity in psoriatic munro-saboureau microabscesses, stratum corneum and blood vessels

Abstract

Background: A characteristic feature of early active psoriatic lesions is the intraepidermal penetration of neutrophils, with attendant formation of Munro-Saboureau microabscesses. Previous immunofluorescence studies have shown reactivity of in vivo binding of stratum corneum antibodies (SCAs) within the Munro-Saboreau microabscesses in cases of psoriasis.

Aims: In our study, we aimed to investigate any correlation between the SCAs and the Munro-Saboureau microabscesses.

Materials and methods: We investigated 50 archival biopsies of psoriasis with Munro-Saboureau microabscesses, and attempted to confirm antibody colocalization within these microabcesses via immunohistochemistry staining. As controls, we utilized 50 skin biopsies from healthy patients undergoing esthetic plastic surgery procedures.

Results: Within the Munro-Saboureau microabscesses, the following markers were statistically significantly positive relative to controls: CD1a, CD8, CD23, cyclooxygenase-2, myeloid histoid antigen, albumin, fibrinogen, kappa, lambda, von Willebrand factor, IgG, IgM, IgD, complement/C3c, C3d, myeloperoxidase, and carcinoembryonic antigen (P < 0.05). Autoreactivity to blood vessels was also detected, with multiple immunoglobulins and complement factors.

Conclusions: We document important correlations between the Munro-Saboureau microabscesses, SCAs, and other immunoreactants.

Keywords: Autoimmunity; Blood vessels; Munro-Saboureau microabscesses carcinoembryonic antigen; Psoriasis; von Willebrand factor.

Figure 1

Relationship between Munro-Saboureau microabscesses and autoantibodies in psoriasis. (a) A representative IHC photomicrograph demonstrating ectopic expression of VWF in the Munro-Saboureau microabscesses (MSMs) and the hyperparakeratotic epidermal stratum corneum as well as in the papillary dermis (brown staining; red arrows). (b) Positive IHC staining in the Munro-Saboureau microabscesses and the hyperparakeratotic epidermal stratum corneum utilizing anti-myeloid histoid antigen antibody (brown staining; red arrow). (c) Positive IHC staining in the Munro-Saboureau microabscesses and the hyperparakeratotic epidermal stratum corneum using anti-human kappa light chains antibody (brown staining; red arrow). (d) Positive IHC staining in the MSMs and the hyperparakeratotic epidermal stratum corneum utilizing anti-human IgD (violet/brown staining; red arrow). (e) Positive IHC staining at the MSMs and the hyperparakeratotic epidermal stratum corneum via anti-human myeloperoxidase (dark staining; red arrow). (f) Positive IHC staining in the MSMs and the hyperparakeratotic epidermal stratum corneum utilizing anti-human CEA antibody (dark staining; red arrows). (g) A representative DIF with double staining, highlighting the SCAs. The green staining represents FITC conjugated anti-human IgG (white arrow). The red arrow indicates simultaneous reactivity as yellow/pink staining of FITC conjugated anti-human IgM. (h) A representative DIF with FITC conjugated anti-human IgG showing the SCAs (green staining, white arrow). The light blue staining represents epidermal stratum spinosum keratinocyte nuclear counterstaining with 4’-6-Diamidino-2-phenylindole (DAPI). The nuclear counterstaining indicates (1) that the primary IgG reactivity is in the upper left, non-nuclear epidermal stratum corneum area where parakeratosis is present; and (2) that the subjacent stratum spinosum keratinocytes have not yet lost their nuclei. (i). IHC staining with anti-human IgG showing positivity at the SCAs (violet/brown staining; red arrows)