[Invisible dermatoses].

Interleukin 1 (IL-1) has been proposed as a possible mediator in Sweet's syndrome. We examined all cases of Sweet's syndrome (n = 12) presenting to the department over a 10-year period, from 1982 to 1992, for the presence of IL-1 and also assessed the nature of the dermal inflammatory infiltrate in those cases. Staining for IL-1 alpha and IL-1 beta was stronger in control tissues than in Sweet's syndrome. This may possibly be explained by the release of IL-1 alpha and IL-1 beta into the dermis in Sweet's syndrome. Contrary to recent reports, we found that neutrophils predominated in all cases examined, although histiocytes were present in increased numbers indicating their possible role in the pathophysiology of Sweet's syndrome.

Epidermis↗

PubMed1996

Keratinocytes resident in normal human skin constitutively express, at low levels, the intercellular adhesion molecule-1. An in situ immunoelectronmicroscopy study.

The expression of intercellular adhesion molecule-1 (ICAM-1) on keratinocytes (KC) was previously demonstrated in biopsies from various inflammatory skin lesions. KC were, however, found virtually ICAM-1 negative, in normal skin, when the same immunocytochemical techniques were employed. By contrast, epithelial cells resident in different organs constitutively express ICAM-1, albeit weakly. The aim of the present study was to use an immunostaining system more sensitive than the conventional immunocytochemistry, namely the in situ immunogold labelling of ultracryosections, to investigate the constitutive ICAM-1 expression by resting KC in normal skin, in vivo. The semiquantitative analysis performed on 500 resident KC, visualized within tissue ultracryosections of normal human skin, revealed that gold granules were present long the cell membrane in a small percentage (14.6%) of resident KC. The density of gold particles (10 nm sized) observed on the cell surface per KC section was as scarce as 13.72 +/- 4.6 (mean +/- standard deviation), although highly significant when compared with controls (P < 0.005). This indicates the presumably low expression of ICAM-1 moieties on the plasma membrane of this KC subset. This ICAM-1 expression could be important in modulating the trafficking to and from normal epidermis of migrating Langerhans cells and occasional leucocytes. The fact that the ICAM-1 expression on KC in normal skin is limited can be considered favourable, because it can account for the prevention of inappropriate KC/leucocyte interactions in the resting cutaneous environment.

Epidermis↗