The oligosaccharidic component of the glycoconjugates in lichen planus, granuloma annulare, seborrheic keratosis and palmoplantar keratoderma: lectin histochemical study
It is well known that cell surface glycoconjugates
play an important role in cell proliferation,
adhesion and differentiation. The aim of this
investigation was to define the changes of the glycoconjugate
saccharidic moieties in the epidermis and
derma of patients affected by several skin pathologies
such as seborrheic keratosis, lichen planus, granuloma
annulare and palmoplantaris keratoderma.
Bioptical specimens from skin lesions as well as
from normal skin were fixed in Carnoy's fluid and
routinely processed. The sections were treated with
HRP-lectins (PNA, DBA, SBA, WGA, ConA, LTA and
UEAI). Cytochemical controls were performed for
specificity of lectin-sugar reaction. Some sections were
pre-treated with neuraminidase prior to staining with
I-IRP lectins. In comparison with normal human skin,
epidermal lectin binding pattern in the considered
diseases showed considerable qualitative and quantitative
variations. In general, in all the considered
pathologies, a lack andtor a decrease in lectin binding at
the epidermal layers was observed; among the various
diseases, differences in cellular localisation of the sugar
residues were also noted. In such respect, an exception
was represented by seborrheic keratosis, where the cells
of the basal layer showed PNA reactivity, which was
absent in the basal layer of the normal skin. Although seborrheic keratosis and lichen planus have been studied
by others authors, our findings are not in total
accordance concerning lectin binding; this is probably
due to the different fixatives employed. Our findings
seem to reveal significant changes in keratinocyte glycoconjugate
oligosaccharides in the previously mentioned
diseases, providing clues to their pathogenesis