Interleukin-6 (IL-6) is a multifunctional
cytokine that participates in the inflammatory and immune responses. In human skin, keratinocytes produces
IL-6, although the in vivo role of this
cytokine is unknown. In the present study we investigated the in situ localization of
IL-6 in normal epidermis (n = 10) and in a group of
skin diseases characterized by epidermal
atrophy.
Formalin-fixed
paraffin-embedded skin biopsies from patients with clinical and histopathological features consistent with
localized scleroderma (n = 10),
systemic scleroderma (n = 5),
lichen sclerosus et atrophicus (n = 9) and
balanitis xerotica obliterans (n = 7) were tested using polyclonal
antibodies and
avidin-
biotin-
peroxidase immunostaining. We demonstrated the presence of
IL-6 in normal epidermis and in atrophic
skin diseases. In normal skin there was moderate intercellular and intracellular reactivity detected using a high antibody concentration. In specimens with epidermal
atrophy we detected intense cytoplasmic and intercellular immunostaining using a lower antibody concentration. The immunoreactivity was independent of the epidermal thickness. Plasma
IL-6, measured by radioimmunoassay, was not elevated in plasma from patients with localized or
systemic scleroderma. Increased
IL-6 in the epidermis of selected
skin diseases suggests that
IL-6 may be related to the pathophysiology of dermatologic diseases characterized by epidermal
atrophy.