Immunohistochemical identification of interleukin 1α and β in human eccrine sweat-gland apparatus

Bouin-fixed paraffin sections or acetone-fixed cryostat sections were labelled with the avidin-biotin complex (ABC) or peroxidase-antiperoxidase (PAP) method using three monoclonal antibodies (MAbs) and two polyclonal antisera to human recombinant interleukin I beta (IL-I beta) and three polyclonal antisera to human recombinant interleukin I alpha (IL-I alpha). In the secretory coil both IL-alpha and beta were detected in the clear, but not in the dark cells. Both luminal and basal cells of the coiled and straight ducts expressed IL-I alpha and beta, the IL-I labelling being more intense in the luminal cells. IL-I was not usually detected in the initial portion of the intraepidermal eccrine sweat duct, whereas intense labelling was seen in the upper part including through the stratum corneum. In skin biopsies of the palm, taken after exercise, there was only faint IL-I labelling of the secretory cells, whereas the luminal cells of the dermal ducts showed intense labelling for both IL-I alpha and beta. In the acrosyringium, exercise did not alter the pattern for IL-I alpha and beta, except that in the palm, some of the antibodies to IL-I beta produced a more intense immunolabelling of the acrosyringeal cells. This study identifies a distinct and similar distribution of the two forms of IL-I throughout the eccrine sweat-gland apparatus and indicates that part of the IL-I epidermal pool originates from the sweat.