ETAF/interleukin-1 and epidermal lymphocyte chemotactic factor in epidermis overlying an irritant patch test.

We have previously demonstrated that the epidermal content of the lymphocyte activating peptide ETAF/IL-1 and lymphocyte chemotactic factor (ELCF) increases during the development of a cell-mediated immune reaction, represented either by the tuberculin skin reaction or by a positive patch test in patients with contact allergy. The present study describes the epidermal content of these mediators during an irritant patch test reaction. The results show that ELCF, but not ETAF/IL-1, is significantly increased in the epidermis of an irritant patch test with 3% SLS or 5% croton oil, irrespective of the intensity of the clinical patch test reaction. We observed that simple occlusion of epidermis did not induce ELCF activity in healthy persons, whereas patients with previous or current eczema had a significant release of ELCF following such occlusion. These results seem to indicate that there exist important functional differences between allergic and irritant patch test reactions with respect to the presence of lymphocyte activating signals in epidermis.