Stratum corneum-induced chemiluminescence in human neutrophils

In an in vitro study to examine whether corneocytes stimulate neutrophils to cause a respiratory burst, we found that stratum corneum (SC) homogenates obtained from the sole of healthy individuals induced a substantial respiratory burst in human neutrophils when assessed by lucigenin-dependent chemiluminescence (CL) in the presence of the nontreated fresh human serum (NTS) . Electronmicroscopically the interaction between corneocyte and neutrophils was shown as distinctive deformation of the neutrophils adhering to the surface of the corneo-cytes that suggested a specific binding between them. In contrast, in the heat-inactivated serum (HIS) -supplemented system the peak inensity of SC-induced CL was significantly decreased, being only slightly higher than that noted in the SC-free background. To circumvent the time-consuming preparation of the SC homogenates we measured CL with a sheet of SC obtained by stripping with adhesive cellophane tape. In this case we used plasma because complement in the serum was easily activated by cellophane tape itself. To evaluate the influence of the location of horny tissue in the SC on the induction of CL responses, we used SC sheets stripped with cellophane tape from various levels of the SC. Howeve, there was no significant difference in CL response between SC sheets obtained 1, 2, 3, 5, 10 or 15 strippings.Our findings suggest that, when the SC comes in contact with serum, it is opsonized by C 3 b and that such SC causes a respiratory burst of neutrophils following their physical contact. Extracellular release of the resultant active oxygen species probably causes damaging effects on the surrounding SC and epider_ mal tissue and such an interaction between SC and neutrophils seems to be involved in the formation of subcorneal sterile pustules noted in pustular dermatoses.