Interleukin-1-beta (IL-1-beta), Interleukin-6 (IL-6) and Interferon-gamma (IFN-gamma) were measured by enzyme immunoassay (EIA) methods in blister fluids (BFs) obtained from both involved (ISBF) and non-involved skin (USBF) and in sera from 14 psoriatic patients. The same determinations were carried out in 14 sera and in 5 suction blister fluids from 14 normal subjects. IL-6 was always detectable in all skin fluids and in 3 psoriasis sera. IL-1-beta was measured only in 5 ISBFs and in 5 sera from the same patients. IFN-gamma was present in 11 ISBFs, in 5 USBFs and in 5 sera. The analysis of the levels found in the samples shows: 1) a local production of these cytokines, 2) the presence of detectable amounts of IL-6 and IFN-gamma in USBFs, and 3) a significant correlation between the IL-6 levels in the ISBFs and erythema score.