DIFFERENTIAL CYTOKINE PROFILES IN PERIPHERAL-BLOOD LYMPHOCYTE SUPERNATANTS AND SKIN BIOPSIES FROM PATIENTS WITH DIFFERENT FORMS OF ATOPIC-DERMATITIS, PSORIASIS AND NORMAL INDIVIDUALS

There is increasing evidence that the activation of a selected T helpe r cell population producing a Th2-related cytokine pattern with IL-4 a nd IL-5 but no IL-2 and interferon-gamma (IFN-gamma) may be involved i n the pathogenesis of IgE-mediated atopic diseases and in particular o f atopic dermatitis (AD). However, the existence of a 'nonatopic' (int rinsic) form of AD (NAD) with normal serum IgE levels, negative RAST t ests, negative immediate type skin reactions towards environmental all ergens and a negative patients and family history for IgE-mediated all ergies raised the question whether this form may be explained by a dif ferent T cell activation and cytokine pattern. In the present study we compared the distribution of peripheral blood leukocyte and lymphocyt e subpopulations, their activation state and cytokine production in pe ripheral blood lymphocyte supernatants and skin biopsies of patients w ith AD (n = 19), NAD (n = 14), psoriasis (n = 6) and normal individual s (n = 13). A characteristic eosinophilia was present in AD and NAD bu t not in psoriasis and normal controls. The three patient groups showe d significantly increased numbers of activated CD4+ and CD8+ cells as measured by IL-2R and HLA-DR expression. Determination of spontaneousl y released IL-2, IL-4, IL-5 and IFN-gamma from peripheral blood lympho cytes demonstrated a Th2-related cytokine pattern with elevated levels for IL-4 and IL-5 in AD patients only. Interestingly enough, patients with NAD displayed high IL-5 but low IL-4 levels. In order to further investigate the possible cytokine involvement in these diseases, supe rnatants obtained from mechanically disrupted lesional skin biopsies w ere analyzed for the presence of the above mentioned cytokines. Again, only in skin biopsies obtained from patients with AD significantly in creased levels of IL-4 could be demonstrated. In contrast, IL-5 was si gnificantly elevated in the skin of AD and NAD patients. When comparin g lesional to nonlesional skin, significantly lower levels of IL-5 wer e observed in the nonlesional skin biopsies for all patient groups. Fo r IL-2 and IFN-gamma, no significant differences were found among the various populations. In conclusion, our data defining differential ski n cytokine profiles extend knowledge about cytokine-mediated inflammat ory processes in the skin of AD and NAD patients and further support t he concept of basic immunological differences between AD and NAD.