INCREASED INTERLEUKIN-7 CONCENTRATIONS IN LESIONAL SKIN AND IN THE SERA OF PATIENTS WITH PLAQUE-TYPE PSORIASIS

Several cytokines have been shown to be increased in psoriasis, mainly at the local and sometimes at the systemic level. At present, no data concerning the relationships between psoriasis and interleukin-7 (IL- 7) are available. This biological modifier regulates immune response b y means of its pleomorphic activities, including the ability to stimul ate different monocyte functions, such as killing of intracellular pat hogens, induction of cytokines, and enhancement of some membrane molec ule expression. Study groups consisted of nine psoriatic and nine norm al subjects. Using a commercially available immune-enzyme method, IL-7 concentrations were determined in various samples: biopsy and scale e xstracts, peripheral blood mononuclear cells (PBMCs) supernatants, and sera. The results show that IL-7 levels are significantly increased b oth in biopsy and in scale extracts obtained from lesional skin compar ed to those obtained from nonlesional and normal skin (P at least <0.0 1). In addition, the serum values were higher in psoriatic patients th an in the controls (P = 0.003). In contrast, no significant difference s were observed in the supernatants of unstimulated PBMCs maintained i n culture for 48 hr. These data suggest that IL-7 is involved in some way in the pathomechanisms of psoriasis and that the keratinocyte may be a candidate for psoriatic IL-7 overproduction. (C) 1997 Academic Pr ess.