No abstract

Overexpression of proinflammatory, type 1 cytokines has been demonstrated in psoriasis and is believed to be of pathophysiological importance. IL-10 is a type 2 cytokine with major impact on immunoregulation, since it inhibits type 1/proinflammatory cytokine formation. Therefore, we investigated its role in psoriasis. We found a relative deficiency in cutaneous IL-10 mRNA expression compared with other inflammatory dermatoses. Interestingly, patients during established antipsoriatic therapy showed higher IL-10 mRNA expression of peripheral blood mononuclear cells than patients before therapy. This suggested that IL-10 may have antipsoriatic capacity. Therefore, we performed a phase 2 pilot trial with subcutaneous IL-10 administration (8 microg/kg/d) over 24 d in three patients. Clinical efficiency measured by objective and subjective parameters was found. Immunosuppressive effects (depressed monocytic HLA-DR expression, TNF-alpha and IL-12 secretion capacity, IL-12 plasma levels, and responsiveness to recall antigens) as well as a shift toward a type 2 cytokine pattern (increasing proportion of IL-4, IL-5, and IL-10 producing T cells, selective increase in IgE serum levels) were observed. Remarkably, IL-10 administration also enhanced the intracutaneous IL-10 mRNA expression. Our investigations demonstrate the major importance of IL-10 in psoriasis and show that IL-10 administration represents a new therapeutic approach. This is the first report on IL-10 therapy for cutaneous disorders.

The mechanism of immunodepression after brain injury is not yet clear. Here we demonstrate rapid systemic release of the immunoinhibitory cytokine interleukin-10, monocytic deactivation and a high incidence of infection in patients with 'sympathetic storm' due to acute accidental or iatrogenic brain trauma. In vitro studies showed that within minutes catecholamines trigger the secretion of interleukin-10 from unstimulated monocytes through a beta-adrenoreceptor-mediated, cAMP/protein kinase A-dependent pathway. We found that in a rat model of acute brain injury, the beta-receptor antagonist propranolol prevented the increase of interleukin-10 plasma levels. Rapid monocytic interleukin-10 release after sympathetic activation may represent a common pathway for immunodepression induced by stress and injury.