Expression of human leucocyte antigen-G primarily targets affected skin of patients with psoriasis.

BACKGROUND: The nonclassical human leucocyte antigen (HLA)-G molecule has been well recognized as a tolerogenic molecule and few studies have evaluated the role of the molecule in inflammatory cutaneous autoimmune diseases. OBJECTIVES: To evaluate the expression of HLA-G in skin specimens of patients with psoriasis and to analyse its correlation with epidemiological and clinical variables. METHODS: Thirty untreated patients with psoriasis and 32 healthy individuals were enrolled. Immunohistochemistry was applied to identify HLA-G expression in formalin-fixed paraffin-embedded cutaneous skin biopsies. RESULTS: Soluble and membrane-bound HLA-G expression was detected in 30 (90%) of the skin specimens from patients presenting clinical and histopathological features of psoriasis. Although infiltrating lymphomononuclear cells of the dermis exhibited HLA-G expression, the epidermis was primarily targeted. HLA-G expression was also observed in 27% (three of 11) of the specimens that exhibited no clinical and histopathological features of psoriasis (nonaffected areas). In contrast, skin specimens obtained from healthy individuals exhibited no HLA-G expression (P < 0·0001). The intensity of HLA-G expression was not associated with type I/II psoriasis, Psoriasis Area and Severity Index score or clinical forms. CONCLUSIONS: As the HLA-G molecule was consistently expressed in affected and, to a lesser extent, in nonaffected areas of untreated patients with psoriasis, irrespective of the severity of the clinical variants, one may hypothesize that the presence of HLA-G may be responsible, at least in part, for the regulation of autoimmune effector cells.

Impaired cytokine production by peripheral blood mononuclear cells in type 1 diabetic patients.

AIMS: The objective of the present investigation was to study the production of IL-1, IL-6, IL-10, IFNgamma and TNFalpha in cultures of peripheral blood mononuclear cells (PBMC) taken from type 1 diabetic patients with inadequate metabolic control. METHODS: Seventeen type 1 diabetic patients and a gender- and age-matched group of 17 healthy individuals were studied. PBMC cultures were stimulated with phytohemagglutinin (PHA; 20 microg/ml) and lipopolysaccharide (LPS; 10 microg/ml), and enzyme immunoassay (Elisa) was used to measure IL-1, IL-6, IL-10, IFNgamma and TNFalpha in the cell-culture supernatants. RESULTS: IFNgamma levels in PHA-stimulated cultures were lower in the type 1 diabetics than in the non-diabetic controls (P<0.0001) while, in contrast, IL-10 levels were increased in the PHA-stimulated culture supernatants of the diabetics compared with the controls (P<0.0001). In addition, supernatant levels of the cytokines IL-1, IL-6 and TNFalpha released in the presence of LPS in the cell cultures from the diabetic patients were significantly lower than in the non-diabetic subjects (P<0.0001, P<0.0001 and P<0.03, respectively). CONCLUSIONS: The impaired production of IL-1, IL-6, TNFalpha and IFNgamma, and the increased production of IL-10, in PBMC cultures from type 1 diabetics with inadequate metabolic control compared with healthy subjects may be an indication of a deficiency in mononuclear cell activation and, consequently, a deficient immune cellular adaptive response that, in turn, may be the cause of the increased incidence of infections in people with type 1 diabetes.