T cells in psoriatic lesional skin that survive conventional therapy with NB-UVB radiation display reduced IFN-gamma expression

Arch Dermatol Res. 2004 May;295(12):509-16. doi: 10.1007/s00403-004-0460-9. Epub 2004 Mar 16.

Abstract

The type 1 T cell-derived cytokine interferon gamma (IFN-gamma) is overexpressed in psoriatic lesional skin. Recently, we have shown that a single high erythemal dose of broad-band ultraviolet B (UVB) irradiation reduces type 1 and favors type 2, i.e. interleukin-4 (IL-4), cytokine expression in normal and psoriatic skin. In this study, we wanted to see whether conventional narrow-band UVB (NB-UVB) therapy (i.e. repeated exposure to nonerythemal doses) also affects type 1/type 2 cytokine expression of T cells present in chronic plaque type psoriatic lesions. Staining of cryostat sections showed decreased expression of both IFN-gamma and IL-4 in situ after NB-UVB therapy. CD4(+) dermal T cell lines, derived from psoriatic lesional skin, displayed significantly decreased intracellular IFN-gamma expression during and after NB-UVB therapy as compared to pretreatment values. Intracellular IL-4 expression was increased in most patients after therapy. Analysis of the supernatants of these stimulated dermal T cells revealed that IFN-gamma production decreased significantly following NB-UVB therapy, whereas IL-4 expression increased in the T cell supernatants from most patients, confirming the intracellular determinations. In addition, IL-10 and transforming growth factor-beta levels in the supernatants appeared to be increased in the majority of patients following UVB therapy. Apart from the well-known killing effect of UVB on T cells, our results show that the improvement in psoriatic skin following NB-UVB therapy is also due to a reduced capacity of the surviving dermal T cells to express the proinflammatory cytokine IFN-gamma.

MeSH terms

  • Humans
  • Interferon-gamma / biosynthesis*
  • Interleukin-4 / biosynthesis
  • Psoriasis / immunology
  • Psoriasis / radiotherapy*
  • Skin / immunology
  • Skin / radiation effects
  • T-Lymphocytes / immunology*
  • Ultraviolet Therapy*

Substances

  • Interleukin-4
  • Interferon-gamma