Ceramide is an integral part of the extracellular lipid bilayer of the stratum corneum (SC) that forms the permeability barrier of the skin. The production of SC ceramides is catalyzed by sphingomyelinase (SMase) and glucocerebrosidase (GCase). Acid-ceramidase (acid-CDase) catalyzes the hydrolysis of ceramide in the SC. We examined the effects of T helper (Th)1 and Th2 cytokines on levels of transcripts of genes for acid-CDase, acid-SMase, and GCase, on levels of ceramide, and on the extent of transepidermal water loss (TEWL) in the human epidermis in an effort to determine whether these cytokines affect the permeability barrier functions. Levels of transcripts for acid-SMase and GCase and the amount of ceramide in human epidermal sheets were enhanced by tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma and these effects were inhibited in the presence of interleukin (IL)-4. In epidermal keratinocytes cultured under submerged conditions, however, no similar inhibitory effects of IL-4 were observed. Consistent with these results, TEWL was suppressed by TNF-alpha and IFN-gamma, and these effects were also inhibited by IL-4. The balance between Th1 and Th2 might affect the construction and/or the repair of the epidermal permeability barrier via regulation of the production of ceramide.

Semiquantitative reverse transcription-polymerase chain reaction was used to analyse the expression of cytokine mRNAs in freshly isolated peripheral blood mononuclear cells obtained from a patient with Kimura's disease. The patient was treated with cyclosporin A (CsA) after incomplete tumour resection and irradiation of lesions. Levels of interleukin (IL)-4, IL-5 and IL-13 mRNA were elevated and the level of interferon (IFN)-gamma mRNA was within normal limits before treatment. The levels of IL-4, IL-5 and IL-13 mRNA, the number of eosinophils, and the serum level of IgE decreased markedly after surgery and radiation therapy. CsA treatment suppressed these values in a dose-dependent manner, but had a minimal effect on the level of IFN-gamma mRNA. The number of peripheral eosinophils decreased in association with decreases in the levels of IL-4, IL-5 and IL-13 mRNAs during CsA therapy; the serum level of IgE remained low during therapy and did not fluctuate in association with changes in cytokine levels. These results suggest the Th2 cytokines play a part in the development of Kimura's disease and that CsA suppresses the activity of this disease.

Semiquantitative reverse transcription-polymerase chain reaction was used to analyse the expression of cytokine mRNAs in freshly isolated peripheral blood mononuclear cells obtained from a patient with Kimura's disease. The patient was treated with cyclosporin A (CsA) after incomplete tumour resection and irradiation of lesions. Levels of interleukin (IL)-4, IL-5 and IL-13 mRNA were elevated and the level of interferon (IFN)-gamma mRNA was within normal limits before treatment. The levels of IL-4, IL-5 and IL-13 mRNA, the number of eosinophils, and the serum level of IgE decreased markedly after surgery and radiation therapy. CsA treatment suppressed these values in a dose-dependent manner, but had a minimal effect on the level of IFN-gamma mRNA. The number of peripheral eosinophils decreased in association with decreases in the levels of IL-4, IL-5 and IL-13 mRNAs during CsA therapy; the serum level of IgE remained low during therapy and did not fluctuate in association with changes in cytokine levels. These results suggest the Th2 cytokines play a part in the development of Kimura's disease and that CsA suppresses the activity of this disease.

Alopecia areata (AA) has been considered to be supported by an aberrant expression of IFN-gamma as a result of antigen dependent immune response. On the other hand, AA sometimes concurs with atopic diseases, although the mechanism of the concurrence is not clear. This study was designed to elucidate the immune status of AA and the similarity between AA and atopic dermatitis (AD) by analysis of in vivo levels of mRNA of Th1, Th2, and suppressive cytokines of peripheral blood mononuclear cells (PBMC). Using semiquantitative RT-PCR, the levels of cytokine mRNA were measured in freshly isolated PBMC of 47 patients with AA, 15 patients with AD, and 12 healthy controls (HC). The levels of IL-4, IFN-gamma, and TGF-beta1 mRNA were lower in patients with AA than those in HC. The levels of IL-10 mRNA in AA were comparable with those in HC. Decreased levels of IFN-gamma and TGF-beta1 were also shown in patients with AD. These results indicated a similarity (decreased levels of IFN-gamma and TGF-beta1) between AD and AA based on the cytokine profile. In addition, decreased levels of IL-4 mRNA in AA might also explain the experience that the severity of atopic disease coincident with AA is mild in the most of cases. Next, we compared the levels of these cytokine mRNA among the three subgroups of AA that were categorized based on the severity of the symptoms: mild, severe and totalis. Although there was no significant difference between any combinations of the subgroups, there was a tendency to increase the levels of IFN-gamma mRNA and to decrease the levels of IL-4 mRNA according to the severity of alopecia. However, the levels of IFN-gamma mRNA in any subgroups were less than those of HC. These results suggest that IFN-gamma is therefore involved in the pathogenesis of AA, although the information from PBMC is limited. In conclusion, AA might be induced by an aberrant expression of IFN-gamma in individuals whose PBMC produce low amounts of IFN-gamma and TGF-beta1. Further analysis is therefore required to investigate the phenotypes of the population in PBMC with or without reference to regulatory T cells.

SUMMARYPrevious studies using in vitro systems with various stimuli have shown that PBMC from patients with AD show increased levels of IL-4 but decreased levels of interferon-gamma (IFN-g) compared with PBMC from normal controls. However, in vitro conditions do not always mimic the in vivo condition. We therefore believe that it is important to quantify the expression of these cytokines in freshly isolated PBMC. This study examines the expression of IFN-g, IL-4 and IL-13 mRNA in freshly isolated PBMC from adult patients with AD, from patients with psoriasis vulgaris and from healthy adults, using the semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) method. Levels of IFN-g mRNA were significantly lower in PBMC of patients with AD than in controls. IL-4 mRNA levels did not differ significantly between groups. Conversely, levels of mRNA for IL-13 were significantly greater in PBMC of patients with AD than in controls. An increase in IL-13 expression may regulate the in vivo synthesis of IgE in patients with AD.